Changeset e2af631 in rtems

Timestamp:

11/25/00 19:35:53 (23 years ago)

Author:

Joel Sherrill <joel.sherrill@…>

Branches:

4.10, 4.11, 4.8, 4.9, 5, master

Children:

a6abd67

Parents:

c8471315

Message:

2000-11-25 Antti P Miettinen <antti.p.miettinen@…>

• libc/termios.c, libc/termiostypes.h: Task driver driver model and line discipline support from Thomas Doerfler <Thomas.Doerfler@…>.

Files:

• c/src/exec/libcsupport/src/Makefile.am (modified) (1 diff)
• c/src/exec/libcsupport/src/termios.c (modified) (37 diffs)
• c/src/lib/ChangeLog (modified) (1 diff)
• c/src/lib/libc/Makefile.am (modified) (1 diff)
• c/src/lib/libc/termios.c (modified) (37 diffs)
• cpukit/libcsupport/src/termios.c (modified) (37 diffs)

c/src/exec/libcsupport/src/Makefile.am

@@ -82 +82 @@
 
 EXTRA_DIST = $(DOC_FILES) $(COMMON_C_FILES) $(EMBEDDED_C_FILES) \
-    $(UNIX_C_FILES)
+    $(UNIX_C_FILES) termiostypes.h
 
 include $(top_srcdir)/../../../automake/local.am

c/src/exec/libcsupport/src/termios.c

@@ -24 +24 @@
 #include <termios.h>
 #include <unistd.h>
+#include <sys/ttycom.h>
+
+#include "termiostypes.h"
 
 /*
@@ -61 +64 @@
 #define RAW_OUTPUT_BUFFER_SIZE  64
 
-/*
- * Variables associated with each termios instance.
- * One structure for each hardware I/O device.
- */
-struct rtems_termios_tty {
-        /*
-         * Linked-list of active TERMIOS devices
-         */
-        struct rtems_termios_tty        *forw;
-        struct rtems_termios_tty        *back;
-
-        /*
-         * How many times has this device been opened
-         */
-        int             refcount;
-
-        /*
-         * This device
-         */
-        rtems_device_major_number       major;
-        rtems_device_major_number       minor;
-
-        /*
-         * Mutual-exclusion semaphores
-         */
-        rtems_id        isem;
-        rtems_id        osem;
-
-        /*
-         * The canonical (cooked) character buffer
-         */
-        char            cbuf[CBUFSIZE];
-        int             ccount;
-        int             cindex;
-
-        /*
-         * Keep track of cursor (printhead) position
-         */
-        int             column;
-        int             read_start_column;
-
-        /*
-         * The ioctl settings
-         */
-        struct termios  termios;
-        rtems_interval  vtimeTicks;
-
-        /*
-         * Raw input character buffer
-         */
-        volatile char           rawInBuf[RAW_INPUT_BUFFER_SIZE];
-        volatile unsigned int   rawInBufHead;
-        volatile unsigned int   rawInBufTail;
-        rtems_id                rawInBufSemaphore;
-        rtems_unsigned32        rawInBufSemaphoreOptions;
-        rtems_interval          rawInBufSemaphoreTimeout;
-        rtems_interval          rawInBufSemaphoreFirstTimeout;
-        unsigned int            rawInBufDropped;        /* Statistics */
-
-        /*
-         * Raw output character buffer
-         */
-        volatile char           rawOutBuf[RAW_OUTPUT_BUFFER_SIZE];
-        volatile unsigned int   rawOutBufHead;
-        volatile unsigned int   rawOutBufTail;
-        rtems_id                rawOutBufSemaphore;
-        volatile enum {rob_idle, rob_busy, rob_wait }   rawOutBufState;
-
-        /*
-         * Callbacks to device-specific routines
-         */
-        rtems_termios_callbacks device;
-        volatile unsigned int   flow_ctrl;
-        unsigned int            lowwater,highwater;
-};
-
 /* fields for "flow_ctrl" status */
 #define FL_IREQXOF 1        /* input queue requests stop of incoming data */
@@ -149 +76 @@
 #define FL_MDXOF   0x400    /* output controlled with XON/XOFF protocol   */
 
+#define NODISC(n) \
+        { NULL, NULL,   NULL,   NULL, \
+          NULL, NULL,   NULL,   NULL }
+/*
+ * FIXME: change linesw entries consistant with linesw entry usage...
+ */
+struct  linesw linesw[MAXLDISC] =
+{
+        NODISC(0),              /* 0- termios-built-in */
+        NODISC(1),              /* 1- defunct */
+        NODISC(2),              /* 2- NTTYDISC */
+        NODISC(3),              /* TABLDISC */
+        NODISC(4),              /* SLIPDISC */
+        NODISC(5),              /* PPPDISC */
+        NODISC(6),              /* loadable */
+        NODISC(7),              /* loadable */
+};
+
+int     nlinesw = sizeof (linesw) / sizeof (linesw[0]);
+
 extern struct rtems_termios_tty *rtems_termios_ttyHead;
 extern struct rtems_termios_tty *rtems_termios_ttyTail;
 extern rtems_id rtems_termios_ttyMutex;
+
+static rtems_task rtems_termios_rxdaemon(rtems_task_argument argument);
+static rtems_task rtems_termios_txdaemon(rtems_task_argument argument);
+/*
+ * some constants for I/O daemon task creation
+ */
+#define TERMIOS_TXTASK_PRIO 10
+#define TERMIOS_RXTASK_PRIO 9
+#define TERMIOS_TXTASK_STACKSIZE 1024
+#define TERMIOS_RXTASK_STACKSIZE 1024
+/*
+ * some events to be sent to the I/O tasks
+ */
+#define TERMIOS_TX_START_EVENT     RTEMS_EVENT_1
+#define TERMIOS_TX_TERMINATE_EVENT RTEMS_EVENT_0
+
+#define TERMIOS_RX_PROC_EVENT      RTEMS_EVENT_1
+#define TERMIOS_RX_TERMINATE_EVENT RTEMS_EVENT_0
 
 /*
@@ -171 +136 @@
          * See if the device has already been opened
          */
-        sc = rtems_semaphore_obtain (rtems_termios_ttyMutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
+        sc = rtems_semaphore_obtain (rtems_termios_ttyMutex,
+                                     RTEMS_WAIT, RTEMS_NO_TIMEOUT);
         if (sc != RTEMS_SUCCESSFUL)
                 return sc;
@@ -189 +155 @@
                         return RTEMS_NO_MEMORY;
                 }
+                /*
+                 * allocate raw input buffer
+                 */
+                tty->rawInBuf.Size = RAW_INPUT_BUFFER_SIZE;
+                tty->rawInBuf.theBuf = malloc (tty->rawInBuf.Size);
+                if (tty->rawInBuf.theBuf == NULL) {
+                        free(tty);
+                        rtems_semaphore_release (rtems_termios_ttyMutex);
+                        return RTEMS_NO_MEMORY;
+                }
+                /*
+                 * allocate raw output buffer
+                 */
+                tty->rawOutBuf.Size = RAW_OUTPUT_BUFFER_SIZE;
+                tty->rawOutBuf.theBuf = malloc (tty->rawOutBuf.Size);
+                if (tty->rawInBuf.theBuf == NULL) {
+                        free((void *)(tty->rawInBuf.theBuf));
+                        free(tty);
+                        rtems_semaphore_release (rtems_termios_ttyMutex);
+                        return RTEMS_NO_MEMORY;
+                }
+                /*
+                 * allocate cooked buffer
+                 */
+                tty->cbuf  = malloc (CBUFSIZE);
+                if (tty->cbuf == NULL) {
+                        free((void *)(tty->rawOutBuf.theBuf));
+                        free((void *)(tty->rawInBuf.theBuf));
+                        free(tty);
+                        rtems_semaphore_release (rtems_termios_ttyMutex);
+                        return RTEMS_NO_MEMORY;
+                }
+                /*
+                 * link tty
+                 */
                 if (rtems_termios_ttyHead)
                         rtems_termios_ttyHead->back = tty;
@@ -222 +223 @@
                         RTEMS_SIMPLE_BINARY_SEMAPHORE | RTEMS_FIFO,
                         RTEMS_NO_PRIORITY,
-                        &tty->rawOutBufSemaphore);
+                        &tty->rawOutBuf.Semaphore);
                 if (sc != RTEMS_SUCCESSFUL)
                         rtems_fatal_error_occurred (sc);
@@ -231 +232 @@
                  */
                 tty->device = *callbacks;
-                if (!tty->device.pollRead) {
+
+                /*
+                 * Create I/O tasks
+                 */
+                if (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN) {
+                        sc = rtems_task_create (
+                                   rtems_build_name ('T', 'x', 'T', c),
+                                   TERMIOS_TXTASK_PRIO,
+                                   TERMIOS_TXTASK_STACKSIZE,
+                                   RTEMS_NO_PREEMPT | RTEMS_NO_TIMESLICE | 
+                                   RTEMS_NO_ASR,
+                                   RTEMS_NO_FLOATING_POINT | RTEMS_LOCAL,
+                                   &tty->txTaskId);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                        sc = rtems_task_create (
+                                   rtems_build_name ('R', 'x', 'T', c),
+                                   TERMIOS_RXTASK_PRIO,
+                                   TERMIOS_RXTASK_STACKSIZE,
+                                   RTEMS_NO_PREEMPT | RTEMS_NO_TIMESLICE | 
+                                   RTEMS_NO_ASR,
+                                   RTEMS_NO_FLOATING_POINT | RTEMS_LOCAL,
+                                   &tty->rxTaskId);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                                
+                }
+                if ((tty->device.pollRead == NULL) ||
+                    (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN)){
                         sc = rtems_semaphore_create (
                                 rtems_build_name ('T', 'R', 'r', c),
@@ -237 +266 @@
                                 RTEMS_COUNTING_SEMAPHORE | RTEMS_PRIORITY,
                                 RTEMS_NO_PRIORITY,
-                                &tty->rawInBufSemaphore);
+                                &tty->rawInBuf.Semaphore);
                         if (sc != RTEMS_SUCCESSFUL)
                                 rtems_fatal_error_occurred (sc);
@@ -270 +299 @@
                  * set low/highwater mark for XON/XOFF support
                  */
-                tty->lowwater  = RAW_INPUT_BUFFER_SIZE * 1/2;
-                tty->highwater = RAW_INPUT_BUFFER_SIZE * 3/4;
+                tty->lowwater  = tty->rawInBuf.Size * 1/2;
+                tty->highwater = tty->rawInBuf.Size * 3/4;
                 /*
                  * Bump name characer
@@ -280 +309 @@
         }
         args->iop->data1 = tty;
-        if (!tty->refcount++ && tty->device.firstOpen)
+        if (!tty->refcount++) {
+          if (tty->device.firstOpen)
                 (*tty->device.firstOpen)(major, minor, arg);
+          /*
+           * start I/O tasks, if needed
+           */
+          if (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN) {
+            sc = rtems_task_start(tty->rxTaskId,
+                                  rtems_termios_rxdaemon,
+                                  (rtems_task_argument)tty);
+            if (sc != RTEMS_SUCCESSFUL)
+              rtems_fatal_error_occurred (sc);
+            
+            sc = rtems_task_start(tty->txTaskId,
+                                  rtems_termios_txdaemon,
+                                  (rtems_task_argument)tty);
+            if (sc != RTEMS_SUCCESSFUL)
+              rtems_fatal_error_occurred (sc);
+          }
+        }
         rtems_semaphore_release (rtems_termios_ttyMutex);
         return RTEMS_SUCCESSFUL;
@@ -295 +342 @@
         rtems_status_code sc;
 
