wl12xx: Switch to a threaded interrupt handler

To achieve maximal throughput, it is very important to react to
interrupts as soon as possible. Currently the interrupt handler wakes up
a worker for handling interrupts in process context. A cleaner and more
efficient design would be to request a threaded interrupt handler.  This
handler's priority is very high, and can do blocking operations such as
SDIO/SPI transactions.

Some work can be deferred, mostly calls to mac80211 APIs
(ieee80211_rx_ni and ieee80211_tx_status). By deferring such work to a
different worker, we can keep the irq handler thread more I/O
responsive. In addition, on multi-core systems the two threads can be
scheduled on different cores, which will improve overall performance.

The use of WL1271_FLAG_IRQ_PENDING & WL1271_FLAG_IRQ_RUNNING was
changed. For simplicity, always query the FW for more pending
interrupts. Since there are relatively long bursts of interrupts, the
extra FW status read overhead is negligible. In addition, this enables
registering the IRQ handler with the ONESHOT option.

Signed-off-by: Ido Yariv <ido@wizery.com>
Reviewed-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

1 files changed, 6 insertions, 10 deletions

diff --git a/drivers/net/wireless/wl12xx/sdio.c b/drivers/net/wireless/wl12xx/sdio.c
index 61fdc9e981bd..b66abb5ebcf3 100644
--- a/drivers/net/wireless/wl12xx/sdio.c
+++ b/drivers/net/wireless/wl12xx/sdio.c
@@ -61,7 +61,7 @@ static struct device *wl1271_sdio_wl_to_dev(struct wl1271 *wl)
 	return &(wl_to_func(wl)->dev);
 }
 
-static irqreturn_t wl1271_irq(int irq, void *cookie)
+static irqreturn_t wl1271_hardirq(int irq, void *cookie)
 {
 	struct wl1271 *wl = cookie;
 	unsigned long flags;
@@ -70,17 +70,14 @@ static irqreturn_t wl1271_irq(int irq, void *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;
 	}
-
-	if (!test_and_set_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags))
-		ieee80211_queue_work(wl->hw, &wl->irq_work);
-	set_bit(WL1271_FLAG_IRQ_PENDING, &wl->flags);
 	spin_unlock_irqrestore(&wl->wl_lock, flags);
 
-	return IRQ_HANDLED;
+	return IRQ_WAKE_THREAD;
 }
 
 static void wl1271_sdio_disable_interrupts(struct wl1271 *wl)
@@ -243,14 +240,14 @@ static int __devinit wl1271_probe(struct sdio_func *func,
 	wl->irq = wlan_data->irq;
 	wl->ref_clock = wlan_data->board_ref_clock;
 
-	ret = request_irq(wl->irq, wl1271_irq, 0, DRIVER_NAME, wl);
+	ret = request_threaded_irq(wl->irq, wl1271_hardirq, wl1271_irq,
+				   IRQF_TRIGGER_RISING,
+				   DRIVER_NAME, wl);
 	if (ret < 0) {
 		wl1271_error("request_irq() failed: %d", ret);
 		goto out_free;
 	}
 
-	set_irq_type(wl->irq, IRQ_TYPE_EDGE_RISING);
-
 	disable_irq(wl->irq);
 
 	ret = wl1271_init_ieee80211(wl);
@@ -273,7 +270,6 @@ static int __devinit wl1271_probe(struct sdio_func *func,
  out_irq:
 	free_irq(wl->irq, wl);
 
-
  out_free:
 	wl1271_free_hw(wl);