// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/slab.h>
#include "speakup.h"
#include "spk_types.h"
#include "spk_priv.h"
struct spk_ldisc_data {
char buf;
struct completion completion;
bool buf_free;
struct spk_synth *synth;
};
/*
* This allows to catch within spk_ttyio_ldisc_open whether it is getting set
* on for a speakup-driven device.
*/
static struct tty_struct *speakup_tty;
/* This mutex serializes the use of such global speakup_tty variable */
static DEFINE_MUTEX(speakup_tty_mutex);
static int ser_to_dev(int ser, dev_t *dev_no)
{
if (ser < 0 || ser > (255 - 64)) {
pr_err("speakup: Invalid ser param. Must be between 0 and 191 inclusive.\n");
return -EINVAL;
}
*dev_no = MKDEV(4, (64 + ser));
return 0;
}
static int get_dev_to_use(struct spk_synth *synth, dev_t *dev_no)
{
/* use ser only when dev is not specified */
if (strcmp(synth->dev_name, SYNTH_DEFAULT_DEV) ||
synth->ser == SYNTH_DEFAULT_SER)
return tty_dev_name_to_number(synth->dev_name, dev_no);
return ser_to_dev(synth->ser, dev_no);
}
static int spk_ttyio_ldisc_open(struct tty_struct *tty)
{
struct spk_ldisc_data *ldisc_data;
if (tty != speakup_tty)
/* Somebody tried to use this line discipline outside speakup */
return -ENODEV;
if (!tty->ops->write)
return -EOPNOTSUPP;
ldisc_data = kmalloc(sizeof(*ldisc_data), GFP_KERNEL);
if (!ldisc_data)
return -ENOMEM;
init_completion(&ldisc_data->completion);
ldisc_data->buf_free = true;
tty->disc_data = ldisc_data;
return 0;
}
static void spk_ttyio_ldisc_close(struct tty_struct *tty)
{
kfree(tty->disc_data);
}
static size_t spk_ttyio_receive_buf2(struct tty_struct *tty, const u8 *cp,
const u8 *fp, size_t count)
{
struct spk_ldisc_data *ldisc_data = tty->disc_data;
struct spk_synth *synth = ldisc_data->synth;
if (synth->read_buff_add) {
unsigned int i;
for (i = 0; i < count; i++)
synth->read_buff_add(cp[i]);
return count;
}
if (!ldisc_data->buf_free)
/* ttyio_in will tty_flip_buffer_push */
return 0;
/* Make sure the consumer has read buf before we have seen
* buf_free == true and overwrite buf
*/
mb();
ldisc_data->buf = cp[0];
ldisc_data->buf_free = false;
complete(&ldisc_data->completion);
return 1;
}
static struct tty_ldisc_ops spk_ttyio_ldisc_ops = {
.owner = THIS_MODULE,
.num = N_SPEAKUP,
.name = "speakup_ldisc",
.open = spk_ttyio_ldisc_open,
.close = spk_ttyio_ldisc_close,
.receive_buf2 = spk_ttyio_receive_buf2,
};
static int spk_ttyio_out(struct spk_synth *in_synth, const char ch);
static int spk_ttyio_out_unicode(struct spk_synth *in_synth, u16 ch);
static void spk_ttyio_send_xchar(struct spk_synth *in_synth, char ch);
static void spk_ttyio_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear);
static unsigned char spk_ttyio_in(struct spk_synth *in_synth);
static unsigned char spk_ttyio_in_nowait(struct spk_synth *in_synth);
static void spk_ttyio_flush_buffer(struct spk_synth *in_synth);
static int spk_ttyio_wait_for_xmitr(struct spk_synth *in_synth);
struct spk_io_ops spk_ttyio_ops = {
.synth_out = spk_ttyio_out,
.synth_out_unicode = spk_ttyio_out_unicode,
.send_xchar = spk_ttyio_send_xchar,
.tiocmset = spk_ttyio_tiocmset,
.synth_in = spk_ttyio_in,
.synth_in_nowait = spk_ttyio_in_nowait,
.flush_buffer = spk_ttyio_flush_buffer,
.wait_for_xmitr = spk_ttyio_wait_for_xmitr,
};
EXPORT_SYMBOL_GPL(spk_ttyio_ops);
static inline void get_termios(struct tty_struct *tty,
struct ktermios *out_termios)
{
down_read(&tty->termios_rwsem);
*out_termios = tty->termios;
up_read(&tty->termios_rwsem);
}
static int spk_ttyio_initialise_ldisc(struct spk_synth *synth)
{
int ret = 0;
struct tty_struct *tty;
struct ktermios tmp_termios;
dev_t dev;
ret = get_dev_to_use(synth, &dev);
if (ret)
return ret;
tty = tty_kopen_exclusive(dev);
if (IS_ERR(tty))
return PTR_ERR(tty);
if (tty->ops->open)
ret = tty->ops->open(tty, NULL);
else
ret = -ENODEV;
if (ret) {
tty_unlock(tty);
return ret;
}
clear_bit(TTY_HUPPED, &tty->flags);
/* ensure hardware flow control is enabled */
get_termios(tty, &tmp_termios);
if (!(tmp_termios.c_cflag & CRTSCTS)) {
tmp_termios.c_cflag |= CRTSCTS;
tty_set_termios(tty, &tmp_termios);
/*
* check c_cflag to see if it's updated as tty_set_termios
* may not return error even when no tty bits are
* changed by the request.
