source: rtems/c/src/lib/libbsp/powerpc/shared/console/uart.c @ 9ca6799

/*
 * This software is Copyright (C) 1998 by T.sqware - all rights limited
 * It is provided in to the public domain "as is", can be freely modified
 * as far as this copyight notice is kept unchanged, but does not imply
 * an endorsement by T.sqware of the product in which it is included.
 */

#include <stdio.h>
#include <bsp.h>
#include <bsp/irq.h>
#include <bsp/uart.h>
#include <rtems/libio.h>
#include <rtems/bspIo.h>
#include <rtems/termiostypes.h>
#include <termios.h>
#include <assert.h>

/*
 * Basic 16552 driver
 */

struct uart_data
{
  unsigned long       ioBase;
  int                 irq;
  int                 hwFlow;
  int                 baud;
  BSP_UartBreakCbRec  breakCallback;
  int                 ioMode;
};

/*
 * Initialization of BSP specific data.
 * The constants are pulled in from a BSP
 * specific file, whereas all of the code
 * in this file is generic and makes no
 * assumptions about addresses, irq vectors
 * etc...
 */

#define UART_UNSUPP ((unsigned long)(-1))

static struct uart_data uart_data[2] = {
        {
#ifdef  BSP_UART_IOBASE_COM1
                BSP_UART_IOBASE_COM1,
                BSP_UART_COM1_IRQ,
#else
                UART_UNSUPP,
                -1,
#endif
        },
        {
#ifdef  BSP_UART_IOBASE_COM2
                BSP_UART_IOBASE_COM2,
                BSP_UART_COM2_IRQ,
#else
                UART_UNSUPP,
                -1,
#endif
        },
};

#define MAX_UARTS (sizeof(uart_data)/sizeof(uart_data[0]))
#define SANITY_CHECK(uart) \
  assert( MAX_UARTS > (unsigned)(uart) && uart_data[(uart)].ioBase != UART_UNSUPP )
/*
 * Macros to read/write register of uart, if configuration is
 * different just rewrite these macros
 */

static inline unsigned char
uread(int uart, unsigned int reg)
{
        return in_8((unsigned char*)(uart_data[uart].ioBase + reg));
}

static inline void
uwrite(int uart, int reg, unsigned int val)
{
        out_8((unsigned char*)(uart_data[uart].ioBase + reg), val);
}


static void
uartError(int uart, void *termiosPrivate)
{
  unsigned char uartStatus, dummy;
  BSP_UartBreakCbProc           h;

  uartStatus = uread(uart, LSR);
  dummy = uread(uart, RBR);

#ifdef UARTDEBUG
  if (uartStatus & OE)
    printk("********* Over run Error **********\n");
  if (uartStatus & PE)
    printk("********* Parity Error   **********\n");
  if (uartStatus & FE)
    printk("********* Framing Error  **********\n");
  if (uartStatus & BI) {
    printk("********* BREAK INTERRUPT *********\n");
#endif
   if ((h=uart_data[uart].breakCallback.handler)) {
     h(uart,
       (dummy<<8)|uartStatus,
       termiosPrivate,
       uart_data[uart].breakCallback.private);
  }
#ifdef UARTDEBUG
  if (uartStatus & ERFIFO)
    printk("********* Error receive Fifo **********\n");
#endif
}

/*
 * Uart initialization, it is hardcoded to 8 bit, no parity,
 * one stop bit, FIFO, things to be changed
 * are baud rate and nad hw flow control,
 * and longest rx fifo setting
 */
void
BSP_uart_init(int uart, int baud, int hwFlow)
{
  unsigned char tmp;

  /* Sanity check */
  SANITY_CHECK(uart);

  /* Make sure any printk activity drains before
   * re-initializing.
   */
  while ( ! (uread(uart, LSR) & TEMT) )
        ;

  switch(baud)
    {
    case 50:
    case 75:
    case 110:
    case 134:
    case 300:
    case 600:
    case 1200:
    case 2400:
    case 9600:
    case 19200:
    case 38400:
    case 57600:
    case 115200:
      break;
    default:
      assert(0);
      return;
    }

