ath10k: re-add support for early fw indication

It's possible for FW to panic during early boot.

The patch re-introduces support to detect and
print those crashes.

This introduces an additional irq handler that is
set for the duration of early boot and shutdown.
The handler is then overriden with regular
handlers upon hif start().

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/pci.c

@@ -248,6 +248,46 @@ static void ath10k_pci_enable_legacy_irq(struct ath10k *ar)
 				 PCIE_INTR_ENABLE_ADDRESS);
 }
 
+static irqreturn_t ath10k_pci_early_irq_handler(int irq, void *arg)
+{
+	struct ath10k *ar = arg;
+	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
+
+	if (ar_pci->num_msi_intrs == 0) {
+		if (!ath10k_pci_irq_pending(ar))
+			return IRQ_NONE;
+
+		ath10k_pci_disable_and_clear_legacy_irq(ar);
+	}
+
+	tasklet_schedule(&ar_pci->early_irq_tasklet);
+
+	return IRQ_HANDLED;
+}
+
+static int ath10k_pci_request_early_irq(struct ath10k *ar)
+{
+	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
+	int ret;
+
+	/* Regardless whether MSI-X/MSI/legacy irqs have been set up the first
+	 * interrupt from irq vector is triggered in all cases for FW
+	 * indication/errors */
+	ret = request_irq(ar_pci->pdev->irq, ath10k_pci_early_irq_handler,
+			  IRQF_SHARED, "ath10k_pci (early)", ar);
+	if (ret) {
+		ath10k_warn("failed to request early irq: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void ath10k_pci_free_early_irq(struct ath10k *ar)
+{
+	free_irq(ath10k_pci_priv(ar)->pdev->irq, ar);
+}
+
 /*
  * Diagnostic read/write access is provided for startup/config/debug usage.
  * Caller must guarantee proper alignment, when applicable, and single user
@@ -937,6 +977,7 @@ static void ath10k_pci_kill_tasklet(struct ath10k *ar)
 
 	tasklet_kill(&ar_pci->intr_tq);
 	tasklet_kill(&ar_pci->msi_fw_err);
+	tasklet_kill(&ar_pci->early_irq_tasklet);
 
 	for (i = 0; i < CE_COUNT; i++)
 		tasklet_kill(&ar_pci->pipe_info[i].intr);
@@ -1249,12 +1290,15 @@ static int ath10k_pci_post_rx(struct ath10k *ar)
 static int ath10k_pci_hif_start(struct ath10k *ar)
 {
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
-	int ret;
+	int ret, ret_early;
+
+	ath10k_pci_free_early_irq(ar);
+	ath10k_pci_kill_tasklet(ar);
 
 	ret = ath10k_pci_alloc_compl(ar);
 	if (ret) {
 		ath10k_warn("failed to allocate CE completions: %d\n", ret);
-		return ret;
+		goto err_early_irq;
 	}
 
 	ret = ath10k_pci_request_irq(ar);
@@ -1289,6 +1333,14 @@ err_stop:
 	ath10k_pci_process_ce(ar);
 err_free_compl:
 	ath10k_pci_cleanup_ce(ar);
+err_early_irq:
+	/* Though there should be no interrupts (device was reset)
+	 * power_down() expects the early IRQ to be installed as per the
+	 * driver lifecycle. */
+	ret_early = ath10k_pci_request_early_irq(ar);
+	if (ret_early)
+		ath10k_warn("failed to re-enable early irq: %d\n", ret_early);
+
 	return ret;
 }
 
@@ -1422,6 +1474,10 @@ static void ath10k_pci_hif_stop(struct ath10k *ar)
 	ath10k_pci_kill_tasklet(ar);
 	ath10k_pci_stop_ce(ar);
 
+	ret = ath10k_pci_request_early_irq(ar);
+	if (ret)
+		ath10k_warn("failed to re-enable early irq: %d\n", ret);
+
 	/* At this point, asynchronous threads are stopped, the target should
 	 * not DMA nor interrupt. We process the leftovers and then free
 	 * everything else up. */
@@ -1970,22 +2026,28 @@ static int ath10k_pci_hif_power_up(struct ath10k *ar)
 		goto err_ce;
 	}
 
