From b9574483ec87ea86143fceea25f24cee2b7c6477 Mon Sep 17 00:00:00 2001
From: Yang Yingliang <yangyingliang@huawei.com>
Date: Mon, 14 Jan 2019 16:36:21 +0800
Subject: [PATCH] Revert "Revert "iommu/arm-smmu-v3: Abort all transactions if
 SMMU is enabled in kdump kernel""

This reverts commit 1d9623d5b010387003f2a6c383f520d711fe4db9.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 drivers/iommu/arm-smmu-v3.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 20da714b234b..93a80abab24d 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -24,6 +24,7 @@
 #include <linux/acpi_iort.h>
 #include <linux/bitfield.h>
 #include <linux/bitops.h>
+#include <linux/crash_dump.h>
 #include <linux/delay.h>
 #include <linux/dma-iommu.h>
 #include <linux/err.h>
@@ -2243,8 +2244,12 @@ static int arm_smmu_update_gbpa(struct arm_smmu_device *smmu, u32 set, u32 clr)
 	reg &= ~clr;
 	reg |= set;
 	writel_relaxed(reg | GBPA_UPDATE, gbpa);
-	return readl_relaxed_poll_timeout(gbpa, reg, !(reg & GBPA_UPDATE),
-					  1, ARM_SMMU_POLL_TIMEOUT_US);
+	ret = readl_relaxed_poll_timeout(gbpa, reg, !(reg & GBPA_UPDATE),
+					 1, ARM_SMMU_POLL_TIMEOUT_US);
+
+	if (ret)
+		dev_err(smmu->dev, "GBPA not responding to update\n");
+	return ret;
 }
 
 static void arm_smmu_free_msis(void *data)
@@ -2424,8 +2429,15 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
 
 	/* Clear CR0 and sync (disables SMMU and queue processing) */
 	reg = readl_relaxed(smmu->base + ARM_SMMU_CR0);
-	if (reg & CR0_SMMUEN)
+	if (reg & CR0_SMMUEN) {
+		if (is_kdump_kernel()) {
+			arm_smmu_update_gbpa(smmu, GBPA_ABORT, 0);
+			arm_smmu_device_disable(smmu);
+			return -EBUSY;
+		}
+
 		dev_warn(smmu->dev, "SMMU currently enabled! Resetting...\n");
+	}
 
 	ret = arm_smmu_device_disable(smmu);
 	if (ret)
@@ -2523,10 +2535,8 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
 		enables |= CR0_SMMUEN;
 	} else {
 		ret = arm_smmu_update_gbpa(smmu, 0, GBPA_ABORT);
-		if (ret) {
-			dev_err(smmu->dev, "GBPA not responding to update\n");
+		if (ret)
 			return ret;
-		}
 	}
 	ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
 				      ARM_SMMU_CR0ACK);
-- 
GitLab