The commit 1ba7622094 (serial: sh-sci: console Runtime PM support,
from Magnus Damm <damm@xxxxxxxxxxxxx>, 2011-08-03), tried to support
console runtime PM, but unfortunately it didn't work for us for some
reason. We did not investigated further at that time, instead would
like to propose a different approach.
In Linux tty/serial world, to get console PM work properly, a serial
client driver does not have to maintain .runtime_suspend()/..resume()
calls itself, but can leave console power power management handling to
the serial core driver.
This patch moves the sh-sci driver in that direction.
Notes:
* There is room to optimize console runtime PM more aggressively by
maintaining additional local runtime PM calls, but as a first step
having .pm() operation would suffice.
* We still have a couple of direct calls to sci_port_enable/..disable
left in the driver. We have to live with them, because they're out
of serial core's help.
Signed-off-by: Teppei Kamijou <teppei.kamijou.yb@xxxxxxxxxxx>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@xxxxxxxxxxx>
---
drivers/tty/serial/sh-sci.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index e9e8883..e65e546 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1746,8 +1746,6 @@ static int sci_startup(struct uart_port *port)
dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);
- sci_port_enable(s);
-
ret = sci_request_irq(s);
if (unlikely(ret < 0))
return ret;
@@ -1771,8 +1769,6 @@ static void sci_shutdown(struct uart_port *port)
sci_free_dma(port);
sci_free_irq(s);
-
- sci_port_disable(s);
}
static unsigned int sci_scbrr_calc(unsigned int algo_id, unsigned int bps,
@@ -1921,6 +1917,21 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
sci_port_disable(s);
}
+static void sci_pm(struct uart_port *port, unsigned int state,
+ unsigned int oldstate)
+{
+ struct sci_port *sci_port = to_sci_port(port);
+
+ switch (state) {
+ case 3:
+ sci_port_disable(sci_port);
+ break;
+ default:
+ sci_port_enable(sci_port);
+ break;
+ }
+}
+
static const char *sci_type(struct uart_port *port)
{
switch (port->type) {
@@ -2042,6 +2053,7 @@ static struct uart_ops sci_uart_ops = {
.startup = sci_startup,
.shutdown = sci_shutdown,
.set_termios = sci_set_termios,
+ .pm = sci_pm,
.type = sci_type,
.release_port = sci_release_port,
.request_port = sci_request_port,
@@ -2195,16 +2207,12 @@ static void serial_console_write(struct console *co, const char *s,
struct uart_port *port = &sci_port->port;
unsigned short bits;
- sci_port_enable(sci_port);
-
uart_console_write(port, s, count, serial_console_putchar);
/* wait until fifo is empty and last bit has been transmitted */
bits = SCxSR_TDxE(port) | SCxSR_TEND(port);
while ((serial_port_in(port, SCxSR) & bits) != bits)
cpu_relax();
-
- sci_port_disable(sci_port);
}
static int __devinit serial_console_setup(struct console *co, char *options)
@@ -2236,12 +2244,9 @@ static int __devinit serial_console_setup(struct console *co, char *options)
if (unlikely(ret != 0))
return ret;
- sci_port_enable(sci_port);
-
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
- /* TODO: disable clock */
return uart_set_options(port, co, baud, parity, bits, flow);
}
--
1.7.12.4
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