-        if (tty->device.outputUsesInterrupts) {
+        if (tty->device.outputUsesInterrupts != TERMIOS_POLLED) {
                 rtems_interrupt_disable (level);
-                while (tty->rawOutBufTail != tty->rawOutBufHead) {
+                while (tty->rawOutBuf.Tail != tty->rawOutBuf.Head) {
                         tty->rawOutBufState = rob_wait;
                         rtems_interrupt_enable (level);
-                        sc = rtems_semaphore_obtain (tty->rawOutBufSemaphore,
+                        sc = rtems_semaphore_obtain (tty->rawOutBuf.Semaphore,
                                                         RTEMS_WAIT,
                                                         RTEMS_NO_TIMEOUT);
@@ -322 +369 @@
                 rtems_fatal_error_occurred (sc);
         if (--tty->refcount == 0) {
-                drainOutput (tty);
+                if (linesw[tty->t_line].l_close != NULL) {
+                        /*
+                         * call discipline-specific close
+                         */
+                        sc = linesw[tty->t_line].l_close(tty);
+                }
+                else {
+                        /*
+                         * default: just flush output buffer
+                         */
+                        drainOutput (tty);
+                }
+          
+                if (tty->device.outputUsesInterrupts 
+                    == TERMIOS_TASK_DRIVEN) {
+                        /*
+                         * send "terminate" to I/O tasks
+                         */
+                        sc = rtems_event_send(
+                                  tty->rxTaskId,
+                                  TERMIOS_RX_TERMINATE_EVENT);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                        sc = rtems_event_send(
+                                  tty->txTaskId,
+                                  TERMIOS_TX_TERMINATE_EVENT);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                }
                 if (tty->device.lastClose)
                          (*tty->device.lastClose)(tty->major, tty->minor, arg);
@@ -335 +410 @@
                 rtems_semaphore_delete (tty->isem);
                 rtems_semaphore_delete (tty->osem);
-                rtems_semaphore_delete (tty->rawOutBufSemaphore);
-                if (!tty->device.pollRead)
-                        rtems_semaphore_delete (tty->rawInBufSemaphore);
+                rtems_semaphore_delete (tty->rawOutBuf.Semaphore);
+                if ((tty->device.pollRead == NULL) ||
+                    (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN))
+                        rtems_semaphore_delete (tty->rawInBuf.Semaphore);
                 free (tty);
         }
@@ -367 +443 @@
         /* if chars available, call write function... */
         (*tty->device.write)(tty->minor,
-                             (char *)&tty->rawOutBuf[tty->rawOutBufTail], 1);
+                     (char *)&tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail],1);
       }
       /* reenable interrupts */
@@ -428 +504 @@
         switch (args->command) {
         default:
-                sc = RTEMS_INVALID_NUMBER;
+                if (linesw[tty->t_line].l_ioctl != NULL) {
+                        sc = linesw[tty->t_line].l_ioctl(tty,args);
+                }
+                else {
+                        sc = RTEMS_INVALID_NUMBER;
+                }
                 break;
 
@@ -477 +558 @@
                 break;
 
+                /*
+                 * FIXME: add various ioctl code handlers
+                 */
+
+#if 1 /* FIXME */
+        case TIOCSETD:
+                /*
+                 * close old line discipline
+                 */
+                if (linesw[tty->t_line].l_close != NULL) {
+                        sc = linesw[tty->t_line].l_close(tty);
+                }
+                tty->t_line=*(int*)(args->buffer);
+                tty->t_sc = NULL; /* ensure that no more valid data */
+                /*
+                 * open new line discipline
+                 */
+                if (linesw[tty->t_line].l_open != NULL) {
+                        sc = linesw[tty->t_line].l_open(tty);
+                }
+                break;
+        case TIOCGETD:  
+                *(int*)(args->buffer)=tty->t_line;
+                break;          
+#endif
         case FIONREAD:
                 /* Half guess that this is the right operation */
@@ -490 +596 @@
  * Send characters to device-specific code
  */
-static void
-osend (const char *buf, int len, struct rtems_termios_tty *tty)
+void
+rtems_termios_puts (const char *buf, int len, struct rtems_termios_tty *tty)
 {
         unsigned int newHead;
@@ -497 +603 @@
         rtems_status_code sc;
 
-        if (!tty->device.outputUsesInterrupts) {
+        if (tty->device.outputUsesInterrupts == TERMIOS_POLLED) {
                 (*tty->device.write)(tty->minor, buf, len);
                 return;
         }
-        newHead = tty->rawOutBufHead;
+        newHead = tty->rawOutBuf.Head;
         while (len) {
                 /*
@@ -515 +621 @@
                  * with interrupts enabled.
                  */
-                newHead = (newHead + 1) % RAW_OUTPUT_BUFFER_SIZE;
+                newHead = (newHead + 1) % tty->rawOutBuf.Size;
                 rtems_interrupt_disable (level);
-                while (newHead == tty->rawOutBufTail) {
+                while (newHead == tty->rawOutBuf.Tail) {
                         tty->rawOutBufState = rob_wait;
                         rtems_interrupt_enable (level);
-                        sc = rtems_semaphore_obtain (tty->rawOutBufSemaphore,
+                        sc = rtems_semaphore_obtain (tty->rawOutBuf.Semaphore,
                                                         RTEMS_WAIT,
                                                         RTEMS_NO_TIMEOUT);
@@ -527 +633 @@
                         rtems_interrupt_disable (level);
                 }
-                tty->rawOutBuf[tty->rawOutBufHead] = *buf++;
-                tty->rawOutBufHead = newHead;
+                tty->rawOutBuf.theBuf[tty->rawOutBuf.Head] = *buf++;
+                tty->rawOutBuf.Head = newHead;
                 if (tty->rawOutBufState == rob_idle) {
                   /* check, whether XOFF has been received */
                   if (!(tty->flow_ctrl & FL_ORCVXOF)) {
                     (*tty->device.write)(tty->minor,
-                                (char *)&tty->rawOutBuf[tty->rawOutBufTail],1);
+                        (char *)&tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail],1);
                   }
                   else {
@@ -560 +666 @@
                                 tty->column = 0;
                         if (tty->termios.c_oflag & ONLCR) {
-                                osend ("\r", 1, tty);
+                                rtems_termios_puts ("\r", 1, tty);
                                 tty->column = 0;
                         }
@@ -581 +687 @@
                         if ((tty->termios.c_oflag & TABDLY) == XTABS) {
                                 tty->column += i;
-                                osend ( "        ",  i, tty);
+                                rtems_termios_puts ( "        ",  i, tty);
                                 return;
                         }
@@ -600 +706 @@
                 }
         }
-        osend (&c, 1, tty);
+        rtems_termios_puts (&c, 1, tty);
 }
 
@@ -613 +719 @@
         if (sc != RTEMS_SUCCESSFUL)
                 return sc;
+        if (linesw[tty->t_line].l_write != NULL) {
+                sc = linesw[tty->t_line].l_write(tty,args);
+                rtems_semaphore_release (tty->osem);
+                return sc;
+        }
         if (tty->termios.c_oflag & OPOST) {
                 unsigned32 count = args->count;
@@ -621 +732 @@
         }
         else {
-                osend (args->buffer, args->count, tty);
+                rtems_termios_puts (args->buffer, args->count, tty);
                 args->bytes_moved = args->count;
         }
@@ -639 +750 @@
                 echobuf[0] = '^';
                 echobuf[1] = c ^ 0x40;
-                osend (echobuf, 2, tty);
+                rtems_termios_puts (echobuf, 2, tty);
                 tty->column += 2;
         }
@@ -702 +813 @@
                                  */
                                 while (tty->column > col) {
-                                        osend ("\b", 1, tty);
+                                        rtems_termios_puts ("\b", 1, tty);
                                         tty->column--;
                                 }
@@ -708 +819 @@
                         else {
                                 if (iscntrl (c) && (tty->termios.c_lflag & ECHOCTL)) {
-                                        osend ("\b \b", 3, tty);
+                                        rtems_termios_puts ("\b \b", 3, tty);
                                         if (tty->column)
                                                 tty->column--;
                                 }
                                 if (!iscntrl (c) || (tty->termios.c_lflag & ECHOCTL)) {
-                                        osend ("\b \b", 3, tty);
+                                        rtems_termios_puts ("\b \b", 3, tty);
                                         if (tty->column)
                                                 tty->column--;
@@ -873 +984 @@
                  * Process characters read from raw queue
                  */
-                while (tty->rawInBufHead != tty->rawInBufTail) {
+                while (tty->rawInBuf.Head != tty->rawInBuf.Tail) {
                         unsigned char c;
                         unsigned int newHead;
 
-                        newHead = (tty->rawInBufHead + 1) % RAW_INPUT_BUFFER_SIZE;
-                        c = tty->rawInBuf[newHead];
-                        tty->rawInBufHead = newHead;
-                        if(((tty->rawInBufTail-newHead+RAW_INPUT_BUFFER_SIZE)
-                            % RAW_INPUT_BUFFER_SIZE) 
+                        newHead = (tty->rawInBuf.Head + 1) % tty->rawInBuf.Size;
+                        c = tty->rawInBuf.theBuf[newHead];
+                        tty->rawInBuf.Head = newHead;
+                        if(((tty->rawInBuf.Tail-newHead+tty->rawInBuf.Size)
+                            % tty->rawInBuf.Size)
                            < tty->lowwater) {
                           tty->flow_ctrl &= ~FL_IREQXOF;
@@ -919 +1030 @@
                  * Wait for characters
                  */
-                sc = rtems_semaphore_obtain (tty->rawInBufSemaphore,
+                sc = rtems_semaphore_obtain (tty->rawInBuf.Semaphore,
                                                 tty->rawInBufSemaphoreOptions,
                                                 timeout);
@@ -940 +1051 @@
         if (sc != RTEMS_SUCCESSFUL)
                 return sc;
+        if (linesw[tty->t_line].l_read != NULL) {
+                sc = linesw[tty->t_line].l_read(tty,args);
+                rtems_semaphore_release (tty->isem);
+                return sc;
+        }
         if (tty->cindex == tty->ccount) {
                 tty->cindex = tty->ccount = 0;
                 tty->read_start_column = tty->column;
-                if (tty->device.pollRead)
+                if (tty->device.pollRead != NULL
+                    && tty->device.outputUsesInterrupts == TERMIOS_POLLED)
                         sc = fillBufferPoll (tty);
                 else
@@ -957 +1074 @@
         rtems_semaphore_release (tty->isem);
         return sc;
+}
+
+/*
+ * signal receive interrupt to rx daemon
+ * NOTE: This routine runs in the context of the
+ *       device receive interrupt handler.
+ */
+void rtems_termios_rxirq_occured(struct rtems_termios_tty *tty)
+{
+        /*
+         * send event to rx daemon task
+         */
+        rtems_event_send(tty->rxTaskId,TERMIOS_RX_PROC_EVENT);
 }
 
@@ -974 +1104 @@
         boolean flow_rcv = FALSE; /* TRUE, if flow control char received */
         rtems_interrupt_level level;
+
+        if (linesw[tty->t_line].l_rint != NULL) {
+          while (len--) {
+            c = *buf++;
+            linesw[tty->t_line].l_rint(c,tty);
+          }
+          return 0;
+        }
 
         while (len--) {
@@ -1011 +1149 @@
               /* if chars available, call write function... */
                 (*tty->device.write)(tty->minor,
-                                     (char *)&tty->rawOutBuf[tty->rawOutBufTail], 1);
+                     (char *)&tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail], 1);
               }
               /* reenable interrupts */
@@ -1018 +1156 @@
           }     
           else {
-                newTail = (tty->rawInBufTail + 1) % RAW_INPUT_BUFFER_SIZE;
+                newTail = (tty->rawInBuf.Tail + 1) % tty->rawInBuf.Size;
                 /* if chars_in_buffer > highwater                */
                 rtems_interrupt_disable(level);
-                if ((((newTail - tty->rawInBufHead + RAW_INPUT_BUFFER_SIZE) 
-                      % RAW_INPUT_BUFFER_SIZE)
+                if ((((newTail - tty->rawInBuf.Head + tty->rawInBuf.Size)
+                      % tty->rawInBuf.Size)
                      > tty->highwater) && 
                     !(tty->flow_ctrl & FL_IREQXOF)) {
@@ -1051 +1189 @@
                 rtems_interrupt_enable(level);
 
