source: rtems/bsps/m68k/mcf5206elite/dev/mcfuart.c @ d7d66d7

/*
 * Generic UART Serial driver for Motorola Coldfire processors
 */

/*
 * Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russian Fed.
 * Author: Victor V. Vengerov <vvv@oktet.ru>
 *
 *  COPYRIGHT (c) 1989-2000.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.org/license/LICENSE.
 */

#include <rtems.h>
#include <termios.h>
#include <rtems/libio.h>
#include "mcf5206/mcfuart.h"

/*
 * int_driven_uart -- mapping between interrupt vector number and
 * UART descriptor structures
 */
static struct {
  mcfuart *uart;
  int      vec;
} int_driven_uart[2];

/* Forward function declarations */
static rtems_isr
mcfuart_interrupt_handler(rtems_vector_number vec);

/*
 * mcfuart_init --
 *     This function verifies the input parameters and perform initialization
 *     of the Motorola Coldfire on-chip UART descriptor structure.
 *
 * PARAMETERS:
 *     uart - pointer to the UART channel descriptor structure
 *     tty - pointer to termios structure
 *     int_driven - interrupt-driven (1) or polled (0) I/O mode
 *     chn - channel number (0/1)
 *     rx_buf - pointer to receive buffer
 *     rx_buf_len - receive buffer length
 *
 * RETURNS:
 *     RTEMS_SUCCESSFUL if all parameters are valid, or error code
 */
rtems_status_code
mcfuart_init(
  mcfuart   *uart,
  void      *tty,
  uint8_t    intvec,
  uint32_t   chn
)
{
  if (uart == NULL)
      return RTEMS_INVALID_ADDRESS;

  if ((chn <= 0) || (chn > MCF5206E_UART_CHANNELS))
      return RTEMS_INVALID_NUMBER;

  uart->chn = chn;
  uart->intvec = intvec;
  uart->tty = tty;

  return RTEMS_SUCCESSFUL;
}

/* mcfuart_set_baudrate --
 *     Program the UART timer to specified baudrate
 *
 * PARAMETERS:
 *     uart - pointer to UART descriptor structure
 *     baud - termios baud rate (B50, B9600, etc...)
 *
 * RETURNS:
 *     none
 */
static void
mcfuart_set_baudrate(mcfuart *uart, speed_t baud)
{
  uint32_t   div;
  uint32_t   rate;

    switch (baud) {
      case B50:     rate = 50; break;
      case B75:     rate = 75; break;
      case B110:    rate = 110; break;
      case B134:    rate = 134; break;
      case B150:    rate = 150; break;
      case B200:    rate = 200; break;
      case B300:    rate = 300; break;
      case B600:    rate = 600; break;
      case B1200:   rate = 1200; break;
      case B2400:   rate = 2400; break;
      case B4800:   rate = 4800; break;
      case B9600:   rate = 9600; break;
      case B19200:  rate = 19200; break;
      case B38400:  rate = 38400; break;
      case B57600:  rate = 57600; break;
#ifdef B115200
      case B115200: rate = 115200; break;
#endif
#ifdef B230400
      case B230400: rate = 230400; break;
#endif
      default:      rate = 9600; break;
    }

  div = SYSTEM_CLOCK_FREQUENCY / (rate * 32);

  *MCF5206E_UBG1(MBAR,uart->chn) = (uint8_t)((div >> 8) & 0xff);
  *MCF5206E_UBG2(MBAR,uart->chn) = (uint8_t)(div & 0xff);
}

/*
 * mcfuart_reset --
 *     This function perform the hardware initialization of Motorola
 *     Coldfire processor on-chip UART controller using parameters
 *     filled by the mcfuart_init function.
 *
 * PARAMETERS:
 *     uart - pointer to UART channel descriptor structure
 *
 * RETURNS:
 *     RTEMS_SUCCESSFUL if channel is initialized successfully, error
 *     code in other case
 *
 * ALGORITHM:
 *     This function in general follows to algorith described in MCF5206e
 *     User's Manual, 12.5 UART Module Initialization Sequence
 */
rtems_status_code mcfuart_reset(mcfuart *uart)
{
  register uint32_t   chn;
  rtems_status_code rc;

  if (uart == NULL)
    return RTEMS_INVALID_ADDRESS;

  chn = uart->chn;

  /* Reset the receiver and transmitter */
  *MCF5206E_UCR(MBAR,chn) = MCF5206E_UCR_MISC_RESET_RX;
  *MCF5206E_UCR(MBAR,chn) = MCF5206E_UCR_MISC_RESET_TX;

