[PATCH net-next 0/2] net: ipa: sc7180 suspend/resume

[PATCH net-next 0/2] net: ipa: sc7180 suspend/resume

[Alex Elder]

This series permits suspend/resume to work for the IPA driver
on the Qualcomm SC7180 SoC.  The IPA version on this SoC requires
interrupts to be enabled when the suspend and resume callbacks are
made, and the first patch moves away from using the noirq variants.
The second patch fixes a problem with resume that occurs because
pending interrupts were being cleared before starting a channel.

					-Alex

Alex Elder (2):
  net: ipa: don't use noirq suspend/resume callbacks
  net: ipa: do not clear interrupt in gsi_channel_start()

 drivers/net/ipa/gsi.c      | 11 +----------
 drivers/net/ipa/ipa_main.c |  4 ++--
 2 files changed, 3 insertions(+), 12 deletions(-)

-- 
2.20.1

[PATCH net-next 1/2] net: ipa: don't use noirq suspend/resume callbacks

[Alex Elder]

Use the suspend and resume callbacks rather than suspend_noirq and
resume_noirq.  With IPA v4.2, we use the CHANNEL_STOP command to
implement a suspend, and without interrupts enabled, that command
won't complete.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ipa/ipa_main.c b/drivers/net/ipa/ipa_main.c
index e0b1fe3c34f9..76d5108b8403 100644
--- a/drivers/net/ipa/ipa_main.c
+++ b/drivers/net/ipa/ipa_main.c
@@ -933,8 +933,8 @@ static int ipa_resume(struct device *dev)
 }
 
 static const struct dev_pm_ops ipa_pm_ops = {
-	.suspend_noirq	= ipa_suspend,
-	.resume_noirq	= ipa_resume,
+	.suspend	= ipa_suspend,
+	.resume		= ipa_resume,
 };
 
 static struct platform_driver ipa_driver = {
-- 
2.20.1

[PATCH net-next 2/2] net: ipa: do not clear interrupt in gsi_channel_start()

[Alex Elder]

In gsi_channel_start() there is harmless-looking comment "Clear the
channel's event ring interrupt in case it's pending".  The intent
was to avoid getting spurious interrupts when first bringing up a
channel.

However we now use channel stop/start to implement suspend and
resume, and an interrupt pending at the time we resume is actually
something we don't want to ignore.

The very first time we bring up the channel we do not expect an
interrupt to be pending, and even if it were, the effect would
simply be to schedule NAPI on that channel, which would find nothing
to do, which is not a problem.

Stop clearing any pending IEOB interrupt in gsi_channel_start().
That leaves one caller of the trivial function gsi_isr_ieob_clear().
Get rid of that function and just open-code it in gsi_isr_ieob()
instead.

This fixes a problem where suspend/resume IPA v4.2 would get stuck
when resuming after a suspend.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/gsi.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 66570609c845..d343dc94cb48 100644
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -238,11 +238,6 @@ static void gsi_irq_ieob_enable(struct gsi *gsi, u32 evt_ring_id)
 	iowrite32(val, gsi->virt + GSI_CNTXT_SRC_IEOB_IRQ_MSK_OFFSET);
 }
 
-static void gsi_isr_ieob_clear(struct gsi *gsi, u32 mask)
-{
-	iowrite32(mask, gsi->virt + GSI_CNTXT_SRC_IEOB_IRQ_CLR_OFFSET);
-}
-
 static void gsi_irq_ieob_disable(struct gsi *gsi, u32 evt_ring_id)
 {
 	u32 val;
@@ -777,7 +772,6 @@ static void gsi_channel_deprogram(struct gsi_channel *channel)
 int gsi_channel_start(struct gsi *gsi, u32 channel_id)
 {
 	struct gsi_channel *channel = &gsi->channel[channel_id];
-	u32 evt_ring_id = channel->evt_ring_id;
 	int ret;
 
 	mutex_lock(&gsi->mutex);
@@ -786,9 +780,6 @@ int gsi_channel_start(struct gsi *gsi, u32 channel_id)
 
 	mutex_unlock(&gsi->mutex);
 
-	/* Clear the channel's event ring interrupt in case it's pending */
-	gsi_isr_ieob_clear(gsi, BIT(evt_ring_id));
-
 	gsi_channel_thaw(channel);
 
 	return ret;
@@ -1093,7 +1084,7 @@ static void gsi_isr_ieob(struct gsi *gsi)
 	u32 event_mask;
 
 	event_mask = ioread32(gsi->virt + GSI_CNTXT_SRC_IEOB_IRQ_OFFSET);
-	gsi_isr_ieob_clear(gsi, event_mask);
+	iowrite32(event_mask, gsi->virt + GSI_CNTXT_SRC_IEOB_IRQ_CLR_OFFSET);
 
 	while (event_mask) {
 		u32 evt_ring_id = __ffs(event_mask);
-- 
2.20.1

Re: [PATCH net-next 0/2] net: ipa: sc7180 suspend/resume

[David Miller]

From: Alex Elder <elder@linaro.org>
Date: Fri, 15 May 2020 15:07:29 -0500

> This series permits suspend/resume to work for the IPA driver
> on the Qualcomm SC7180 SoC.  The IPA version on this SoC requires
> interrupts to be enabled when the suspend and resume callbacks are
> made, and the first patch moves away from using the noirq variants.
> The second patch fixes a problem with resume that occurs because
> pending interrupts were being cleared before starting a channel.

Series applied, thanks Alex.