ath9k_hw: check GPM HW write pointer before chip reset

Both "MAC Warm Reset" and "MCI Reset Rx" will reset GPM HW write_ptr.
We should check software cached write_ptr against HW write_ptr before
reset. Otherwise the pending DMA data will be lost.

Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 22 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath9k/ar9003_mci.c b/drivers/net/wireless/ath/ath9k/ar9003_mci.c
index 13907f63bdc0..cbeff9c4b5d8 100644
--- a/drivers/net/wireless/ath/ath9k/ar9003_mci.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_mci.c
@@ -893,6 +893,9 @@ void ar9003_mci_reset(struct ath_hw *ah, bool en_int, bool is_2g,
                 udelay(100);
         }
 
+        /* Check pending GPM msg before MCI Reset Rx */
+        ar9003_mci_state(ah, MCI_STATE_CHECK_GPM_OFFSET, NULL);
+
         regval |= SM(1, AR_MCI_COMMAND2_RESET_RX);
         REG_WRITE(ah, AR_MCI_COMMAND2, regval);
         udelay(1);
@@ -1190,6 +1193,21 @@ u32 ar9003_mci_state(struct ath_hw *ah, u32 state_type, u32 *p_data)
                 value = MS(REG_READ(ah, AR_MCI_GPM_1), AR_MCI_GPM_WRITE_PTR);
                 mci->gpm_idx = value;
                 break;
+        case MCI_STATE_CHECK_GPM_OFFSET:
+                /*
+                 * This should only be called before "MAC Warm Reset" or
+                 * "MCI Reset Rx".
+                 */
+                value = MS(REG_READ(ah, AR_MCI_GPM_1), AR_MCI_GPM_WRITE_PTR);
+                if (mci->gpm_idx == value)
+                        break;
+                ath_dbg(common, MCI,
+                        "GPM cached write pointer mismatch %d %d\n",
+                        mci->gpm_idx, value);
+                mci->query_bt = true;
+                mci->need_flush_btinfo = true;
+                mci->gpm_idx = 0;
+                break;
         case MCI_STATE_NEXT_GPM_OFFSET:
         case MCI_STATE_LAST_GPM_OFFSET:
                 /*
diff --git a/drivers/net/wireless/ath/ath9k/ar9003_mci.h b/drivers/net/wireless/ath/ath9k/ar9003_mci.h
index 2a8c764281ba..45624e1d3960 100644
--- a/drivers/net/wireless/ath/ath9k/ar9003_mci.h
+++ b/drivers/net/wireless/ath/ath9k/ar9003_mci.h
@@ -190,6 +190,7 @@ enum mci_bt_state {
 enum mci_state_type {
         MCI_STATE_ENABLE,
         MCI_STATE_INIT_GPM_OFFSET,
+        MCI_STATE_CHECK_GPM_OFFSET,
         MCI_STATE_NEXT_GPM_OFFSET,
         MCI_STATE_LAST_GPM_OFFSET,
         MCI_STATE_BT,
diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 6d893335f42b..8412128b842a 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1348,6 +1348,9 @@ static bool ath9k_hw_set_reset(struct ath_hw *ah, int type)
                 }
         }
 
+        if (ath9k_hw_mci_is_enabled(ah))
+                ar9003_mci_state(ah, MCI_STATE_CHECK_GPM_OFFSET, NULL);
+
         REG_WRITE(ah, AR_RTC_RC, rst_flags);
 
         REGWRITE_BUFFER_FLUSH(ah);