From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Gautam Subject: [PATCH v3 0/4] Qcom smmu-500 wait-for-safe handling for sdm845 Date: Wed, 12 Jun 2019 12:45:50 +0530 Message-ID: <20190612071554.13573-1-vivek.gautam@codeaurora.org> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: agross@kernel.org, robh+dt@kernel.org, will.deacon@arm.com, robin.murphy@arm.com, joro@8bytes.org, bjorn.andersson@linaro.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org, david.brown@linaro.org, Vivek Gautam List-Id: devicetree@vger.kernel.org Subject changed, older subject was - Qcom smmu-500 TLB invalidation errata for sdm845. Previous version of the patches are at [1]: Qcom's implementation of smmu-500 on sdm845 adds a hardware logic called wait-for-safe. This logic helps in meeting the invalidation requirements from 'real-time clients', such as display and camera. This wait-for-safe logic ensures that the invalidations happen after getting an ack from these devices. In this patch-series we are disabling this wait-for-safe logic from the arm-smmu driver's probe as with this enabled the hardware tries to throttle invalidations from 'non-real-time clients', such as USB and UFS. For detailed information please refer to patch [3/4] in this series. I have included the device tree patch too in this series for someone who would like to test out this. Here's a branch [2] that gets display on MTP SDM845 device. This patch series is inspired from downstream work to handle under-performance issues on real-time clients on sdm845. In downstream we add separate page table ops to handle TLB maintenance and toggle wait-for-safe in tlb_sync call so that achieve required performance for display and camera [3, 4]. Changes since v2: * Dropped the patch to add atomic io_read/write scm API. * Removed support for any separate page table ops to handle wait-for-safe. Currently just disabling this wait-for-safe logic from arm_smmu_device_probe() to achieve performance on USB/UFS on sdm845. * Added a device tree patch to add smmu option for fw-implemented support for SCM call to take care of SAFE toggling. 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://lore.kernel.org/patchwork/cover/983913/ [2] https://github.com/vivekgautam1/linux/tree/v5.2-rc4/sdm845-display-working [3] https://source.codeaurora.org/quic/la/kernel/msm-4.9/commit/drivers/iommu/arm-smmu.c?h=CogSystems-msm-49/msm-4.9&id=da765c6c75266b38191b38ef086274943f353ea7 [4] https://source.codeaurora.org/quic/la/kernel/msm-4.9/commit/drivers/iommu/arm-smmu.c?h=CogSystems-msm-49/msm-4.9&id=8696005aaaf745de68f57793c1a534a34345c30a Vivek Gautam (4): firmware: qcom_scm-64: Add atomic version of qcom_scm_call firmware/qcom_scm: Add scm call to handle smmu errata iommu/arm-smmu: Add support to handle Qcom's wait-for-safe logic arm64: dts/sdm845: Enable FW implemented safe sequence handler on MTP arch/arm64/boot/dts/qcom/sdm845.dtsi | 1 + drivers/firmware/qcom_scm-32.c | 5 ++ drivers/firmware/qcom_scm-64.c | 149 ++++++++++++++++++++++++----------- drivers/firmware/qcom_scm.c | 6 ++ drivers/firmware/qcom_scm.h | 5 ++ drivers/iommu/arm-smmu.c | 16 ++++ include/linux/qcom_scm.h | 2 + 7 files changed, 140 insertions(+), 44 deletions(-) -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation