[PATCH 1/2] iommu/arm-smmu: use relaxed accessors where possible

[PATCH 1/2] iommu/arm-smmu: use relaxed accessors where possible

[Will Deacon]

Apart from fault handling and page table manipulation, we don't care
about memory ordering between SMMU control registers and normal,
cacheable memory, so use the _relaxed I/O accessors wherever possible.

Signed-off-by: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>
---
 drivers/iommu/arm-smmu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 4b9158a..c3642cc 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -778,7 +778,7 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain)
 #ifdef __BIG_ENDIAN
 	reg |= SCTLR_E;
 #endif
-	writel(reg, cb_base + ARM_SMMU_CB_SCTLR);
+	writel_relaxed(reg, cb_base + ARM_SMMU_CB_SCTLR);
 }
 
 static int arm_smmu_init_domain_context(struct iommu_domain *domain,
@@ -1595,7 +1595,7 @@ static void arm_smmu_device_reset(struct arm_smmu_device *smmu)
 
 	/* Push the button */
 	arm_smmu_tlb_sync(smmu);
-	writel(scr0, gr0_base + ARM_SMMU_GR0_sCR0);
+	writel_relaxed(scr0, gr0_base + ARM_SMMU_GR0_sCR0);
 }
 
 static int arm_smmu_id_size_to_bits(int size)
@@ -1928,7 +1928,7 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
 		free_irq(smmu->irqs[i], smmu);
 
 	/* Turn the thing off */
-	writel(sCR0_CLIENTPD, ARM_SMMU_GR0(smmu) + ARM_SMMU_GR0_sCR0);
+	writel_relaxed(sCR0_CLIENTPD, ARM_SMMU_GR0(smmu) + ARM_SMMU_GR0_sCR0);
 	return 0;
 }
 
-- 
1.8.2.2

[PATCH 2/2] iommu/arm-smmu: don't enable SMMU device until probing has completed

[Will Deacon]

We currently reset and enable the SMMU before the device has finished
being probed, so if we fail later on (for example, because we couldn't
request a global irq successfully) then we will leave the device in an
active state.

This patch delays the reset and enabling of the SMMU hardware until
probing has completed.

Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
 drivers/iommu/arm-smmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index c3642cc..2931921 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1853,8 +1853,6 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
 		goto out_put_parent;
 	}
 
-	arm_smmu_device_reset(smmu);
-
 	for (i = 0; i < smmu->num_global_irqs; ++i) {
 		err = request_irq(smmu->irqs[i],
 				  arm_smmu_global_fault,
@@ -1872,6 +1870,8 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
 	spin_lock(&arm_smmu_devices_lock);
 	list_add(&smmu->list, &arm_smmu_devices);
 	spin_unlock(&arm_smmu_devices_lock);
+
+	arm_smmu_device_reset(smmu);
 	return 0;
 
 out_free_irqs:
-- 
1.8.2.2