hvc_console: Add kdb support
Add poll_get_char and poll_put_char for kdb. Enable kdb at boot with:
kgdboc=hvc0
or at runtime with:
echo hvc0 > /sys/module/kgdboc/parameters/kgdboc
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index 5900075..e1aaf4f 100644
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -39,6 +39,7 @@
#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/slab.h>
+#include <linux/serial_core.h>
#include <asm/uaccess.h>
@@ -766,6 +767,39 @@
return hp->ops->tiocmset(hp, set, clear);
}
+#ifdef CONFIG_CONSOLE_POLL
+int hvc_poll_init(struct tty_driver *driver, int line, char *options)
+{
+ return 0;
+}
+
+static int hvc_poll_get_char(struct tty_driver *driver, int line)
+{
+ struct tty_struct *tty = driver->ttys[0];
+ struct hvc_struct *hp = tty->driver_data;
+ int n;
+ char ch;
+
+ n = hp->ops->get_chars(hp->vtermno, &ch, 1);
+
+ if (n == 0)
+ return NO_POLL_CHAR;
+
+ return ch;
+}
+
+static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch)
+{
+ struct tty_struct *tty = driver->ttys[0];
+ struct hvc_struct *hp = tty->driver_data;
+ int n;
+
+ do {
+ n = hp->ops->put_chars(hp->vtermno, &ch, 1);
+ } while (n <= 0);
+}
+#endif
+
static const struct tty_operations hvc_ops = {
.open = hvc_open,
.close = hvc_close,
@@ -776,6 +810,11 @@
.chars_in_buffer = hvc_chars_in_buffer,
.tiocmget = hvc_tiocmget,
.tiocmset = hvc_tiocmset,
+#ifdef CONFIG_CONSOLE_POLL
+ .poll_init = hvc_poll_init,
+ .poll_get_char = hvc_poll_get_char,
+ .poll_put_char = hvc_poll_put_char,
+#endif
};
struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,