1 files changed, 387 insertions, 0 deletions
diff --git a/drivers/accessibility/speakup/spk_ttyio.c b/drivers/accessibility/speakup/spk_ttyio.c
new file mode 100644
index 000000000..4c0a6e1f0
--- /dev/null
+++ b/drivers/accessibility/speakup/spk_ttyio.c
@@ -0,0 +1,387 @@
+// 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);