[PATCH net-next 0/4] net: ipa: IPA interrupt cleanup

[PATCH net-next 0/4] net: ipa: IPA interrupt cleanup

[Alex Elder]

The first patch in this series makes all IPA interrupt handling be
done in a threaded context.  The remaining ones refactor some code
to simplify that threaded handler function.

					-Alex

Alex Elder (4):
  net: ipa: make IPA interrupt handler threaded only
  net: ipa: clear disabled IPA interrupt conditions
  net: ipa: get rid of some unneeded IPA interrupt code
  net: ipa: kill ipa_interrupt_process_all()

 drivers/net/ipa/ipa_interrupt.c | 57 +++++++++++----------------------
 1 file changed, 19 insertions(+), 38 deletions(-)

-- 
2.27.0

[PATCH net-next 1/4] net: ipa: make IPA interrupt handler threaded only

[Alex Elder]

When the IPA interrupt handler runs, the IPA core clock must already
be operational, and the interconnect providing access by the AP to
IPA config space must be enabled too.

Currently we ensure this by taking a top-level "stay awake" IPA
clock reference, but that will soon go away.  In preparation for
that, move all handling for the IPA IRQ into the thread function.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_interrupt.c | 29 +++++++++++------------------
 1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/drivers/net/ipa/ipa_interrupt.c b/drivers/net/ipa/ipa_interrupt.c
index 9fd158dd90473..7dee4ebaf5a95 100644
--- a/drivers/net/ipa/ipa_interrupt.c
+++ b/drivers/net/ipa/ipa_interrupt.c
@@ -100,32 +100,22 @@ static void ipa_interrupt_process_all(struct ipa_interrupt *interrupt)
 	}
 }
 
-/* Threaded part of the IPA IRQ handler */
+/* IPA IRQ handler is threaded */
 static irqreturn_t ipa_isr_thread(int irq, void *dev_id)
-{
-	struct ipa_interrupt *interrupt = dev_id;
-
-	ipa_clock_get(interrupt->ipa);
-
-	ipa_interrupt_process_all(interrupt);
-
-	ipa_clock_put(interrupt->ipa);
-
-	return IRQ_HANDLED;
-}
-
-/* Hard part (i.e., "real" IRQ handler) of the IRQ handler */
-static irqreturn_t ipa_isr(int irq, void *dev_id)
 {
 	struct ipa_interrupt *interrupt = dev_id;
 	struct ipa *ipa = interrupt->ipa;
 	u32 offset;
 	u32 mask;
 
+	ipa_clock_get(ipa);
+
 	offset = ipa_reg_irq_stts_offset(ipa->version);
 	mask = ioread32(ipa->reg_virt + offset);
-	if (mask & interrupt->enabled)
-		return IRQ_WAKE_THREAD;
+	if (mask & interrupt->enabled) {
+		ipa_interrupt_process_all(interrupt);
+		goto out_clock_put;
+	}
 
 	/* Nothing in the mask was supposed to cause an interrupt */
 	offset = ipa_reg_irq_clr_offset(ipa->version);
@@ -134,6 +124,9 @@ static irqreturn_t ipa_isr(int irq, void *dev_id)
 	dev_err(&ipa->pdev->dev, "%s: unexpected interrupt, mask 0x%08x\n",
 		__func__, mask);
 
+out_clock_put:
+	ipa_clock_put(ipa);
+
 	return IRQ_HANDLED;
 }
 
@@ -260,7 +253,7 @@ struct ipa_interrupt *ipa_interrupt_config(struct ipa *ipa)
 	offset = ipa_reg_irq_en_offset(ipa->version);
 	iowrite32(0, ipa->reg_virt + offset);
 
-	ret = request_threaded_irq(irq, ipa_isr, ipa_isr_thread, IRQF_ONESHOT,
+	ret = request_threaded_irq(irq, NULL, ipa_isr_thread, IRQF_ONESHOT,
 				   "ipa", interrupt);
 	if (ret) {
 		dev_err(dev, "error %d requesting \"ipa\" IRQ\n", ret);
-- 
2.27.0

[PATCH net-next 2/4] net: ipa: clear disabled IPA interrupt conditions

[Alex Elder]

We ignore any IPA interrupt that has no handler.  If any interrupt
conditions without a handler exist when an IPA interrupt occurs,
clear those conditions.  Add a debug message to report which ones
are being cleared.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_interrupt.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ipa/ipa_interrupt.c b/drivers/net/ipa/ipa_interrupt.c
index 7dee4ebaf5a95..c12d0c33557cd 100644
--- a/drivers/net/ipa/ipa_interrupt.c
+++ b/drivers/net/ipa/ipa_interrupt.c
@@ -79,6 +79,7 @@ static void ipa_interrupt_process_all(struct ipa_interrupt *interrupt)
 {
 	struct ipa *ipa = interrupt->ipa;
 	u32 enabled = interrupt->enabled;
+	u32 pending;
 	u32 offset;
 	u32 mask;
 
@@ -87,8 +88,8 @@ static void ipa_interrupt_process_all(struct ipa_interrupt *interrupt)
 	 * only the enabled ones.
 	 */
 	offset = ipa_reg_irq_stts_offset(ipa->version);
-	mask = ioread32(ipa->reg_virt + offset);
-	while ((mask &= enabled)) {
+	pending = ioread32(ipa->reg_virt + offset);
+	while ((mask = pending & enabled)) {
 		do {
 			u32 irq_id = __ffs(mask);
 
