This is the revised fourth attempt of inheriting the stream mapping for
the framebuffer on many Qualcomm platforms, in order to not hit
catastrophic faults during arm-smmu initialization.
The new approach does, based on Robin's suggestion, take a much more
direct approach with the allocation of a context bank for bypass
emulation and use of this context bank pretty much isolated to the
Qualcomm specific implementation.
The patchset has been tested to boot DB845c and RB5 (with splash screen)
and Lenovo Yoga C630 (with EFI framebuffer).
Bjorn Andersson (3):
iommu/arm-smmu: Allow implementation specific write_s2cr
iommu/arm-smmu-qcom: Read back stream mappings
iommu/arm-smmu-qcom: Implement S2CR quirk
drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 90 ++++++++++++++++++++++
drivers/iommu/arm/arm-smmu/arm-smmu.c | 13 +++-
drivers/iommu/arm/arm-smmu/arm-smmu.h | 1 +
3 files changed, 101 insertions(+), 3 deletions(-)
--
2.28.0
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.
Reviewed-by: Robin Murphy <[email protected]>
Signed-off-by: Bjorn Andersson <[email protected]>
---
Changes since v4:
- Return early instead of indenting the rest of the function
drivers/iommu/arm/arm-smmu/arm-smmu.c | 13 ++++++++++---
drivers/iommu/arm/arm-smmu/arm-smmu.h | 1 +
2 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index dad7fa86fbd4..bcbacf22331d 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -929,9 +929,16 @@ 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);
+ u32 reg;
+
+ if (smmu->impl && smmu->impl->write_s2cr) {
+ smmu->impl->write_s2cr(smmu, idx);
+ return;
+ }
+
+ 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)
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
--
2.28.0
On 10/19/20 1:23 PM, Bjorn Andersson wrote:
> This is the revised fourth attempt of inheriting the stream mapping for
> the framebuffer on many Qualcomm platforms, in order to not hit
> catastrophic faults during arm-smmu initialization.
>
> The new approach does, based on Robin's suggestion, take a much more
> direct approach with the allocation of a context bank for bypass
> emulation and use of this context bank pretty much isolated to the
> Qualcomm specific implementation.
>
> The patchset has been tested to boot DB845c and RB5 (with splash screen)
> and Lenovo Yoga C630 (with EFI framebuffer).
>
> Bjorn Andersson (3):
> iommu/arm-smmu: Allow implementation specific write_s2cr
> iommu/arm-smmu-qcom: Read back stream mappings
> iommu/arm-smmu-qcom: Implement S2CR quirk
>
> drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 90 ++++++++++++++++++++++
> drivers/iommu/arm/arm-smmu/arm-smmu.c | 13 +++-
> drivers/iommu/arm/arm-smmu/arm-smmu.h | 1 +
> 3 files changed, 101 insertions(+), 3 deletions(-)
>
Tested series here on my Lenovo C630.
Tested-by: Steev Klimaszewski <[email protected]>
On Mon, 19 Oct 2020 11:23:20 -0700, Bjorn Andersson wrote:
> This is the revised fourth attempt of inheriting the stream mapping for
> the framebuffer on many Qualcomm platforms, in order to not hit
> catastrophic faults during arm-smmu initialization.
>
> The new approach does, based on Robin's suggestion, take a much more
> direct approach with the allocation of a context bank for bypass
> emulation and use of this context bank pretty much isolated to the
> Qualcomm specific implementation.
>
> [...]
Applied to will (for-joerg/arm-smmu/updates), thanks!
[1/3] iommu/arm-smmu: Allow implementation specific write_s2cr
https://git.kernel.org/will/c/56b75b51ed6d
[2/3] iommu/arm-smmu-qcom: Read back stream mappings
https://git.kernel.org/will/c/07a7f2caaa5a
[3/3] iommu/arm-smmu-qcom: Implement S2CR quirk
https://git.kernel.org/will/c/f9081b8ff593
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev