OpenCloudOS-Kernel/drivers/accessibility/speakup/spk_ttyio.c

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// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/tty.h>
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
#include <linux/tty_flip.h>
#include <linux/slab.h>
#include "speakup.h"
#include "spk_types.h"
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
#include "spk_priv.h"
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
struct spk_ldisc_data {
char buf;
struct completion completion;
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
bool buf_free;
};
static struct spk_synth *spk_ttyio_synth;
static struct tty_struct *speakup_tty;
/* mutex to protect against speakup_tty disappearing from underneath us while
* we are using it. this can happen when the device physically unplugged,
* while in use. it also serialises access to speakup_tty.
*/
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)
{
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
struct spk_ldisc_data *ldisc_data;
if (!tty->ops->write)
return -EOPNOTSUPP;
speakup_tty = tty;
ldisc_data = kmalloc(sizeof(*ldisc_data), GFP_KERNEL);
if (!ldisc_data)
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
return -ENOMEM;
init_completion(&ldisc_data->completion);
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
ldisc_data->buf_free = true;
speakup_tty->disc_data = ldisc_data;
return 0;
}
static void spk_ttyio_ldisc_close(struct tty_struct *tty)
{
mutex_lock(&speakup_tty_mutex);
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
kfree(speakup_tty->disc_data);
speakup_tty = NULL;
mutex_unlock(&speakup_tty_mutex);
}
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
static int spk_ttyio_receive_buf2(struct tty_struct *tty,
const unsigned char *cp, char *fp, int count)
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
{
struct spk_ldisc_data *ldisc_data = tty->disc_data;
if (spk_ttyio_synth->read_buff_add) {
int i;
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
for (i = 0; i < count; i++)
spk_ttyio_synth->read_buff_add(cp[i]);
return count;
}
if (!ldisc_data->buf_free)
/* ttyio_in will tty_schedule_flip */
return 0;
/* Make sure the consumer has read buf before we have seen
* buf_free == true and overwrite buf
*/
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
mb();
ldisc_data->buf = cp[0];
ldisc_data->buf_free = false;
complete(&ldisc_data->completion);
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
return 1;
}
static struct tty_ldisc_ops spk_ttyio_ldisc_ops = {
.owner = THIS_MODULE,
.magic = TTY_LDISC_MAGIC,
.name = "speakup_ldisc",
.open = spk_ttyio_ldisc_open,
.close = spk_ttyio_ldisc_close,
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
.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);
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
static void spk_ttyio_send_xchar(char ch);
static void spk_ttyio_tiocmset(unsigned int set, unsigned int clear);
static unsigned char spk_ttyio_in(void);
static unsigned char spk_ttyio_in_nowait(void);
static void spk_ttyio_flush_buffer(void);
static int spk_ttyio_wait_for_xmitr(struct spk_synth *in_synth);
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
struct spk_io_ops spk_ttyio_ops = {
.synth_out = spk_ttyio_out,
.synth_out_unicode = spk_ttyio_out_unicode,
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
.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(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);
ret = tty_set_ldisc(tty, N_SPEAKUP);
if (ret)
pr_err("speakup: Failed to set N_SPEAKUP on tty\n");
return ret;
}
void spk_ttyio_register_ldisc(void)
{
if (tty_register_ldisc(N_SPEAKUP, &spk_ttyio_ldisc_ops))
pr_warn("speakup: Error registering line discipline. Most synths won't work.\n");
}
void spk_ttyio_unregister_ldisc(void)
{
if (tty_unregister_ldisc(N_SPEAKUP))
pr_warn("speakup: Couldn't unregister ldisc\n");
}
static int spk_ttyio_out(struct spk_synth *in_synth, const char ch)
{
mutex_lock(&speakup_tty_mutex);
if (in_synth->alive && speakup_tty && speakup_tty->ops->write) {
int ret = speakup_tty->ops->write(speakup_tty, &ch, 1);
mutex_unlock(&speakup_tty_mutex);
if (ret == 0)
/* No room */
return 0;
if (ret < 0) {
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;
}
return 1;
}
mutex_unlock(&speakup_tty_mutex);
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 int check_tty(struct tty_struct *tty)
{
if (!tty) {
pr_warn("%s: I/O error, deactivating speakup\n",