-                if (newTail == tty->rawInBufHead) {
+                if (newTail == tty->rawInBuf.Head) {
                         dropped++;
                 }
                 else {
-                        tty->rawInBuf[newTail] = c;
-                        tty->rawInBufTail = newTail;
+                        tty->rawInBuf.theBuf[newTail] = c;
+                        tty->rawInBuf.Tail = newTail;
                 }               
           }
         }
         tty->rawInBufDropped += dropped;
-        rtems_semaphore_release (tty->rawInBufSemaphore);
+        rtems_semaphore_release (tty->rawInBuf.Semaphore);
         return dropped;
+}
+
+/*
+ * in task-driven mode, this function is called in Tx task context
+ * in interrupt-driven mode, this function is called in TxIRQ context
+ */
+int
+rtems_termios_refill_transmitter (struct rtems_termios_tty *tty)
+{
+        unsigned int newTail;
+        int nToSend;
+        rtems_interrupt_level level;
+        int len;
+
+        /* check for XOF/XON to send */
+        if ((tty->flow_ctrl & (FL_MDXOF | FL_IREQXOF | FL_ISNTXOF))
+            == (FL_MDXOF | FL_IREQXOF)) {
+          /* XOFF should be sent now... */
+          (*tty->device.write)(tty->minor, 
+                               &(tty->termios.c_cc[VSTOP]), 1);
+
+          rtems_interrupt_disable(level);
+          tty->t_dqlen--;
+          tty->flow_ctrl |= FL_ISNTXOF;
+          rtems_interrupt_enable(level);
+
+          nToSend = 1;
+        }
+        else if ((tty->flow_ctrl & (FL_IREQXOF | FL_ISNTXOF))
+                 == FL_ISNTXOF) {
+          /* NOTE: send XON even, if no longer in XON/XOFF mode... */
+          /* XON should be sent now... */
+                /*
+                 * FIXME: this .write call will generate another 
+                 * dequeue callback. This will advance the "Tail" in the data
+                 * buffer, although the corresponding data is not yet out!
+                 * Therefore the dequeue "length" should be reduced by 1
+                 */
+          (*tty->device.write)(tty->minor, 
+                               &(tty->termios.c_cc[VSTART]), 1);
+
+          rtems_interrupt_disable(level);
+          tty->t_dqlen--;
+          tty->flow_ctrl &= ~FL_ISNTXOF;
+          rtems_interrupt_enable(level);
+
+          nToSend = 1;
+        }
+        else {
+          if ( tty->rawOutBuf.Head == tty->rawOutBuf.Tail ) {
+            /*
+             * buffer was empty
+             */
+            if (tty->rawOutBufState == rob_wait) {
+              /* 
+               * this should never happen... 
+               */
+              rtems_semaphore_release (tty->rawOutBuf.Semaphore);
+            }
+            return 0;   
+          }
+
+          rtems_interrupt_disable(level);
+          len = tty->t_dqlen;
+          tty->t_dqlen = 0;
+          rtems_interrupt_enable(level);
+
+          newTail = (tty->rawOutBuf.Tail + len) % tty->rawOutBuf.Size;
+          tty->rawOutBuf.Tail = newTail;
+          if (tty->rawOutBufState == rob_wait) {
+            /* 
+             * wake up any pending writer task
+             */
+            rtems_semaphore_release (tty->rawOutBuf.Semaphore);
+          }
+          if (newTail == tty->rawOutBuf.Head) {
+            /*
+             * Buffer has become empty
+             */
+            tty->rawOutBufState = rob_idle;
+            nToSend = 0;
+          }
+          /* check, whether output should stop due to received XOFF */
+          else if ((tty->flow_ctrl & (FL_MDXON | FL_ORCVXOF)) 
+                   ==                (FL_MDXON | FL_ORCVXOF)) {
+                  /* Buffer not empty, but output stops due to XOFF */
+                  /* set flag, that output has been stopped */
+                  rtems_interrupt_disable(level);
+                  tty->flow_ctrl |= FL_OSTOP;
+                  tty->rawOutBufState = rob_busy; /*apm*/
+                  rtems_interrupt_enable(level);
+                  nToSend = 0;
+          }
+          else {
+            /*
+             * Buffer not empty, start tranmitter
+             */
+            if (newTail > tty->rawOutBuf.Head)
+                    nToSend = tty->rawOutBuf.Size - newTail;
+            else
+                    nToSend = tty->rawOutBuf.Head - newTail;
+            /* when flow control XON or XOF, don't send blocks of data     */
+            /* to allow fast reaction on incoming flow ctrl and low latency*/
+            /* for outgoing flow control                                   */
+            if (tty->flow_ctrl & (FL_MDXON | FL_MDXOF)) {
+                    nToSend = 1;
+            }
+            tty->rawOutBufState = rob_busy; /*apm*/
+            (*tty->device.write)(tty->minor, 
+                                 (char *)&tty->rawOutBuf.theBuf[newTail], 
+                                 nToSend);
+          }
+          tty->rawOutBuf.Tail = newTail; /*apm*/
+        }
+        return nToSend;
 }
 
@@ -1078 +1331 @@
 {
         struct rtems_termios_tty *tty = ttyp;
-        unsigned int newTail;
-        int nToSend;
-
-        /* check for XOF/XON to send */
-        if ((tty->flow_ctrl & (FL_MDXOF | FL_IREQXOF | FL_ISNTXOF))
-            == (FL_MDXOF | FL_IREQXOF)) {
-          /* XOFF should be sent now... */
-          (*tty->device.write)(tty->minor, 
-                               &(tty->termios.c_cc[VSTOP]), 1);
-          tty->flow_ctrl |= FL_ISNTXOF;
-          nToSend = 1;
-        }
-        else if ((tty->flow_ctrl & (FL_IREQXOF | FL_ISNTXOF))
-                 == FL_ISNTXOF) {
-          /* NOTE: send XON even, if no longer in XON/XOFF mode... */
-          /* XON should be sent now... */
-          (*tty->device.write)(tty->minor, 
-                               &(tty->termios.c_cc[VSTART]), 1);
-          tty->flow_ctrl &= ~FL_ISNTXOF;
-          nToSend = 1;
+        rtems_status_code sc;
+
+        /*
+         * sum up character count already sent
+         */
+        tty->t_dqlen += len;
+
+        if (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN) {
+                /*
+                 * send wake up to transmitter task
+                 */
+                sc = rtems_event_send(tty->txTaskId,
+                                      TERMIOS_TX_START_EVENT);
+                if (sc != RTEMS_SUCCESSFUL)
+                        rtems_fatal_error_occurred (sc);
+                return 0; /* nothing to output in IRQ... */
         }
         else {
-          if (tty->rawOutBufState == rob_wait)
-            rtems_semaphore_release (tty->rawOutBufSemaphore);
-          if ( tty->rawOutBufHead == tty->rawOutBufTail ) {
-            tty->rawOutBufState = rob_idle;
-            return 0;   
-          }
-          newTail = (tty->rawOutBufTail + len) % RAW_OUTPUT_BUFFER_SIZE;
-          if (newTail == tty->rawOutBufHead) {
-            /*
-             * Buffer empty
-             */
-            tty->rawOutBufState = rob_idle;
-            nToSend = 0;
-          }
-          /* check, whether output should stop due to received XOFF */
-          else if ((tty->flow_ctrl & (FL_MDXON | FL_ORCVXOF)) 
-                   ==                (FL_MDXON | FL_ORCVXOF)) {
-            /* Buffer not empty, but output stops due to XOFF */
-            /* set flag, that output has been stopped */
-            tty->flow_ctrl |= FL_OSTOP;
-            tty->rawOutBufState = rob_busy;
-            nToSend = 0;
-          }
-          else {
-            /*
-             * Buffer not empty, start tranmitter
-             */
-            if (newTail > tty->rawOutBufHead)
-              nToSend = RAW_OUTPUT_BUFFER_SIZE - newTail;
-            else
-              nToSend = tty->rawOutBufHead - newTail;
-            /* when flow control XON or XOF, don't send blocks of data     */
-            /* to allow fast reaction on incoming flow ctrl and low latency*/
-            /* for outgoing flow control                                   */
-            if (tty->flow_ctrl & (FL_MDXON | FL_MDXOF))
-              nToSend = 1;
-            tty->rawOutBufState = rob_busy;
-            (*tty->device.write)(tty->minor, (char *)&tty->rawOutBuf[newTail], nToSend);
-          }
-          tty->rawOutBufTail = newTail;
-        }
-        return nToSend;
-}
+                return rtems_termios_refill_transmitter(tty);
+        }
+}
+
+/*
+ * this task actually processes any transmit events
+ */
+static rtems_task rtems_termios_txdaemon(rtems_task_argument argument)
+{
+        struct rtems_termios_tty *tty = (struct rtems_termios_tty *)argument;
+        rtems_event_set the_event;
+
+        while (1) {
+                /*
+                 * wait for rtems event
+                 */
+                rtems_event_receive((TERMIOS_TX_START_EVENT | 
+                                     TERMIOS_TX_TERMINATE_EVENT),
+                                    RTEMS_EVENT_ANY | RTEMS_WAIT,
+                                    RTEMS_NO_TIMEOUT,
+                                    &the_event);
+                if ((the_event & TERMIOS_TX_TERMINATE_EVENT) != 0) {
+                        tty->txTaskId = 0;
+                        rtems_task_delete(RTEMS_SELF);
+                }
+                else {
+                        /*
+                         * call any line discipline start function
+                         */
+                        if (linesw[tty->t_line].l_start != NULL) {
+                                linesw[tty->t_line].l_start(tty);
+                        }
+                        /*
+                         * try to push further characters to device
+                         */
+                        rtems_termios_refill_transmitter(tty);
+                }
+        }
+}
+
+/*
+ * this task actually processes any receive events
+ */
+static rtems_task rtems_termios_rxdaemon(rtems_task_argument argument)
+{
+        struct rtems_termios_tty *tty = (struct rtems_termios_tty *)argument;
+        rtems_event_set the_event;
+        int c;
+        char c_buf;
+        while (1) {
+                /*
+                 * wait for rtems event
+                 */
+                rtems_event_receive((TERMIOS_RX_PROC_EVENT | 
+                                     TERMIOS_RX_TERMINATE_EVENT),
+                                    RTEMS_EVENT_ANY | RTEMS_WAIT,
+                                    RTEMS_NO_TIMEOUT,
+                                    &the_event);
+                if ((the_event & TERMIOS_RX_TERMINATE_EVENT) != 0) {
+                        tty->rxTaskId = 0;
+                        rtems_task_delete(RTEMS_SELF);
+                }
+                else {
+                        /*
+                         * do something
+                         */
+                        c = tty->device.pollRead(tty->minor);
+                        if (c != EOF) {
+                                /*
+                                 * pollRead did call enqueue on its own
+                                 */
+                                c_buf = c;
+                                rtems_termios_enqueue_raw_characters (
+                                      tty,&c_buf,1);
+                        }
+                }
+        }
+}

c/src/lib/ChangeLog

@@ +1 @@
+
+2000-11-25  Antti P Miettinen  <antti.p.miettinen@nokia.com>
+
+        * libc/termios.c, libc/termiostypes.h: Task driver driver model
+        and line discipline support from Thomas Doerfler
+        <Thomas.Doerfler@imd-systems.de>.
 
 2000-11-20       Dmitry Kargapolov <dk@gentex.ru>

c/src/lib/libc/Makefile.am

@@ -82 +82 @@
 
 EXTRA_DIST = $(DOC_FILES) $(COMMON_C_FILES) $(EMBEDDED_C_FILES) \
-    $(UNIX_C_FILES)
+    $(UNIX_C_FILES) termiostypes.h
 
 include $(top_srcdir)/../../../automake/local.am

c/src/lib/libc/termios.c

@@ -24 +24 @@
 #include <termios.h>
 #include <unistd.h>
+#include <sys/ttycom.h>
+
+#include "termiostypes.h"
 
 /*
@@ -61 +64 @@
 #define RAW_OUTPUT_BUFFER_SIZE  64
 
-/*
- * Variables associated with each termios instance.
- * One structure for each hardware I/O device.
- */
-struct rtems_termios_tty {
-        /*
-         * Linked-list of active TERMIOS devices
-         */
-        struct rtems_termios_tty        *forw;
-        struct rtems_termios_tty        *back;
-
-        /*
-         * How many times has this device been opened
-         */
-        int             refcount;
-
-        /*
-         * This device
-         */
-        rtems_device_major_number       major;
-        rtems_device_major_number       minor;
-
-        /*
-         * Mutual-exclusion semaphores
-         */
-        rtems_id        isem;
-        rtems_id        osem;
-
-        /*
-         * The canonical (cooked) character buffer
-         */
-        char            cbuf[CBUFSIZE];
-        int             ccount;
-        int             cindex;
-
-        /*
-         * Keep track of cursor (printhead) position
-         */
-        int             column;
-        int             read_start_column;
-
-        /*
-         * The ioctl settings
-         */
-        struct termios  termios;
-        rtems_interval  vtimeTicks;
-
-        /*
-         * Raw input character buffer
-         */
-        volatile char           rawInBuf[RAW_INPUT_BUFFER_SIZE];
-        volatile unsigned int   rawInBufHead;
-        volatile unsigned int   rawInBufTail;
-        rtems_id                rawInBufSemaphore;
-        rtems_unsigned32        rawInBufSemaphoreOptions;
-        rtems_interval          rawInBufSemaphoreTimeout;
-        rtems_interval          rawInBufSemaphoreFirstTimeout;
-        unsigned int            rawInBufDropped;        /* Statistics */
-
-        /*
-         * Raw output character buffer
-         */
-        volatile char           rawOutBuf[RAW_OUTPUT_BUFFER_SIZE];
-        volatile unsigned int   rawOutBufHead;
-        volatile unsigned int   rawOutBufTail;
-        rtems_id                rawOutBufSemaphore;
-        volatile enum {rob_idle, rob_busy, rob_wait }   rawOutBufState;
-
-        /*
-         * Callbacks to device-specific routines
-         */
-        rtems_termios_callbacks device;
-        volatile unsigned int   flow_ctrl;
-        unsigned int            lowwater,highwater;
-};
-
 /* fields for "flow_ctrl" status */
 #define FL_IREQXOF 1        /* input queue requests stop of incoming data */
@@ -149 +76 @@
 #define FL_MDXOF   0x400    /* output controlled with XON/XOFF protocol   */
 
