From f41a9b3b15e0f74656f69e6da403d870c53ea4e6 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Wed, 8 Aug 2012 16:25:03 +0200
Subject: [PATCH] ath9k: fix interrupt storms on queued hardware reset
commit b74713d04effbacd3d126ce94cec18742187b6ce
"ath9k: Handle fatal interrupts properly" introduced a race condition, where
IRQs are being left enabled, however the irq handler returns IRQ_HANDLED
while the reset is still queued without addressing the IRQ cause.
This leads to an IRQ storm that prevents the system from even getting to
the reset code.
Fix this by disabling IRQs in the handler without touching intr_ref_cnt.
Cc: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Cc: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
---
drivers/net/wireless/ath/ath9k/mac.c | 18 ++++++++++++------
drivers/net/wireless/ath/ath9k/mac.h | 1 +
drivers/net/wireless/ath/ath9k/main.c | 4 +++-
3 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/mac.c b/drivers/net/wireless/ath/ath9k/mac.c
index 7990cd55599cd..b42be910a83dc 100644
--- a/drivers/net/wireless/ath/ath9k/mac.c
+++ b/drivers/net/wireless/ath/ath9k/mac.c
@@ -773,15 +773,10 @@ bool ath9k_hw_intrpend(struct ath_hw *ah)
}
EXPORT_SYMBOL(ath9k_hw_intrpend);
-void ath9k_hw_disable_interrupts(struct ath_hw *ah)
+void ath9k_hw_kill_interrupts(struct ath_hw *ah)
{
struct ath_common *common = ath9k_hw_common(ah);
- if (!(ah->imask & ATH9K_INT_GLOBAL))
- atomic_set(&ah->intr_ref_cnt, -1);
- else
- atomic_dec(&ah->intr_ref_cnt);
-
ath_dbg(common, INTERRUPT, "disable IER\n");
REG_WRITE(ah, AR_IER, AR_IER_DISABLE);
(void) REG_READ(ah, AR_IER);
@@ -793,6 +788,17 @@ void ath9k_hw_disable_interrupts(struct ath_hw *ah)
(void) REG_READ(ah, AR_INTR_SYNC_ENABLE);
}
}
+EXPORT_SYMBOL(ath9k_hw_kill_interrupts);
+
+void ath9k_hw_disable_interrupts(struct ath_hw *ah)
+{
+ if (!(ah->imask & ATH9K_INT_GLOBAL))
+ atomic_set(&ah->intr_ref_cnt, -1);
+ else
+ atomic_dec(&ah->intr_ref_cnt);
+
+ ath9k_hw_kill_interrupts(ah);
+}
EXPORT_SYMBOL(ath9k_hw_disable_interrupts);
void ath9k_hw_enable_interrupts(struct ath_hw *ah)
diff --git a/drivers/net/wireless/ath/ath9k/mac.h b/drivers/net/wireless/ath/ath9k/mac.h
index 0eba36dca6f8f..4a745e68dd941 100644
--- a/drivers/net/wireless/ath/ath9k/mac.h
+++ b/drivers/net/wireless/ath/ath9k/mac.h
@@ -738,6 +738,7 @@ bool ath9k_hw_intrpend(struct ath_hw *ah);
void ath9k_hw_set_interrupts(struct ath_hw *ah);
void ath9k_hw_enable_interrupts(struct ath_hw *ah);
void ath9k_hw_disable_interrupts(struct ath_hw *ah);
+void ath9k_hw_kill_interrupts(struct ath_hw *ah);
void ar9002_hw_attach_mac_ops(struct ath_hw *ah);
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 6049d8b82855a..a22df749b8db3 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -462,8 +462,10 @@ irqreturn_t ath_isr(int irq, void *dev)
if (!ath9k_hw_intrpend(ah))
return IRQ_NONE;
- if(test_bit(SC_OP_HW_RESET, &sc->sc_flags))
+ if (test_bit(SC_OP_HW_RESET, &sc->sc_flags)) {
+ ath9k_hw_kill_interrupts(ah);
return IRQ_HANDLED;
+ }
/*
* Figure out the reason(s) for the interrupt. Note