| Message ID | 20180910062551.28175-1-vivek.gautam@codeaurora.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | Qcom smmu-500 TLB invalidation errata for sdm845 | expand |
+linux-arm-msm On 09/10/2018 11:55 AM, Vivek Gautam wrote: > Qcom's implementation of arm,mmu-500 on sdm845 has a functional/performance > errata [1] because of which the TCU cache look ups are stalled during > invalidation cycle. This is mitigated by serializing all the invalidation > requests coming to the smmu. > > This patch series addresses this errata by adding new tlb_ops for > qcom,sdm845-smmu-500 [2]. These ops take context bank locks for all the > tlb_ops that queue and sync the TLB invalidation requests. > > Besides adding locks, there's a way to expadite these TLB invalidations > for display and camera devices by turning off the 'wait-for-safe' logic > in hardware that holds the tlb invalidations until a safe level. > This 'wait-for-safe' logic is controlled by toggling a chicken bit > through a secure register. This secure register is accessed by making an > explicit SCM call into the EL3 firmware. > There are two ways of handling this logic - > * Firmware, such as tz present on sdm845-mtp devices has a handler to do > all the register access and bit set/clear. So is the handling in > downstream arm-smmu driver [3]. > * Other firmwares can have handlers to just read/write this secure > register. In such cases the kernel make io_read/writel scm calls to > modify the register. > This patch series adds APIs in qcom-scm driver to handle both of these > cases. > > Lastly, since these TLB invalidations can happen in atomic contexts > there's a need to add atomic versions of qcom_scm_io_readl/writel() and > qcom_scm_call() APIs. The traditional scm calls take mutex and we therefore > can't use these calls in atomic contexts. > > This patch series is adapted version of how the errata is handled in > downstream [1]. > > Changes since v1: > * Addressed Will and Robin's comments: > - Dropped the patch[4] that forked out __arm_smmu_tlb_inv_range_nosync(), > and __arm_smmu_tlb_sync(). > - Cleaned up the errata patch further to use downstream polling mechanism > for tlb sync. > * No change in SCM call patches - patches 1 to 3. > > [1] https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree/drivers/iommu/arm-smmu.c?h=msm-4.9#n4842 > [2] https://lore.kernel.org/patchwork/patch/974114/ > [3] https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree/drivers/iommu/arm-smmu.c?h=msm-4.9#n4864 > [4] https://patchwork.kernel.org/patch/10565349/ > > Vivek Gautam (4): > firmware: qcom_scm-64: Add atomic version of qcom_scm_call > firmware/qcom_scm: Add atomic version of io read/write APIs > firmware/qcom_scm: Add scm call to handle smmu errata > iommu/arm-smmu: Add support to handle Qcom's TLBI serialization errata > > drivers/firmware/qcom_scm-32.c | 17 ++++ > drivers/firmware/qcom_scm-64.c | 181 +++++++++++++++++++++++++++++++---------- > drivers/firmware/qcom_scm.c | 18 ++++ > drivers/firmware/qcom_scm.h | 9 ++ > drivers/iommu/arm-smmu-regs.h | 2 + > drivers/iommu/arm-smmu.c | 133 +++++++++++++++++++++++++++++- > include/linux/qcom_scm.h | 6 ++ > 7 files changed, 320 insertions(+), 46 deletions(-) >
Hi Bjorn, On Mon, Sep 10, 2018 at 4:08 PM Vivek Gautam <vivek.gautam@codeaurora.org> wrote: > > +linux-arm-msm > > > On 09/10/2018 11:55 AM, Vivek Gautam wrote: > > Qcom's implementation of arm,mmu-500 on sdm845 has a functional/performance > > errata [1] because of which the TCU cache look ups are stalled during > > invalidation cycle. This is mitigated by serializing all the invalidation > > requests coming to the smmu. > > > > This patch series addresses this errata by adding new tlb_ops for > > qcom,sdm845-smmu-500 [2]. These ops take context bank locks for all the > > tlb_ops that queue and sync the TLB invalidation requests. > > > > Besides adding locks, there's a way to expadite these TLB invalidations > > for display and camera devices by turning off the 'wait-for-safe' logic > > in hardware that holds the tlb invalidations until a safe level. > > This 'wait-for-safe' logic is controlled by toggling a chicken bit > > through a secure register. This secure register is accessed by making an > > explicit SCM call into the EL3 firmware. > > There are