[PATCHv2 0/4] Improvments for wlcore irq and resume for v5.9

[PATCHv2 0/4] Improvments for wlcore irq and resume for v5.9

[Tony Lindgren]

Hi,

Here are few improvments for wlcore resume ELP handling and interrupt
handling for v5.9.

Regards,

Tony

Changes since v1:

- Update patch descriptions for simplifying the complicated locking
  between interrupt handler and tx

- Change patch order for the ELP handling to be the first change
  as the others are mostly clean-up type improvments

Tony Lindgren (4):
  wlcore: Simplify runtime resume ELP path
  wlcore: Use spin_trylock in wlcore_irq_locked() for running the queue
  wlcore: Use spin_trylock in wlcore_irq() to see if we need to queue tx
  wlcore: Remove pointless spinlock

 drivers/net/wireless/ti/wlcore/main.c | 84 +++++++++++++--------------
 1 file changed, 39 insertions(+), 45 deletions(-)

-- 
2.27.0

[PATCH 1/4] wlcore: Simplify runtime resume ELP path

[Tony Lindgren]

We can simplify the runtime resume ELP path by always setting and
clearing the completion in runtime resume. This way we can test for
WL1271_FLAG_IRQ_RUNNING after the resume write to see if we need
completion at all.

And in wlcore_irq(), we need to take spinlock for running the
completion and for the pm_wakeup_event(). Spinlock is not needed
around the bitops flags check for WL1271_FLAG_SUSPENDED so the
spinlocked sections get shorter.

Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/net/wireless/ti/wlcore/main.c | 43 ++++++++++-----------------
 1 file changed, 15 insertions(+), 28 deletions(-)

diff --git a/drivers/net/wireless/ti/wlcore/main.c b/drivers/net/wireless/ti/wlcore/main.c
--- a/drivers/net/wireless/ti/wlcore/main.c
+++ b/drivers/net/wireless/ti/wlcore/main.c
@@ -649,24 +649,26 @@ static irqreturn_t wlcore_irq(int irq, void *cookie)
 	unsigned long flags;
 	struct wl1271 *wl = cookie;
 
-	/* complete the ELP completion */
-	spin_lock_irqsave(&wl->wl_lock, flags);
 	set_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags);
-	if (wl->elp_compl) {
-		complete(wl->elp_compl);
-		wl->elp_compl = NULL;
+
+	/* complete the ELP completion */
+	if (test_bit(WL1271_FLAG_IN_ELP, &wl->flags)) {
+		spin_lock_irqsave(&wl->wl_lock, flags);
+		if (wl->elp_compl)
+			complete(wl->elp_compl);
+		spin_unlock_irqrestore(&wl->wl_lock, flags);
 	}
 
 	if (test_bit(WL1271_FLAG_SUSPENDED, &wl->flags)) {
 		/* don't enqueue a work right now. mark it as pending */
 		set_bit(WL1271_FLAG_PENDING_WORK, &wl->flags);
 		wl1271_debug(DEBUG_IRQ, "should not enqueue work");
+		spin_lock_irqsave(&wl->wl_lock, flags);
 		disable_irq_nosync(wl->irq);
 		pm_wakeup_event(wl->dev, 0);
 		spin_unlock_irqrestore(&wl->wl_lock, flags);
 		goto out_handled;
 	}
-	spin_unlock_irqrestore(&wl->wl_lock, flags);
 
 	/* TX might be handled here, avoid redundant work */
 	set_bit(WL1271_FLAG_TX_PENDING, &wl->flags);
@@ -6732,7 +6734,6 @@ static int __maybe_unused wlcore_runtime_resume(struct device *dev)
 	unsigned long flags;
 	int ret;
 	unsigned long start_time = jiffies;
-	bool pending = false;
 	bool recovery = false;
 
 	/* Nothing to do if no ELP mode requested */
@@ -6742,49 +6743,35 @@ static int __maybe_unused wlcore_runtime_resume(struct device *dev)
 	wl1271_debug(DEBUG_PSM, "waking up chip from elp");
 
 	spin_lock_irqsave(&wl->wl_lock, flags);
-	if (test_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags))
-		pending = true;
-	else
-		wl->elp_compl = &compl;
+	wl->elp_compl = &compl;
 	spin_unlock_irqrestore(&wl->wl_lock, flags);
 
 	ret = wlcore_raw_write32(wl, HW_ACCESS_ELP_CTRL_REG, ELPCTRL_WAKE_UP);
 	if (ret < 0) {
 		recovery = true;
-		goto err;
-	}
-
-	if (!pending) {
+	} else if (!test_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags)) {
 		ret = wait_for_completion_timeout(&compl,
 			msecs_to_jiffies(WL1271_WAKEUP_TIMEOUT));
 		if (ret == 0) {
 			wl1271_warning("ELP wakeup timeout!");
-
-			/* Return no error for runtime PM for recovery */
-			ret = 0;
 			recovery = true;
-			goto err;
 		}
 	}
 
