| Message ID | 1659172664-10345-1-git-send-email-quic_akhilpo@quicinc.com |
|---|---|
| Headers | show |
| Series | clk/qcom: Support gdsc collapse polling using 'reset' inteface | expand |
On 8/3/2022 12:02 AM, Rob Clark wrote: > On Tue, Aug 2, 2022 at 12:02 AM Dmitry Baryshkov > <dmitry.baryshkov@linaro.org> wrote: >> On 30/07/2022 12:17, Akhil P Oommen wrote: >>> Some clients like adreno gpu driver would like to ensure that its gdsc >>> is collapsed at hardware during a gpu reset sequence. This is because it >>> has a votable gdsc which could be ON due to a vote from another subsystem >>> like tz, hyp etc or due to an internal hardware signal. >> If this is votable, do we have any guarantee that the gdsc will collapse >> at all? How can we proceed if it did not collapse? > Other potential votes should be transient. But I guess we eventually > need to timeout and give up. At which point we are no worse off than > before. > > But hmm, we aren't using RBBM_SW_RESET_CMD for sw reset like we have > on previous generations? That does seem a bit odd. Looks like kgsl > does use it. > > BR, > -R Like Rob mentioned there could be transient votes from other clients/subsystem. It could be even stuck ON when hardware is in bad shape in some very rare cases. For the worst case scenario, I have added a timeout (500msec) in the gdsc reset op. I have added the Soft reset in [1]. But this resets only the core gpu blocks, not everything. For eg. GMU. [1] [PATCH v3 7/8] drm/msm/a6xx: Improve gpu recovery sequence > >>> To allow >>> this, gpucc driver can expose an interface to the client driver using >>> reset framework. Using this the client driver can trigger a polling within >>> the gdsc driver. >> Trigger the polling made me think initially that we will actually >> trigger something in the HW. Instead the client uses reset framework to >> poll for the gdsc to be reset. Yes. I should replace 'trigger' with 'start' here. -Akhil. >> >>> This series is rebased on top of linus's master branch. >>> >>> Related discussion: https://patchwork.freedesktop.org/patch/493144/ >>> >>> >>> Akhil P Oommen (5): >>> dt-bindings: clk: qcom: Support gpu cx gdsc reset >>> clk: qcom: Allow custom reset ops >>> clk: qcom: gpucc-sc7280: Add cx collapse reset support >>> clk: qcom: gdsc: Add a reset op to poll gdsc collapse >>> arm64: dts: qcom: sc7280: Add Reset support for gpu >>> >>> arch/arm64/boot/dts/qcom/sc7280.dtsi | 3 +++ >>> drivers/clk/qcom/gdsc.c | 23 +++++++++++++++++++---- >>> drivers/clk/qcom/gdsc.h | 7 +++++++ >>> drivers/clk/qcom/gpucc-sc7280.c | 6 ++++++ >>> drivers/clk/qcom/reset.c | 6 ++++++ >>> drivers/clk/qcom/reset.h | 2 ++ >>> include/dt-bindings/clock/qcom,gpucc-sc7280.h | 3 +++ >>> 7 files changed, 46 insertions(+), 4 deletions(-) >>> >> >> -- >> With best wishes >> Dmitry