two ways of handling this logic - > > * Firmware, such as tz present on sdm845-mtp devices has a handler to do > > all the register access and bit set/clear. So is the handling in > > downstream arm-smmu driver [3]. > > * Other firmwares can have handlers to just read/write this secure > > register. In such cases the kernel make io_read/writel scm calls to > > modify the register. > > This patch series adds APIs in qcom-scm driver to handle both of these > > cases. > > > > Lastly, since these TLB invalidations can happen in atomic contexts > > there's a need to add atomic versions of qcom_scm_io_readl/writel() and > > qcom_scm_call() APIs. The traditional scm calls take mutex and we therefore > > can't use these calls in atomic contexts. > > > > This patch series is adapted version of how the errata is handled in > > downstream [1]. Gentle ping. Please let me know if you have comments on the SCM pieces in this series. Thanks & Regards Vivek > > > > Changes since v1: > > * Addressed Will and Robin's comments: > > - Dropped the patch[4] that forked out __arm_smmu_tlb_inv_range_nosync(), > > and __arm_smmu_tlb_sync(). > > - Cleaned up the errata patch further to use downstream polling mechanism > > for tlb sync. > > * No change in SCM call patches - patches 1 to 3. > > > > [1] https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree/drivers/iommu/arm-smmu.c?h=msm-4.9#n4842 > > [2] https://lore.kernel.org/patchwork/patch/974114/ > > [3] https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree/drivers/iommu/arm-smmu.c?h=msm-4.9#n4864 > > [4] https://patchwork.kernel.org/patch/10565349/ > > > > Vivek Gautam (4): > > firmware: qcom_scm-64: Add atomic version of qcom_scm_call > > firmware/qcom_scm: Add atomic version of io read/write APIs > > firmware/qcom_scm: Add scm call to handle smmu errata > > iommu/arm-smmu: Add support to handle Qcom's TLBI serialization errata > > > > drivers/firmware/qcom_scm-32.c | 17 ++++ > > drivers/firmware/qcom_scm-64.c | 181 +++++++++++++++++++++++++++++++---------- > > drivers/firmware/qcom_scm.c | 18 ++++ > > drivers/firmware/qcom_scm.h | 9 ++ > > drivers/iommu/arm-smmu-regs.h | 2 + > > drivers/iommu/arm-smmu.c | 133 +++++++++++++++++++++++++++++- > > include/linux/qcom_scm.h | 6 ++ > > 7 files changed, 320 insertions(+), 46 deletions(-) > > > > -- > The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > a Linux Foundation Collaborative Project > > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu
On Mon, Sep 10, 2018 at 11:55:47AM +0530, Vivek Gautam wrote: > Vivek Gautam (4): > firmware: qcom_scm-64: Add atomic version of qcom_scm_call > firmware/qcom_scm: Add atomic version of io read/write APIs > firmware/qcom_scm: Add scm call to handle smmu errata > iommu/arm-smmu: Add support to handle Qcom's TLBI serialization errata > > drivers/firmware/qcom_scm-32.c | 17 ++++ > drivers/firmware/qcom_scm-64.c | 181 +++++++++++++++++++++++++++++++---------- > drivers/firmware/qcom_scm.c | 18 ++++ > drivers/firmware/qcom_scm.h | 9 ++ > drivers/iommu/arm-smmu-regs.h | 2 + > drivers/iommu/arm-smmu.c | 133 +++++++++++++++++++++++++++++- > include/linux/qcom_scm.h | 6 ++ > 7 files changed, 320 insertions(+), 46 deletions(-) Should this go through the iommu-tree? In that case I need Acked-by's for the firmware code changes. Regards, Joerg
On Tue, Sep 25, 2018 at 02:09:34PM +0200, Joerg Roedel wrote: > On Mon, Sep 10, 2018 at 11:55:47AM +0530, Vivek Gautam wrote: > > Vivek Gautam (4): > > firmware: qcom_scm-64: Add atomic version of qcom_scm_call > > firmware/qcom_scm: Add atomic version of io read/write APIs > > firmware/qcom_scm: Add scm call to handle smmu errata > > iommu/arm-smmu: Add support to handle Qcom's TLBI serialization errata > > > > drivers/firmware/qcom_scm-32.c | 17 ++++ > > drivers/firmware/qcom_scm-64.c | 181 +++++++++++++++++++++++++++++++---------- > > drivers/firmware/qcom_scm.c | 18 ++++ > > drivers/firmware/qcom_scm.h | 9 ++ > > drivers/iommu/arm-smmu-regs.h | 2 + > > drivers/iommu/arm-smmu.c | 133 +++++++++++++++++++++++++++++- > > include/linux/qcom_scm.h | 6 ++ > > 7 files changed, 320 insertions(+), 46 deletions(-) > > Should this go through the iommu-tree? In that case I need Acked-by's > for the firmware code changes. Yup, and I'd also like Robin's ack on the arm-smmu*.c changes (I see he has some comments on the code as it stands). Will
