source: rtems/c/src/lib/libcpu/powerpc/ppc403/tty_drv/tty_drv.c @ 73b5bd5d

/*
 * This file contains the PowerPC 405GP tty driver.
 *
 * Derived from /c/src/lib/libbsp/i386/shared/comm/tty_drv.c
 *
 * Modifications to PPC405GP by Dennis Ehlin 
 *
 */

#define NO_BSP_INIT

#include <stdio.h>
#include <rtems/termiostypes.h>
#include <termios.h>
#include <assert.h>
#include <rtems.h>
#include <rtems/libio.h>
#include "../ictrl/ictrl.h"
#include <stdlib.h>                                     /* for atexit() */


struct ttyasync {
/*---------------------------------------------------------------------------+
| Data Register.
+---------------------------------------------------------------------------*/
  unsigned char RBR;    /* 0x00 */
  #define THR   RBR
/*---------------------------------------------------------------------------+
| Interrupt registers
+---------------------------------------------------------------------------*/
  unsigned char IER;    /* Interrupt Enable Register 0x01 */
  #define IER_RCV                0x01
  #define IER_XMT                0x02
  #define IER_LS                 0x04
  #define IER_MS                 0x08

  unsigned char ISR;    /* Interrupt Status Register 0x02 */
  #define ISR_MS                 0x00
  #define ISR_nIP                0x01
  #define ISR_Tx                 0x02
  #define ISR_Rx                 0x04
  #define ISR_LS                 0x06
  #define ISR_RxTO               0x0C
  #define ISR_64BFIFO            0x20
  #define ISR_FIFOworks          0x40
  #define ISR_FIFOen             0x80

/*---------------------------------------------------------------------------+
| FIFO Control registers
+---------------------------------------------------------------------------*/
  #define FCR   ISR
  #define FCR_FE                0x01    /* FIFO enable */
  #define FCR_CRF               0x02    /* Clear receive FIFO */
  #define FCR_CTF               0x04    /* Clear transmit FIFO */
  #define FCR_DMA               0x08    /* DMA mode select */
  #define FCR_F64               0x20    /* Enable 64 byte fifo (16750+) */
  #define FCR_RT14              0xC0    /* Set Rx trigger at 14 */
  #define FCR_RT8               0x80    /* Set Rx trigger at 8 */
  #define FCR_RT4               0x40    /* Set Rx trigger at 4 */
  #define FCR_RT1               0x00    /* Set Rx trigger at 1 */

/*---------------------------------------------------------------------------+
| Baud rate divisor registers
+---------------------------------------------------------------------------*/
  #define DLL   RBR
  #define DLM   IER

/*---------------------------------------------------------------------------+
| Alternate function registers
+---------------------------------------------------------------------------*/
  #define AFR   ISR     

/*---------------------------------------------------------------------------+
| Line control Register.
+---------------------------------------------------------------------------*/
  unsigned char LCR;    /* 0x03 */
  #define LCR_WL5                0x00   /* Word length 5 */
  #define LCR_WL6                0x01   /* Word length 6 */
  #define LCR_WL7                0x02   /* Word length 7 */
  #define LCR_WL8                0x03   /* Word length 8 */

  #define LCR_SB1                0x00   /* 1 stop bits */
  #define LCR_SB1_5              0x04   /* 1.5 stop bits , only valid with 5 bit words*/
  #define LCR_SB1_5              0x04   /* 2 stop bits */

  #define LCR_PN                 0x00   /* Parity NONE */
  #define LCR_PE                 0x0C   /* Parity EVEN */
  #define LCR_PO                 0x08   /* Parity ODD */
  #define LCR_PM                 0x28   /* Forced "mark" parity */
  #define LCR_PS                 0x38   /* Forced "space" parity */

  #define LCR_DL                 0x80   /* Enable baudrate latch */

/*---------------------------------------------------------------------------+
| Modem control Register.
+---------------------------------------------------------------------------*/
  unsigned char MCR;    /* 0x04 */
  #define MCR_DTR                0x01
  #define MCR_RTS                0x02
  #define MCR_INT                0x08   /* Enable interrupts */
  #define MCR_LOOP               0x10   /* Loopback mode */