@@ -96,7 +97,17 @@ static void ipa_interrupt_process_all(struct ipa_interrupt *interrupt)
 
 			ipa_interrupt_process(interrupt, irq_id);
 		} while (mask);
-		mask = ioread32(ipa->reg_virt + offset);
+		pending = ioread32(ipa->reg_virt + offset);
+	}
+
+	/* If any disabled interrupts are pending, clear them */
+	if (pending) {
+		struct device *dev = &ipa->pdev->dev;
+
+		dev_dbg(dev, "clearing disabled IPA interrupts 0x%08x\n",
+			pending);
+		offset = ipa_reg_irq_clr_offset(ipa->version);
+		iowrite32(pending, ipa->reg_virt + offset);
 	}
 }
 
-- 
2.27.0

[PATCH net-next 3/4] net: ipa: get rid of some unneeded IPA interrupt code

[Alex Elder]

The pending IPA interrupts are checked by ipa_isr_thread(), and
interrupts are processed only if an enabled interrupt has a
condition pending.  But ipa_interrupt_process_all() now makes the
same check, so the one in ipa_isr_thread() can just be skipped.

Also in ipa_isr_thread(), any interrupt conditions pending which are
not enabled are cleared.  Here too, ipa_interrupt_process_all() now
clears such excess interrupt conditions, so ipa_isr_thread() doesn't
have to.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_interrupt.c | 17 +----------------
 1 file changed, 1 insertion(+), 16 deletions(-)

diff --git a/drivers/net/ipa/ipa_interrupt.c b/drivers/net/ipa/ipa_interrupt.c
index c12d0c33557cd..d149e496ffa72 100644
--- a/drivers/net/ipa/ipa_interrupt.c
+++ b/drivers/net/ipa/ipa_interrupt.c
@@ -116,26 +116,11 @@ static irqreturn_t ipa_isr_thread(int irq, void *dev_id)
 {
 	struct ipa_interrupt *interrupt = dev_id;
 	struct ipa *ipa = interrupt->ipa;
-	u32 offset;
-	u32 mask;
 
 	ipa_clock_get(ipa);
 
-	offset = ipa_reg_irq_stts_offset(ipa->version);
-	mask = ioread32(ipa->reg_virt + offset);
-	if (mask & interrupt->enabled) {
-		ipa_interrupt_process_all(interrupt);
-		goto out_clock_put;
-	}
+	ipa_interrupt_process_all(interrupt);
 
-	/* Nothing in the mask was supposed to cause an interrupt */
-	offset = ipa_reg_irq_clr_offset(ipa->version);
-	iowrite32(mask, ipa->reg_virt + offset);
-
-	dev_err(&ipa->pdev->dev, "%s: unexpected interrupt, mask 0x%08x\n",
-		__func__, mask);
-
-out_clock_put:
 	ipa_clock_put(ipa);
 
 	return IRQ_HANDLED;
-- 
2.27.0

[PATCH net-next 4/4] net: ipa: kill ipa_interrupt_process_all()

[Alex Elder]

Now that ipa_isr_thread() is a simple wrapper that gets a clock
reference around ipa_interrupt_process_all(), get rid of the
called function and just open-code it in ipa_isr_thread().

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_interrupt.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ipa/ipa_interrupt.c b/drivers/net/ipa/ipa_interrupt.c
index d149e496ffa72..aa37f03f4557f 100644
--- a/drivers/net/ipa/ipa_interrupt.c
+++ b/drivers/net/ipa/ipa_interrupt.c
@@ -74,15 +74,18 @@ static void ipa_interrupt_process(struct ipa_interrupt *interrupt, u32 irq_id)
 		iowrite32(mask, ipa->reg_virt + offset);
 }
 
-/* Process all IPA interrupt types that have been signaled */
-static void ipa_interrupt_process_all(struct ipa_interrupt *interrupt)
+/* IPA IRQ handler is threaded */
+static irqreturn_t ipa_isr_thread(int irq, void *dev_id)
 {
+	struct ipa_interrupt *interrupt = dev_id;
 	struct ipa *ipa = interrupt->ipa;
 	u32 enabled = interrupt->enabled;
 	u32 pending;
 	u32 offset;
 	u32 mask;
 
+	ipa_clock_get(ipa);
+
 	/* The status register indicates which conditions are present,
 	 * including conditions whose interrupt is not enabled.  Handle
 	 * only the enabled ones.
@@ -109,17 +112,6 @@ static void ipa_interrupt_process_all(struct ipa_interrupt *interrupt)
 		offset = ipa_reg_irq_clr_offset(ipa->version);
 		iowrite32(pending, ipa->reg_virt + offset);
 	}
-}
-
-/* IPA IRQ handler is threaded */
-static irqreturn_t ipa_isr_thread(int irq, void *dev_id)
-{
-	struct ipa_interrupt *interrupt = dev_id;
-	struct ipa *ipa = interrupt->ipa;
-
-	ipa_clock_get(ipa);
-
-	ipa_interrupt_process_all(interrupt);
 
 	ipa_clock_put(ipa);
 
-- 
2.27.0