linux-kernel - [PATCH 3.14 051/140] serial: omap: Fix missing pm_runtime

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Message-Id: <20140529043055.989714164@linuxfoundation.org>
Date:	Wed, 28 May 2014 21:33:10 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Tony Lindgren <tony@...mide.com>,
	Felipe Balbi <balbi@...com>
Subject: [PATCH 3.14 051/140] serial: omap: Fix missing pm_runtime_resume handling by simplifying code

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tony Lindgren <tony@...mide.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@...mide.com>
Acked-by: Felipe Balbi <balbi@...com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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);

--
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