/*---------------------------------------------------------------------------+
| Line status Register.
+---------------------------------------------------------------------------*/
  unsigned char LSR;    /* 0x05 */
  #define LSR_RSR                0x01
  #define LSR_OE                 0x02
  #define LSR_PE                 0x04
  #define LSR_FE                 0x08
  #define LSR_BI                 0x10
  #define LSR_THE                0x20
  #define LSR_TEMT               0x40
  #define LSR_FIE                0x80

/*---------------------------------------------------------------------------+
| Modem status Register.
+---------------------------------------------------------------------------*/
  unsigned char MSR;    /* 0x06 */
  #define MSR_DCTS               0x01
  #define MSR_DDSR               0x02
  #define MSR_TERI               0x04
  #define MSR_DDCD               0x08
  #define MSR_CTS                0x10
  #define MSR_DSR                0x20
  #define MSR_RI                 0x40
  #define MSR_CD                 0x80

/*---------------------------------------------------------------------------+
| Scratch pad Register.
+---------------------------------------------------------------------------*/
  unsigned char SCR;    /* 0x07 */
};


#define TTY0_USE_UART 1 /* 0=UART0 1=UART1 */
#define TTY0_UART_INTERNAL_CLOCK_DIVISOR 16
#define TTY0_USE_INTERRUPT


typedef volatile struct ttyasync *tty0pasync;
static const tty0pasync tty0port = (tty0pasync)(0xEF600300   + (TTY0_USE_UART*0x100));  /* 0xEF600300 - port A,  0xEF600400 - port B */

static void *tty0ttyp;         /* handle for termios */


int tty0_round(double x)
{
  return (int)((int)((x-(int)x)*1000)>500 ? x+1 : x);
}

void 
tty0BaudSet(uint32_t   baudrate)
{
  uint32_t   tmp;

  tmp = tty0_round( (double)rtems_cpu_configuration_get_serial_per_sec() / (baudrate * 16) );

  tty0port->LCR = tty0port->LCR | LCR_DL;

  tty0port->DLL = tmp & 0xff;
  tty0port->DLM = tmp >> 8;

  tty0port->LCR = tty0port->LCR & ~LCR_DL;
}
/*
 * Hardware-dependent portion of tcsetattr().
 */
static int
tty0SetAttributes (int minor, const struct termios *t)
{
  int baud;

  /* FIXME: check c_cflag & CRTSCTS for hardware flowcontrol */
  /* FIXME: check and IMPLEMENT XON/XOFF                     */
  switch (t->c_cflag & CBAUD) {
  default:      baud = -1;      break;
  case B50:     baud = 50;      break;
  case B75:     baud = 75;      break;
  case B110:    baud = 110;     break;
  case B134:    baud = 134;     break;
  case B150:    baud = 150;     break;
  case B200:    baud = 200;     break;
  case B300:    baud = 300;     break;
  case B600:    baud = 600;     break;
  case B1200:   baud = 1200;    break;
  case B1800:   baud = 1800;    break;
  case B2400:   baud = 2400;    break;
  case B4800:   baud = 4800;    break;
  case B9600:   baud = 9600;    break;
  case B19200:  baud = 19200;   break;
  case B38400:  baud = 38400;   break;
  case B57600:  baud = 57600;   break;
  case B115200: baud = 115200;  break;
  case B230400: baud = 230400;  break;
  case B460800: baud = 460800;  break;
  }
  if (baud > 0) {
    tty0BaudSet(baud);
  }
  return 0;
}

static int
tty0PollRead (int minor)
{

  /* Wait for character */
  while ((tty0port->LSR & LSR_RSR)==0);;

  return tty0port->RBR;  
}


static int 
tty0PollWrite(int minor,const char *buf,int len)
{  

  while (len-- > 0) {
    while (!(tty0port->LSR & LSR_THE));;
    tty0port->THR = *buf++;
  }
  return 0;
}

