[PATCH 3.8 115/166] ath9k: Fix interrupt handling for the AR9002 family

Kamal Mostafa
2014-01-15T21:52:09Z

From: Sujith Manoharan <c_manoha@qca.qualcomm.com>

commit 73f0b56a1ff64e7fb6c3a62088804bab93bcedc2 upstream.

This patch adds a driver workaround for a HW issue.

A race condition in the HW results in missing interrupts,
which can be avoided by a read/write with the ISR register.
All chips in the AR9002 series are affected by this bug - AR9003
and above do not have this problem.

Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
drivers/net/wireless/ath/ath9k/ar9002_mac.c | 52 ++++++++++++++++++++++++-----
1 file changed, 43 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ar9002_mac.c b/drivers/net/wireless/ath/ath9k/ar9002_mac.c
index 8d78253..a366d6b 100644
--- a/drivers/net/wireless/ath/ath9k/ar9002_mac.c
+++ b/drivers/net/wireless/ath/ath9k/ar9002_mac.c
@@ -76,9 +76,16 @@ static bool ar9002_hw_get_isr(struct ath_hw *ah, enum ath9k_int *masked)
mask2 |= ATH9K_INT_CST;
if (isr2 & AR_ISR_S2_TSFOOR)
mask2 |= ATH9K_INT_TSFOOR;
+
+ if (!(pCap->hw_caps & ATH9K_HW_CAP_RAC_SUPPORTED)) {
+ REG_WRITE(ah, AR_ISR_S2, isr2);
+ isr &= ~AR_ISR_BCNMISC;
+ }
}

- isr = REG_READ(ah, AR_ISR_RAC);
+ if (pCap->hw_caps & ATH9K_HW_CAP_RAC_SUPPORTED)
+ isr = REG_READ(ah, AR_ISR_RAC);
+
if (isr == 0xffffffff) {
*masked = 0;
return false;
@@ -97,11 +104,23 @@ static bool ar9002_hw_get_isr(struct ath_hw *ah, enum ath9k_int *masked)

*masked |= ATH9K_INT_TX;

- s0_s = REG_READ(ah, AR_ISR_S0_S);
+ if (pCap->hw_caps & ATH9K_HW_CAP_RAC_SUPPORTED) {
+ s0_s = REG_READ(ah, AR_ISR_S0_S);
+ s1_s = REG_READ(ah, AR_ISR_S1_S);
+ } else {
+ s0_s = REG_READ(ah, AR_ISR_S0);
+ REG_WRITE(ah, AR_ISR_S0, s0_s);
+ s1_s = REG_READ(ah, AR_ISR_S1);
+ REG_WRITE(ah, AR_ISR_S1, s1_s);
+
+ isr &= ~(AR_ISR_TXOK |
+ AR_ISR_TXDESC |
+ AR_ISR_TXERR |
+ AR_ISR_TXEOL);
+ }
+
ah->intr_txqs |= MS(s0_s, AR_ISR_S0_QCU_TXOK);
ah->intr_txqs |= MS(s0_s, AR_ISR_S0_QCU_TXDESC);
-
- s1_s = REG_READ(ah, AR_ISR_S1_S);
ah->intr_txqs |= MS(s1_s, AR_ISR_S1_QCU_TXERR);
ah->intr_txqs |= MS(s1_s, AR_ISR_S1_QCU_TXEOL);
}
@@ -114,13 +133,15 @@ static bool ar9002_hw_get_isr(struct ath_hw *ah, enum ath9k_int *masked)
*masked |= mask2;
}

- if (AR_SREV_9100(ah))
- return true;
-
- if (isr & AR_ISR_GENTMR) {
+ if (!AR_SREV_9100(ah) && (isr & AR_ISR_GENTMR)) {
u32 s5_s;

- s5_s = REG_READ(ah, AR_ISR_S5_S);
+ if (pCap->hw_caps & ATH9K_HW_CAP_RAC_SUPPORTED) {
+ s5_s = REG_READ(ah, AR_ISR_S5_S);
+ } else {
+ s5_s = REG_READ(ah, AR_ISR_S5);
+ }
+
ah->intr_gen_timer_trigger =
MS(s5_s, AR_ISR_S5_GENTIMER_TRIG);

@@ -133,8 +154,21 @@ static bool ar9002_hw_get_isr(struct ath_hw *ah, enum ath9k_int *masked)
if ((s5_s & AR_ISR_S5_TIM_TIMER) &&
!(pCap->hw_caps & ATH9K_HW_CAP_AUTOSLEEP))
*masked |= ATH9K_INT_TIM_TIMER;
+
+ if (!(pCap->hw_caps & ATH9K_HW_CAP_RAC_SUPPORTED)) {
+ REG_WRITE(ah, AR_ISR_S5, s5_s);
+ isr &= ~AR_ISR_GENTMR;
+ }
}

+ if (!(pCap->hw_caps & ATH9K_HW_CAP_RAC_SUPPORTED)) {
+ REG_WRITE(ah, AR_ISR, isr);
+ REG_READ(ah, AR_ISR);
+ }
+
+ if (AR_SREV_9100(ah))
+ return true;
+
if (sync_cause) {
ath9k_debug_sync_cause(common, sync_cause);
fatal_int =
--
1.8.3.2