spk_ttyio_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
*/
spk_ttyio_synth->alive = 0;
speakup_start_ttys();
return 1;
}
return 0;
}
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
static void spk_ttyio_send_xchar(char ch)
{
mutex_lock(&speakup_tty_mutex);
if (check_tty(speakup_tty)) {
mutex_unlock(&speakup_tty_mutex);
return;
}
if (speakup_tty->ops->send_xchar)
speakup_tty->ops->send_xchar(speakup_tty, ch);
mutex_unlock(&speakup_tty_mutex);
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
}
static void spk_ttyio_tiocmset(unsigned int set, unsigned int clear)
{
mutex_lock(&speakup_tty_mutex);
if (check_tty(speakup_tty)) {
mutex_unlock(&speakup_tty_mutex);
return;
}
if (speakup_tty->ops->tiocmset)
speakup_tty->ops->tiocmset(speakup_tty, set, clear);
mutex_unlock(&speakup_tty_mutex);
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
}
static int spk_ttyio_wait_for_xmitr(struct spk_synth *in_synth)
{
return 1;
}
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
static unsigned char ttyio_in(int timeout)
{
struct spk_ldisc_data *ldisc_data = speakup_tty->disc_data;
char rv;
if (wait_for_completion_timeout(&ldisc_data->completion,
usecs_to_jiffies(timeout)) == 0) {
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
if (timeout)
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
*/
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
mb();
ldisc_data->buf_free = true;
/* Let TTY push more characters */
tty_schedule_flip(speakup_tty->port);
return rv;
}
static unsigned char spk_ttyio_in(void)
{
return ttyio_in(SPK_SYNTH_TIMEOUT);
}
static unsigned char spk_ttyio_in_nowait(void)
{
u8 rv = ttyio_in(0);
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
return (rv == 0xff) ? 0 : rv;
}
static void spk_ttyio_flush_buffer(void)
{
mutex_lock(&speakup_tty_mutex);
if (check_tty(speakup_tty)) {
mutex_unlock(&speakup_tty_mutex);
return;
}
if (speakup_tty->ops->flush_buffer)
speakup_tty->ops->flush_buffer(speakup_tty);
mutex_unlock(&speakup_tty_mutex);
}
int spk_ttyio_synth_probe(struct spk_synth *synth)
{
int rv = spk_ttyio_initialise_ldisc(synth);
if (rv)
return rv;
synth->alive = 1;
staging: speakup: add send_xchar, tiocmset and input functionality for tty This patch adds further TTY-based functionality, specifically implementation of send_xchar and tiocmset methods, and input. send_xchar and tiocmset methods simply delegate to corresponding TTY operations. For input, it implements the receive_buf2 callback in tty_ldisc_ops of speakup's ldisc. If a synth defines read_buff_add method then receive_buf2 simply delegates to that and returns. For spk_ttyio_in, the data is passed from receive_buf2 thread to spk_ttyio_in thread through spk_ldisc_data structure. It has following members: - char buf: represents data received - struct semaphore sem: used to signal to spk_ttyio_in thread that data is available to be read without having to busy wait - bool buf_free: this is used in comination with mb() calls to syncronise the two threads over buf receive_buf2 only writes to buf if buf_free is true. The check for buf_free and writing to buf are separated by mb() to ensure that spk_ttyio_in has read buf before receive_buf2 writes to it. After writing, it ups the semaphore to signal to spk_ttyio_in that there is now data to read. spk_ttyio_in waits for data to read by downing the semaphore. Thus when signalled by receive_buf2 thread above, it reads from buf and sets buf_free to true. These two operations are separated by mb() to ensure that receive_buf2 thread finds buf_free to be true only after buf has been read. After that spk_ttyio_in calls tty_schedule_flip for subsequent data to come in through receive_buf2. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-16 01:45:35 +08:00
spk_ttyio_synth = synth;
return 0;
}
EXPORT_SYMBOL_GPL(spk_ttyio_synth_probe);
void spk_ttyio_release(void)
{
if (!speakup_tty)
return;
tty_lock(speakup_tty);
if (speakup_tty->ops->close)
speakup_tty->ops->close(speakup_tty, NULL);
tty_ldisc_flush(speakup_tty);
tty_unlock(speakup_tty);
tty_kclose(speakup_tty);
}
EXPORT_SYMBOL_GPL(spk_ttyio_release);
const char *spk_ttyio_synth_immediate(struct spk_synth *synth, const char *buff)
{
u_char ch;
while ((ch = *buff)) {
if (ch == '\n')
ch = synth->procspeech;
if (tty_write_room(speakup_tty) < 1 ||
!synth->io_ops->synth_out(synth, ch))
return buff;
buff++;
}
return NULL;
}
EXPORT_SYMBOL_GPL(spk_ttyio_synth_immediate);