  /*
   * Program the vector number for a UART module interrupt, or
   * disable UART interrupts if polled I/O. Enable the desired
   * interrupt sources.
   */
  if (uart->intvec != 0) {
    int_driven_uart[chn - 1].uart = uart;
    int_driven_uart[chn - 1].vec = uart->intvec;
    rc = rtems_interrupt_catch(mcfuart_interrupt_handler, uart->intvec,
                               &uart->old_handler);
    if (rc != RTEMS_SUCCESSFUL)
      return rc;
    *MCF5206E_UIVR(MBAR,chn) = uart->intvec;
    *MCF5206E_UIMR(MBAR,chn) = MCF5206E_UIMR_FFULL;
    *MCF5206E_UACR(MBAR,chn) = MCF5206E_UACR_IEC;
    *MCF5206E_IMR(MBAR) &= ~MCF5206E_INTR_BIT(uart->chn == 1 ?
                                              MCF5206E_INTR_UART_1 :
                                              MCF5206E_INTR_UART_2);
  } else {
    *MCF5206E_UIMR(MBAR,chn) = 0;
  }

  /* Select the receiver and transmitter clock. */
  mcfuart_set_baudrate(uart, B19200); /* dBUG defaults (unfortunately,
                                         it is differ to termios default */
  *MCF5206E_UCSR(MBAR,chn) = MCF5206E_UCSR_RCS_TIMER | MCF5206E_UCSR_TCS_TIMER;

  /* Mode Registers 1,2 - set termios defaults (8N1) */
  *MCF5206E_UCR(MBAR,chn) = MCF5206E_UCR_MISC_RESET_MR;
  *MCF5206E_UMR(MBAR,chn) =
/*      MCF5206E_UMR1_RXRTS | */
      MCF5206E_UMR1_PM_NO_PARITY |
      MCF5206E_UMR1_BC_8;
  *MCF5206E_UMR(MBAR,chn) =
      MCF5206E_UMR2_CM_NORMAL |
/*      MCF5206E_UMR2_TXCTS | */
      MCF5206E_UMR2_SB_1;

  /* Enable Receiver and Transmitter */
  *MCF5206E_UCR(MBAR,chn) = MCF5206E_UCR_MISC_RESET_ERR;
  *MCF5206E_UCR(MBAR,chn) = MCF5206E_UCR_TC_ENABLE;
  *MCF5206E_UCR(MBAR,chn) = MCF5206E_UCR_RC_ENABLE;

  return RTEMS_SUCCESSFUL;
}

/*
 * mcfuart_disable --
 *     This function disable the operations on Motorola Coldfire UART
 *     controller
 *
 * PARAMETERS:
 *     uart - pointer to UART channel descriptor structure
 *
 * RETURNS:
 *     RTEMS_SUCCESSFUL if UART closed successfuly, or error code in
 *     other case
 */
rtems_status_code mcfuart_disable(mcfuart *uart)
{
  rtems_status_code rc;

  *MCF5206E_UCR(MBAR,uart->chn) =
      MCF5206E_UCR_TC_DISABLE |
      MCF5206E_UCR_RC_DISABLE;
  if (uart->intvec != 0) {
      *MCF5206E_IMR(MBAR) |=  MCF5206E_INTR_BIT(uart->chn == 1 ?
                                                MCF5206E_INTR_UART_1 :
                                                MCF5206E_INTR_UART_2);
      rc = rtems_interrupt_catch(uart->old_handler, uart->intvec, NULL);
      int_driven_uart[uart->chn - 1].uart = NULL;
      int_driven_uart[uart->chn - 1].vec = 0;
      if (rc != RTEMS_SUCCESSFUL)
          return rc;
  }
  return RTEMS_SUCCESSFUL;
}

/*
 * mcfuart_set_attributes --
 *     This function parse the termios attributes structure and perform
 *     the appropriate settings in hardware.
 *
 * PARAMETERS:
 *     uart - pointer to the UART descriptor structure
 *     t - pointer to termios parameters
 *
 * RETURNS:
 *     RTEMS_SUCCESSFUL
 */
int mcfuart_set_attributes(mcfuart *uart, const struct termios *t)
{
  int level;
  speed_t baud;
  uint8_t   umr1, umr2;

  baud = cfgetospeed(t);
  umr1 = 0;
  umr2 = MCF5206E_UMR2_CM_NORMAL;

  /* Set flow control */
  if ((t->c_cflag & CRTSCTS) != 0) {
    umr1 |= MCF5206E_UMR1_RXRTS;
    umr2 |= MCF5206E_UMR2_TXCTS;
  }

