Quelle  serialio.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
#include <linux/interrupt.h>
#include <linux/ioport.h>

#include "spk_types.h"
#include "speakup.h"
#include "spk_priv.h"
#include "serialio.h"

#include <linux/serial_core.h>
/* WARNING:  Do not change this to <linux/serial.h> without testing that
 * SERIAL_PORT_DFNS does get defined to the appropriate value.
 */
#include <asm/serial.h>

#ifndef SERIAL_PORT_DFNS
#define SERIAL_PORT_DFNS
#endif

static void start_serial_interrupt(int irq);

static const struct old_serial_port rs_table[] = {
 SERIAL_PORT_DFNS
};

static const struct old_serial_port *serstate;
static int timeouts;

static int spk_serial_out(struct spk_synth *in_synth, const char ch);
static void spk_serial_send_xchar(struct spk_synth *in_synth, char ch);
static void spk_serial_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear);
static unsigned char spk_serial_in(struct spk_synth *in_synth);
static unsigned char spk_serial_in_nowait(struct spk_synth *in_synth);
static void spk_serial_flush_buffer(struct spk_synth *in_synth);
static int spk_serial_wait_for_xmitr(struct spk_synth *in_synth);

struct spk_io_ops spk_serial_io_ops = {
 .synth_out = spk_serial_out,
 .send_xchar = spk_serial_send_xchar,
 .tiocmset = spk_serial_tiocmset,
 .synth_in = spk_serial_in,
 .synth_in_nowait = spk_serial_in_nowait,
 .flush_buffer = spk_serial_flush_buffer,
 .wait_for_xmitr = spk_serial_wait_for_xmitr,
};
EXPORT_SYMBOL_GPL(spk_serial_io_ops);

const struct old_serial_port *spk_serial_init(int index)
{
 int baud = 9600, quot = 0;
 unsigned int cval = 0;
 int cflag = CREAD | HUPCL | CLOCAL | B9600 | CS8;
 const struct old_serial_port *ser;
 int err;

 if (index >= ARRAY_SIZE(rs_table)) {
  pr_info("no port info for ttyS%d\n", index);
  return NULL;
 }
 ser = rs_table + index;

 /* Divisor, byte size and parity */
 quot = ser->baud_base / baud;
 cval = cflag & (CSIZE | CSTOPB);
#if defined(__powerpc__) || defined(__alpha__)
 cval >>= 8;
#else /* !__powerpc__ && !__alpha__ */
 cval >>= 4;
#endif /* !__powerpc__ && !__alpha__ */
 if (cflag & PARENB)
  cval |= UART_LCR_PARITY;
 if (!(cflag & PARODD))
  cval |= UART_LCR_EPAR;
 if (synth_request_region(ser->port, 8)) {
  /* try to take it back. */
  pr_info("Ports not available, trying to steal them\n");
  __release_region(&ioport_resource, ser->port, 8);
  err = synth_request_region(ser->port, 8);
  if (err) {
   pr_warn("Unable to allocate port at %x, errno %i",
    ser->port, err);
   return NULL;
  }
 }

 /* Disable UART interrupts, set DTR and RTS high
 * and set speed.
 */
 outb(cval | UART_LCR_DLAB, ser->port + UART_LCR); /* set DLAB */
 outb(quot & 0xff, ser->port + UART_DLL); /* LS of divisor */
 outb(quot >> 8, ser->port + UART_DLM);  /* MS of divisor */
 outb(cval, ser->port + UART_LCR);  /* reset DLAB */

 /* Turn off Interrupts */
 outb(0, ser->port + UART_IER);
 outb(UART_MCR_DTR | UART_MCR_RTS, ser->port + UART_MCR);

 /* If we read 0xff from the LSR, there is no UART here. */
 if (inb(ser->port + UART_LSR) == 0xff) {
  synth_release_region(ser->port, 8);
  serstate = NULL;
  return NULL;
 }

 mdelay(1);
 speakup_info.port_tts = ser->port;
 serstate = ser;

 start_serial_interrupt(ser->irq);

 return ser;
}

static irqreturn_t synth_readbuf_handler(int irq, void *dev_id)
{
 unsigned long flags;
 int c;

 spin_lock_irqsave(&speakup_info.spinlock, flags);
 while (inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR) {
  c = inb_p(speakup_info.port_tts + UART_RX);
  synth->read_buff_add((u_char)c);
 }
 spin_unlock_irqrestore(&speakup_info.spinlock, flags);
 return IRQ_HANDLED;
}

static void start_serial_interrupt(int irq)
{
 int rv;

 if (!synth->read_buff_add)
  return;

 rv = request_irq(irq, synth_readbuf_handler, IRQF_SHARED,
    "serial", (void *)synth_readbuf_handler);

 if (rv)
  pr_err("Unable to request Speakup serial I R Q\n");
 /* Set MCR */
 outb(UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2,
      speakup_info.port_tts + UART_MCR);
 /* Turn on Interrupts */
 outb(UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI,
      speakup_info.port_tts + UART_IER);
 inb(speakup_info.port_tts + UART_LSR);
 inb(speakup_info.port_tts + UART_RX);
 inb(speakup_info.port_tts + UART_IIR);
 inb(speakup_info.port_tts + UART_MSR);
 outb(1, speakup_info.port_tts + UART_FCR); /* Turn FIFO On */
}

