[PATCH v8 06/12] iommu/arm-smmu-v3: Handle gerror during suspend

[Pranjal Shrivastava <praan@google.com>]

The GERROR register's state might be lost when the SMMU is powered down
during runtime suspend. Handle any pending errors before suspending.

Refactor the gerror handling logic into a helper function and invoke it
from the runtime suspend callback after disabling the SMMU. This ensures
that any late-breaking gerrors are logged and ack'ed before the hardware
state is lost.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Pranjal Shrivastava <praan@google.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 93cee32f6c99..6c8631e2f153 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2257,10 +2257,10 @@ static irqreturn_t arm_smmu_priq_thread(int irq, void *dev)
 
 static int arm_smmu_device_disable(struct arm_smmu_device *smmu);
 
-static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev)
+/* Lockless; must ensure that there are no concurrent callers */
+static irqreturn_t arm_smmu_handle_gerror(struct arm_smmu_device *smmu)
 {
 	u32 gerror, gerrorn, active;
-	struct arm_smmu_device *smmu = dev;
 
 	gerror = readl_relaxed(smmu->base + ARM_SMMU_GERROR);
 	gerrorn = readl_relaxed(smmu->base + ARM_SMMU_GERRORN);
@@ -2300,9 +2300,17 @@ static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev)
 		arm_smmu_cmdq_skip_err(smmu);
 
 	writel(gerror, smmu->base + ARM_SMMU_GERRORN);
+
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev)
+{
+	struct arm_smmu_device *smmu = dev;
+
+	return arm_smmu_handle_gerror(smmu);
+}
+
 static irqreturn_t arm_smmu_combined_irq_thread(int irq, void *dev)
 {
 	struct arm_smmu_device *smmu = dev;
-- 
2.54.0.1013.g208068f2d8-goog