| Message ID | 20201017043907.2656013-2-bjorn.andersson@linaro.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | iommu/arm-smmu-qcom: Support maintaining bootloader mappings | expand |
On 2020-10-17 05:39, Bjorn Andersson wrote: > The firmware found in some Qualcomm platforms intercepts writes to the > S2CR register in order to replace the BYPASS type with FAULT. Further > more it treats faults at this level as catastrophic and restarts the > device. > > Add support for providing implementation specific versions of the S2CR > write function, to allow the Qualcomm driver to work around this > behavior. > > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> > --- > > Changes since v3: > - New patch > > drivers/iommu/arm/arm-smmu/arm-smmu.c | 22 ++++++++++++++-------- > drivers/iommu/arm/arm-smmu/arm-smmu.h | 1 + > 2 files changed, 15 insertions(+), 8 deletions(-) > > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c > index dad7fa86fbd4..ed3f0428c110 100644 > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c > @@ -929,14 +929,20 @@ static void arm_smmu_write_smr(struct arm_smmu_device *smmu, int idx) > static void arm_smmu_write_s2cr(struct arm_smmu_device *smmu, int idx) > { > struct arm_smmu_s2cr *s2cr = smmu->s2crs + idx; > - u32 reg = FIELD_PREP(ARM_SMMU_S2CR_TYPE, s2cr->type) | > - FIELD_PREP(ARM_SMMU_S2CR_CBNDX, s2cr->cbndx) | > - FIELD_PREP(ARM_SMMU_S2CR_PRIVCFG, s2cr->privcfg); > - > - if (smmu->features & ARM_SMMU_FEAT_EXIDS && smmu->smrs && > - smmu->smrs[idx].valid) > - reg |= ARM_SMMU_S2CR_EXIDVALID; > - arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_S2CR(idx), reg); > + u32 reg; > + > + if (smmu->impl && smmu->impl->write_s2cr) { > + smmu->impl->write_s2cr(smmu, idx); Nit: just add an early return here to avoid reindenting the whole function. Otherwise this looks like a reasonable level of abstraction to me - we'll still have plenty of flexibility to adjust things in future if necessary. With that change, Reviewed-by: Robin Murphy <robin.murphy@arm.com> > + } else { > + reg = FIELD_PREP(ARM_SMMU_S2CR_TYPE, s2cr->type) | > + FIELD_PREP(ARM_SMMU_S2CR_CBNDX, s2cr->cbndx) | > + FIELD_PREP(ARM_SMMU_S2CR_PRIVCFG, s2cr->privcfg); > + > + if (smmu->features & ARM_SMMU_FEAT_EXIDS && smmu->smrs && > + smmu->smrs[idx].valid) > + reg |= ARM_SMMU_S2CR_EXIDVALID; > + arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_S2CR(idx), reg); > + } > } > > static void arm_smmu_write_sme(struct arm_smmu_device *smmu, int idx) > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h > index 1a746476927c..b71647eaa319 100644 > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h > @@ -436,6 +436,7 @@ struct arm_smmu_impl { > int (*alloc_context_bank)(struct arm_smmu_domain *smmu_domain, > struct arm_smmu_device *smmu, > struct device *dev, int start); > + void (*write_s2cr)(struct arm_smmu_device *smmu, int idx); > }; > > #define INVALID_SMENDX -1 >
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index dad7fa86fbd4..ed3f0428c110 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c @@ -929,14 +929,20 @@ static void arm_smmu_write_smr(struct arm_smmu_device *smmu, int idx) static void arm_smmu_write_s2cr(struct arm_smmu_device *smmu, int idx) { struct arm_smmu_s2cr *s2cr = smmu->s2crs + idx; - u32 reg = FIELD_PREP(ARM_SMMU_S2CR_TYPE, s2cr->type) | - FIELD_PREP(ARM_SMMU_S2CR_CBNDX, s2cr->cbndx) | - FIELD_PREP(ARM_SMMU_S2CR_PRIVCFG, s2cr->privcfg); - - if (smmu->features & ARM_SMMU_FEAT_EXIDS && smmu->smrs && - smmu->smrs[idx].valid) - reg |= ARM_SMMU_S2CR_EXIDVALID; - arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_S2CR(idx), reg); + u32 reg; + + if (smmu->impl && smmu->impl->write_s2cr) { + smmu->impl->write_s2cr(smmu, idx); + } else { + reg = FIELD_PREP(ARM_SMMU_S2CR_TYPE, s2cr->type) | + FIELD_PREP(ARM_SMMU_S2CR_CBNDX, s2cr->cbndx) | + FIELD_PREP(ARM_SMMU_S2CR_PRIVCFG, s2cr->privcfg); + + if (smmu->features & ARM_SMMU_FEAT_EXIDS && smmu->smrs && + smmu->smrs[idx].valid) + reg |= ARM_SMMU_S2CR_EXIDVALID; + arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_S2CR(idx), reg); + } } static void arm_smmu_write_sme(struct arm_smmu_device *smmu, int idx) diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h index 1a746476927c..b71647eaa319 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h @@ -436,6 +436,7 @@ struct arm_smmu_impl { int (*alloc_context_bank)(struct arm_smmu_domain *smmu_domain, struct arm_smmu_device *smmu, struct device *dev, int start); + void (*write_s2cr)(struct arm_smmu_device *smmu, int idx); }; #define INVALID_SMENDX -1
The firmware found in some Qualcomm platforms intercepts writes to the S2CR register in order to replace the BYPASS type with FAULT. Further more it treats faults at this level as catastrophic and restarts the device. Add support for providing implementation specific versions of the S2CR write function, to allow the Qualcomm driver to work around this behavior. Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> --- Changes since v3: - New patch drivers/iommu/arm/arm-smmu/arm-smmu.c | 22 ++++++++++++++-------- drivers/iommu/arm/arm-smmu/arm-smmu.h | 1 + 2 files changed, 15 insertions(+), 8 deletions(-)