  /* Set DLAB bit to 1 */
  uwrite(uart, LCR, DLAB);

  if ( (int)BSPBaseBaud <= 0 ) {
        /* Use current divisor assuming BSPBaseBaud gives us the current speed */
        BSPBaseBaud  = BSPBaseBaud ? -BSPBaseBaud : 9600;
        BSPBaseBaud *= ((uread(uart, DLM) << 8) | uread(uart, DLL));
  }

  /* Set baud rate */
  uwrite(uart, DLL,  (BSPBaseBaud/baud) & 0xff);
  uwrite(uart, DLM,  ((BSPBaseBaud/baud) >> 8) & 0xff);

  /* 8-bit, no parity , 1 stop */
  uwrite(uart, LCR, CHR_8_BITS);

  /* Set DTR, RTS and OUT2 high */
  uwrite(uart, MCR, DTR | RTS | OUT_2);

  /* Enable FIFO */
  uwrite(uart, FCR, FIFO_EN | XMIT_RESET | RCV_RESET | RECEIVE_FIFO_TRIGGER12);

  /* Disable Interrupts */
  uwrite(uart, IER, 0);

  /* Read status to clear them */
  tmp = uread(uart, LSR);
  tmp = uread(uart, RBR);
  tmp = uread(uart, MSR);
  (void) tmp; /* avoid set but not used warning */

  /* Remember state */
  uart_data[uart].hwFlow     = hwFlow;
  uart_data[uart].baud       = baud;
  return;
}

/*
 * Set baud
 */
void
BSP_uart_set_baud(int uart, int baud)
{
  unsigned char mcr, ier;

  /* Sanity check */
  SANITY_CHECK(uart);

  /*
   * This function may be called whenever TERMIOS parameters
   * are changed, so we have to make sure that baud change is
   * indeed required.
   */

  if(baud == uart_data[uart].baud)
    {
      return;
    }

  mcr = uread(uart, MCR);
  ier = uread(uart, IER);

  BSP_uart_init(uart, baud, uart_data[uart].hwFlow);

  uwrite(uart, MCR, mcr);
  uwrite(uart, IER, ier);

  return;
}

/*
 * Enable/disable interrupts
 */
void
BSP_uart_intr_ctrl(int uart, int cmd)
{

  SANITY_CHECK(uart);

  switch(cmd)
    {
    case BSP_UART_INTR_CTRL_DISABLE:
      uwrite(uart, IER, INTERRUPT_DISABLE);
      break;
    case BSP_UART_INTR_CTRL_ENABLE:
      if(uart_data[uart].hwFlow)
        {
          uwrite(uart, IER,
                 (RECEIVE_ENABLE  |
                  TRANSMIT_ENABLE |
                  RECEIVER_LINE_ST_ENABLE |
                  MODEM_ENABLE
                 )
                );
        }
      else
        {
          uwrite(uart, IER,
                 (RECEIVE_ENABLE  |
                  TRANSMIT_ENABLE |
                  RECEIVER_LINE_ST_ENABLE
                 )
                );
        }
      break;
    case BSP_UART_INTR_CTRL_TERMIOS:
      if(uart_data[uart].hwFlow)
        {
          uwrite(uart, IER,
                 (RECEIVE_ENABLE  |
                  RECEIVER_LINE_ST_ENABLE |
                  MODEM_ENABLE
                 )
                );
        }
      else
        {
          uwrite(uart, IER,
                 (RECEIVE_ENABLE  |
                  RECEIVER_LINE_ST_ENABLE
                 )
                );
        }
      break;
    case BSP_UART_INTR_CTRL_GDB:
      uwrite(uart, IER, RECEIVE_ENABLE);
      break;
    default:
      assert(0);
      break;
    }

  return;
}

void
BSP_uart_throttle(int uart)
{
  unsigned int mcr;

  SANITY_CHECK(uart);

  if(!uart_data[uart].hwFlow)
    {
      /* Should not happen */
      assert(0);
      return;
    }
  mcr = uread (uart, MCR);
  /* RTS down */
  mcr &= ~RTS;
  uwrite(uart, MCR, mcr);

  return;
}

void
BSP_uart_unthrottle(int uart)
{
  unsigned int mcr;

