From a620865edf62ea2d024bbfe62162244473badfcb Mon Sep 17 00:00:00 2001 From: Ido Yariv Date: Tue, 1 Mar 2011 15:14:41 +0200 Subject: 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 Reviewed-by: Luciano Coelho Signed-off-by: Luciano Coelho --- drivers/net/wireless/wl12xx/spi.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) (limited to 'drivers/net/wireless/wl12xx/spi.c') diff --git a/drivers/net/wireless/wl12xx/spi.c b/drivers/net/wireless/wl12xx/spi.c index 0132dad756c..df5a00f103e 100644 --- a/drivers/net/wireless/wl12xx/spi.c +++ b/drivers/net/wireless/wl12xx/spi.c @@ -320,28 +320,23 @@ static void wl1271_spi_raw_write(struct wl1271 *wl, int addr, void *buf, spi_sync(wl_to_spi(wl), &m); } -static irqreturn_t wl1271_irq(int irq, void *cookie) +static irqreturn_t wl1271_hardirq(int irq, void *cookie) { - struct wl1271 *wl; + struct wl1271 *wl = cookie; unsigned long flags; wl1271_debug(DEBUG_IRQ, "IRQ"); - 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; } - - 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 int wl1271_spi_set_power(struct wl1271 *wl, bool enable) @@ -413,14 +408,14 @@ static int __devinit wl1271_probe(struct spi_device *spi) goto out_free; } - 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); -- cgit v1.2.3-70-g09d2 From 2da69b890f47852dc368136375f49a5d24e2d9a1 Mon Sep 17 00:00:00 2001 From: Ido Yariv Date: Tue, 1 Mar 2011 15:14:42 +0200 Subject: wl12xx: Switch to level trigger interrupts The interrupt of the wl12xx is a level interrupt in nature, since the interrupt line is not auto-reset. However, since resetting the interrupt requires bus transactions, this cannot be done from an interrupt context. Thus, requesting a level interrupt would require to disable the irq and re-enable it after the HW is acknowledged. Since we now request a threaded irq, this can also be done by specifying the IRQF_ONESHOT flag. Triggering on an edge can be problematic in some platforms, if the sampling frequency is not sufficient for detecting very frequent interrupts. In case an interrupt is missed, the driver will hang as the interrupt line will stay high until it is acknowledged by the driver, which will never happen. Fix this by requesting a level triggered interrupt, with the IRQF_ONESHOT flag. Signed-off-by: Ido Yariv Reviewed-by: Luciano Coelho Signed-off-by: Luciano Coelho --- drivers/net/wireless/wl12xx/sdio.c | 2 +- drivers/net/wireless/wl12xx/spi.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/net/wireless/wl12xx/spi.c') diff --git a/drivers/net/wireless/wl12xx/sdio.c b/drivers/net/wireless/wl12xx/sdio.c index b66abb5ebcf..5b9dbeafec0 100644 --- a/drivers/net/wireless/wl12xx/sdio.c +++ b/drivers/net/wireless/wl12xx/sdio.c @@ -241,7 +241,7 @@ static int __devinit wl1271_probe(struct sdio_func *func, wl->ref_clock = wlan_data->board_ref_clock; ret = request_threaded_irq(wl->irq, wl1271_hardirq, wl1271_irq, - IRQF_TRIGGER_RISING, + IRQF_TRIGGER_HIGH | IRQF_ONESHOT, DRIVER_NAME, wl); if (ret < 0) { wl1271_error("request_irq() failed: %d", ret); diff --git a/drivers/net/wireless/wl12xx/spi.c b/drivers/net/wireless/wl12xx/spi.c index df5a00f103e..18cf01719ae 100644 --- a/drivers/net/wireless/wl12xx/spi.c +++ b/drivers/net/wireless/wl12xx/spi.c @@ -409,7 +409,7 @@ static int __devinit wl1271_probe(struct spi_device *spi) } ret = request_threaded_irq(wl->irq, wl1271_hardirq, wl1271_irq, - IRQF_TRIGGER_RISING, + IRQF_TRIGGER_HIGH | IRQF_ONESHOT, DRIVER_NAME, wl); if (ret < 0) { wl1271_error("request_irq() failed: %d", ret); -- cgit v1.2.3-70-g09d2