/* ================ Termios support  =================*/
    
static int tty0InterruptWrite (int minor, const char *buf, int len)
{

  if(len <= 0)
    {
      return 0;
    }
 
  /* Write character */
  
  tty0port->THR = (*buf &0xff);
  tty0port->IER |= IER_XMT;     /* always enable tx interrupt */

  return 0;

}

static rtems_isr tty0serial_ISR(rtems_vector_number v)
{
  char buf[128];
  int      off, ret, vect;

  off = 0;

  for(;;)
    {
          vect = tty0port->ISR & 0x0f;
          if(vect & 1) 
          {
                  /* no more interrupts */
          if(off > 0) {
                  /* Update rx buffer */
                  rtems_termios_enqueue_raw_characters(tty0ttyp, buf, off );

                  tty0port->IER |= IER_RCV;     /* always enable rx interrupt */
                 /*rtems_termios_rxirq_occured(tty0ttyp);*/
          }
            return;
          }

        vect = vect & 0xe; /*mask out all except interrupt pending*/
      
    switch(vect)
        {

        case ISR_Tx :
          /* 
           * TX holding empty: we have to disable these interrupts 
           * if there is nothing more to send. 
           */

          /* If nothing else to send disable interrupts */
          ret = rtems_termios_dequeue_characters(tty0ttyp, 1);
         
          if ( ret == 0 ) {
            tty0port->IER &= ~IER_XMT;
          }
                   
          break;
        case ISR_RxTO:
        case ISR_Rx :

              /* disable interrupts and notify termios */
               tty0port->IER &= ~IER_RCV; 

              /* read all bytes in fifo*/
               while (( off < sizeof(buf) ) && (  tty0port->LSR & LSR_RSR )) 
                          {
                                buf[off++] = tty0port->RBR;
                          }

          break;
        case ISR_LS:
          /* RX error: eat character */
          /* printk("********* Error **********\n"); */
          break;
        default:
          /* Should not happen */
          /* printk("error vect=%x",vect); */
          return;
        }
    }

}


/* 
 *
 * deinit TTY0 
 *
 */
void
tty0DeInit(void) 
{
  /*
   * disable interrupts for serial tty0port 
   * set it to state to work with polling boot monitor, if any... 
   */

  /* set up baud rate to original state */
  tty0BaudSet(rtems_cpu_configuration_get_serial_rate());

  tty0port->IER = 0;

}

/* 
 *
 * init SPI 
 *
 */
rtems_status_code 
tty0Initialize(void) 
{
  register unsigned tmp;
  rtems_isr_entry previous_isr; /* this is a dummy */
  unsigned char _ier;
  unsigned char _tmp;

  /*
   * Initialise the serial tty0port 
   */

  /* 
   * Select clock source and set uart internal clock divisor
   */

  asm volatile ("mfdcr %0, 0x0b1" : "=r" (tmp)); /* CPC_CR0 0x0b1 */

  /* UART0 bit 24 0x80, UART1 bit 25 0x40 */
  tmp |= (rtems_cpu_configuration_get_serial_external_clock() ?  (TTY0_USE_UART ? 0x40 : 0x80) : 0);

  tmp |= (rtems_cpu_configuration_get_serial_external_clock() ?  0: ((TTY0_UART_INTERNAL_CLOCK_DIVISOR -1) << 1));

  asm volatile ("mtdcr 0x0b1, %0" : "=r" (tmp) : "0" (tmp)); /* CPC_CR0 0x0b1*/

  /* Disable tty0port interrupts while changing hardware */
  _ier = tty0port->IER;
  tty0port->IER = 0;

  /* set up tty0port control: 8 bit,1 stop,no parity */
  tty0port->LCR = LCR_WL8 | LCR_SB1 | LCR_PN;

  /* set up baud rate */
  tty0BaudSet(rtems_cpu_configuration_get_serial_rate());
 

