ath10k: split reset logic from power up

The power up procedure was overly complex due to
warm/cold reset workarounds and issues.
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

@@ -1792,83 +1792,78 @@ static int ath10k_pci_warm_reset(struct ath10k *ar)
 	return 0;
 }
 
-static int __ath10k_pci_hif_power_up(struct ath10k *ar, bool cold_reset)
+static int ath10k_pci_chip_reset(struct ath10k *ar)
 {
-	int ret;
+	int i, ret;
+	u32 val;
 
-	/*
-	 * Bring the target up cleanly.
+	ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot chip reset\n");
+
+	/* Some hardware revisions (e.g. CUS223v2) has issues with cold reset.
+	 * It is thus preferred to use warm reset which is safer but may not be
+	 * able to recover the device from all possible fail scenarios.
 	 *
-	 * The target may be in an undefined state with an AUX-powered Target
-	 * and a Host in WoW mode. If the Host crashes, loses power, or is
-	 * restarted (without unloading the driver) then the Target is left
-	 * (aux) powered and running. On a subsequent driver load, the Target
-	 * is in an unexpected state. We try to catch that here in order to
-	 * reset the Target and retry the probe.
+	 * Warm reset doesn't always work on first try so attempt it a few
+	 * times before giving up.
 	 */
-	if (cold_reset)
-		ret = ath10k_pci_cold_reset(ar);
-	else
+	for (i = 0; i < ATH10K_PCI_NUM_WARM_RESET_ATTEMPTS; i++) {
 		ret = ath10k_pci_warm_reset(ar);
-
 		if (ret) {
-		ath10k_err(ar, "failed to reset target: %d\n", ret);
-		goto err;
+			ath10k_warn(ar, "failed to warm reset attempt %d of %d: %d\n",
+				    i + 1, ATH10K_PCI_NUM_WARM_RESET_ATTEMPTS,
+				    ret);
+			continue;
 		}
 
+		/* FIXME: Sometimes copy engine doesn't recover after warm
+		 * reset. In most cases this needs cold reset. In some of these
+		 * cases the device is in such a state that a cold reset may
+		 * lock up the host.
+		 *
+		 * Reading any host interest register via copy engine is
+		 * sufficient to verify if device is capable of booting
+		 * firmware blob.
+		 */
 		ret = ath10k_pci_init_pipes(ar);
 		if (ret) {
-		ath10k_err(ar, "failed to initialize CE: %d\n", ret);
-		goto err;
+			ath10k_warn(ar, "failed to init copy engine: %d\n",
+				    ret);
+			continue;
 		}
 
-	ret = ath10k_pci_wait_for_target_init(ar);
+		ret = ath10k_pci_diag_read32(ar, QCA988X_HOST_INTEREST_ADDRESS,
+					     &val);
 		if (ret) {
-		ath10k_err(ar, "failed to wait for target to init: %d\n", ret);
-		goto err_ce;
+			ath10k_warn(ar, "failed to poke copy engine: %d\n",
+				    ret);
+			continue;
 		}
 
-	ret = ath10k_pci_init_config(ar);
-	if (ret) {
-		ath10k_err(ar, "failed to setup init config: %d\n", ret);
-		goto err_ce;
+		ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot chip reset complete (warm)\n");
+		return 0;
 	}
 
-	ret = ath10k_pci_wake_target_cpu(ar);
-	if (ret) {
-		ath10k_err(ar, "could not wake up target CPU: %d\n", ret);
-		goto err_ce;
+	if (ath10k_pci_reset_mode == ATH10K_PCI_RESET_WARM_ONLY) {
+		ath10k_warn(ar, "refusing cold reset as requested\n");
+		return -EPERM;
 	}
 
-	return 0;
-
-err_ce:
-	ath10k_pci_ce_deinit(ar);
-	ath10k_pci_warm_reset(ar);
-err:
+	ret = ath10k_pci_cold_reset(ar);
+	if (ret) {
+		ath10k_warn(ar, "failed to cold reset: %d\n", ret);
 		return ret;
-}
-
-static int ath10k_pci_hif_power_up_warm(struct ath10k *ar)
-{
-	int i, ret;
-
-	/*
-	 * Sometime warm reset succeeds after retries.
-	 *
-	 * FIXME: It might be possible to tune ath10k_pci_warm_reset() to work
-	 * at first try.
-	 */
-	for (i = 0; i < ATH10K_PCI_NUM_WARM_RESET_ATTEMPTS; i++) {
-		ret = __ath10k_pci_hif_power_up(ar, false);
-		if (ret == 0)
-			break;
-
-		ath10k_warn(ar, "failed to warm reset (attempt %d out of %d): %d\n",
-			    i + 1, ATH10K_PCI_NUM_WARM_RESET_ATTEMPTS, ret);
 	}
 
+	ret = ath10k_pci_wait_for_target_init(ar);
+	if (ret) {
+		ath10k_warn(ar, "failed to wait for target after cold reset: %d\n",
+			    ret);
 		return ret;
+	}
+
+	ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot chip reset complete (cold)\n");
+
+	return 0;
 }
 
 static int ath10k_pci_hif_power_up(struct ath10k *ar)
@@ -1878,32 +1873,46 @@ static int ath10k_pci_hif_power_up(struct ath10k *ar)
 	ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot hif power up\n");
 
 	/*
-	 * Hardware CUS232 version 2 has some issues with cold reset and the
-	 * preferred (and safer) way to perform a device reset is through a
-	 * warm reset.
+	 * Bring the target up cleanly.
 	 *
-	 * Warm reset doesn't always work though so fall back to cold reset may
-	 * be necessary.
+	 * The target may be in an undefined state with an AUX-powered Target
+	 * and a Host in WoW mode. If the Host crashes, loses power, or is
+	 * restarted (without unloading the driver) then the Target is left
+	 * (aux) powered and running. On a subsequent driver load, the Target
+	 * is in an unexpected state. We try to catch that here in order to
+	 * reset the Target and retry the probe.
 	 */
-	ret = ath10k_pci_hif_power_up_warm(ar);
+	ret = ath10k_pci_chip_reset(ar);
 	if (ret) {
-		ath10k_warn(ar, "failed to power up target using warm reset: %d\n",
-			    ret);
-
-		if (ath10k_pci_reset_mode == ATH10K_PCI_RESET_WARM_ONLY)
-			return ret;
+		ath10k_err(ar, "failed to reset chip: %d\n", ret);
+		goto err;
+	}
 
-		ath10k_warn(ar, "trying cold reset\n");
+	ret = ath10k_pci_init_pipes(ar);
+	if (ret) {
+		ath10k_err(ar, "failed to initialize CE: %d\n", ret);
+		goto err;
+	}
 
-		ret = __ath10k_pci_hif_power_up(ar, true);
+	ret = ath10k_pci_init_config(ar);
 	if (ret) {
-			ath10k_err(ar, "failed to power up target using cold reset too (%d)\n",
-				   ret);
-			return ret;
+		ath10k_err(ar, "failed to setup init config: %d\n", ret);
+		goto err_ce;
 	}
+
+	ret = ath10k_pci_wake_target_cpu(ar);
+	if (ret) {
+		ath10k_err(ar, "could not wake up target CPU: %d\n", ret);
+		goto err_ce;
 	}
 
 	return 0;
+
+err_ce:
+	ath10k_pci_ce_deinit(ar);
+
+err:
+	return ret;
 }
 
 static void ath10k_pci_hif_power_down(struct ath10k *ar)