On 12/2/2022 12:30 PM, Akhil P Oommen wrote: > On 12/2/2022 4:27 AM, Bjorn Andersson wrote: >> On Wed, Oct 05, 2022 at 02:36:58PM +0530, Akhil P Oommen wrote: >> @Ulf, Akhil has a power-domain for a piece of hardware which may be >> voted active by multiple different subsystems (co-processors/execution >> contexts) in the system. >> >> As such, during the powering down sequence we don't wait for the >> power-domain to turn off. But in the event of an error, the recovery >> mechanism relies on waiting for the hardware to settle in a powered off >> state. >> >> The proposal here is to use the reset framework to wait for this state >> to be reached, before continuing with the recovery mechanism in the >> client driver. >> >> Given our other discussions on quirky behavior, do you have any >> input/suggestions on this? Ulf, Gentle ping! Could you please share your feedback? -Akhil. >> >>> 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. 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. >> @Akhil, this description is fairly generic. As we've reached the state >> where the hardware has settled and we return to the client, what >> prevents it from being powered up again? >> >> Or is it simply a question of it hitting the powered-off state, not >> necessarily staying there? > Correct. It doesn't need to stay there. The intention is to hit the powered-off state at least once to clear all the internal hw states (basically a hw reset). > > -Akhil. >> Regards, >> Bjorn >> >>> This series is rebased on top of qcom/linux:for-next branch. >>> >>> Related discussion: https://patchwork.freedesktop.org/patch/493144/ >>> >>> Changes in v7: >>> - Update commit message (Bjorn) >>> - Rebased on top of qcom/linux:for-next branch. >>> >>> Changes in v6: >>> - No code changes in this version. Just captured the Acked-by tags >>> >>> Changes in v5: >>> - Nit: Remove a duplicate blank line (Krzysztof) >>> >>> Changes in v4: >>> - Update gpu dt-binding schema >>> - Typo fix in commit text >>> >>> Changes in v3: >>> - Use pointer to const for "struct qcom_reset_ops" in qcom_reset_map (Krzysztof) >>> >>> Changes in v2: >>> - Return error when a particular custom reset op is not implemented. (Dmitry) >>> >>> Akhil P Oommen (6): >>> dt-bindings: clk: qcom: Support gpu cx gdsc reset >>> clk: qcom: Allow custom reset ops >>> clk: qcom: gdsc: Add a reset op to poll gdsc collapse >>> clk: qcom: gpucc-sc7280: Add cx collapse reset support >>> dt-bindings: drm/msm/gpu: Add optional resets >>> arm64: dts: qcom: sc7280: Add Reset support for gpu >>> >>> .../devicetree/bindings/display/msm/gpu.yaml | 6 +++++ >>> 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 | 10 ++++++++ >>> drivers/clk/qcom/reset.c | 27 +++++++++++++++++++++- >>> drivers/clk/qcom/reset.h | 8 +++++++ >>> include/dt-bindings/clock/qcom,gpucc-sc7280.h | 3 +++ >>> 8 files changed, 82 insertions(+), 5 deletions(-) >>> >>> -- >>> 2.7.4 >>>