  /* Set character size */
  switch (t->c_cflag & CSIZE) {
    case CS5: umr1 |= MCF5206E_UMR1_BC_5; break;
    case CS6: umr1 |= MCF5206E_UMR1_BC_6; break;
    case CS7: umr1 |= MCF5206E_UMR1_BC_7; break;
    case CS8: umr1 |= MCF5206E_UMR1_BC_8; break;
  }

  /* Set number of stop bits */
  if ((t->c_cflag & CSTOPB) != 0) {
    if ((t->c_cflag & CSIZE) == CS5) {
      umr2 |= MCF5206E_UMR2_SB5_2;
    } else {
      umr2 |= MCF5206E_UMR2_SB_2;
    }
  } else {
    if ((t->c_cflag & CSIZE) == CS5) {
      umr2 |= MCF5206E_UMR2_SB5_1;
    } else {
      umr2 |= MCF5206E_UMR2_SB_1;
    }
  }

  /* Set parity mode */
  if ((t->c_cflag & PARENB) != 0) {
    if ((t->c_cflag & PARODD) != 0) {
      umr1 |= MCF5206E_UMR1_PM_ODD;
    } else {
      umr1 |= MCF5206E_UMR1_PM_EVEN;
    }
  } else {
    umr1 |= MCF5206E_UMR1_PM_NO_PARITY;
  }

  rtems_interrupt_disable(level);
  *MCF5206E_UCR(MBAR,uart->chn) =
      MCF5206E_UCR_TC_DISABLE | MCF5206E_UCR_RC_DISABLE;
  mcfuart_set_baudrate(uart, baud);
  *MCF5206E_UCR(MBAR,uart->chn) = MCF5206E_UCR_MISC_RESET_MR;
  *MCF5206E_UMR(MBAR,uart->chn) = umr1;
  *MCF5206E_UMR(MBAR,uart->chn) = umr2;
  if ((t->c_cflag & CREAD) != 0) {
    *MCF5206E_UCR(MBAR,uart->chn) =
        MCF5206E_UCR_TC_ENABLE | MCF5206E_UCR_RC_ENABLE;
  } else {
    *MCF5206E_UCR(MBAR,uart->chn) = MCF5206E_UCR_TC_ENABLE;
  }
  rtems_interrupt_enable(level);

  return RTEMS_SUCCESSFUL;
}

/*
 * mcfuart_poll_read --
 *     This function tried to read character from MCF UART and perform
 *     error handling. When parity or framing error occured, return
 *     value dependent on termios input mode flags:
 *         - received character, if IGNPAR == 1
 *         - 0, if IGNPAR == 0 and PARMRK == 0
 *         - 0xff and 0x00 on next poll_read invocation, if IGNPAR == 0 and
 *           PARMRK == 1
 *
 * PARAMETERS:
 *     uart - pointer to UART descriptor structure
 *
 * RETURNS:
 *     code of received character or -1 if no characters received.
 */
int mcfuart_poll_read(mcfuart *uart)
{
  uint8_t   usr;
  int ch;

  if (uart->parerr_mark_flag == true) {
    uart->parerr_mark_flag = false;
    return 0;
  }

  usr = *MCF5206E_USR(MBAR,uart->chn);
  if ((usr & MCF5206E_USR_RXRDY) != 0) {
    if (((usr & (MCF5206E_USR_FE | MCF5206E_USR_PE)) != 0) &&
        !(uart->c_iflag & IGNPAR)) {
      ch = *MCF5206E_URB(MBAR,uart->chn); /* Clear error bits */
      if (uart->c_iflag & PARMRK) {
        uart->parerr_mark_flag = true;
        ch = 0xff;
      } else {
        ch = 0;
      }
    } else {
      ch = *MCF5206E_URB(MBAR,uart->chn);
    }
  } else
    ch = -1;
  return ch;
}

/*
 * mcfuart_poll_write --
 *     This function transmit buffer byte-by-byte in polling mode.
 *
 * PARAMETERS:
 *     uart - pointer to the UART descriptor structure
 *     buf - pointer to transmit buffer
 *     len - transmit buffer length
 *
 * RETURNS:
 *     0
 */
ssize_t mcfuart_poll_write(mcfuart *uart, const char *buf, size_t len)
{
  size_t retval = len;

  while (len--) {
    while ((*MCF5206E_USR(MBAR, uart->chn) & MCF5206E_USR_TXRDY) == 0);
    *MCF5206E_UTB(MBAR, uart->chn) = *buf++;
  }
  return retval;
}

/* mcfuart_interrupt_handler --
 *     UART interrupt handler routine
 *
 * PARAMETERS:
 *     vec - interrupt vector number
 *
 * RETURNS:
 *     none
 */
static rtems_isr mcfuart_interrupt_handler(rtems_vector_number vec)
{
  mcfuart *uart;
  register uint8_t   usr;
  register uint8_t   uisr;
  register int chn;
  register int bp = 0;