  SANITY_CHECK(uart);

  if(!uart_data[uart].hwFlow)
    {
      /* Should not happen */
      assert(0);
      return;
    }
  mcr = uread (uart, MCR);
  /* RTS up */
  mcr |= RTS;
  uwrite(uart, MCR, mcr);

  return;
}

/*
 * Status function, -1 if error
 * detected, 0 if no received chars available,
 * 1 if received char available, 2 if break
 * is detected, it will eat break and error
 * chars. It ignores overruns - we cannot do
 * anything about - it execpt count statistics
 * and we are not counting it.
 */
int
BSP_uart_polled_status(int uart)
{
  unsigned char val;

  SANITY_CHECK(uart);

  val = uread(uart, LSR);

  if(val & BI)
    {
      /* BREAK found, eat character */
      uread(uart, RBR);
      return BSP_UART_STATUS_BREAK;
    }

  if((val & (DR | OE | FE)) ==  1)
    {
      /* No error, character present */
      return BSP_UART_STATUS_CHAR;
    }

  if((val & (DR | OE | FE)) == 0)
    {
      /* Nothing */
      return BSP_UART_STATUS_NOCHAR;
    }

  /*
   * Framing or parity error
   * eat character
   */
  uread(uart, RBR);

  return BSP_UART_STATUS_ERROR;
}

/*
 * Polled mode write function
 */
void
BSP_uart_polled_write(int uart, int val)
{
  unsigned char val1;

  /* Sanity check */
  SANITY_CHECK(uart);

  for(;;)
    {
      if((val1=uread(uart, LSR)) & THRE)
        {
          break;
        }
    }

  if(uart_data[uart].hwFlow)
    {
      for(;;)
        {
          if(uread(uart, MSR) & CTS)
            {
              break;
            }
        }
    }

  uwrite(uart, THR, val & 0xff);

  return;
}

void
BSP_output_char_via_serial(const char val)
{
  BSP_uart_polled_write(BSPConsolePort, val);
  if (val == '\n') BSP_uart_polled_write(BSPConsolePort,'\r');
}

/*
 * Polled mode read function
 */
int
BSP_uart_polled_read(int uart)
{
  unsigned char val;

  SANITY_CHECK(uart);

  for(;;)
    {
      if(uread(uart, LSR) & DR)
        {
          break;
        }
    }

  val = uread(uart, RBR);

  return (int)(val & 0xff);
}

unsigned
BSP_poll_char_via_serial()
{
        return BSP_uart_polled_read(BSPConsolePort);
}

static void
uart_noop(const rtems_irq_connect_data *unused)
{
  return;
}

/* note that the IRQ names contain _ISA_ for legacy
 * reasons. They can be any interrupt, depending
 * on the particular BSP...
 */

static int
uart_isr_is_on(const rtems_irq_connect_data *irq)
{
  int uart;

  uart = (irq->name == BSP_UART_COM1_IRQ) ?
                        BSP_UART_COM1 : BSP_UART_COM2;

  return uread(uart,IER);
}

static int
doit(int uart, rtems_irq_hdl handler, int (*p)(const rtems_irq_connect_data*))
{
        rtems_irq_connect_data d={0};
        d.name = uart_data[uart].irq;
        d.off  = d.on = uart_noop;
        d.isOn = uart_isr_is_on;
        d.hdl  = handler;
        return p(&d);
}

int
BSP_uart_install_isr(int uart, rtems_irq_hdl handler)
{
/* Using shared interrupts by default might break things.. the
 * shared IRQ installer uses malloc() and if a BSP had called this
 * during early init it might not work...
 */
#ifdef BSP_UART_USE_SHARED_IRQS
        return doit(uart, handler, BSP_install_rtems_shared_irq_handler);
#else
        return doit(uart, handler, BSP_install_rtems_irq_handler);
#endif
}

int
BSP_uart_remove_isr(int uart, rtems_irq_hdl handler)
{
        return doit(uart, handler, BSP_remove_rtems_irq_handler);
}

