wifi: brcmfmac: Handle PCIe MSI properly

On newer firmwares under at least certain conditions, MSI mode does not
leave interrupt flags set (they are cleared by the firmware). Handle
this by always checking for ring data when we get an MSI, regardless of
whether any IRQ flags were set.

Signed-off-by: Hector Martin <marcan@marcan.st>

Author: marcan

drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c

@@ -401,6 +401,7 @@ struct brcmf_pciedev_info {
 	wait_queue_head_t mbdata_resp_wait;
 	bool mbdata_completed;
 	bool irq_allocated;
+	bool have_msi;
 	bool wowl_enabled;
 	u8 dma_idx_sz;
 	void *idxbuf;
@@ -985,6 +986,11 @@ static irqreturn_t brcmf_pcie_quick_check_isr(int irq, void *arg)
 		brcmf_dbg(PCIE, "Enter\n");
 		return IRQ_WAKE_THREAD;
 	}
+
+	/* mailboxint is cleared by the firmware in MSI mode */
+	if (devinfo->have_msi)
+		return IRQ_WAKE_THREAD;
+
 	return IRQ_NONE;
 }
 
@@ -1002,12 +1008,12 @@ static irqreturn_t brcmf_pcie_isr_thread(int irq, void *arg)
 				       status);
 		if (status & devinfo->reginfo->int_fn0)
 			brcmf_pcie_handle_mb_data(devinfo);
-		if (status & devinfo->reginfo->int_d2h_db) {
-			if (devinfo->state == BRCMFMAC_PCIE_STATE_UP)
-				brcmf_proto_msgbuf_rx_trigger(
-							&devinfo->pdev->dev);
-		}
 	}
+	if (devinfo->have_msi || status & devinfo->reginfo->int_d2h_db) {
+		if (devinfo->state == BRCMFMAC_PCIE_STATE_UP)
+			brcmf_proto_msgbuf_rx_trigger(&devinfo->pdev->dev);
+	}
+
 	brcmf_pcie_bus_console_read(devinfo, false);
 	if (devinfo->state == BRCMFMAC_PCIE_STATE_UP)
 		brcmf_pcie_intr_enable(devinfo);
@@ -1025,7 +1031,10 @@ static int brcmf_pcie_request_irq(struct brcmf_pciedev_info *devinfo)
 
 	brcmf_dbg(PCIE, "Enter\n");
 
-	pci_enable_msi(pdev);
+	devinfo->have_msi = pci_enable_msi(pdev) >= 0;
+	if (devinfo->have_msi)
+		brcmf_dbg(PCIE, "MSI enabled\n");
+
 	if (request_threaded_irq(pdev->irq, brcmf_pcie_quick_check_isr,
 				 brcmf_pcie_isr_thread, IRQF_SHARED,
 				 "brcmf_pcie_intr", devinfo)) {