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path: root/drivers/accessibility/speakup/spk_ttyio.c
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Diffstat (limited to 'drivers/accessibility/speakup/spk_ttyio.c')
-rw-r--r--drivers/accessibility/speakup/spk_ttyio.c384
1 files changed, 384 insertions, 0 deletions
diff --git a/drivers/accessibility/speakup/spk_ttyio.c b/drivers/accessibility/speakup/spk_ttyio.c
new file mode 100644
index 000000000000..9b95f77f9265
--- /dev/null
+++ b/drivers/accessibility/speakup/spk_ttyio.c
@@ -0,0 +1,384 @@
+// 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;
+};
+
+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)
+{
+ 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)
+ return -ENOMEM;
+
+ init_completion(&ldisc_data->completion);
+ 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);
+ kfree(speakup_tty->disc_data);
+ speakup_tty = NULL;
+ mutex_unlock(&speakup_tty_mutex);
+}
+
+static int spk_ttyio_receive_buf2(struct tty_struct *tty,
+ const unsigned char *cp, char *fp, int count)
+{
+ struct spk_ldisc_data *ldisc_data = tty->disc_data;
+
+ if (spk_ttyio_synth->read_buff_add) {
+ int i;
+
+ 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
+ */
+ 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,
+ .magic = TTY_LDISC_MAGIC,
+ .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(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);
+
+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,
+};
+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;
+}
+
+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);
+}
+
+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);
+}
+
+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) {
+ 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
+ */
+ 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);
+
+ 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;
+ 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);