/* ================ Termios support  =================*/

static volatile int  termios_stopped_com[2]        = {0,0};
static volatile int  termios_tx_active_com[2]      = {0,0};
static void*         termios_ttyp_com[2]           = {NULL,NULL};
static char          termios_tx_hold_com[2]        = {0,0};
static volatile char termios_tx_hold_valid_com[2]  = {0,0};

/*
 * Set channel parameters
 */
void
BSP_uart_termios_set(int uart, void *p)
{
  struct rtems_termios_tty *ttyp = p;
  unsigned char val;
  SANITY_CHECK(uart);

  if(uart_data[uart].hwFlow)
    {
      val = uread(uart, MSR);

      termios_stopped_com[uart]    = (val & CTS) ? 0 : 1;
    }
  else
  {
      termios_stopped_com[uart] = 0;
  }
  termios_tx_active_com[uart]      = 0;
  termios_ttyp_com[uart]           = ttyp;
  termios_tx_hold_com[uart]        = 0;
  termios_tx_hold_valid_com[uart]  = 0;

  uart_data[uart].ioMode           = ttyp->device.outputUsesInterrupts;

  return;
}

ssize_t
BSP_uart_termios_write_polled(int minor, const char *buf, size_t len)
{
  int uart=minor;       /* could differ, theoretically */
  int nwrite;
  const char *b = buf;

  for (nwrite=0 ; nwrite < len ; nwrite++) {
    BSP_uart_polled_write(uart, *b++);
  }
  return nwrite;
}

ssize_t
BSP_uart_termios_write_com(int minor, const char *buf, size_t len)
{
  int uart=minor;       /* could differ, theoretically */

  if(len <= 0)
    {
      return 0;
    }

  /* If the TX buffer is busy - something is royally screwed up */
  /*   assert((uread(BSP_UART_COM1, LSR) & THRE) != 0); */

  if(termios_stopped_com[uart])
    {
      /* CTS low */
      termios_tx_hold_com[uart]       = *buf;
      termios_tx_hold_valid_com[uart] = 1;
      return 0;
    }

  /* Write character */
  uwrite(uart, THR, *buf & 0xff);

  /* Enable interrupts if necessary */
  if(!termios_tx_active_com[uart] && uart_data[uart].hwFlow)
    {
      termios_tx_active_com[uart] = 1;
      uwrite(uart, IER,
             (RECEIVE_ENABLE  |
              TRANSMIT_ENABLE |
              RECEIVER_LINE_ST_ENABLE |
              MODEM_ENABLE
             )
            );
    }
  else if(!termios_tx_active_com[uart])
    {
      termios_tx_active_com[uart] = 1;
      uwrite(uart, IER,
             (RECEIVE_ENABLE  |
              TRANSMIT_ENABLE |
              RECEIVER_LINE_ST_ENABLE
             )
            );
    }

  return 0;
}

int
BSP_uart_termios_read_com(int uart)
{
  int     off = (int)0;
  char    buf[40];
  rtems_interrupt_level l;

  /* read bytes */
  while (( off < sizeof(buf) ) && ( uread(uart, LSR) & DR )) {
    buf[off++] = uread(uart, RBR);
  }

  /* write out data */
  if ( off > 0 ) {
    rtems_termios_enqueue_raw_characters(termios_ttyp_com[uart], buf, off);
  }

  /* enable receive interrupts */
  rtems_interrupt_disable(l);
  uwrite(uart, IER, uread(uart, IER) | (RECEIVE_ENABLE | RECEIVER_LINE_ST_ENABLE));
  rtems_interrupt_enable(l);

  return ( EOF );
}

static void
BSP_uart_termios_isr_com(int uart)
{
  unsigned char buf[40];
  unsigned char val, ier;
  int      off, ret, vect;

  off = 0;

  for(;;)
    {
      vect = uread(uart, IIR) & 0xf;

