[PATCH 3.14 051/140] serial: omap: Fix missing pm_runtime_resume handling by simplifying code

Greg Kroah-Hartman
2014-05-29T05:28:55Z

From: Tony Lindgren <tony@atomide.com>

commit d758c9c1b36b4d9a141c2146c70398d756167ed1 upstream.

The lack of pm_runtime_resume handling for the device state leads into
device wake-up interrupts not working after a while for runtime PM.

Also, serial-omap is confused about the use of device_may_wakeup.
The checks for device_may_wakeup should only be done for suspend and
resume, not for pm_runtime_suspend and pm_runtime_resume. The wake-up
events for PM runtime should always be enabled.

The lack of pm_runtime_resume handling leads into device wake-up
interrupts not working after a while for runtime PM.

Rather than try to patch over the issue of adding complex tests to
the pm_runtime_resume, let's fix the issues properly:

1. Make serial_omap_enable_wakeup deal with all internal PM state
handling so we don't need to test for up->wakeups_enabled elsewhere.

Later on once omap3 boots in device tree only mode we can also
remove the up->wakeups_enabled flag and rely on the wake-up
interrupt enable/disable state alone.

2. Do the device_may_wakeup checks in suspend and resume only,
for runtime PM the wake-up events need to be always enabled.

3. Finally just call serial_omap_enable_wakeup and make sure we
call it also in pm_runtime_resume.

4. Note that we also have to use disable_irq_nosync as serial_omap_irq
calls pm_runtime_get_sync.

Fixes: 2a0b965cfb6e (serial: omap: Add support for optional wake-up)
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/tty/serial/omap-serial.c | 29 +++++++++++++++++------------
1 file changed, 17 insertions(+), 12 deletions(-)

--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -225,14 +225,19 @@ static inline void serial_omap_enable_wa
if (enable)
enable_irq(up->wakeirq);
else
- disable_irq(up->wakeirq);
+ disable_irq_nosync(up->wakeirq);
}

static void serial_omap_enable_wakeup(struct uart_omap_port *up, bool enable)
{
struct omap_uart_port_info *pdata = dev_get_platdata(up->dev);

+ if (enable == up->wakeups_enabled)
+ return;
+
serial_omap_enable_wakeirq(up, enable);
+ up->wakeups_enabled = enable;
+
if (!pdata || !pdata->enable_wakeup)
return;

@@ -1488,6 +1493,11 @@ static int serial_omap_suspend(struct de
uart_suspend_port(&serial_omap_reg, &up->port);
flush_work(&up->qos_work);

+ if (device_may_wakeup(dev))
+ serial_omap_enable_wakeup(up, true);
+ else
+ serial_omap_enable_wakeup(up, false);
+
return 0;
}

@@ -1495,6 +1505,9 @@ static int serial_omap_resume(struct dev
{
struct uart_omap_port *up = dev_get_drvdata(dev);

+ if (device_may_wakeup(dev))
+ serial_omap_enable_wakeup(up, false);
+
uart_resume_port(&serial_omap_reg, &up->port);

return 0;
@@ -1870,17 +1883,7 @@ static int serial_omap_runtime_suspend(s

up->context_loss_cnt = serial_omap_get_context_loss_count(up);

- if (device_may_wakeup(dev)) {
- if (!up->wakeups_enabled) {
- serial_omap_enable_wakeup(up, true);
- up->wakeups_enabled = true;
- }
- } else {
- if (up->wakeups_enabled) {
- serial_omap_enable_wakeup(up, false);
- up->wakeups_enabled = false;
- }
- }
+ serial_omap_enable_wakeup(up, true);

up->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
schedule_work(&up->qos_work);
@@ -1894,6 +1897,8 @@ static int serial_omap_runtime_resume(st

int loss_cnt = serial_omap_get_context_loss_count(up);

+ serial_omap_enable_wakeup(up, false);
+
if (loss_cnt < 0) {
dev_dbg(dev, "serial_omap_get_context_loss_count failed : %d\n",
loss_cnt);