rtems/bsps/shared/grlib/uart/apbuart_termios.c

/* SPDX-License-Identifier: BSD-2-Clause */

/*
 *  COPYRIGHT (c) 1989-1998.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  Modified for LEON3 BSP.
 *  COPYRIGHT (c) 2004.
 *  Gaisler Research.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <grlib/apbuart_termios.h>
#include <grlib/apbuart.h>
#include <grlib/io.h>
#include <bsp.h>

static void apbuart_isr( void *arg )
{
  rtems_termios_tty      *tty = arg;
  struct apbuart_context *uart = rtems_termios_get_device_context( tty );
  unsigned int            status;
  char                    data;

  /* Get all received characters */
  while (
    ( status = grlib_load_32( &uart->regs->status ) ) & APBUART_STATUS_DR
  ) {
    /* Data has arrived, get new data */
    data = (char) grlib_load_32( &uart->regs->data );

    /* Tell termios layer about new character */
    rtems_termios_enqueue_raw_characters( tty, &data, 1 );
  }

  if (
    ( status & APBUART_STATUS_TE ) &&
    ( grlib_load_32( &uart->regs->ctrl ) & APBUART_CTRL_TI ) != 0
  ) {
    /* write_interrupt will get called from this function */
    rtems_termios_dequeue_characters( tty, 1 );
  }
}

static void apbuart_write_support(
  rtems_termios_device_context *base,
  const char                   *buf,
  size_t                        len
)
{
  struct apbuart_context *uart = (struct apbuart_context *) base;
  int                     sending;
  uint32_t                ctrl;

  ctrl = grlib_load_32( &uart->regs->ctrl );

  if ( len > 0 ) {
    /* Enable TX interrupt (interrupt is edge-triggered) */
    ctrl |= APBUART_CTRL_TI;

    /* start UART TX, this will result in an interrupt when done */
    grlib_store_32( &uart->regs->data, (uint8_t) *buf );

    sending = 1;
  } else {
    /* No more to send, disable TX interrupts */
    ctrl &= ~APBUART_CTRL_TI;

    /* Tell close that we sent everything */
    sending = 0;
  }

  grlib_store_32( &uart->regs->ctrl, ctrl );
  uart->sending = sending;
}

static void apbuart_write_polled(
  rtems_termios_device_context *base,
  const char                   *buf,
  size_t                        len
)
{
  struct apbuart_context *uart = (struct apbuart_context *) base;
  size_t                  nwrite = 0;

  while ( nwrite < len ) {
    apbuart_outbyte_polled( uart->regs, *buf++ );
    nwrite++;
  }
}

static int apbuart_poll_read( rtems_termios_device_context *base )
{
  struct apbuart_context *uart = (struct apbuart_context *) base;

  return apbuart_inbyte_nonblocking( uart->regs );
}

static bool apbuart_set_attributes(
  rtems_termios_device_context *base,
  const struct termios         *t
)
{
  struct apbuart_context      *uart = (struct apbuart_context *) base;
  rtems_interrupt_lock_context lock_context;
  unsigned int                 scaler;
  unsigned int                 ctrl;
  int                          baud;

  switch ( t->c_cflag & CSIZE ) {
    default:
    case CS5:
    case CS6:
    case CS7:
      /* Hardware doesn't support other than CS8 */
      return false;
    case CS8:
      break;
  }

  rtems_termios_device_lock_acquire( base, &lock_context );

  /* Read out current value */
  ctrl = grlib_load_32( &uart->regs->ctrl );

  switch ( t->c_cflag & ( PARENB | PARODD ) ) {
    case ( PARENB | PARODD ):
      /* Odd parity */
      ctrl |= APBUART_CTRL_PE | APBUART_CTRL_PS;
      break;

    case PARENB:
      /* Even parity */
      ctrl &= ~APBUART_CTRL_PS;
      ctrl |= APBUART_CTRL_PE;
      break;

    default:
    case 0:
    case PARODD:
      /* No Parity */
      ctrl &= ~( APBUART_CTRL_PS | APBUART_CTRL_PE );
  }

  if ( !( t->c_cflag & CLOCAL ) ) {
    ctrl |= APBUART_CTRL_FL;
  } else {
    ctrl &= ~APBUART_CTRL_FL;
  }

  /* Update new settings */
  grlib_store_32( &uart->regs->ctrl, ctrl );

  rtems_termios_device_lock_release( base, &lock_context );

