[PATCH v1] wifi: ath9k: fix AR9003 mac hardware hang check register offset calculation

[Peter Seiderer <ps.report@gmx.net>]

Fix ath9k_hw_verify_hang()/ar9003_hw_detect_mac_hang() register offset
calculation (do not overflow the shift for the second register/queues
above five, use the register layout described in the comments above
ath9k_hw_verify_hang() instead).

Fixes: 222e04830ff0 ("ath9k: Fix MAC HW hang check for AR9003")

Reported-by: Gregg Wonderly <greggwonderly@seqtechllc.com>
Link: https://lore.kernel.org/linux-wireless/E3A9C354-0CB7-420C-ADEF-F0177FB722F4@seqtechllc.com/
Signed-off-by: Peter Seiderer <ps.report@gmx.net>
---
Notes:
  - tested with MikroTik R11e-5HnD/Atheros AR9300 Rev:4 (lspci: 168c:0033
    Qualcomm Atheros AR958x 802.11abgn Wireless Network Adapter (rev 01))
    card
---
 drivers/net/wireless/ath/ath9k/ar9003_hw.c | 27 ++++++++++++++--------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ar9003_hw.c b/drivers/net/wireless/ath/ath9k/ar9003_hw.c
index 4f27a9fb1482..0ccf13a35fb4 100644
--- a/drivers/net/wireless/ath/ath9k/ar9003_hw.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_hw.c
@@ -1099,17 +1099,22 @@ static bool ath9k_hw_verify_hang(struct ath_hw *ah, unsigned int queue)
 {
 	u32 dma_dbg_chain, dma_dbg_complete;
 	u8 dcu_chain_state, dcu_complete_state;
+	unsigned int dbg_reg, reg_offset;
 	int i;
 
-	for (i = 0; i < NUM_STATUS_READS; i++) {
-		if (queue < 6)
-			dma_dbg_chain = REG_READ(ah, AR_DMADBG_4);
-		else
-			dma_dbg_chain = REG_READ(ah, AR_DMADBG_5);
+	if (queue < 6) {
+		dbg_reg = AR_DMADBG_4;
+		reg_offset = i * 5;
+	} else {
+		dbg_reg = AR_DMADBG_5;
+		reg_offset = (i - 6) * 5;
+	}
 
+	for (i = 0; i < NUM_STATUS_READS; i++) {
+		dma_dbg_chain = REG_READ(ah, dbg_reg);
 		dma_dbg_complete = REG_READ(ah, AR_DMADBG_6);
 
-		dcu_chain_state = (dma_dbg_chain >> (5 * queue)) & 0x1f;
+		dcu_chain_state = (dma_dbg_chain >> reg_offset) & 0x1f;
 		dcu_complete_state = dma_dbg_complete & 0x3;
 
 		if ((dcu_chain_state != 0x6) || (dcu_complete_state != 0x1))
@@ -1128,6 +1133,7 @@ static bool ar9003_hw_detect_mac_hang(struct ath_hw *ah)
 	u8 dcu_chain_state, dcu_complete_state;
 	bool dcu_wait_frdone = false;
 	unsigned long chk_dcu = 0;
+	unsigned int reg_offset;
 	unsigned int i = 0;
 
 	dma_dbg_4 = REG_READ(ah, AR_DMADBG_4);
@@ -1139,12 +1145,15 @@ static bool ar9003_hw_detect_mac_hang(struct ath_hw *ah)
 		goto exit;
 
 	for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
-		if (i < 6)
+		if (i < 6) {
 			chk_dbg = dma_dbg_4;
-		else
+			reg_offset = i * 5;
+		} else {
 			chk_dbg = dma_dbg_5;
+			reg_offset = (i - 6) * 5;
+		}
 
-		dcu_chain_state = (chk_dbg >> (5 * i)) & 0x1f;
+		dcu_chain_state = (chk_dbg >> reg_offset) & 0x1f;
 		if (dcu_chain_state == 0x6) {
 			dcu_wait_frdone = true;
 			chk_dcu |= BIT(i);
-- 
2.40.0