Staging: add speakup to the staging directory

Speakup is a kernel based screen review package for the linux operating
system.  It allows blind users to interact with applications on the
linux console by means of synthetic speech.

The authors and maintainers of this code include the following:

Kirk Reiser, Andy Berdan, John Covici, Brian and
David Borowski, Christopher Brannon, Samuel Thibault and William Hubbs.

Signed-off-by: William Hubbs <w.d.hubbs@gmail.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 108 insertions, 0 deletions

diff --git a/drivers/staging/speakup/buffers.c b/drivers/staging/speakup/buffers.c
new file mode 100644
index 000000000000..6dd53cf348f6
--- /dev/null
+++ b/drivers/staging/speakup/buffers.c
@@ -0,0 +1,108 @@
+#include <linux/console.h>
+#include <linux/smp_lock.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include "speakup.h"
+#include "spk_priv.h"
+
+#define synthBufferSize 8192	/* currently 8K bytes */
+
+static u_char synth_buffer[synthBufferSize];	/* guess what this is for! */
+static u_char *buff_in = synth_buffer;
+static u_char *buff_out = synth_buffer;
+static u_char *buffer_end = synth_buffer+synthBufferSize-1;
+
+/* These try to throttle applications by stopping the TTYs
+ * Note: we need to make sure that we will restart them eventually, which is
+ * usually not possible to do from the notifiers. TODO: it should be possible
+ * starting from linux 2.6.26.
+ *
+ * So we only stop when we know alive == 1 (else we discard the data anyway),
+ * and the alive synth will eventually call start_ttys from the thread context.
+ */
+void speakup_start_ttys(void)
+{
+	int i;
+
+	for (i = 0; i < MAX_NR_CONSOLES; i++) {
+		if (speakup_console[i] && speakup_console[i]->tty_stopped)
+			continue;
+		if ((vc_cons[i].d != NULL) && (vc_cons[i].d->vc_tty != NULL))
+			start_tty(vc_cons[i].d->vc_tty);
+	}
+}
+EXPORT_SYMBOL_GPL(speakup_start_ttys);
+
+static void speakup_stop_ttys(void)
+{
+	int i;
+
+	for (i = 0; i < MAX_NR_CONSOLES; i++)
+		if ((vc_cons[i].d != NULL) && (vc_cons[i].d->vc_tty != NULL))
+			stop_tty(vc_cons[i].d->vc_tty);
+	return;
+}
+
+static int synth_buffer_free(void)
+{
+	int bytesFree;
+
+	if (buff_in >= buff_out)
+		bytesFree = synthBufferSize - (buff_in - buff_out);
+	else
+		bytesFree = buff_out - buff_in;
+	return bytesFree;
+}
+
+int synth_buffer_empty(void)
+{
+	return (buff_in == buff_out);
+}
+EXPORT_SYMBOL_GPL(synth_buffer_empty);
+
+void synth_buffer_add(char ch)
+{
+	if (!synth->alive) {
+		/* This makes sure that we won't stop TTYs if there is no synth
+		 * to restart them */
+		return;
+	}
+	if (synth_buffer_free() <= 100) {
+		synth_start();
+		speakup_stop_ttys();
+	}
+	if (synth_buffer_free() <= 1)
+		return;
+	*buff_in++ = ch;
+	if (buff_in > buffer_end)
+		buff_in = synth_buffer;
+}
+
+char synth_buffer_getc(void)
+{
+	char ch;
+
+	if (buff_out == buff_in)
+		return 0;
+	ch = *buff_out++;
+	if (buff_out > buffer_end)
+		buff_out = synth_buffer;
+	return ch;
+}
+EXPORT_SYMBOL_GPL(synth_buffer_getc);
+
+char synth_buffer_peek(void)
+{
+	if (buff_out == buff_in)
+		return 0;
+	return *buff_out;
+}
+EXPORT_SYMBOL_GPL(synth_buffer_peek);
+
+void synth_buffer_clear(void)
+{
+	buff_in = buff_out = synth_buffer;
+	return;
+}
+EXPORT_SYMBOL_GPL(synth_buffer_clear);