+#define NODISC(n) \
+        { NULL, NULL,   NULL,   NULL, \
+          NULL, NULL,   NULL,   NULL }
+/*
+ * FIXME: change linesw entries consistant with linesw entry usage...
+ */
+struct  linesw linesw[MAXLDISC] =
+{
+        NODISC(0),              /* 0- termios-built-in */
+        NODISC(1),              /* 1- defunct */
+        NODISC(2),              /* 2- NTTYDISC */
+        NODISC(3),              /* TABLDISC */
+        NODISC(4),              /* SLIPDISC */
+        NODISC(5),              /* PPPDISC */
+        NODISC(6),              /* loadable */
+        NODISC(7),              /* loadable */
+};
+
+int     nlinesw = sizeof (linesw) / sizeof (linesw[0]);
+
 extern struct rtems_termios_tty *rtems_termios_ttyHead;
 extern struct rtems_termios_tty *rtems_termios_ttyTail;
 extern rtems_id rtems_termios_ttyMutex;
+
+static rtems_task rtems_termios_rxdaemon(rtems_task_argument argument);
+static rtems_task rtems_termios_txdaemon(rtems_task_argument argument);
+/*
+ * some constants for I/O daemon task creation
+ */
+#define TERMIOS_TXTASK_PRIO 10
+#define TERMIOS_RXTASK_PRIO 9
+#define TERMIOS_TXTASK_STACKSIZE 1024
+#define TERMIOS_RXTASK_STACKSIZE 1024
+/*
+ * some events to be sent to the I/O tasks
+ */
+#define TERMIOS_TX_START_EVENT     RTEMS_EVENT_1
+#define TERMIOS_TX_TERMINATE_EVENT RTEMS_EVENT_0
+
+#define TERMIOS_RX_PROC_EVENT      RTEMS_EVENT_1
+#define TERMIOS_RX_TERMINATE_EVENT RTEMS_EVENT_0
 
 /*
@@ -171 +136 @@
          * See if the device has already been opened
          */
-        sc = rtems_semaphore_obtain (rtems_termios_ttyMutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
+        sc = rtems_semaphore_obtain (rtems_termios_ttyMutex,
+                                     RTEMS_WAIT, RTEMS_NO_TIMEOUT);
         if (sc != RTEMS_SUCCESSFUL)
                 return sc;
@@ -189 +155 @@
                         return RTEMS_NO_MEMORY;
                 }
+                /*
+                 * allocate raw input buffer
+                 */
+                tty->rawInBuf.Size = RAW_INPUT_BUFFER_SIZE;
+                tty->rawInBuf.theBuf = malloc (tty->rawInBuf.Size);
+                if (tty->rawInBuf.theBuf == NULL) {
+                        free(tty);
+                        rtems_semaphore_release (rtems_termios_ttyMutex);
+                        return RTEMS_NO_MEMORY;
+                }
+                /*
+                 * allocate raw output buffer
+                 */
+                tty->rawOutBuf.Size = RAW_OUTPUT_BUFFER_SIZE;
+                tty->rawOutBuf.theBuf = malloc (tty->rawOutBuf.Size);
+                if (tty->rawInBuf.theBuf == NULL) {
+                        free((void *)(tty->rawInBuf.theBuf));
+                        free(tty);
+                        rtems_semaphore_release (rtems_termios_ttyMutex);
+                        return RTEMS_NO_MEMORY;
+                }
+                /*
+                 * allocate cooked buffer
+                 */
+                tty->cbuf  = malloc (CBUFSIZE);
+                if (tty->cbuf == NULL) {
+                        free((void *)(tty->rawOutBuf.theBuf));
+                        free((void *)(tty->rawInBuf.theBuf));
+                        free(tty);
+                        rtems_semaphore_release (rtems_termios_ttyMutex);
+                        return RTEMS_NO_MEMORY;
+                }
+                /*
+                 * link tty
+                 */
                 if (rtems_termios_ttyHead)
                         rtems_termios_ttyHead->back = tty;
@@ -222 +223 @@
                         RTEMS_SIMPLE_BINARY_SEMAPHORE | RTEMS_FIFO,
                         RTEMS_NO_PRIORITY,
-                        &tty->rawOutBufSemaphore);
+                        &tty->rawOutBuf.Semaphore);
                 if (sc != RTEMS_SUCCESSFUL)
                         rtems_fatal_error_occurred (sc);
@@ -231 +232 @@
                  */
                 tty->device = *callbacks;
-                if (!tty->device.pollRead) {
+
+                /*
+                 * Create I/O tasks
+                 */
+                if (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN) {
+                        sc = rtems_task_create (
+                                   rtems_build_name ('T', 'x', 'T', c),
+                                   TERMIOS_TXTASK_PRIO,
+                                   TERMIOS_TXTASK_STACKSIZE,
+                                   RTEMS_NO_PREEMPT | RTEMS_NO_TIMESLICE | 
+                                   RTEMS_NO_ASR,
+                                   RTEMS_NO_FLOATING_POINT | RTEMS_LOCAL,
+                                   &tty->txTaskId);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                        sc = rtems_task_create (
+                                   rtems_build_name ('R', 'x', 'T', c),
+                                   TERMIOS_RXTASK_PRIO,
+                                   TERMIOS_RXTASK_STACKSIZE,
+                                   RTEMS_NO_PREEMPT | RTEMS_NO_TIMESLICE | 
+                                   RTEMS_NO_ASR,
+                                   RTEMS_NO_FLOATING_POINT | RTEMS_LOCAL,
+                                   &tty->rxTaskId);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                                
+                }
+                if ((tty->device.pollRead == NULL) ||
+                    (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN)){
                         sc = rtems_semaphore_create (
                                 rtems_build_name ('T', 'R', 'r', c),
@@ -237 +266 @@
                                 RTEMS_COUNTING_SEMAPHORE | RTEMS_PRIORITY,
                                 RTEMS_NO_PRIORITY,
-                                &tty->rawInBufSemaphore);
+                                &tty->rawInBuf.Semaphore);
                         if (sc != RTEMS_SUCCESSFUL)
                                 rtems_fatal_error_occurred (sc);
@@ -270 +299 @@
                  * set low/highwater mark for XON/XOFF support
                  */
-                tty->lowwater  = RAW_INPUT_BUFFER_SIZE * 1/2;
-                tty->highwater = RAW_INPUT_BUFFER_SIZE * 3/4;
+                tty->lowwater  = tty->rawInBuf.Size * 1/2;
+                tty->highwater = tty->rawInBuf.Size * 3/4;
                 /*
                  * Bump name characer
@@ -280 +309 @@
         }
         args->iop->data1 = tty;
-        if (!tty->refcount++ && tty->device.firstOpen)
+        if (!tty->refcount++) {
+          if (tty->device.firstOpen)
                 (*tty->device.firstOpen)(major, minor, arg);
+          /*
+           * start I/O tasks, if needed
+           */
+          if (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN) {
+            sc = rtems_task_start(tty->rxTaskId,
+                                  rtems_termios_rxdaemon,
+                                  (rtems_task_argument)tty);
+            if (sc != RTEMS_SUCCESSFUL)
+              rtems_fatal_error_occurred (sc);
+            
+            sc = rtems_task_start(tty->txTaskId,
+                                  rtems_termios_txdaemon,
+                                  (rtems_task_argument)tty);
+            if (sc != RTEMS_SUCCESSFUL)
+              rtems_fatal_error_occurred (sc);
+          }
+        }
         rtems_semaphore_release (rtems_termios_ttyMutex);
         return RTEMS_SUCCESSFUL;
@@ -295 +342 @@
         rtems_status_code sc;
 
-        if (tty->device.outputUsesInterrupts) {
+        if (tty->device.outputUsesInterrupts != TERMIOS_POLLED) {
                 rtems_interrupt_disable (level);
-                while (tty->rawOutBufTail != tty->rawOutBufHead) {
+                while (tty->rawOutBuf.Tail != tty->rawOutBuf.Head) {
                         tty->rawOutBufState = rob_wait;
                         rtems_interrupt_enable (level);
-                        sc = rtems_semaphore_obtain (tty->rawOutBufSemaphore,
+                        sc = rtems_semaphore_obtain (tty->rawOutBuf.Semaphore,
                                                         RTEMS_WAIT,
                                                         RTEMS_NO_TIMEOUT);
@@ -322 +369 @@
                 rtems_fatal_error_occurred (sc);
         if (--tty->refcount == 0) {
-                drainOutput (tty);
+                if (linesw[tty->t_line].l_close != NULL) {
+                        /*
+                         * call discipline-specific close
+                         */
+                        sc = linesw[tty->t_line].l_close(tty);
+                }
+                else {
+                        /*
+                         * default: just flush output buffer
+                         */
+                        drainOutput (tty);
+                }
+          
+                if (tty->device.outputUsesInterrupts 
+                    == TERMIOS_TASK_DRIVEN) {
+                        /*
+                         * send "terminate" to I/O tasks
+                         */
+                        sc = rtems_event_send(
+                                  tty->rxTaskId,
+                                  TERMIOS_RX_TERMINATE_EVENT);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                        sc = rtems_event_send(
+                                  tty->txTaskId,
+                                  TERMIOS_TX_TERMINATE_EVENT);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                }
                 if (tty->device.lastClose)
                          (*tty->device.lastClose)(tty->major, tty->minor, arg);
@@ -335 +410 @@
                 rtems_semaphore_delete (tty->isem);
                 rtems_semaphore_delete (tty->osem);
-                rtems_semaphore_delete (tty->rawOutBufSemaphore);
-                if (!tty->device.pollRead)
-                        rtems_semaphore_delete (tty->rawInBufSemaphore);
+                rtems_semaphore_delete (tty->rawOutBuf.Semaphore);
+                if ((tty->device.pollRead == NULL) ||
+                    (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN))
+                        rtems_semaphore_delete (tty->rawInBuf.Semaphore);
                 free (tty);
         }
@@ -367 +443 @@
         /* if chars available, call write function... */
         (*tty->device.write)(tty->minor,
-                             (char *)&tty->rawOutBuf[tty->rawOutBufTail], 1);
+                     (char *)&tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail],1);
       }
       /* reenable interrupts */
@@ -428 +504 @@
         switch (args->command) {
         default:
-                sc = RTEMS_INVALID_NUMBER;
+                if (linesw[tty->t_line].l_ioctl != NULL) {
+                        sc = linesw[tty->t_line].l_ioctl(tty,args);
+                }
+                else {
+                        sc = RTEMS_INVALID_NUMBER;
+                }
                 break;
 
@@ -477 +558 @@
                 break;
 
+                /*
+                 * FIXME: add various ioctl code handlers
+                 */
+
+#if 1 /* FIXME */
+        case TIOCSETD:
+                /*
+                 * close old line discipline
+                 */
+                if (linesw[tty->t_line].l_close != NULL) {
+                        sc = linesw[tty->t_line].l_close(tty);
+                }
+                tty->t_line=*(int*)(args->buffer);
+                tty->t_sc = NULL; /* ensure that no more valid data */
+                /*
+                 * open new line discipline
+                 */
+                if (linesw[tty->t_line].l_open != NULL) {
+                        sc = linesw[tty->t_line].l_open(tty);
+                }
+                break;
+        case TIOCGETD:  
+                *(int*)(args->buffer)=tty->t_line;
+                break;          
+#endif
         case FIONREAD:
                 /* Half guess that this is the right operation */
@@ -490 +596 @@
  * Send characters to device-specific code
  */
-static void
-osend (const char *buf, int len, struct rtems_termios_tty *tty)
+void
+rtems_termios_puts (const char *buf, int len, struct rtems_termios_tty *tty)
 {
         unsigned int newHead;
@@ -497 +603 @@
         rtems_status_code sc;
 
-        if (!tty->device.outputUsesInterrupts) {
+        if (tty->device.outputUsesInterrupts == TERMIOS_POLLED) {
                 (*tty->device.write)(tty->minor, buf, len);
                 return;
         }
-        newHead = tty->rawOutBufHead;
+        newHead = tty->rawOutBuf.Head;
         while (len) {
                 /*
@@ -515 +621 @@
                  * with interrupts enabled.
                  */
-                newHead = (newHead + 1) % RAW_OUTPUT_BUFFER_SIZE;
+                newHead = (newHead + 1) % tty->rawOutBuf.Size;
                 rtems_interrupt_disable (level);
-                while (newHead == tty->rawOutBufTail) {
+                while (newHead == tty->rawOutBuf.Tail) {
                         tty->rawOutBufState = rob_wait;
                         rtems_interrupt_enable (level);
-                        sc = rtems_semaphore_obtain (tty->rawOutBufSemaphore,
+                        sc = rtems_semaphore_obtain (tty->rawOutBuf.Semaphore,
                                                         RTEMS_WAIT,
                                                         RTEMS_NO_TIMEOUT);
@@ -527 +633 @@
                         rtems_interrupt_disable (level);
                 }
-                tty->rawOutBuf[tty->rawOutBufHead] = *buf++;
-                tty->rawOutBufHead = newHead;
+                tty->rawOutBuf.theBuf[tty->rawOutBuf.Head] = *buf++;
+                tty->rawOutBuf.Head = newHead;
                 if (tty->rawOutBufState == rob_idle) {
                   /* check, whether XOFF has been received */
                   if (!(tty->flow_ctrl & FL_ORCVXOF)) {
                     (*tty->device.write)(tty->minor,
-                                (char *)&tty->rawOutBuf[tty->rawOutBufTail],1);
+                        (char *)&tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail],1);
                   }
                   else {
@@ -560 +666 @@
                                 tty->column = 0;
                         if (tty->termios.c_oflag & ONLCR) {
-                                osend ("\r", 1, tty);
+                                rtems_termios_puts ("\r", 1, tty);
                                 tty->column = 0;
                         }
@@ -581 +687 @@
                         if ((tty->termios.c_oflag & TABDLY) == XTABS) {
                                 tty->column += i;
-                                osend ( "        ",  i, tty);
+                                rtems_termios_puts ( "        ",  i, tty);
                                 return;
                         }
@@ -600 +706 @@
                 }
         }
-        osend (&c, 1, tty);
+        rtems_termios_puts (&c, 1, tty);
 }
 