#ifdef TTY0_USE_INTERRUPT

    /* add rx/tx isr to vector table */

    if (TTY0_USE_UART==0) 
        ictrl_set_vector(tty0serial_ISR,PPC_IRQ_EXT_UART0,&previous_isr);
    else
        ictrl_set_vector(tty0serial_ISR,PPC_IRQ_EXT_UART1,&previous_isr);
    
    /* Enable and clear FIFO */
    tty0port->FCR = FCR_FE | FCR_CRF | FCR_CTF | FCR_RT14;

    /* Read status to clear them */
    _tmp = tty0port->LSR;   
    _tmp = tty0port->RBR;
    _tmp = tty0port->MSR;

    /* Enable recive interrupts, don't enable TxInt yet */
    tty0port->IER=IER_RCV;

#else

    tty0port->IER=_ier;

#endif

  atexit(tty0DeInit);

  return RTEMS_SUCCESSFUL;
}

/*
 ***************
 * BOILERPLATE *
 ***************
 */

/*  console_initialize
 *
 *  This routine initializes the console IO driver.
 *
 *  Input parameters: NONE
 *
 *  Output parameters:  NONE
 *
 *  Return values:
 */

rtems_device_driver tty0_initialize(
  rtems_device_major_number  major,
  rtems_device_minor_number  minor,
  void                      *arg
)
{
  rtems_status_code status;


  /*
   * Set up TERMIOS
   */
  rtems_termios_initialize ();

  /*
   * Do device-specific initialization
   */
   
  /*tty0Initialize ();   Moved this to open instead */
 
  /*
   * Register the device
   */
  status = rtems_io_register_name ("/dev/ttyS0", major, 0);
  if (status != RTEMS_SUCCESSFUL)
    rtems_fatal_error_occurred (status);
  return RTEMS_SUCCESSFUL;
}


/*
 *  Open entry point
 */
 
rtems_device_driver tty0_open(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void                    * arg
)
{
  rtems_status_code sc;

#ifdef TTY0_USE_INTERRUPT

  static const rtems_termios_callbacks intrCallbacks = {
    NULL,               /* firstOpen */
    NULL,               /* lastClose */
    NULL,               /* pollRead */
    tty0InterruptWrite, /* write */
    tty0SetAttributes,  /* setAttributes */
    NULL,               /* stopRemoteTx */
    NULL,               /* startRemoteTx */
    TERMIOS_TASK_DRIVEN /* outputUsesInterrupts */
  };
  rtems_libio_open_close_args_t *args = arg;

    tty0Initialize ();  /* Initalize hardware */

    sc = rtems_termios_open (major, minor, arg, &intrCallbacks);
    tty0ttyp = args->iop->data1;

#else

  static const rtems_termios_callbacks pollCallbacks = {
    NULL,               /* firstOpen */
    NULL,               /* lastClose */
    tty0PollRead,       /* pollRead */
    tty0PollWrite,      /* write */
    tty0SetAttributes,  /* setAttributes */
    NULL,               /* stopRemoteTx */
    NULL,               /* startRemoteTx */
    0                   /* outputUsesInterrupts */
  };

    tty0Initialize ();  /* Initalize hardware */

    sc = rtems_termios_open (major, minor, arg, &pollCallbacks);

#endif

    return sc;
}
 
/*
 *  Close entry point
 */
 
rtems_device_driver tty0_close(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void                    * arg
)
{
  return rtems_termios_close (arg);
}
 
/*
 * read bytes from the serial port. We only have stdin.
 */
 
rtems_device_driver tty0_read(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void                    * arg
)
{
  return rtems_termios_read (arg);
}
 
/*
 * write bytes to the serial port. Stdout and stderr are the same.
 */
 
rtems_device_driver tty0_write(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void                    * arg
)
{
  return rtems_termios_write (arg);
}
 
/*
 *  IO Control entry point
 */
 
rtems_device_driver tty0_control(
  rtems_device_major_number major,
  rtems_device_minor_number minor,
  void                    * arg
)
{
  return rtems_termios_ioctl (arg);
}