static void spk_serial_send_xchar(struct spk_synth *synth, char ch)
{
 int timeout = SPK_XMITR_TIMEOUT;

 while (spk_serial_tx_busy()) {
  if (!--timeout)
   break;
  udelay(1);
 }
 outb(ch, speakup_info.port_tts);
}

static void spk_serial_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear)
{
 int old = inb(speakup_info.port_tts + UART_MCR);

 outb((old & ~clear) | set, speakup_info.port_tts + UART_MCR);
}

int spk_serial_synth_probe(struct spk_synth *synth)
{
 const struct old_serial_port *ser;
 int failed = 0;

 if ((synth->ser >= SPK_LO_TTY) && (synth->ser <= SPK_HI_TTY)) {
  ser = spk_serial_init(synth->ser);
  if (!ser) {
   failed = -1;
  } else {
   outb_p(0, ser->port);
   mdelay(1);
   outb_p('\r', ser->port);
  }
 } else {
  failed = -1;
  pr_warn("ttyS%i is an invalid port\n", synth->ser);
 }
 if (failed) {
  pr_info("%s: not found\n", synth->long_name);
  return -ENODEV;
 }
 pr_info("%s: ttyS%i, Driver Version %s\n",
  synth->long_name, synth->ser, synth->version);
 synth->alive = 1;
 return 0;
}
EXPORT_SYMBOL_GPL(spk_serial_synth_probe);

void spk_stop_serial_interrupt(void)
{
 if (speakup_info.port_tts == 0)
  return;

 if (!synth->read_buff_add)
  return;

 /* Turn off interrupts */
 outb(0, speakup_info.port_tts + UART_IER);
 /* Free IRQ */
 free_irq(serstate->irq, (void *)synth_readbuf_handler);
}
EXPORT_SYMBOL_GPL(spk_stop_serial_interrupt);

static int spk_serial_wait_for_xmitr(struct spk_synth *in_synth)
{
 int tmout = SPK_XMITR_TIMEOUT;

 if ((in_synth->alive) && (timeouts >= NUM_DISABLE_TIMEOUTS)) {
  pr_warn("%s: too many timeouts, deactivating speakup\n",
   in_synth->long_name);
  in_synth->alive = 0;
  /* No synth any more, so nobody will restart TTYs, and we thus
 * need to do it ourselves.  Now that there is no synth we can
 * let application flood anyway
 */
  speakup_start_ttys();
  timeouts = 0;
  return 0;
 }
 while (spk_serial_tx_busy()) {
  if (--tmout == 0) {
   pr_warn("%s: timed out (tx busy)\n",
    in_synth->long_name);
   timeouts++;
   return 0;
  }
  udelay(1);
 }
 tmout = SPK_CTS_TIMEOUT;
 while (!((inb_p(speakup_info.port_tts + UART_MSR)) & UART_MSR_CTS)) {
  /* CTS */
  if (--tmout == 0) {
   timeouts++;
   return 0;
  }
  udelay(1);
 }
 timeouts = 0;
 return 1;
}

static unsigned char spk_serial_in(struct spk_synth *in_synth)
{
 int tmout = SPK_SERIAL_TIMEOUT;

 while (!(inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR)) {
  if (--tmout == 0) {
   pr_warn("time out while waiting for input.\n");
   return 0xff;
  }
  udelay(1);
 }
 return inb_p(speakup_info.port_tts + UART_RX);
}

static unsigned char spk_serial_in_nowait(struct spk_synth *in_synth)
{
 unsigned char lsr;

 lsr = inb_p(speakup_info.port_tts + UART_LSR);
 if (!(lsr & UART_LSR_DR))
  return 0;
 return inb_p(speakup_info.port_tts + UART_RX);
}

static void spk_serial_flush_buffer(struct spk_synth *in_synth)
{
 /* TODO: flush the UART 16550 buffer */
}

static int spk_serial_out(struct spk_synth *in_synth, const char ch)
{
 if (in_synth->alive && spk_serial_wait_for_xmitr(in_synth)) {
  outb_p(ch, speakup_info.port_tts);
  return 1;
 }
 return 0;
}

const char *spk_serial_synth_immediate(struct spk_synth *synth,
           const char *buff)
{
 u_char ch;

 while ((ch = *buff)) {
  if (ch == '\n')
   ch = synth->procspeech;
  if (spk_serial_wait_for_xmitr(synth))
   outb(ch, speakup_info.port_tts);
  else
   return buff;
  buff++;
 }
 return NULL;
}
EXPORT_SYMBOL_GPL(spk_serial_synth_immediate);

void spk_serial_release(struct spk_synth *synth)
{
 spk_stop_serial_interrupt();
 if (speakup_info.port_tts == 0)
  return;
 synth_release_region(speakup_info.port_tts, 8);
 speakup_info.port_tts = 0;
}
EXPORT_SYMBOL_GPL(spk_serial_release);