@@ -613 +719 @@
         if (sc != RTEMS_SUCCESSFUL)
                 return sc;
+        if (linesw[tty->t_line].l_write != NULL) {
+                sc = linesw[tty->t_line].l_write(tty,args);
+                rtems_semaphore_release (tty->osem);
+                return sc;
+        }
         if (tty->termios.c_oflag & OPOST) {
                 unsigned32 count = args->count;
@@ -621 +732 @@
         }
         else {
-                osend (args->buffer, args->count, tty);
+                rtems_termios_puts (args->buffer, args->count, tty);
                 args->bytes_moved = args->count;
         }
@@ -639 +750 @@
                 echobuf[0] = '^';
                 echobuf[1] = c ^ 0x40;
-                osend (echobuf, 2, tty);
+                rtems_termios_puts (echobuf, 2, tty);
                 tty->column += 2;
         }
@@ -702 +813 @@
                                  */
                                 while (tty->column > col) {
-                                        osend ("\b", 1, tty);
+                                        rtems_termios_puts ("\b", 1, tty);
                                         tty->column--;
                                 }
@@ -708 +819 @@
                         else {
                                 if (iscntrl (c) && (tty->termios.c_lflag & ECHOCTL)) {
-                                        osend ("\b \b", 3, tty);
+                                        rtems_termios_puts ("\b \b", 3, tty);
                                         if (tty->column)
                                                 tty->column--;
                                 }
                                 if (!iscntrl (c) || (tty->termios.c_lflag & ECHOCTL)) {
-                                        osend ("\b \b", 3, tty);
+                                        rtems_termios_puts ("\b \b", 3, tty);
                                         if (tty->column)
                                                 tty->column--;
@@ -873 +984 @@
                  * Process characters read from raw queue
                  */
-                while (tty->rawInBufHead != tty->rawInBufTail) {
+                while (tty->rawInBuf.Head != tty->rawInBuf.Tail) {
                         unsigned char c;
                         unsigned int newHead;
 
-                        newHead = (tty->rawInBufHead + 1) % RAW_INPUT_BUFFER_SIZE;
-                        c = tty->rawInBuf[newHead];
-                        tty->rawInBufHead = newHead;
-                        if(((tty->rawInBufTail-newHead+RAW_INPUT_BUFFER_SIZE)
-                            % RAW_INPUT_BUFFER_SIZE) 
+                        newHead = (tty->rawInBuf.Head + 1) % tty->rawInBuf.Size;
+                        c = tty->rawInBuf.theBuf[newHead];
+                        tty->rawInBuf.Head = newHead;
+                        if(((tty->rawInBuf.Tail-newHead+tty->rawInBuf.Size)
+                            % tty->rawInBuf.Size)
                            < tty->lowwater) {
                           tty->flow_ctrl &= ~FL_IREQXOF;
@@ -919 +1030 @@
                  * Wait for characters
                  */
-                sc = rtems_semaphore_obtain (tty->rawInBufSemaphore,
+                sc = rtems_semaphore_obtain (tty->rawInBuf.Semaphore,
                                                 tty->rawInBufSemaphoreOptions,
                                                 timeout);
@@ -940 +1051 @@
         if (sc != RTEMS_SUCCESSFUL)
                 return sc;
+        if (linesw[tty->t_line].l_read != NULL) {
+                sc = linesw[tty->t_line].l_read(tty,args);
+                rtems_semaphore_release (tty->isem);
+                return sc;
+        }
         if (tty->cindex == tty->ccount) {
                 tty->cindex = tty->ccount = 0;
                 tty->read_start_column = tty->column;
-                if (tty->device.pollRead)
+                if (tty->device.pollRead != NULL
+                    && tty->device.outputUsesInterrupts == TERMIOS_POLLED)
                         sc = fillBufferPoll (tty);
                 else
@@ -957 +1074 @@
         rtems_semaphore_release (tty->isem);
         return sc;
+}
+
+/*
+ * signal receive interrupt to rx daemon
+ * NOTE: This routine runs in the context of the
+ *       device receive interrupt handler.
+ */
+void rtems_termios_rxirq_occured(struct rtems_termios_tty *tty)
+{
+        /*
+         * send event to rx daemon task
+         */
+        rtems_event_send(tty->rxTaskId,TERMIOS_RX_PROC_EVENT);
 }
 
@@ -974 +1104 @@
         boolean flow_rcv = FALSE; /* TRUE, if flow control char received */
         rtems_interrupt_level level;
+
+        if (linesw[tty->t_line].l_rint != NULL) {
+          while (len--) {
+            c = *buf++;
+            linesw[tty->t_line].l_rint(c,tty);
+          }
+          return 0;
+        }
 
         while (len--) {
@@ -1011 +1149 @@
               /* if chars available, call write function... */
                 (*tty->device.write)(tty->minor,
-                                     (char *)&tty->rawOutBuf[tty->rawOutBufTail], 1);
+                     (char *)&tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail], 1);
               }
               /* reenable interrupts */
@@ -1018 +1156 @@
           }     
           else {
-                newTail = (tty->rawInBufTail + 1) % RAW_INPUT_BUFFER_SIZE;
+                newTail = (tty->rawInBuf.Tail + 1) % tty->rawInBuf.Size;
                 /* if chars_in_buffer > highwater                */
                 rtems_interrupt_disable(level);
-                if ((((newTail - tty->rawInBufHead + RAW_INPUT_BUFFER_SIZE) 
-                      % RAW_INPUT_BUFFER_SIZE)
+                if ((((newTail - tty->rawInBuf.Head + tty->rawInBuf.Size)
+                      % tty->rawInBuf.Size)
                      > tty->highwater) && 
                     !(tty->flow_ctrl & FL_IREQXOF)) {
@@ -1051 +1189 @@
                 rtems_interrupt_enable(level);
 
-                if (newTail == tty->rawInBufHead) {
+                if (newTail == tty->rawInBuf.Head) {
                         dropped++;
                 }
                 else {
-                        tty->rawInBuf[newTail] = c;
-                        tty->rawInBufTail = newTail;
+                        tty->rawInBuf.theBuf[newTail] = c;
+                        tty->rawInBuf.Tail = newTail;
                 }               
           }
         }
         tty->rawInBufDropped += dropped;
-        rtems_semaphore_release (tty->rawInBufSemaphore);
+        rtems_semaphore_release (tty->rawInBuf.Semaphore);
         return dropped;
+}
+
+/*
+ * in task-driven mode, this function is called in Tx task context
+ * in interrupt-driven mode, this function is called in TxIRQ context
+ */
+int
+rtems_termios_refill_transmitter (struct rtems_termios_tty *tty)
+{
+        unsigned int newTail;
+        int nToSend;
+        rtems_interrupt_level level;
+        int len;
+
+        /* check for XOF/XON to send */
+        if ((tty->flow_ctrl & (FL_MDXOF | FL_IREQXOF | FL_ISNTXOF))
+            == (FL_MDXOF | FL_IREQXOF)) {
+          /* XOFF should be sent now... */
+          (*tty->device.write)(tty->minor, 
+                               &(tty->termios.c_cc[VSTOP]), 1);
+
+          rtems_interrupt_disable(level);
+          tty->t_dqlen--;
+          tty->flow_ctrl |= FL_ISNTXOF;
+          rtems_interrupt_enable(level);
+
+          nToSend = 1;
+        }
+        else if ((tty->flow_ctrl & (FL_IREQXOF | FL_ISNTXOF))
+                 == FL_ISNTXOF) {
+          /* NOTE: send XON even, if no longer in XON/XOFF mode... */
+          /* XON should be sent now... */
+                /*
+                 * FIXME: this .write call will generate another 
+                 * dequeue callback. This will advance the "Tail" in the data
+                 * buffer, although the corresponding data is not yet out!
+                 * Therefore the dequeue "length" should be reduced by 1
+                 */
+          (*tty->device.write)(tty->minor, 
+                               &(tty->termios.c_cc[VSTART]), 1);
+
+          rtems_interrupt_disable(level);
+          tty->t_dqlen--;
+          tty->flow_ctrl &= ~FL_ISNTXOF;
+          rtems_interrupt_enable(level);
+
+          nToSend = 1;
+        }
+        else {
+          if ( tty->rawOutBuf.Head == tty->rawOutBuf.Tail ) {
+            /*
+             * buffer was empty
+             */
+            if (tty->rawOutBufState == rob_wait) {
+              /* 
+               * this should never happen... 
+               */
+              rtems_semaphore_release (tty->rawOutBuf.Semaphore);
+            }
+            return 0;   
+          }
+
+          rtems_interrupt_disable(level);
+          len = tty->t_dqlen;
+          tty->t_dqlen = 0;
+          rtems_interrupt_enable(level);
+
+          newTail = (tty->rawOutBuf.Tail + len) % tty->rawOutBuf.Size;
+          tty->rawOutBuf.Tail = newTail;
+          if (tty->rawOutBufState == rob_wait) {
+            /* 
+             * wake up any pending writer task
+             */
+            rtems_semaphore_release (tty->rawOutBuf.Semaphore);
+          }
+          if (newTail == tty->rawOutBuf.Head) {
+            /*
+             * Buffer has become empty
+             */
+            tty->rawOutBufState = rob_idle;
+            nToSend = 0;
+          }
+          /* check, whether output should stop due to received XOFF */
+          else if ((tty->flow_ctrl & (FL_MDXON | FL_ORCVXOF)) 
+                   ==                (FL_MDXON | FL_ORCVXOF)) {
+                  /* Buffer not empty, but output stops due to XOFF */
+                  /* set flag, that output has been stopped */
+                  rtems_interrupt_disable(level);
+                  tty->flow_ctrl |= FL_OSTOP;
+                  tty->rawOutBufState = rob_busy; /*apm*/
+                  rtems_interrupt_enable(level);
+                  nToSend = 0;
+          }
+          else {
+            /*
+             * Buffer not empty, start tranmitter
+             */
+            if (newTail > tty->rawOutBuf.Head)
+                    nToSend = tty->rawOutBuf.Size - newTail;
+            else
+                    nToSend = tty->rawOutBuf.Head - newTail;
+            /* when flow control XON or XOF, don't send blocks of data     */
+            /* to allow fast reaction on incoming flow ctrl and low latency*/
+            /* for outgoing flow control                                   */
+            if (tty->flow_ctrl & (FL_MDXON | FL_MDXOF)) {
+                    nToSend = 1;
+            }
+            tty->rawOutBufState = rob_busy; /*apm*/
+            (*tty->device.write)(tty->minor, 
+                                 (char *)&tty->rawOutBuf.theBuf[newTail], 
+                                 nToSend);
+          }
+          tty->rawOutBuf.Tail = newTail; /*apm*/
+        }
+        return nToSend;
 }
 