  /* Baud rate */
  baud = rtems_termios_baud_to_number( t->c_ospeed );
  if ( baud > 0 ) {
    /* Calculate Baud rate generator "scaler" number */
    scaler = ( ( ( uart->freq_hz * 10 ) / ( baud * 8 ) ) - 5 ) / 10;

    /* Set new baud rate by setting scaler */
    grlib_store_32( &uart->regs->scaler, scaler );
  }

  return true;
}

static void apbuart_set_best_baud(
  const struct apbuart_context *uart,
  struct termios               *term
)
{
  uint32_t baud = ( uart->freq_hz * 10 ) /
                  ( ( grlib_load_32( &uart->regs->scaler ) * 10 + 5 ) * 8 );

  rtems_termios_set_best_baud( term, baud );
}

static bool apbuart_first_open_polled(
  rtems_termios_tty             *tty,
  rtems_termios_device_context  *base,
  struct termios                *term,
  rtems_libio_open_close_args_t *args
)
{
  (void) tty;
  (void) args;

  struct apbuart_context *uart = (struct apbuart_context *) base;
  uint32_t                ctrl;

  apbuart_set_best_baud( uart, term );

  /* Initialize UART on opening */
  ctrl = grlib_load_32( &uart->regs->ctrl );
  ctrl |= APBUART_CTRL_RE | APBUART_CTRL_TE;
  grlib_store_32( &uart->regs->ctrl, ctrl );
  grlib_store_32( &uart->regs->status, 0 );

  return true;
}

static bool apbuart_first_open_interrupt(
  rtems_termios_tty             *tty,
  rtems_termios_device_context  *base,
  struct termios                *term,
  rtems_libio_open_close_args_t *args
)
{
  (void) args;

  struct apbuart_context *uart = (struct apbuart_context *) base;
  rtems_status_code       sc;
  uint32_t                ctrl;

  apbuart_set_best_baud( uart, term );

  /* Register Interrupt handler */
  sc = rtems_interrupt_handler_install(
    uart->irq,
    "console",
    RTEMS_INTERRUPT_SHARED,
    apbuart_isr,
    tty
  );
  if ( sc != RTEMS_SUCCESSFUL ) {
    return false;
  }

  uart->sending = 0;
  /* Enable Receiver and transmitter and Turn on RX interrupts */
  ctrl = grlib_load_32( &uart->regs->ctrl );
  ctrl |= APBUART_CTRL_RE | APBUART_CTRL_TE | APBUART_CTRL_RI;
  grlib_store_32( &uart->regs->ctrl, ctrl );
  /* Initialize UART on opening */
  ctrl |= APBUART_CTRL_RE | APBUART_CTRL_TE;
  grlib_store_32( &uart->regs->ctrl, ctrl );
  grlib_store_32( &uart->regs->status, 0 );

  return true;
}

static void apbuart_last_close_interrupt(
  rtems_termios_tty             *tty,
  rtems_termios_device_context  *base,
  rtems_libio_open_close_args_t *args
)
{
  (void) args;

  struct apbuart_context      *uart = (struct apbuart_context *) base;
  rtems_interrupt_lock_context lock_context;
  uint32_t                     ctrl;

  /* Turn off RX interrupts */
  rtems_termios_device_lock_acquire( base, &lock_context );
  ctrl = grlib_load_32( &uart->regs->ctrl );
  ctrl &= ~APBUART_CTRL_RI;
  grlib_store_32( &uart->regs->ctrl, ctrl );
  rtems_termios_device_lock_release( base, &lock_context );

  /**** Flush device ****/
  while ( uart->sending ) {
    /* Wait until all data has been sent */
  }

  /* uninstall ISR */
  rtems_interrupt_handler_remove( uart->irq, apbuart_isr, tty );
}

const rtems_termios_device_handler apbuart_handler_interrupt = {
  .first_open = apbuart_first_open_interrupt,
  .last_close = apbuart_last_close_interrupt,
  .write = apbuart_write_support,
  .set_attributes = apbuart_set_attributes,
  .mode = TERMIOS_IRQ_DRIVEN
};

const rtems_termios_device_handler apbuart_handler_polled = {
  .first_open = apbuart_first_open_polled,
  .poll_read = apbuart_poll_read,
  .write = apbuart_write_polled,
  .set_attributes = apbuart_set_attributes,
  .mode = TERMIOS_POLLED
};