ath5k: Add new function to stop rx/tx DMA

 * Add a new function to stop rx/tx dma and use in when reset starts

 Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>

Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 59 insertions, 9 deletions

diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h b/drivers/net/wireless/ath/ath5k/ath5k.h
index 85ff822c81f4..629a5eebe302 100644
--- a/drivers/net/wireless/ath/ath5k/ath5k.h
+++ b/drivers/net/wireless/ath/ath5k/ath5k.h
@@ -1180,8 +1180,9 @@ bool ath5k_hw_is_intr_pending(struct ath5k_hw *ah);
 int ath5k_hw_get_isr(struct ath5k_hw *ah, enum ath5k_int *interrupt_mask);
 enum ath5k_int ath5k_hw_set_imr(struct ath5k_hw *ah, enum ath5k_int new_mask);
 void ath5k_hw_update_mib_counters(struct ath5k_hw *ah);
-/* Init function */
+/* Init/Stop functions */
 void ath5k_hw_dma_init(struct ath5k_hw *ah);
+int ath5k_hw_dma_stop(struct ath5k_hw *ah);
 
 /* EEPROM access functions */
 int ath5k_eeprom_init(struct ath5k_hw *ah);
diff --git a/drivers/net/wireless/ath/ath5k/dma.c b/drivers/net/wireless/ath/ath5k/dma.c
index b991b0585090..ca0467e21e56 100644
--- a/drivers/net/wireless/ath/ath5k/dma.c
+++ b/drivers/net/wireless/ath/ath5k/dma.c
@@ -126,7 +126,7 @@ int ath5k_hw_start_tx_dma(struct ath5k_hw *ah, unsigned int queue)
 
         /* Return if queue is declared inactive */
         if (ah->ah_txq[queue].tqi_type == AR5K_TX_QUEUE_INACTIVE)
-                return -EIO;
+                return -EINVAL;
 
         if (ah->ah_version == AR5K_AR5210) {
                 tx_queue = ath5k_hw_reg_read(ah, AR5K_CR);
@@ -174,7 +174,7 @@ int ath5k_hw_start_tx_dma(struct ath5k_hw *ah, unsigned int queue)
  *
  * Stop DMA transmit on a specific hw queue and drain queue so we don't
  * have any pending frames. Returns -EBUSY if we still have pending frames,
- * -EINVAL if queue number is out of range.
+ * -EINVAL if queue number is out of range or inactive.
  *
  */
 int ath5k_hw_stop_tx_dma(struct ath5k_hw *ah, unsigned int queue)
@@ -186,7 +186,7 @@ int ath5k_hw_stop_tx_dma(struct ath5k_hw *ah, unsigned int queue)
 
         /* Return if queue is declared inactive */
         if (ah->ah_txq[queue].tqi_type == AR5K_TX_QUEUE_INACTIVE)
-                return -EIO;
+                return -EINVAL;
 
         if (ah->ah_version == AR5K_AR5210) {
                 tx_queue = ath5k_hw_reg_read(ah, AR5K_CR);
@@ -733,3 +733,49 @@ void ath5k_hw_dma_init(struct ath5k_hw *ah)
                 ath5k_hw_set_imr(ah, ah->ah_imr);
 
 }
+
+/**
+ * ath5k_hw_dma_stop - stop DMA unit
+ *
+ * @ah: The &struct ath5k_hw
+ *
+ * Stop tx/rx DMA and interrupts. Returns
+ * -EBUSY if tx or rx dma failed to stop.
+ *
+ * XXX: Sometimes DMA unit hangs and we have
+ * stuck frames on tx queues, only a reset
+ * can fix that.
+ */
+int ath5k_hw_dma_stop(struct ath5k_hw *ah)
+{
+        int i, qmax, err;
+        err = 0;
+
+        /* Disable interrupts */
+        ath5k_hw_set_imr(ah, 0);
+
+        /* Stop rx dma */
+        err = ath5k_hw_stop_rx_dma(ah);
+        if (err)
+                return err;
+
+        /* Clear any pending interrupts
+         * and disable tx dma */
+        if (ah->ah_version != AR5K_AR5210) {
+                ath5k_hw_reg_write(ah, 0xffffffff, AR5K_PISR);
+                qmax = AR5K_NUM_TX_QUEUES;
+        } else {
+                /* PISR/SISR Not available on 5210 */
+                ath5k_hw_reg_read(ah, AR5K_ISR);
+                qmax = AR5K_NUM_TX_QUEUES_NOQCU;
+        }
+
+        for (i = 0; i < qmax; i++) {
+                err = ath5k_hw_stop_tx_dma(ah, i);
+                /* -EINVAL -> queue inactive */
+                if (err != -EINVAL)
+                        return err;
+        }
+
+        return err;
+}
diff --git a/drivers/net/wireless/ath/ath5k/reset.c b/drivers/net/wireless/ath/ath5k/reset.c
index 9dd5792780ba..083367712d67 100644
--- a/drivers/net/wireless/ath/ath5k/reset.c
+++ b/drivers/net/wireless/ath/ath5k/reset.c
@@ -823,6 +823,14 @@ int ath5k_hw_reset(struct ath5k_hw *ah, enum nl80211_iftype op_mode,
         mode = 0;
 
         /*
+         * Stop DMA
+         *
+         * Note: If DMA didn't stop continue
+         * since only a reset will fix it.
+         */
+        ath5k_hw_dma_stop(ah);
+
+        /*
          * Save some registers before a reset
          */
         /*DCU/Antenna selection not available on 5210*/
@@ -1015,11 +1023,6 @@ int ath5k_hw_reset(struct ath5k_hw *ah, enum nl80211_iftype op_mode,
          */
         ath5k_hw_pcu_init(ah, op_mode, mode);
 
-        /* Clear any pending interrupts
-         * PISR/SISR Not available on 5210 */
-        if (ah->ah_version != AR5K_AR5210)
-                ath5k_hw_reg_write(ah, 0xffffffff, AR5K_PISR);
-
         /*
          * Initialize PHY
          */