@@ -1078 +1331 @@
 {
         struct rtems_termios_tty *tty = ttyp;
-        unsigned int newTail;
-        int nToSend;
-
-        /* check for XOF/XON to send */
-        if ((tty->flow_ctrl & (FL_MDXOF | FL_IREQXOF | FL_ISNTXOF))
-            == (FL_MDXOF | FL_IREQXOF)) {
-          /* XOFF should be sent now... */
-          (*tty->device.write)(tty->minor, 
-                               &(tty->termios.c_cc[VSTOP]), 1);
-          tty->flow_ctrl |= FL_ISNTXOF;
-          nToSend = 1;
-        }
-        else if ((tty->flow_ctrl & (FL_IREQXOF | FL_ISNTXOF))
-                 == FL_ISNTXOF) {
-          /* NOTE: send XON even, if no longer in XON/XOFF mode... */
-          /* XON should be sent now... */
-          (*tty->device.write)(tty->minor, 
-                               &(tty->termios.c_cc[VSTART]), 1);
-          tty->flow_ctrl &= ~FL_ISNTXOF;
-          nToSend = 1;
+        rtems_status_code sc;
+
+        /*
+         * sum up character count already sent
+         */
+        tty->t_dqlen += len;
+
+        if (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN) {
+                /*
+                 * send wake up to transmitter task
+                 */
+                sc = rtems_event_send(tty->txTaskId,
+                                      TERMIOS_TX_START_EVENT);
+                if (sc != RTEMS_SUCCESSFUL)
+                        rtems_fatal_error_occurred (sc);
+                return 0; /* nothing to output in IRQ... */
         }
         else {
-          if (tty->rawOutBufState == rob_wait)
-            rtems_semaphore_release (tty->rawOutBufSemaphore);
-          if ( tty->rawOutBufHead == tty->rawOutBufTail ) {
-            tty->rawOutBufState = rob_idle;
-            return 0;   
-          }
-          newTail = (tty->rawOutBufTail + len) % RAW_OUTPUT_BUFFER_SIZE;
-          if (newTail == tty->rawOutBufHead) {
-            /*
-             * Buffer empty
-             */
-            tty->rawOutBufState = rob_idle;
-            nToSend = 0;
-          }
-          /* check, whether output should stop due to received XOFF */
-          else if ((tty->flow_ctrl & (FL_MDXON | FL_ORCVXOF)) 
-                   ==                (FL_MDXON | FL_ORCVXOF)) {
-            /* Buffer not empty, but output stops due to XOFF */
-            /* set flag, that output has been stopped */
-            tty->flow_ctrl |= FL_OSTOP;
-            tty->rawOutBufState = rob_busy;
-            nToSend = 0;
-          }
-          else {
-            /*
-             * Buffer not empty, start tranmitter
-             */
-            if (newTail > tty->rawOutBufHead)
-              nToSend = RAW_OUTPUT_BUFFER_SIZE - newTail;
-            else
-              nToSend = tty->rawOutBufHead - newTail;
-            /* when flow control XON or XOF, don't send blocks of data     */
-            /* to allow fast reaction on incoming flow ctrl and low latency*/
-            /* for outgoing flow control                                   */
-            if (tty->flow_ctrl & (FL_MDXON | FL_MDXOF))
-              nToSend = 1;
-            tty->rawOutBufState = rob_busy;
-            (*tty->device.write)(tty->minor, (char *)&tty->rawOutBuf[newTail], nToSend);
-          }
-          tty->rawOutBufTail = newTail;
-        }
-        return nToSend;
-}
+                return rtems_termios_refill_transmitter(tty);
+        }
+}
+
+/*
+ * this task actually processes any transmit events
+ */
+static rtems_task rtems_termios_txdaemon(rtems_task_argument argument)
+{
+        struct rtems_termios_tty *tty = (struct rtems_termios_tty *)argument;
+        rtems_event_set the_event;
+
+        while (1) {
+                /*
+                 * wait for rtems event
+                 */
+                rtems_event_receive((TERMIOS_TX_START_EVENT | 
+                                     TERMIOS_TX_TERMINATE_EVENT),
+                                    RTEMS_EVENT_ANY | RTEMS_WAIT,
+                                    RTEMS_NO_TIMEOUT,
+                                    &the_event);
+                if ((the_event & TERMIOS_TX_TERMINATE_EVENT) != 0) {
+                        tty->txTaskId = 0;
+                        rtems_task_delete(RTEMS_SELF);
+                }
+                else {
+                        /*
+                         * call any line discipline start function
+                         */
+                        if (linesw[tty->t_line].l_start != NULL) {
+                                linesw[tty->t_line].l_start(tty);
+                        }
+                        /*
+                         * try to push further characters to device
+                         */
+                        rtems_termios_refill_transmitter(tty);
+                }
+        }
+}
+
+/*
+ * this task actually processes any receive events
+ */
+static rtems_task rtems_termios_rxdaemon(rtems_task_argument argument)
+{
+        struct rtems_termios_tty *tty = (struct rtems_termios_tty *)argument;
+        rtems_event_set the_event;
+        int c;
+        char c_buf;
+        while (1) {
+                /*
+                 * wait for rtems event
+                 */
+                rtems_event_receive((TERMIOS_RX_PROC_EVENT | 
+                                     TERMIOS_RX_TERMINATE_EVENT),
+                                    RTEMS_EVENT_ANY | RTEMS_WAIT,
+                                    RTEMS_NO_TIMEOUT,
+                                    &the_event);
+                if ((the_event & TERMIOS_RX_TERMINATE_EVENT) != 0) {
+                        tty->rxTaskId = 0;
+                        rtems_task_delete(RTEMS_SELF);
+                }
+                else {
+                        /*
+                         * do something
+                         */
+                        c = tty->device.pollRead(tty->minor);
+                        if (c != EOF) {
+                                /*
+                                 * pollRead did call enqueue on its own
+                                 */
+                                c_buf = c;
+                                rtems_termios_enqueue_raw_characters (
+                                      tty,&c_buf,1);
+                        }
+                }
+        }
+}

cpukit/libcsupport/src/termios.c

@@ -24 +24 @@
 #include <termios.h>
 #include <unistd.h>
+#include <sys/ttycom.h>
+
+#include "termiostypes.h"
 
 /*
@@ -61 +64 @@
 #define RAW_OUTPUT_BUFFER_SIZE  64
 
-/*
- * Variables associated with each termios instance.
- * One structure for each hardware I/O device.
- */
-struct rtems_termios_tty {
-        /*
-         * Linked-list of active TERMIOS devices
-         */
-        struct rtems_termios_tty        *forw;
-        struct rtems_termios_tty        *back;
-
-        /*
-         * How many times has this device been opened
-         */
-        int             refcount;
-
-        /*
-         * This device
-         */
-        rtems_device_major_number       major;
-        rtems_device_major_number       minor;
-
-        /*
-         * Mutual-exclusion semaphores
-         */
-        rtems_id        isem;
-        rtems_id        osem;
-
-        /*
-         * The canonical (cooked) character buffer
-         */
-        char            cbuf[CBUFSIZE];
-        int             ccount;
-        int             cindex;
-
-        /*
-         * Keep track of cursor (printhead) position
-         */
-        int             column;
-        int             read_start_column;
-
-        /*
-         * The ioctl settings
-         */
-        struct termios  termios;
-        rtems_interval  vtimeTicks;
-
-        /*
-         * Raw input character buffer
-         */
-        volatile char           rawInBuf[RAW_INPUT_BUFFER_SIZE];
-        volatile unsigned int   rawInBufHead;
-        volatile unsigned int   rawInBufTail;
-        rtems_id                rawInBufSemaphore;
-        rtems_unsigned32        rawInBufSemaphoreOptions;
-        rtems_interval          rawInBufSemaphoreTimeout;
-        rtems_interval          rawInBufSemaphoreFirstTimeout;
-        unsigned int            rawInBufDropped;        /* Statistics */
-
-        /*
-         * Raw output character buffer
-         */
-        volatile char           rawOutBuf[RAW_OUTPUT_BUFFER_SIZE];
-        volatile unsigned int   rawOutBufHead;
-        volatile unsigned int   rawOutBufTail;
-        rtems_id                rawOutBufSemaphore;
-        volatile enum {rob_idle, rob_busy, rob_wait }   rawOutBufState;
-
-        /*
-         * Callbacks to device-specific routines
-         */
-        rtems_termios_callbacks device;
-        volatile unsigned int   flow_ctrl;
-        unsigned int            lowwater,highwater;
-};
-
 /* fields for "flow_ctrl" status */
 #define FL_IREQXOF 1        /* input queue requests stop of incoming data */
@@ -149 +76 @@
 #define FL_MDXOF   0x400    /* output controlled with XON/XOFF protocol   */
 
+#define NODISC(n) \
+        { NULL, NULL,   NULL,   NULL, \
+          NULL, NULL,   NULL,   NULL }
+/*
+ * FIXME: change linesw entries consistant with linesw entry usage...
+ */
+struct  linesw linesw[MAXLDISC] =
+{
+        NODISC(0),              /* 0- termios-built-in */
+        NODISC(1),              /* 1- defunct */
+        NODISC(2),              /* 2- NTTYDISC */
+        NODISC(3),              /* TABLDISC */
+        NODISC(4),              /* SLIPDISC */
+        NODISC(5),              /* PPPDISC */
+        NODISC(6),              /* loadable */
+        NODISC(7),              /* loadable */
+};
+
+int     nlinesw = sizeof (linesw) / sizeof (linesw[0]);
+
 extern struct rtems_termios_tty *rtems_termios_ttyHead;
 extern struct rtems_termios_tty *rtems_termios_ttyTail;
 extern rtems_id rtems_termios_ttyMutex;
+
+static rtems_task rtems_termios_rxdaemon(rtems_task_argument argument);
+static rtems_task rtems_termios_txdaemon(rtems_task_argument argument);
+/*
+ * some constants for I/O daemon task creation
+ */
+#define TERMIOS_TXTASK_PRIO 10
+#define TERMIOS_RXTASK_PRIO 9
+#define TERMIOS_TXTASK_STACKSIZE 1024
+#define TERMIOS_RXTASK_STACKSIZE 1024
+/*
+ * some events to be sent to the I/O tasks
+ */
+#define TERMIOS_TX_START_EVENT     RTEMS_EVENT_1
+#define TERMIOS_TX_TERMINATE_EVENT RTEMS_EVENT_0
+
+#define TERMIOS_RX_PROC_EVENT      RTEMS_EVENT_1
+#define TERMIOS_RX_TERMINATE_EVENT RTEMS_EVENT_0
 
 /*
@@ -171 +136 @@
          * See if the device has already been opened
          */
-        sc = rtems_semaphore_obtain (rtems_termios_ttyMutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
+        sc = rtems_semaphore_obtain (rtems_termios_ttyMutex,
+                                     RTEMS_WAIT, RTEMS_NO_TIMEOUT);
         if (sc != RTEMS_SUCCESSFUL)
                 return sc;
@@ -189 +155 @@
                         return RTEMS_NO_MEMORY;
                 }
+                /*
+                 * allocate raw input buffer
+                 */
+                tty->rawInBuf.Size = RAW_INPUT_BUFFER_SIZE;
+                tty->rawInBuf.theBuf = malloc (tty->rawInBuf.Size);
+                if (tty->rawInBuf.theBuf == NULL) {
+                        free(tty);
+                        rtems_semaphore_release (rtems_termios_ttyMutex);
+                        return RTEMS_NO_MEMORY;
+                }
+                /*
+                 * allocate raw output buffer
+                 */
+                tty->rawOutBuf.Size = RAW_OUTPUT_BUFFER_SIZE;
+                tty->rawOutBuf.theBuf = malloc (tty->rawOutBuf.Size);
+                if (tty->rawInBuf.theBuf == NULL) {
+                        free((void *)(tty->rawInBuf.theBuf));
+                        free(tty);
+                        rtems_semaphore_release (rtems_termios_ttyMutex);
+                        return RTEMS_NO_MEMORY;
+                }
+                /*
+                 * allocate cooked buffer
+                 */
+                tty->cbuf  = malloc (CBUFSIZE);
+                if (tty->cbuf == NULL) {
+                        free((void *)(tty->rawOutBuf.theBuf));
+                        free((void *)(tty->rawInBuf.theBuf));
+                        free(tty);
+                        rtems_semaphore_release (rtems_termios_ttyMutex);
+                        return RTEMS_NO_MEMORY;
+                }
+                /*
+                 * link tty
+                 */
                 if (rtems_termios_ttyHead)
                         rtems_termios_ttyHead->back = tty;
@@ -222 +223 @@
                         RTEMS_SIMPLE_BINARY_SEMAPHORE | RTEMS_FIFO,
                         RTEMS_NO_PRIORITY,
-                        &tty->rawOutBufSemaphore);
+                        &tty->rawOutBuf.Semaphore);
                 if (sc != RTEMS_SUCCESSFUL)
                         rtems_fatal_error_occurred (sc);
@@ -231 +232 @@
                  */
                 tty->device = *callbacks;
-                if (!tty->device.pollRead) {
+
+                /*
+                 * Create I/O tasks
+                 */
+                if (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN) {
+                        sc = rtems_task_create (
+                                   rtems_build_name ('T', 'x', 'T', c),
+                                   TERMIOS_TXTASK_PRIO,
+                                   TERMIOS_TXTASK_STACKSIZE,
+                                   RTEMS_NO_PREEMPT | RTEMS_NO_TIMESLICE | 
+                                   RTEMS_NO_ASR,
+                                   RTEMS_NO_FLOATING_POINT | RTEMS_LOCAL,
+                                   &tty->txTaskId);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                        sc = rtems_task_create (
+                                   rtems_build_name ('R', 'x', 'T', c),
+                                   TERMIOS_RXTASK_PRIO,
+                                   TERMIOS_RXTASK_STACKSIZE,
+                                   RTEMS_NO_PREEMPT | RTEMS_NO_TIMESLICE | 
+                                   RTEMS_NO_ASR,
+                                   RTEMS_NO_FLOATING_POINT | RTEMS_LOCAL,
+                                   &tty->rxTaskId);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                                
+                }
+                if ((tty->device.pollRead == NULL) ||
+                    (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN)){
                         sc = rtems_semaphore_create (
                                 rtems_build_name ('T', 'R', 'r', c),
@@ -237 +266 @@
                                 RTEMS_COUNTING_SEMAPHORE | RTEMS_PRIORITY,
                                 RTEMS_NO_PRIORITY,
-                                &tty->rawInBufSemaphore);
+                                &tty->rawInBuf.Semaphore);
                         if (sc != RTEMS_SUCCESSFUL)
                                 rtems_fatal_error_occurred (sc);
@@ -270 +299 @@
                  * set low/highwater mark for XON/XOFF support
                  */
-                tty->lowwater  = RAW_INPUT_BUFFER_SIZE * 1/2;
-                tty->highwater = RAW_INPUT_BUFFER_SIZE * 3/4;
+                tty->lowwater  = tty->rawInBuf.Size * 1/2;
+                tty->highwater = tty->rawInBuf.Size * 3/4;
                 /*
                  * Bump name characer
@@ -280 +309 @@
         }
         args->iop->data1 = tty;
-        if (!tty->refcount++ && tty->device.firstOpen)
+        if (!tty->refcount++) {
+          if (tty->device.firstOpen)
                 (*tty->device.firstOpen)(major, minor, arg);
+          /*
+           * start I/O tasks, if needed
+           */
+          if (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN) {
+            sc = rtems_task_start(tty->rxTaskId,
+                                  rtems_termios_rxdaemon,
+                                  (rtems_task_argument)tty);
+            if (sc != RTEMS_SUCCESSFUL)
+              rtems_fatal_error_occurred (sc);
+            
+            sc = rtems_task_start(tty->txTaskId,
+                                  rtems_termios_txdaemon,
+                                  (rtems_task_argument)tty);
+            if (sc != RTEMS_SUCCESSFUL)
+              rtems_fatal_error_occurred (sc);
+          }
+        }
         rtems_semaphore_release (rtems_termios_ttyMutex);
         return RTEMS_SUCCESSFUL;
@@ -295 +342 @@
         rtems_status_code sc;
 