+	ret = ath10k_pci_request_early_irq(ar);
+	if (ret) {
+		ath10k_err("failed to request early irq: %d\n", ret);
+		goto err_deinit_irq;
+	}
+
 	ret = ath10k_pci_wait_for_target_init(ar);
 	if (ret) {
 		ath10k_err("failed to wait for target to init: %d\n", ret);
-		goto err_deinit_irq;
+		goto err_free_early_irq;
 	}
 
 	ret = ath10k_pci_init_config(ar);
 	if (ret) {
 		ath10k_err("failed to setup init config: %d\n", ret);
-		goto err_deinit_irq;
+		goto err_free_early_irq;
 	}
 
 	ret = ath10k_pci_wake_target_cpu(ar);
 	if (ret) {
 		ath10k_err("could not wake up target CPU: %d\n", ret);
-		goto err_deinit_irq;
+		goto err_free_early_irq;
 	}
 
 	if (ar_pci->num_msi_intrs > 1)
@@ -2000,6 +2062,8 @@ static int ath10k_pci_hif_power_up(struct ath10k *ar)
 
 	return 0;
 
+err_free_early_irq:
+	ath10k_pci_free_early_irq(ar);
 err_deinit_irq:
 	ath10k_pci_deinit_irq(ar);
 err_ce:
@@ -2016,6 +2080,8 @@ static void ath10k_pci_hif_power_down(struct ath10k *ar)
 {
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
 
+	ath10k_pci_free_early_irq(ar);
+	ath10k_pci_kill_tasklet(ar);
 	ath10k_pci_deinit_irq(ar);
 	ath10k_pci_device_reset(ar);
 
@@ -2164,6 +2230,34 @@ static irqreturn_t ath10k_pci_interrupt_handler(int irq, void *arg)
 	return IRQ_HANDLED;
 }
 
+static void ath10k_pci_early_irq_tasklet(unsigned long data)
+{
+	struct ath10k *ar = (struct ath10k *)data;
+	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
+	u32 fw_ind;
+	int ret;
+
+	ret = ath10k_pci_wake(ar);
+	if (ret) {
+		ath10k_warn("failed to wake target in early irq tasklet: %d\n",
+			    ret);
+		return;
+	}
+
+	fw_ind = ath10k_pci_read32(ar, ar_pci->fw_indicator_address);
+	if (fw_ind & FW_IND_EVENT_PENDING) {
+		ath10k_pci_write32(ar, ar_pci->fw_indicator_address,
+				   fw_ind & ~FW_IND_EVENT_PENDING);
+
+		/* Some structures are unavailable during early boot or at
+		 * driver teardown so just print that the device has crashed. */
+		ath10k_warn("device crashed - no diagnostics available\n");
+	}
+
+	ath10k_pci_sleep(ar);
+	ath10k_pci_enable_legacy_irq(ar);
+}
+
 static void ath10k_pci_tasklet(unsigned long data)
 {
 	struct ath10k *ar = (struct ath10k *)data;
@@ -2280,6 +2374,8 @@ static void ath10k_pci_init_irq_tasklets(struct ath10k *ar)
 	tasklet_init(&ar_pci->intr_tq, ath10k_pci_tasklet, (unsigned long)ar);
 	tasklet_init(&ar_pci->msi_fw_err, ath10k_msi_err_tasklet,
 		     (unsigned long)ar);
+	tasklet_init(&ar_pci->early_irq_tasklet, ath10k_pci_early_irq_tasklet,
+		     (unsigned long)ar);
 
 	for (i = 0; i < CE_COUNT; i++) {
 		ar_pci->pipe_info[i].ar_pci = ar_pci;

drivers/net/wireless/ath/ath10k/pci.h

@@ -198,6 +198,7 @@ struct ath10k_pci {
 
 	struct tasklet_struct intr_tq;
 	struct tasklet_struct msi_fw_err;
+	struct tasklet_struct early_irq_tasklet;
 
 	int started;