ath9k: fix irq storm issues (#18483)

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

SVN-Revision: 43971

package/kernel/mac80211/patches/329-ath9k-fix-race-condition-in-irq-processing-during-ha.patch

@@ -0,0 +1,53 @@
+From: Felix Fietkau <nbd@openwrt.org>
+Date: Wed, 14 Jan 2015 14:13:15 +0100
+Subject: [PATCH] ath9k: fix race condition in irq processing during hardware
+ reset
+
+To fix invalid hardware accesses, the commit
+"ath9k: do not access hardware on IRQs during reset" made the irq
+handler ignore interrupts emitted after queueing a hardware reset (which
+disables the IRQ). This left a small time window for the IRQ to get
+re-enabled by the tasklet, which caused IRQ storms.
+Instead of returning IRQ_NONE when ATH_OP_HW_RESET is set, disable the
+IRQ entirely for the duration of the reset.
+
+Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+---
+
+--- a/drivers/net/wireless/ath/ath9k/main.c
++++ b/drivers/net/wireless/ath/ath9k/main.c
+@@ -285,6 +285,7 @@ static int ath_reset_internal(struct ath
+ 
+ 	__ath_cancel_work(sc);
+ 
++	disable_irq(sc->irq);
+ 	tasklet_disable(&sc->intr_tq);
+ 	tasklet_disable(&sc->bcon_tasklet);
+ 	spin_lock_bh(&sc->sc_pcu_lock);
+@@ -331,6 +332,7 @@ static int ath_reset_internal(struct ath
+ 		r = -EIO;
+ 
+ out:
++	enable_irq(sc->irq);
+ 	spin_unlock_bh(&sc->sc_pcu_lock);
+ 	tasklet_enable(&sc->bcon_tasklet);
+ 	tasklet_enable(&sc->intr_tq);
+@@ -512,9 +514,6 @@ irqreturn_t ath_isr(int irq, void *dev)
+ 	if (!ah || test_bit(ATH_OP_INVALID, &common->op_flags))
+ 		return IRQ_NONE;
+ 
+-	if (!AR_SREV_9100(ah) && test_bit(ATH_OP_HW_RESET, &common->op_flags))
+-		return IRQ_NONE;
+-
+ 	/* shared irq, not for us */
+ 	if (!ath9k_hw_intrpend(ah))
+ 		return IRQ_NONE;
+@@ -529,7 +528,7 @@ irqreturn_t ath_isr(int irq, void *dev)
+ 	ath9k_debug_sync_cause(sc, sync_cause);
+ 	status &= ah->imask;	/* discard unasked-for bits */
+ 
+-	if (AR_SREV_9100(ah) && test_bit(ATH_OP_HW_RESET, &common->op_flags))
++	if (test_bit(ATH_OP_HW_RESET, &common->op_flags))
+ 		return IRQ_HANDLED;
+ 
+ 	/*

package/kernel/mac80211/patches/542-ath9k_debugfs_diag.patch

@@ -125,8 +125,8 @@
  		REG_SET_BIT(ah, AR_BTCOEX_WL_LNADIV, AR_BTCOEX_WL_LNADIV_FORCE_ON);
 --- a/drivers/net/wireless/ath/ath9k/main.c
 +++ b/drivers/net/wireless/ath/ath9k/main.c
-@@ -532,6 +532,11 @@ irqreturn_t ath_isr(int irq, void *dev)
+@@ -531,6 +531,11 @@ irqreturn_t ath_isr(int irq, void *dev)
- 	if (AR_SREV_9100(ah) && test_bit(ATH_OP_HW_RESET, &common->op_flags))
+ 	if (test_bit(ATH_OP_HW_RESET, &common->op_flags))
  		return IRQ_HANDLED;
  
 +	if (test_bit(ATH_DIAG_TRIGGER_ERROR, &ah->diag)) {