Re: [PATCH v3 6/8] iommu/arm-smmu: Add impl hook for inherit boot mappings
From: Robin Murphy <robin.murphy@arm.com>
Date: 2020-09-11 17:16:44
Also in:
linux-arm-msm, linux-iommu, lkml
On 2020-09-04 16:55, Bjorn Andersson wrote:
Add a new operation to allow platform implementations to inherit any stream mappings from the boot loader.
Is there a reason we need an explicit step for this? The aim of the cfg_probe hook is that the SMMU software state should all be set up by then, and you can mess about with it however you like before arm_smmu_reset() actually commits anything to hardware. I would have thought you could permanently steal a context bank, configure it as your bypass hole, read out the previous SME configuration and tweak smmu->smrs and smmu->s2crs appropriately all together "invisibly" at that point. If that can't work, I'm very curious as to what I've overlooked. Robin.
quoted hunk ↗ jump to hunk
Signed-off-by: Bjorn Andersson <redacted> --- Changes since v2: - New patch/interface drivers/iommu/arm/arm-smmu/arm-smmu.c | 11 ++++++----- drivers/iommu/arm/arm-smmu/arm-smmu.h | 6 ++++++ 2 files changed, 12 insertions(+), 5 deletions(-)diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index eb5c6ca5c138..4c4d302cd747 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c@@ -85,11 +85,6 @@ static inline void arm_smmu_rpm_put(struct arm_smmu_device *smmu) pm_runtime_put_autosuspend(smmu->dev); } -static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom) -{ - return container_of(dom, struct arm_smmu_domain, domain); -} - static struct platform_driver arm_smmu_driver; static struct iommu_ops arm_smmu_ops;@@ -2188,6 +2183,12 @@ static int arm_smmu_device_probe(struct platform_device *pdev) if (err) return err; + if (smmu->impl->inherit_mappings) { + err = smmu->impl->inherit_mappings(smmu); + if (err) + return err; + } + if (smmu->version == ARM_SMMU_V2) { if (smmu->num_context_banks > smmu->num_context_irqs) { dev_err(dev,diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h index 235d9a3a6ab6..f58164976e74 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h@@ -378,6 +378,11 @@ struct arm_smmu_domain { struct iommu_domain domain; }; +static inline struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom) +{ + return container_of(dom, struct arm_smmu_domain, domain); +} + struct arm_smmu_master_cfg { struct arm_smmu_device *smmu; s16 smendx[];@@ -442,6 +447,7 @@ struct arm_smmu_impl { int (*alloc_context_bank)(struct arm_smmu_domain *smmu_domain, struct arm_smmu_device *smmu, struct device *dev, int start); + int (*inherit_mappings)(struct arm_smmu_device *smmu); }; #define INVALID_SMENDX -1
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