linux-kernel - [PATCH v3 1/8] iommu/arm-smmu: Refactor context bank allocation

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Date:   Fri,  4 Sep 2020 15:55:06 +0000
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>,
        Jordan Crouse <jcrouse@...eaurora.org>,
        Rob Clark <robdclark@...omium.org>
Cc:     Sibi Sankar <sibis@...eaurora.org>,
        linux-arm-kernel@...ts.infradead.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org
Subject: [PATCH v3 1/8] iommu/arm-smmu: Refactor context bank allocation

Extract the conditional invocation of the platform defined
alloc_context_bank() to a separate function to keep
arm_smmu_init_domain_context() cleaner.

Instead pass a reference to the arm_smmu_device as parameter to the
call. Also remove the count parameter, as this can be read from the
newly passed object.

This allows us to not assign smmu_domain->smmu before attempting to
allocate the context bank and as such we don't need to roll back this
assignment on failure.

Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
---

Note that this series applies ontop of:
https://lore.kernel.org/linux-arm-msm/20200901164707.2645413-1-robdclark@gmail.com/

This could either go on its own, or be squashed with "[PATCH v16 14/20]
iommu/arm-smmu: Prepare for the adreno-smmu implementation" from Rob's series.

Changes since v2:
- New patch

 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c |  6 ++++--
 drivers/iommu/arm/arm-smmu/arm-smmu.c      | 23 ++++++++++++----------
 drivers/iommu/arm/arm-smmu/arm-smmu.h      |  3 ++-
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 2aa6249050ff..0663d7d26908 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -91,9 +91,10 @@ static int qcom_adreno_smmu_set_ttbr0_cfg(const void *cookie,
 }
 
 static int qcom_adreno_smmu_alloc_context_bank(struct arm_smmu_domain *smmu_domain,
-		struct device *dev, int start, int count)
+					       struct arm_smmu_device *smmu,
+					       struct device *dev, int start)
 {
-	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	int count;
 
 	/*
 	 * Assign context bank 0 to the GPU device so the GPU hardware can
@@ -104,6 +105,7 @@ static int qcom_adreno_smmu_alloc_context_bank(struct arm_smmu_domain *smmu_doma
 		count = 1;
 	} else {
 		start = 1;
+		count = smmu->num_context_banks;
 	}
 
 	return __arm_smmu_alloc_bitmap(smmu->context_map, start, count);
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index bbec5793faf8..e19d7bdc7674 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -623,6 +623,16 @@ void arm_smmu_write_context_bank(struct arm_smmu_device *smmu, int idx)
 	arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_SCTLR, reg);
 }
 
+static int arm_smmu_alloc_context_bank(struct arm_smmu_domain *smmu_domain,
+				       struct arm_smmu_device *smmu,
+				       struct device *dev, unsigned int start)
+{
+	if (smmu->impl && smmu->impl->alloc_context_bank)
+		return smmu->impl->alloc_context_bank(smmu_domain, smmu, dev, start);
+
+	return __arm_smmu_alloc_bitmap(smmu->context_map, start, smmu->num_context_banks);
+}
+
 static int arm_smmu_init_domain_context(struct iommu_domain *domain,
 					struct arm_smmu_device *smmu,
 					struct device *dev)
@@ -741,20 +751,13 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
 		goto out_unlock;
 	}
 
-	smmu_domain->smmu = smmu;
-
-	if (smmu->impl && smmu->impl->alloc_context_bank)
-		ret = smmu->impl->alloc_context_bank(smmu_domain, dev,
-				start, smmu->num_context_banks);
-	else
-		ret = __arm_smmu_alloc_bitmap(smmu->context_map, start,
-				      smmu->num_context_banks);
-
+	ret = arm_smmu_alloc_context_bank(smmu_domain, smmu, dev, start);
 	if (ret < 0) {
-		smmu_domain->smmu = NULL;
 		goto out_unlock;
 	}
 
+	smmu_domain->smmu = smmu;
+
 	cfg->cbndx = ret;
 	if (smmu->version < ARM_SMMU_V2) {
 		cfg->irptndx = atomic_inc_return(&smmu->irptndx);
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
index 2df3a70a8a41..ddf2ca4c923d 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
@@ -437,7 +437,8 @@ struct arm_smmu_impl {
 	irqreturn_t (*global_fault)(int irq, void *dev);
 	irqreturn_t (*context_fault)(int irq, void *dev);
 	int (*alloc_context_bank)(struct arm_smmu_domain *smmu_domain,
-			struct device *dev, int start, int max);
+				  struct arm_smmu_device *smmu,
+				  struct device *dev, int start);
 };
 
 #define INVALID_SMENDX			-1
-- 
2.28.0