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Commit d758c9c1 authored by Tony Lindgren's avatar Tony Lindgren Committed by Greg Kroah-Hartman
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serial: omap: Fix missing pm_runtime_resume handling by simplifying code 



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: 2a0b965c (serial: omap: Add support for optional wake-up)
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
Acked-by: default avatarFelipe Balbi <balbi@ti.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bf903c0c

drivers/tty/serial/omap-serial.c

+17 −12
Original line number Diff line number Diff line
@@ -225,14 +225,19 @@ static inline void serial_omap_enable_wakeirq(struct uart_omap_port *up, 
	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;
@@ -1495,6 +1500,11 @@ static int serial_omap_suspend(struct device *dev) 
	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;

}
@@ -1502,6 +1512,9 @@ static int serial_omap_resume(struct device *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;
@@ -1878,17 +1891,7 @@ static int serial_omap_runtime_suspend(struct device *dev) 


	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;

		}

	}



	up->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;

	schedule_work(&up->qos_work);
@@ -1902,6 +1905,8 @@ static int serial_omap_runtime_resume(struct device *dev) 


	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);