-	clear_bit(WL1271_FLAG_IN_ELP, &wl->flags);
-
-	wl1271_debug(DEBUG_PSM, "wakeup time: %u ms",
-		     jiffies_to_msecs(jiffies - start_time));
-
-	return 0;
-
-err:
 	spin_lock_irqsave(&wl->wl_lock, flags);
 	wl->elp_compl = NULL;
 	spin_unlock_irqrestore(&wl->wl_lock, flags);
+	clear_bit(WL1271_FLAG_IN_ELP, &wl->flags);
 
 	if (recovery) {
 		set_bit(WL1271_FLAG_INTENDED_FW_RECOVERY, &wl->flags);
 		wl12xx_queue_recovery_work(wl);
+	} else {
+		wl1271_debug(DEBUG_PSM, "wakeup time: %u ms",
+			     jiffies_to_msecs(jiffies - start_time));
 	}
 
-	return ret;
+	return 0;
 }
 
 static const struct dev_pm_ops wlcore_pm_ops = {
-- 
2.27.0

[PATCH 2/4] wlcore: Use spin_trylock in wlcore_irq_locked() for running the queue

[Tony Lindgren]

We currently have a collection of flags and locking between the
threaded irq and tx work:

- wl->flags bitops
- wl->mutex
- wl->wl_lock spinlock

The bitops flags do not need a spinlock around them, and
wlcore_irq() already holds the mutex calling wlcore_irq_locked().
And we only need the spinlock to see if we need to run the queue
or not.

To simplify the locking, we can use spin_trylock and always run the
tx queue unless we know there's nothing to do.

Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/net/wireless/ti/wlcore/main.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/ti/wlcore/main.c b/drivers/net/wireless/ti/wlcore/main.c
--- a/drivers/net/wireless/ti/wlcore/main.c
+++ b/drivers/net/wireless/ti/wlcore/main.c
@@ -521,6 +521,7 @@ static int wlcore_irq_locked(struct wl1271 *wl)
 	int ret = 0;
 	u32 intr;
 	int loopcount = WL1271_IRQ_MAX_LOOPS;
+	bool run_tx_queue = true;
 	bool done = false;
 	unsigned int defer_count;
 	unsigned long flags;
@@ -586,19 +587,22 @@ static int wlcore_irq_locked(struct wl1271 *wl)
 				goto err_ret;
 
 			/* Check if any tx blocks were freed */
-			spin_lock_irqsave(&wl->wl_lock, flags);
-			if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags) &&
-			    wl1271_tx_total_queue_count(wl) > 0) {
-				spin_unlock_irqrestore(&wl->wl_lock, flags);
+			if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags)) {
+				if (spin_trylock_irqsave(&wl->wl_lock, flags)) {
+					if (!wl1271_tx_total_queue_count(wl))
+						run_tx_queue = false;
+					spin_unlock_irqrestore(&wl->wl_lock, flags);
+				}
+
 				/*
 				 * In order to avoid starvation of the TX path,
 				 * call the work function directly.
 				 */
-				ret = wlcore_tx_work_locked(wl);
-				if (ret < 0)
-					goto err_ret;
-			} else {
-				spin_unlock_irqrestore(&wl->wl_lock, flags);
+				if (run_tx_queue) {
+					ret = wlcore_tx_work_locked(wl);
+					if (ret < 0)
+						goto err_ret;
+				}
 			}
 
 			/* check for tx results */
-- 
2.27.0

[PATCH 3/4] wlcore: Use spin_trylock in wlcore_irq() to see if we need to queue tx

[Tony Lindgren]

We currently have a collection of flags and locking between the
threaded irq and tx work:

- wl->flags bitops
- wl->mutex
- wl->wl_lock spinlock

The bitops flags do not need a spinlock around them, and we only need
the spinlock to see if we need to queue tx work or not. And wlcore_irq()
holds the mutex.

To simplify the locking, we can use spin_trylock and always queue tx
work unless we know there's nothing to do.

Let's also update the comment a bit while at it.

Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/net/wireless/ti/wlcore/main.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/ti/wlcore/main.c b/drivers/net/wireless/ti/wlcore/main.c
--- a/drivers/net/wireless/ti/wlcore/main.c
+++ b/drivers/net/wireless/ti/wlcore/main.c
@@ -652,6 +652,7 @@ static irqreturn_t wlcore_irq(int irq, void *cookie)
 	int ret;
 	unsigned long flags;
 	struct wl1271 *wl = cookie;
+	bool queue_tx_work = true;
 
 	set_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags);
 
@@ -684,13 +685,17 @@ static irqreturn_t wlcore_irq(int irq, void *cookie)
 	if (ret)
 		wl12xx_queue_recovery_work(wl);
 
-	spin_lock_irqsave(&wl->wl_lock, flags);
-	/* In case TX was not handled here, queue TX work */
+	/* In case TX was not handled in wlcore_irq_locked(), queue TX work */
 	clear_bit(WL1271_FLAG_TX_PENDING, &wl->flags);
-	if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags) &&
-	    wl1271_tx_total_queue_count(wl) > 0)
-		ieee80211_queue_work(wl->hw, &wl->tx_work);
-	spin_unlock_irqrestore(&wl->wl_lock, flags);
+	if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags)) {
+		if (spin_trylock_irqsave(&wl->wl_lock, flags)) {
+			if (!wl1271_tx_total_queue_count(wl))
+				queue_tx_work = false;
+			spin_unlock_irqrestore(&wl->wl_lock, flags);
+		}
+		if (queue_tx_work)
+			ieee80211_queue_work(wl->hw, &wl->tx_work);
+	}
 
 	mutex_unlock(&wl->mutex);
 
-- 
2.27.0

[PATCH 4/4] wlcore: Remove pointless spinlock

[Tony Lindgren]

No need to take a spinlock here for bitops.

Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/net/wireless/ti/wlcore/main.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/net/wireless/ti/wlcore/main.c b/drivers/net/wireless/ti/wlcore/main.c
--- a/drivers/net/wireless/ti/wlcore/main.c
+++ b/drivers/net/wireless/ti/wlcore/main.c
@@ -700,9 +700,7 @@ static irqreturn_t wlcore_irq(int irq, void *cookie)
 	mutex_unlock(&wl->mutex);
 
 out_handled:
-	spin_lock_irqsave(&wl->wl_lock, flags);
 	clear_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags);
-	spin_unlock_irqrestore(&wl->wl_lock, flags);
 
 	return IRQ_HANDLED;
 }
-- 
2.27.0

Re: [PATCH 1/4] wlcore: Simplify runtime resume ELP path

[Kalle Valo]

Tony Lindgren <tony@atomide.com> wrote:

> We can simplify the runtime resume ELP path by always setting and
> clearing the completion in runtime resume. This way we can test for
> WL1271_FLAG_IRQ_RUNNING after the resume write to see if we need
> completion at all.
> 
> And in wlcore_irq(), we need to take spinlock for running the
> completion and for the pm_wakeup_event(). Spinlock is not needed
> around the bitops flags check for WL1271_FLAG_SUSPENDED so the
> spinlocked sections get shorter.
> 
> Signed-off-by: Tony Lindgren <tony@atomide.com>

4 patches applied to wireless-drivers-next.git, thanks.

eb215c33f308 wlcore: Simplify runtime resume ELP path
f0325e38ab39 wlcore: Use spin_trylock in wlcore_irq_locked() for running the queue
35fba0f0fd76 wlcore: Use spin_trylock in wlcore_irq() to see if we need to queue tx
2c3601e6a340 wlcore: Remove pointless spinlock

-- 
https://patchwork.kernel.org/patch/11639577/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

[PATCH 4/4] wlcore: Remove pointless spinlock

[Tony Lindgren]

No need to take a spinlock here.

Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/net/wireless/ti/wlcore/main.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/net/wireless/ti/wlcore/main.c b/drivers/net/wireless/ti/wlcore/main.c
--- a/drivers/net/wireless/ti/wlcore/main.c
+++ b/drivers/net/wireless/ti/wlcore/main.c
@@ -700,9 +700,7 @@ static irqreturn_t wlcore_irq(int irq, void *cookie)
 	mutex_unlock(&wl->mutex);
 
 out_handled:
-	spin_lock_irqsave(&wl->wl_lock, flags);
 	clear_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags);
-	spin_unlock_irqrestore(&wl->wl_lock, flags);
 
 	return IRQ_HANDLED;
 }
-- 
2.27.0