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authorAnton Vorontsov <anton.vorontsov@linaro.org>2012-09-24 14:27:53 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-09-26 13:47:02 -0700
commitc7f3e7087ab0abb52bb1286010f2c104fd38ca5c (patch)
tree322207554769abe35110e41a4de93aa273b8c901 /drivers/tty/serial
parent729043e82cdd403a131127254528afea8031ebab (diff)
tty/serial/core: Introduce poll_init callback
It was noticed that polling drivers (like KGDB) are not able to use serial ports if the ports were not previously initialized via console. I.e. when booting with console=ttyAMA0 kgdboc=ttyAMA0, everything works fine, but with console=ttyFOO kgdboc=ttyAMA0, the kgdboc doesn't work. This is because we don't initialize the hardware. Calling ->startup() is not an option, because drivers request interrupts there, and drivers fail to handle situations when tty isn't opened with interrupts enabled. So, we have to implement a new callback (actually, tty_ops already have a similar callback), which does everything needed to initialize just the hardware. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial')
-rw-r--r--drivers/tty/serial/serial_core.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 78036c510ccc..0fcfd98a9566 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2129,6 +2129,7 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options)
int bits = 8;
int parity = 'n';
int flow = 'n';
+ int ret;
if (!state || !state->uart_port)
return -1;
@@ -2137,6 +2138,22 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options)
if (!(port->ops->poll_get_char && port->ops->poll_put_char))
return -1;
+ if (port->ops->poll_init) {
+ struct tty_port *tport = &state->port;
+
+ ret = 0;
+ mutex_lock(&tport->mutex);
+ /*
+ * We don't set ASYNCB_INITIALIZED as we only initialized the
+ * hw, e.g. state->xmit is still uninitialized.
+ */
+ if (!test_bit(ASYNCB_INITIALIZED, &tport->flags))
+ ret = port->ops->poll_init(port);
+ mutex_unlock(&tport->mutex);
+ if (ret)
+ return ret;
+ }
+
if (options) {
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, NULL, baud, parity, bits, flow);