mwifiex: fix interrupt processing corner case in MSI mode

As interrupt is read in interrupt handler as well as interrupt processing
thread, we observed a corner case issue for MSI in which interrupt gets
processed twice.

This patch moves interrupt reading code for MSI mode from
mwifiex_interrupt_status() to mwifiex_pcie_process_int() to avoid the
issue.

Signed-off-by: Shengzhen Li <szli@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/marvell/mwifiex/pcie.c

@@ -2091,6 +2091,13 @@ static void mwifiex_interrupt_status(struct mwifiex_adapter *adapter,
 	unsigned long flags;
 	struct pcie_service_card *card = adapter->card;
 
+	if (card->msi_enable) {
+		spin_lock_irqsave(&adapter->int_lock, flags);
+		adapter->int_status = 1;
+		spin_unlock_irqrestore(&adapter->int_lock, flags);
+		return;
+	}
+
 	if (!mwifiex_pcie_ok_to_access_hw(adapter))
 		return;
 
@@ -2192,15 +2199,44 @@ exit:
 static int mwifiex_process_pcie_int(struct mwifiex_adapter *adapter)
 {
 	int ret;
-	u32 pcie_ireg;
+	u32 pcie_ireg = 0;
 	unsigned long flags;
+	struct pcie_service_card *card = adapter->card;
 
 	spin_lock_irqsave(&adapter->int_lock, flags);
-	/* Clear out unused interrupts */
-	pcie_ireg = adapter->int_status;
+	if (!card->msi_enable) {
+		/* Clear out unused interrupts */
+		pcie_ireg = adapter->int_status;
+	}
 	adapter->int_status = 0;
 	spin_unlock_irqrestore(&adapter->int_lock, flags);
 
+	if (card->msi_enable) {
+		if (mwifiex_pcie_ok_to_access_hw(adapter)) {
+			if (mwifiex_read_reg(adapter, PCIE_HOST_INT_STATUS,
+					     &pcie_ireg)) {
+				mwifiex_dbg(adapter, ERROR,
+					    "Read register failed\n");
+				return -1;
+			}
+
+			if ((pcie_ireg != 0xFFFFFFFF) && (pcie_ireg)) {
+				if (mwifiex_write_reg(adapter,
+						      PCIE_HOST_INT_STATUS,
+						      ~pcie_ireg)) {
+					mwifiex_dbg(adapter, ERROR,
+						    "Write register failed\n");
+					return -1;
+				}
+				if (!adapter->pps_uapsd_mode &&
+				    adapter->ps_state == PS_STATE_SLEEP) {
+					adapter->ps_state = PS_STATE_AWAKE;
+					adapter->pm_wakeup_fw_try = false;
+					del_timer(&adapter->wakeup_timer);
+				}
+			}
+		}
+	}
 	while (pcie_ireg & HOST_INTR_MASK) {
 		if (pcie_ireg & HOST_INTR_DNLD_DONE) {
 			pcie_ireg &= ~HOST_INTR_DNLD_DONE;
@@ -2240,6 +2276,12 @@ static int mwifiex_process_pcie_int(struct mwifiex_adapter *adapter)
 				return ret;
 		}
 
+		if (card->msi_enable) {
+			spin_lock_irqsave(&adapter->int_lock, flags);
+			adapter->int_status = 0;
+			spin_unlock_irqrestore(&adapter->int_lock, flags);
+		}
+
 		if (mwifiex_pcie_ok_to_access_hw(adapter)) {
 			if (mwifiex_read_reg(adapter, PCIE_HOST_INT_STATUS,
 					     &pcie_ireg)) {
@@ -2263,7 +2305,7 @@ static int mwifiex_process_pcie_int(struct mwifiex_adapter *adapter)
 	mwifiex_dbg(adapter, INTR,
 		    "info: cmd_sent=%d data_sent=%d\n",
 		    adapter->cmd_sent, adapter->data_sent);
-	if (adapter->ps_state != PS_STATE_SLEEP)
+	if (!card->msi_enable && adapter->ps_state != PS_STATE_SLEEP)
 		mwifiex_pcie_enable_host_int(adapter);
 
 	return 0;