-        if (tty->device.outputUsesInterrupts) {
+        if (tty->device.outputUsesInterrupts != TERMIOS_POLLED) {
                 rtems_interrupt_disable (level);
-                while (tty->rawOutBufTail != tty->rawOutBufHead) {
+                while (tty->rawOutBuf.Tail != tty->rawOutBuf.Head) {
                         tty->rawOutBufState = rob_wait;
                         rtems_interrupt_enable (level);
-                        sc = rtems_semaphore_obtain (tty->rawOutBufSemaphore,
+                        sc = rtems_semaphore_obtain (tty->rawOutBuf.Semaphore,
                                                         RTEMS_WAIT,
                                                         RTEMS_NO_TIMEOUT);
@@ -322 +369 @@
                 rtems_fatal_error_occurred (sc);
         if (--tty->refcount == 0) {
-                drainOutput (tty);
+                if (linesw[tty->t_line].l_close != NULL) {
+                        /*
+                         * call discipline-specific close
+                         */
+                        sc = linesw[tty->t_line].l_close(tty);
+                }
+                else {
+                        /*
+                         * default: just flush output buffer
+                         */
+                        drainOutput (tty);
+                }
+          
+                if (tty->device.outputUsesInterrupts 
+                    == TERMIOS_TASK_DRIVEN) {
+                        /*
+                         * send "terminate" to I/O tasks
+                         */
+                        sc = rtems_event_send(
+                                  tty->rxTaskId,
+                                  TERMIOS_RX_TERMINATE_EVENT);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                        sc = rtems_event_send(
+                                  tty->txTaskId,
+                                  TERMIOS_TX_TERMINATE_EVENT);
+                        if (sc != RTEMS_SUCCESSFUL)
+                                rtems_fatal_error_occurred (sc);
+                }
                 if (tty->device.lastClose)
                          (*tty->device.lastClose)(tty->major, tty->minor, arg);
@@ -335 +410 @@
                 rtems_semaphore_delete (tty->isem);
                 rtems_semaphore_delete (tty->osem);
-                rtems_semaphore_delete (tty->rawOutBufSemaphore);
-                if (!tty->device.pollRead)
-                        rtems_semaphore_delete (tty->rawInBufSemaphore);
+                rtems_semaphore_delete (tty->rawOutBuf.Semaphore);
+                if ((tty->device.pollRead == NULL) ||
+                    (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN))
+                        rtems_semaphore_delete (tty->rawInBuf.Semaphore);
                 free (tty);
         }
@@ -367 +443 @@
         /* if chars available, call write function... */
         (*tty->device.write)(tty->minor,
-                             (char *)&tty->rawOutBuf[tty->rawOutBufTail], 1);
+                     (char *)&tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail],1);
       }
       /* reenable interrupts */
@@ -428 +504 @@
         switch (args->command) {
         default:
-                sc = RTEMS_INVALID_NUMBER;
+                if (linesw[tty->t_line].l_ioctl != NULL) {
+                        sc = linesw[tty->t_line].l_ioctl(tty,args);
+                }
+                else {
+                        sc = RTEMS_INVALID_NUMBER;
+                }
                 break;
 
@@ -477 +558 @@
                 break;
 
+                /*
+                 * FIXME: add various ioctl code handlers
+                 */
+
+#if 1 /* FIXME */
+        case TIOCSETD:
+                /*
+                 * close old line discipline
+                 */
+                if (linesw[tty->t_line].l_close != NULL) {
+                        sc = linesw[tty->t_line].l_close(tty);
+                }
+                tty->t_line=*(int*)(args->buffer);
+                tty->t_sc = NULL; /* ensure that no more valid data */
+                /*
+                 * open new line discipline
+                 */
+                if (linesw[tty->t_line].l_open != NULL) {
+                        sc = linesw[tty->t_line].l_open(tty);
+                }
+                break;
+        case TIOCGETD:  
+                *(int*)(args->buffer)=tty->t_line;
+                break;          
+#endif
         case FIONREAD:
                 /* Half guess that this is the right operation */
@@ -490 +596 @@
  * Send characters to device-specific code
  */
-static void
-osend (const char *buf, int len, struct rtems_termios_tty *tty)
+void
+rtems_termios_puts (const char *buf, int len, struct rtems_termios_tty *tty)
 {
         unsigned int newHead;
@@ -497 +603 @@
         rtems_status_code sc;
 
-        if (!tty->device.outputUsesInterrupts) {
+        if (tty->device.outputUsesInterrupts == TERMIOS_POLLED) {
                 (*tty->device.write)(tty->minor, buf, len);
                 return;
         }
-        newHead = tty->rawOutBufHead;
+        newHead = tty->rawOutBuf.Head;
         while (len) {
                 /*
@@ -515 +621 @@
                  * with interrupts enabled.
                  */
-                newHead = (newHead + 1) % RAW_OUTPUT_BUFFER_SIZE;
+                newHead = (newHead + 1) % tty->rawOutBuf.Size;
                 rtems_interrupt_disable (level);
-                while (newHead == tty->rawOutBufTail) {
+                while (newHead == tty->rawOutBuf.Tail) {
                         tty->rawOutBufState = rob_wait;
                         rtems_interrupt_enable (level);
-                        sc = rtems_semaphore_obtain (tty->rawOutBufSemaphore,
+                        sc = rtems_semaphore_obtain (tty->rawOutBuf.Semaphore,
                                                         RTEMS_WAIT,
                                                         RTEMS_NO_TIMEOUT);
@@ -527 +633 @@
                         rtems_interrupt_disable (level);
                 }
-                tty->rawOutBuf[tty->rawOutBufHead] = *buf++;
-                tty->rawOutBufHead = newHead;
+                tty->rawOutBuf.theBuf[tty->rawOutBuf.Head] = *buf++;
+                tty->rawOutBuf.Head = newHead;
                 if (tty->rawOutBufState == rob_idle) {
                   /* check, whether XOFF has been received */
                   if (!(tty->flow_ctrl & FL_ORCVXOF)) {
                     (*tty->device.write)(tty->minor,
-                                (char *)&tty->rawOutBuf[tty->rawOutBufTail],1);
+                        (char *)&tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail],1);
                   }
                   else {
@@ -560 +666 @@
                                 tty->column = 0;
                         if (tty->termios.c_oflag & ONLCR) {
-                                osend ("\r", 1, tty);
+                                rtems_termios_puts ("\r", 1, tty);
                                 tty->column = 0;
                         }
@@ -581 +687 @@
                         if ((tty->termios.c_oflag & TABDLY) == XTABS) {
                                 tty->column += i;
-                                osend ( "        ",  i, tty);
+                                rtems_termios_puts ( "        ",  i, tty);
                                 return;
                         }
@@ -600 +706 @@
                 }
         }
-        osend (&c, 1, tty);
+        rtems_termios_puts (&c, 1, tty);
 }
 
@@ -613 +719 @@
         if (sc != RTEMS_SUCCESSFUL)
                 return sc;
+        if (linesw[tty->t_line].l_write != NULL) {
+                sc = linesw[tty->t_line].l_write(tty,args);
+                rtems_semaphore_release (tty->osem);
+                return sc;
+        }
         if (tty->termios.c_oflag & OPOST) {
                 unsigned32 count = args->count;
@@ -621 +732 @@
         }
         else {
-                osend (args->buffer, args->count, tty);
+                rtems_termios_puts (args->buffer, args->count, tty);
                 args->bytes_moved = args->count;
         }
@@ -639 +750 @@
                 echobuf[0] = '^';
                 echobuf[1] = c ^ 0x40;
-                osend (echobuf, 2, tty);
+                rtems_termios_puts (echobuf, 2, tty);
                 tty->column += 2;
         }
@@ -702 +813 @@
                                  */
                                 while (tty->column > col) {
-                                        osend ("\b", 1, tty);
+                                        rtems_termios_puts ("\b", 1, tty);
                                         tty->column--;
                                 }
@@ -708 +819 @@
                         else {
                                 if (iscntrl (c) && (tty->termios.c_lflag & ECHOCTL)) {
-                                        osend ("\b \b", 3, tty);
+                                        rtems_termios_puts ("\b \b", 3, tty);
                                         if (tty->column)
                                                 tty->column--;
                                 }
                                 if (!iscntrl (c) || (tty->termios.c_lflag & ECHOCTL)) {
-                                        osend ("\b \b", 3, tty);
+                                        rtems_termios_puts ("\b \b", 3, tty);
                                         if (tty->column)
                                                 tty->column--;
@@ -873 +984 @@
                  * Process characters read from raw queue
                  */
-                while (tty->rawInBufHead != tty->rawInBufTail) {
+                while (tty->rawInBuf.Head != tty->rawInBuf.Tail) {
                         unsigned char c;
                         unsigned int newHead;
 
-                        newHead = (tty->rawInBufHead + 1) % RAW_INPUT_BUFFER_SIZE;
-                        c = tty->rawInBuf[newHead];
-                        tty->rawInBufHead = newHead;
-                        if(((tty->rawInBufTail-newHead+RAW_INPUT_BUFFER_SIZE)
-                            % RAW_INPUT_BUFFER_SIZE) 
+                        newHead = (tty->rawInBuf.Head + 1) % tty->rawInBuf.Size;
+                        c = tty->rawInBuf.theBuf[newHead];
+                        tty->rawInBuf.Head = newHead;
+                        if(((tty->rawInBuf.Tail-newHead+tty->rawInBuf.Size)
+                            % tty->rawInBuf.Size)
                            < tty->lowwater) {
                           tty->flow_ctrl &= ~FL_IREQXOF;
@@ -919 +1030 @@
                  * Wait for characters
                  */
-                sc = rtems_semaphore_obtain (tty->rawInBufSemaphore,
+                sc = rtems_semaphore_obtain (tty->rawInBuf.Semaphore,
                                                 tty->rawInBufSemaphoreOptions,
                                                 timeout);
@@ -940 +1051 @@
         if (sc != RTEMS_SUCCESSFUL)
                 return sc;
+        if (linesw[tty->t_line].l_read != NULL) {
+                sc = linesw[tty->t_line].l_read(tty,args);
+                rtems_semaphore_release (tty->isem);
+                return sc;
+        }
         if (tty->cindex == tty->ccount) {
                 tty->cindex = tty->ccount = 0;
                 tty->read_start_column = tty->column;
-                if (tty->device.pollRead)
+                if (tty->device.pollRead != NULL
+                    && tty->device.outputUsesInterrupts == TERMIOS_POLLED)
                         sc = fillBufferPoll (tty);
                 else
@@ -957 +1074 @@
         rtems_semaphore_release (tty->isem);
         return sc;
+}
+
+/*
+ * signal receive interrupt to rx daemon
+ * NOTE: This routine runs in the context of the
+ *       device receive interrupt handler.
+ */
+void rtems_termios_rxirq_occured(struct rtems_termios_tty *tty)
+{
+        /*
+         * send event to rx daemon task
+         */
+        rtems_event_send(tty->rxTaskId,TERMIOS_RX_PROC_EVENT);
 }
 
@@ -974 +1104 @@
         boolean flow_rcv = FALSE; /* TRUE, if flow control char received */
         rtems_interrupt_level level;
+
+        if (linesw[tty->t_line].l_rint != NULL) {
+          while (len--) {
+            c = *buf++;
+            linesw[tty->t_line].l_rint(c,tty);
+          }
+          return 0;
+        }
 
         while (len--) {
@@ -1011 +1149 @@
               /* if chars available, call write function... */
                 (*tty->device.write)(tty->minor,
-                                     (char *)&tty->rawOutBuf[tty->rawOutBufTail], 1);
+                     (char *)&tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail], 1);
               }
               /* reenable interrupts */
@@ -1018 +1156 @@
           }     
           else {
-                newTail = (tty->rawInBufTail + 1) % RAW_INPUT_BUFFER_SIZE;
+                newTail = (tty->rawInBuf.Tail + 1) % tty->rawInBuf.Size;
                 /* if chars_in_buffer > highwater                */
                 rtems_interrupt_disable(level);
-                if ((((newTail - tty->rawInBufHead + RAW_INPUT_BUFFER_SIZE) 
-                      % RAW_INPUT_BUFFER_SIZE)
+                if ((((newTail - tty->rawInBuf.Head + tty->rawInBuf.Size)
+                      % tty->rawInBuf.Size)
                      > tty->highwater) && 
                     !(tty->flow_ctrl & FL_IREQXOF)) {
@@ -1051 +1189 @@
                 rtems_interrupt_enable(level);
 
-                if (newTail == tty->rawInBufHead) {
+                if (newTail == tty->rawInBuf.Head) {
                         dropped++;
                 }
                 else {
-                        tty->rawInBuf[newTail] = c;
-                        tty->rawInBufTail = newTail;
+                        tty->rawInBuf.theBuf[newTail] = c;
+                        tty->rawInBuf.Tail = newTail;
                 }               
           }
         }
         tty->rawInBufDropped += dropped;
-        rtems_semaphore_release (tty->rawInBufSemaphore);
+        rtems_semaphore_release (tty->rawInBuf.Semaphore);
         return dropped;
+}
+
+/*
+ * in task-driven mode, this function is called in Tx task context
+ * in interrupt-driven mode, this function is called in TxIRQ context
+ */
+int
+rtems_termios_refill_transmitter (struct rtems_termios_tty *tty)
+{
+        unsigned int newTail;
+        int nToSend;
+        rtems_interrupt_level level;
+        int len;
+
+        /* check for XOF/XON to send */
+        if ((tty->flow_ctrl & (FL_MDXOF | FL_IREQXOF | FL_ISNTXOF))
+            == (FL_MDXOF | FL_IREQXOF)) {
+          /* XOFF should be sent now... */
+          (*tty->device.write)(tty->minor, 
+                               &(tty->termios.c_cc[VSTOP]), 1);
+
+          rtems_interrupt_disable(level);
+          tty->t_dqlen--;
+          tty->flow_ctrl |= FL_ISNTXOF;
+          rtems_interrupt_enable(level);
+
+          nToSend = 1;
+        }
+        else if ((tty->flow_ctrl & (FL_IREQXOF | FL_ISNTXOF))
+                 == FL_ISNTXOF) {
+          /* NOTE: send XON even, if no longer in XON/XOFF mode... */
+          /* XON should be sent now... */
+                /*
+                 * FIXME: this .write call will generate another 
+                 * dequeue callback. This will advance the "Tail" in the data
+                 * buffer, although the corresponding data is not yet out!
+                 * Therefore the dequeue "length" should be reduced by 1
+                 */
+          (*tty->device.write)(tty->minor, 
+                               &(tty->termios.c_cc[VSTART]), 1);
+
+          rtems_interrupt_disable(level);
+          tty->t_dqlen--;
+          tty->flow_ctrl &= ~FL_ISNTXOF;
+          rtems_interrupt_enable(level);
+
+          nToSend = 1;
+        }
+        else {
+          if ( tty->rawOutBuf.Head == tty->rawOutBuf.Tail ) {
+            /*
+             * buffer was empty
+             */
+            if (tty->rawOutBufState == rob_wait) {
+              /* 
+               * this should never happen... 
+               */
+              rtems_semaphore_release (tty->rawOutBuf.Semaphore);
+            }
+            return 0;   
+          }
+
+          rtems_interrupt_disable(level);
+          len = tty->t_dqlen;
+          tty->t_dqlen = 0;
+          rtems_interrupt_enable(level);
+
+          newTail = (tty->rawOutBuf.Tail + len) % tty->rawOutBuf.Size;
+          tty->rawOutBuf.Tail = newTail;
+          if (tty->rawOutBufState == rob_wait) {
+            /* 
+             * wake up any pending writer task
+             */
+            rtems_semaphore_release (tty->rawOutBuf.Semaphore);
+          }
+          if (newTail == tty->rawOutBuf.Head) {
+            /*
+             * Buffer has become empty
+             */
+            tty->rawOutBufState = rob_idle;
+            nToSend = 0;
+          }
+          /* check, whether output should stop due to received XOFF */
+          else if ((tty->flow_ctrl & (FL_MDXON | FL_ORCVXOF)) 
+                   ==                (FL_MDXON | FL_ORCVXOF)) {
+                  /* Buffer not empty, but output stops due to XOFF */
+                  /* set flag, that output has been stopped */
+                  rtems_interrupt_disable(level);
+                  tty->flow_ctrl |= FL_OSTOP;
+                  tty->rawOutBufState = rob_busy; /*apm*/
+                  rtems_interrupt_enable(level);
+                  nToSend = 0;
+          }
+          else {
+            /*
+             * Buffer not empty, start tranmitter
+             */
+            if (newTail > tty->rawOutBuf.Head)
+                    nToSend = tty->rawOutBuf.Size - newTail;
+            else
+                    nToSend = tty->rawOutBuf.Head - newTail;
+            /* when flow control XON or XOF, don't send blocks of data     */
+            /* to allow fast reaction on incoming flow ctrl and low latency*/
+            /* for outgoing flow control                                   */
+            if (tty->flow_ctrl & (FL_MDXON | FL_MDXOF)) {
+                    nToSend = 1;
+            }
+            tty->rawOutBufState = rob_busy; /*apm*/
+            (*tty->device.write)(tty->minor, 
+                                 (char *)&tty->rawOutBuf.theBuf[newTail], 
+                                 nToSend);
+          }
+          tty->rawOutBuf.Tail = newTail; /*apm*/
+        }
+        return nToSend;
 }
 
@@ -1078 +1331 @@
 {
         struct rtems_termios_tty *tty = ttyp;
-        unsigned int newTail;
-        int nToSend;
-
-        /* check for XOF/XON to send */
-        if ((tty->flow_ctrl & (FL_MDXOF | FL_IREQXOF | FL_ISNTXOF))
-            == (FL_MDXOF | FL_IREQXOF)) {
-          /* XOFF should be sent now... */
-          (*tty->device.write)(tty->minor, 
-                               &(tty->termios.c_cc[VSTOP]), 1);
-          tty->flow_ctrl |= FL_ISNTXOF;
-          nToSend = 1;
-        }
-        else if ((tty->flow_ctrl & (FL_IREQXOF | FL_ISNTXOF))
-                 == FL_ISNTXOF) {
-          /* NOTE: send XON even, if no longer in XON/XOFF mode... */
-          /* XON should be sent now... */
-          (*tty->device.write)(tty->minor, 
-                               &(tty->termios.c_cc[VSTART]), 1);
-          tty->flow_ctrl &= ~FL_ISNTXOF;
-          nToSend = 1;
+        rtems_status_code sc;
+
+        /*
+         * sum up character count already sent
+         */
+        tty->t_dqlen += len;
+
+        if (tty->device.outputUsesInterrupts == TERMIOS_TASK_DRIVEN) {
+                /*
+                 * send wake up to transmitter task
+                 */
+                sc = rtems_event_send(tty->txTaskId,
+                                      TERMIOS_TX_START_EVENT);
+                if (sc != RTEMS_SUCCESSFUL)
+                        rtems_fatal_error_occurred (sc);
+                return 0; /* nothing to output in IRQ... */
         }
         else {
-          if (tty->rawOutBufState == rob_wait)
-            rtems_semaphore_release (tty->rawOutBufSemaphore);
-          if ( tty->rawOutBufHead == tty->rawOutBufTail ) {
-            tty->rawOutBufState = rob_idle;
-            return 0;   
-          }
-          newTail = (tty->rawOutBufTail + len) % RAW_OUTPUT_BUFFER_SIZE;
-          if (newTail == tty->rawOutBufHead) {
-            /*
-             * Buffer empty
-             */
-            tty->rawOutBufState = rob_idle;
-            nToSend = 0;
-          }
-          /* check, whether output should stop due to received XOFF */
-          else if ((tty->flow_ctrl & (FL_MDXON | FL_ORCVXOF)) 
-                   ==                (FL_MDXON | FL_ORCVXOF)) {
-            /* Buffer not empty, but output stops due to XOFF */
-            /* set flag, that output has been stopped */
-            tty->flow_ctrl |= FL_OSTOP;
-            tty->rawOutBufState = rob_busy;
-            nToSend = 0;
-          }
-          else {
-            /*
-             * Buffer not empty, start tranmitter
-             */
-            if (newTail > tty->rawOutBufHead)
-              nToSend = RAW_OUTPUT_BUFFER_SIZE - newTail;
-            else
-              nToSend = tty->rawOutBufHead - newTail;
-            /* when flow control XON or XOF, don't send blocks of data     */
-            /* to allow fast reaction on incoming flow ctrl and low latency*/
-            /* for outgoing flow control                                   */
-            if (tty->flow_ctrl & (FL_MDXON | FL_MDXOF))
-              nToSend = 1;
-            tty->rawOutBufState = rob_busy;
-            (*tty->device.write)(tty->minor, (char *)&tty->rawOutBuf[newTail], nToSend);
-          }
-          tty->rawOutBufTail = newTail;
-        }
-        return nToSend;
-}
+                return rtems_termios_refill_transmitter(tty);
+        }
+}
+
+/*
+ * this task actually processes any transmit events
+ */
+static rtems_task rtems_termios_txdaemon(rtems_task_argument argument)
+{
+        struct rtems_termios_tty *tty = (struct rtems_termios_tty *)argument;
+        rtems_event_set the_event;
+
+        while (1) {
+                /*
+                 * wait for rtems event
+                 */
+                rtems_event_receive((TERMIOS_TX_START_EVENT | 
+                                     TERMIOS_TX_TERMINATE_EVENT),
+                                    RTEMS_EVENT_ANY | RTEMS_WAIT,
+                                    RTEMS_NO_TIMEOUT,
+                                    &the_event);
+                if ((the_event & TERMIOS_TX_TERMINATE_EVENT) != 0) {
+                        tty->txTaskId = 0;
+                        rtems_task_delete(RTEMS_SELF);
+                }
+                else {
+                        /*
+                         * call any line discipline start function
+                         */
+                        if (linesw[tty->t_line].l_start != NULL) {
+                                linesw[tty->t_line].l_start(tty);
+                        }
+                        /*
+                         * try to push further characters to device
+                         */
+                        rtems_termios_refill_transmitter(tty);
+                }
+        }
+}
+
+/*
+ * this task actually processes any receive events
+ */
+static rtems_task rtems_termios_rxdaemon(rtems_task_argument argument)
+{
+        struct rtems_termios_tty *tty = (struct rtems_termios_tty *)argument;
+        rtems_event_set the_event;
+        int c;
+        char c_buf;
+        while (1) {
+                /*
+                 * wait for rtems event
+                 */
+                rtems_event_receive((TERMIOS_RX_PROC_EVENT | 
+                                     TERMIOS_RX_TERMINATE_EVENT),
+                                    RTEMS_EVENT_ANY | RTEMS_WAIT,
+                                    RTEMS_NO_TIMEOUT,
+                                    &the_event);
+                if ((the_event & TERMIOS_RX_TERMINATE_EVENT) != 0) {
+                        tty->rxTaskId = 0;
+                        rtems_task_delete(RTEMS_SELF);
+                }
+                else {
+                        /*
+                         * do something
+                         */
+                        c = tty->device.pollRead(tty->minor);
+                        if (c != EOF) {
+                                /*
+                                 * pollRead did call enqueue on its own
+                                 */
+                                c_buf = c;
+                                rtems_termios_enqueue_raw_characters (
+                                      tty,&c_buf,1);
+                        }
+                }
+        }
+}