*/
get_termios(tty, &tmp_termios);
if (!(tmp_termios.c_cflag & CRTSCTS))
pr_warn("speakup: Failed to set hardware flow control\n");
}
tty_unlock(tty);
mutex_lock(&speakup_tty_mutex);
speakup_tty = tty;
ret = tty_set_ldisc(tty, N_SPEAKUP);
speakup_tty = NULL;
mutex_unlock(&speakup_tty_mutex);
if (!ret) {
/* Success */
struct spk_ldisc_data *ldisc_data = tty->disc_data;
ldisc_data->synth = synth;
synth->dev = tty;
return 0;
}
pr_err("speakup: Failed to set N_SPEAKUP on tty\n");
tty_lock(tty);
if (tty->ops->close)
tty->ops->close(tty, NULL);
tty_unlock(tty);
tty_kclose(tty);
return ret;
}
void spk_ttyio_register_ldisc(void)
{
if (tty_register_ldisc(&spk_ttyio_ldisc_ops))
pr_warn("speakup: Error registering line discipline. Most synths won't work.\n");
}
void spk_ttyio_unregister_ldisc(void)
{
tty_unregister_ldisc(&spk_ttyio_ldisc_ops);
}
static int spk_ttyio_out(struct spk_synth *in_synth, const char ch)
{
struct tty_struct *tty = in_synth->dev;
int ret;
if (!in_synth->alive || !tty->ops->write)
return 0;
ret = tty->ops->write(tty, &ch, 1);
if (ret == 0)
/* No room */
return 0;
if (ret > 0)
/* Success */
return 1;
pr_warn("%s: I/O error, deactivating speakup\n",
in_synth->long_name);
/* 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
*/
in_synth->alive = 0;
speakup_start_ttys();
return 0;
}
static int spk_ttyio_out_unicode(struct spk_synth *in_synth, u16 ch)
{
int ret;
if (ch < 0x80) {
ret = spk_ttyio_out(in_synth, ch);
} else if (ch < 0x800) {
ret = spk_ttyio_out(in_synth, 0xc0 | (ch >> 6));
ret &= spk_ttyio_out(in_synth, 0x80 | (ch & 0x3f));
} else {
ret = spk_ttyio_out(in_synth, 0xe0 | (ch >> 12));
ret &= spk_ttyio_out(in_synth, 0x80 | ((ch >> 6) & 0x3f));
ret &= spk_ttyio_out(in_synth, 0x80 | (ch & 0x3f));
}
return ret;
}
static void spk_ttyio_send_xchar(struct spk_synth *in_synth, char ch)
{
struct tty_struct *tty = in_synth->dev;
if (tty->ops->send_xchar)
tty->ops->send_xchar(tty, ch);
}
static void spk_ttyio_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear)
{
struct tty_struct *tty = in_synth->dev;
if (tty->ops->tiocmset)
tty->ops->tiocmset(tty, set, clear);
}
static int spk_ttyio_wait_for_xmitr(struct spk_synth *in_synth)
{
return 1;
}
static unsigned char ttyio_in(struct spk_synth *in_synth, int timeout)
{
struct tty_struct *tty = in_synth->dev;
struct spk_ldisc_data *ldisc_data = tty->disc_data;
char rv;
if (!timeout) {
if (!try_wait_for_completion(&ldisc_data->completion))
return 0xff;
} else if (wait_for_completion_timeout(&ldisc_data->completion,
usecs_to_jiffies(timeout)) == 0) {
pr_warn("spk_ttyio: timeout (%d) while waiting for input\n",
timeout);
return 0xff;
}
rv = ldisc_data->buf;
/* Make sure we have read buf before we set buf_free to let
* the producer overwrite it
*/
mb();
ldisc_data->buf_free = true;
/* Let TTY push more characters */
tty_flip_buffer_push(tty->port);
return rv;
}
static unsigned char spk_ttyio_in(struct spk_synth *in_synth)
{
return ttyio_in(in_synth, SPK_SYNTH_TIMEOUT);
}
static unsigned char spk_ttyio_in_nowait(struct spk_synth *in_synth)
{
u8 rv = ttyio_in(in_synth, 0);
return (rv == 0xff) ? 0 : rv;
}
static void spk_ttyio_flush_buffer(struct spk_synth *in_synth)
{
struct tty_struct *tty = in_synth->dev;
if (tty->ops->flush_buffer)
tty->ops->flush_buffer(tty);
}
int spk_ttyio_synth_probe(struct spk_synth *synth)
{
int rv = spk_ttyio_initialise_ldisc(synth);
if (rv)
return rv;
synth->alive = 1;
return 0;
}
EXPORT_SYMBOL_GPL(spk_ttyio_synth_probe);
void spk_ttyio_release(struct spk_synth *in_synth)
{
struct tty_struct *tty = in_synth->dev;
if (tty == NULL)
return;
tty_lock(tty);
if (tty->ops->close)
tty->ops->close(tty, NULL);
tty_ldisc_flush(tty);
tty_unlock(tty);
tty_kclose(tty);
in_synth->dev = NULL;
}
EXPORT_SYMBOL_GPL(spk_ttyio_release);
const char *spk_ttyio_synth_immediate(struct spk_synth *in_synth, const char *buff)
{
struct tty_struct *tty = in_synth->dev;
u_char ch;
while ((ch = *buff)) {
if (ch == '\n')
ch = in_synth->procspeech;
if (tty_write_room(tty) < 1 ||
!in_synth->io_ops->synth_out(in_synth, ch))
return buff;
buff++;
}
return NULL;
}
EXPORT_SYMBOL_GPL(spk_ttyio_synth_immediate);
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