On Tue, Sep 25, 2018 at 10:09 PM Will Deacon <will.deacon@arm.com> wrote: > > On Tue, Sep 25, 2018 at 02:09:34PM +0200, Joerg Roedel wrote: > > On Mon, Sep 10, 2018 at 11:55:47AM +0530, Vivek Gautam wrote: > > > Vivek Gautam (4): > > > firmware: qcom_scm-64: Add atomic version of qcom_scm_call > > > firmware/qcom_scm: Add atomic version of io read/write APIs > > > firmware/qcom_scm: Add scm call to handle smmu errata > > > iommu/arm-smmu: Add support to handle Qcom's TLBI serialization errata > > > > > > drivers/firmware/qcom_scm-32.c | 17 ++++ > > > drivers/firmware/qcom_scm-64.c | 181 +++++++++++++++++++++++++++++++---------- > > > drivers/firmware/qcom_scm.c | 18 ++++ > > > drivers/firmware/qcom_scm.h | 9 ++ > > > drivers/iommu/arm-smmu-regs.h | 2 + > > > drivers/iommu/arm-smmu.c | 133 +++++++++++++++++++++++++++++- > > > include/linux/qcom_scm.h | 6 ++ > > > 7 files changed, 320 insertions(+), 46 deletions(-) > > > > Should this go through the iommu-tree? In that case I need Acked-by's > > for the firmware code changes. > > Yup, and I'd also like Robin's ack on the arm-smmu*.c changes (I see he has > some comments on the code as it stands). Thanks Joerg, and Will for taking a look at it. I will answer and address Robin's comments for smmu part. Best regards Vivek > > Will > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu
Qcom's implementation of arm,mmu-500 on sdm845 has a functional/performance errata [1] because of which the TCU cache look ups are stalled during invalidation cycle. This is mitigated by serializing all the invalidation requests coming to the smmu. This patch series addresses this errata by adding new tlb_ops for qcom,sdm845-smmu-500 [2]. These ops take context bank locks for all the tlb_ops that queue and sync the TLB invalidation requests. Besides adding locks, there's a way to expadite these TLB invalidations for display and camera devices by turning off the 'wait-for-safe' logic in hardware that holds the tlb invalidations until a safe level. This 'wait-for-safe' logic is controlled by toggling a chicken bit through a secure register. This secure register is accessed by making an explicit SCM call into the EL3 firmware. There are two ways of handling this logic - * Firmware, such as tz present on sdm845-mtp devices has a handler to do all the register access and bit set/clear. So is the handling in downstream arm-smmu driver [3]. * Other firmwares can have handlers to just read/write this secure register. In such cases the kernel make io_read/writel scm calls to modify the register. This patch series adds APIs in qcom-scm driver to handle both of these cases. Lastly, since these TLB invalidations can happen in atomic contexts there's a need to add atomic versions of qcom_scm_io_readl/writel() and qcom_scm_call() APIs. The traditional scm calls take mutex and we therefore can't use these calls in atomic contexts. This patch series is adapted version of how the errata is handled in downstream [1]. Changes since v1: * Addressed Will and Robin's comments: - Dropped the patch[4] that forked out __arm_smmu_tlb_inv_range_nosync(), and __arm_smmu_tlb_sync(). - Cleaned up the errata patch further to use downstream polling mechanism for tlb sync. * No change in SCM call patches - patches 1 to 3. [1] https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree/drivers/iommu/arm-smmu.c?h=msm-4.9#n4842 [2] https://lore.kernel.org/patchwork/patch/974114/ [3] https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree/drivers/iommu/arm-smmu.c?h=msm-4.9#n4864 [4] https://patchwork.kernel.org/patch/10565349/ Vivek Gautam (4): firmware: qcom_scm-64: Add atomic version of qcom_scm_call firmware/qcom_scm: Add atomic version of io read/write APIs firmware/qcom_scm: Add scm call to handle smmu errata iommu/arm-smmu: Add support to handle Qcom's TLBI serialization errata drivers/firmware/qcom_scm-32.c | 17 ++++ drivers/firmware/qcom_scm-64.c | 181 +++++++++++++++++++++++++++++++---------- drivers/firmware/qcom_scm.c | 18 ++++ drivers/firmware/qcom_scm.h | 9 ++ drivers/iommu/arm-smmu-regs.h | 2 + drivers/iommu/arm-smmu.c | 133 +++++++++++++++++++++++++++++- include/linux/qcom_scm.h | 6 ++ 7 files changed, 320 insertions(+), 46 deletions(-)