      switch(vect)
        {
        case MODEM_STATUS :
          val = uread(uart, MSR);
          if(uart_data[uart].hwFlow)
            {
              if(val & CTS)
                {
                  /* CTS high */
                  termios_stopped_com[uart] = 0;
                  if(termios_tx_hold_valid_com[uart])
                    {
                      termios_tx_hold_valid_com[uart] = 0;
                      BSP_uart_termios_write_com(uart, &termios_tx_hold_com[uart],
                                                    1);
                    }
                }
              else
                {
                  /* CTS low */
                  termios_stopped_com[uart] = 1;
                }
            }
          break;
        case NO_MORE_INTR :
          /* No more interrupts */
          if(off != 0)
            {
              /* Update rx buffer */
              rtems_termios_enqueue_raw_characters(termios_ttyp_com[uart],
                                                   (char *)buf,
                                                   off);
            }
          return;
        case TRANSMITTER_HODING_REGISTER_EMPTY :
          /*
           * TX holding empty: we have to disable these interrupts
           * if there is nothing more to send.
           */

          ret = rtems_termios_dequeue_characters(termios_ttyp_com[uart], 1);

          /* If nothing else to send disable interrupts */
          if(ret == 0 && uart_data[uart].hwFlow)
            {
              uwrite(uart, IER,
                     (RECEIVE_ENABLE  |
                      RECEIVER_LINE_ST_ENABLE |
                      MODEM_ENABLE
                     )
                    );
              termios_tx_active_com[uart] = 0;
            }
          else if(ret == 0)
            {
              uwrite(uart, IER,
                     (RECEIVE_ENABLE  |
                      RECEIVER_LINE_ST_ENABLE
                     )
                    );
              termios_tx_active_com[uart] = 0;
            }
          break;
        case RECEIVER_DATA_AVAIL :
        case CHARACTER_TIMEOUT_INDICATION:
          if ( uart_data[uart].ioMode == TERMIOS_TASK_DRIVEN )
            {
              /* ensure interrupts are enabled */
              if ( (ier = uread(uart,IER)) & RECEIVE_ENABLE )
                {
                   /* disable interrupts and notify termios */
                   ier &= ~(RECEIVE_ENABLE | RECEIVER_LINE_ST_ENABLE);
                   uwrite(uart, IER, ier);
                   rtems_termios_rxirq_occured(termios_ttyp_com[uart]);
                }
            }
          else
            {
              /* RX data ready */
              assert(off < sizeof(buf));
              while ( off < sizeof(buf) && ( DR & uread(uart, LSR) ) )
                buf[off++] = uread(uart, RBR);
            }
          break;
        case RECEIVER_ERROR:
          /* RX error: eat character */
           uartError(uart, termios_ttyp_com[uart]);
          break;
        default:
          /* Should not happen */
          assert(0);
          return;
        }
    }
}

/*
 * XXX - Note that this can now be one isr with the uart
 *       passed as the parameter.
 */
void
BSP_uart_termios_isr_com1(void *unused)
{
        BSP_uart_termios_isr_com(BSP_UART_COM1);
}

void
BSP_uart_termios_isr_com2(void *unused)
{
        BSP_uart_termios_isr_com(BSP_UART_COM2);
}

/* retrieve 'break' handler info */
int
BSP_uart_get_break_cb(int uart, rtems_libio_ioctl_args_t *arg)
{
BSP_UartBreakCb cb=arg->buffer;
unsigned long flags;
        SANITY_CHECK(uart);
        rtems_interrupt_disable(flags);
                *cb = uart_data[uart].breakCallback;
        rtems_interrupt_enable(flags);
        arg->ioctl_return=0;
        return RTEMS_SUCCESSFUL;
}

/* install 'break' handler */
int
BSP_uart_set_break_cb(int uart, rtems_libio_ioctl_args_t *arg)
{
BSP_UartBreakCb cb=arg->buffer;
unsigned long flags;
        SANITY_CHECK(uart);
        rtems_interrupt_disable(flags);
                uart_data[uart].breakCallback = *cb;
        rtems_interrupt_enable(flags);
        arg->ioctl_return=0;
        return RTEMS_SUCCESSFUL;
}