  /* Find UART descriptor from vector number */
  if (int_driven_uart[0].vec == vec)
    uart = int_driven_uart[0].uart;
  else if (int_driven_uart[1].vec == vec)
    uart = int_driven_uart[1].uart;
  else
    return;

  chn = uart->chn;

  uisr = *MCF5206E_UISR(MBAR, chn);
  if (uisr & MCF5206E_UISR_DB) {
    *MCF5206E_UCR(MBAR, chn) = MCF5206E_UCR_MISC_RESET_BRK;
  }

  /* Receiving */
  while (1) {
    char buf[32];
    usr = *MCF5206E_USR(MBAR,chn);
    if ((bp < sizeof(buf) - 1) && ((usr & MCF5206E_USR_RXRDY) != 0)) {
      /* Receive character and handle frame/parity errors */
      if (((usr & (MCF5206E_USR_FE | MCF5206E_USR_PE)) != 0) &&
          !(uart->c_iflag & IGNPAR)) {
          if (uart->c_iflag & PARMRK) {
            buf[bp++] = 0xff;
            buf[bp++] = 0x00;
          } else {
            buf[bp++] = 0x00;
          }
      } else {
        buf[bp++] = *MCF5206E_URB(MBAR, chn);
      }

      /* Reset error condition if any errors has been detected */
      if (usr & (MCF5206E_USR_RB | MCF5206E_USR_FE |
                 MCF5206E_USR_PE | MCF5206E_USR_OE)) {
        *MCF5206E_UCR(MBAR, chn) = MCF5206E_UCR_MISC_RESET_ERR;
      }
    } else {
      if (bp != 0)
        rtems_termios_enqueue_raw_characters(uart->tty, buf, bp);
      break;
    }
  }

  /* Transmitting */
  while (1) {
    if ((*MCF5206E_USR(MBAR, chn) & MCF5206E_USR_TXRDY) == 0)
      break;
    if (uart->tx_buf != NULL) {
      if (uart->tx_ptr >= uart->tx_buf_len) {
        register int dequeue = uart->tx_buf_len;

        *MCF5206E_UIMR(MBAR, uart->chn) = MCF5206E_UIMR_FFULL;
        uart->tx_buf = NULL;
        uart->tx_ptr = uart->tx_buf_len = 0;
        rtems_termios_dequeue_characters(uart->tty, dequeue);
      } else {
        *MCF5206E_UTB(MBAR, chn) = uart->tx_buf[uart->tx_ptr++];
      }
    }
    else
      break;
  }
}

/* mcfuart_interrupt_write --
 *     This function initiate transmitting of the buffer in interrupt mode.
 *
 * PARAMETERS:
 *     uart - pointer to the UART descriptor structure
 *     buf - pointer to transmit buffer
 *     len - transmit buffer length
 *
 * RETURNS:
 *     0
 */
ssize_t mcfuart_interrupt_write(
  mcfuart *uart,
  const char *buf,
  size_t len
)
{
  if (len > 0) {
    uart->tx_buf = buf;
    uart->tx_buf_len = len;
    uart->tx_ptr = 0;
    *MCF5206E_UIMR(MBAR, uart->chn) =
            MCF5206E_UIMR_FFULL | MCF5206E_UIMR_TXRDY;
    while (((*MCF5206E_USR(MBAR,uart->chn) & MCF5206E_USR_TXRDY) != 0) &&
           (uart->tx_ptr < uart->tx_buf_len)) {
        *MCF5206E_UTB(MBAR,uart->chn) = uart->tx_buf[uart->tx_ptr++];
    }
  }

  return 0;
}

/* mcfuart_stop_remote_tx --
 *     This function stop data flow from remote device.
 *
 * PARAMETERS:
 *     uart - pointer to the UART descriptor structure
 *
 * RETURNS:
 *     RTEMS_SUCCESSFUL
 */
int mcfuart_stop_remote_tx(mcfuart *uart)
{
  *MCF5206E_UOP0(MBAR, uart->chn) = 1;
  return RTEMS_SUCCESSFUL;
}

/* mcfuart_start_remote_tx --
 *     This function resume data flow from remote device.
 *
 * PARAMETERS:
 *     uart - pointer to the UART descriptor structure
 *
 * RETURNS:
 *     RTEMS_SUCCESSFUL
 */
int mcfuart_start_remote_tx(mcfuart *uart)
{
  *MCF5206E_UOP1(MBAR, uart->chn) = 1;
  return RTEMS_SUCCESSFUL;
}