ath10k: fix missing checks for bmi reads and writes

ath10k_bmi_write32 and ath10k_bmi_read32 can fail. The fix
checks their statuses to avoid potential undefined behaviors.
Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -677,13 +677,22 @@ static void ath10k_send_suspend_complete(struct ath10k *ar)
 	complete(&ar->target_suspend);
 }
 
-static void ath10k_init_sdio(struct ath10k *ar, enum ath10k_firmware_mode mode)
+static int ath10k_init_sdio(struct ath10k *ar, enum ath10k_firmware_mode mode)
 {
+	int ret;
 	u32 param = 0;
 
-	ath10k_bmi_write32(ar, hi_mbox_io_block_sz, 256);
-	ath10k_bmi_write32(ar, hi_mbox_isr_yield_limit, 99);
-	ath10k_bmi_read32(ar, hi_acs_flags, &param);
+	ret = ath10k_bmi_write32(ar, hi_mbox_io_block_sz, 256);
+	if (ret)
+		return ret;
+
+	ret = ath10k_bmi_write32(ar, hi_mbox_isr_yield_limit, 99);
+	if (ret)
+		return ret;
+
+	ret = ath10k_bmi_read32(ar, hi_acs_flags, &param);
+	if (ret)
+		return ret;
 
 	/* Data transfer is not initiated, when reduced Tx completion
 	 * is used for SDIO. disable it until fixed
@@ -700,14 +709,23 @@ static void ath10k_init_sdio(struct ath10k *ar, enum ath10k_firmware_mode mode)
 	else
 		param |= HI_ACS_FLAGS_SDIO_SWAP_MAILBOX_SET;
 
-	ath10k_bmi_write32(ar, hi_acs_flags, param);
+	ret = ath10k_bmi_write32(ar, hi_acs_flags, param);
+	if (ret)
+		return ret;
 
 	/* Explicitly set fwlog prints to zero as target may turn it on
 	 * based on scratch registers.
 	 */
-	ath10k_bmi_read32(ar, hi_option_flag, &param);
+	ret = ath10k_bmi_read32(ar, hi_option_flag, &param);
+	if (ret)
+		return ret;
+
 	param |= HI_OPTION_DISABLE_DBGLOG;
-	ath10k_bmi_write32(ar, hi_option_flag, param);
+	ret = ath10k_bmi_write32(ar, hi_option_flag, param);
+	if (ret)
+		return ret;
+
+	return 0;
 }
 
 static int ath10k_init_configure_target(struct ath10k *ar)
@@ -2565,8 +2583,13 @@ int ath10k_core_start(struct ath10k *ar, enum ath10k_firmware_mode mode,
 		if (status)
 			goto err;
 
-		if (ar->hif.bus == ATH10K_BUS_SDIO)
-			ath10k_init_sdio(ar, mode);
+		if (ar->hif.bus == ATH10K_BUS_SDIO) {
+			status = ath10k_init_sdio(ar, mode);
+			if (status) {
+				ath10k_err(ar, "failed to init SDIO: %d\n", status);
+				goto err;
+			}
+		}
 	}
 
 	ar->htc.htc_ops.target_send_suspend_complete =