linux-kernel - Re: [Freedreno] [PATCH v3 4/7] drm/msm/a2xx: Implement .gpu

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Message-ID: <CAF6AEGvYJg1r4A7bvfNrck-wfWv7+sQ8DnN=R_RaSK=tE1tzGw@mail.gmail.com>
Date:   Mon, 20 Mar 2023 11:02:16 -0700
From:   Rob Clark <robdclark@...il.com>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>
Cc:     Jonathan Marek <jonathan@...ek.ca>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org
Subject: Re: [Freedreno] [PATCH v3 4/7] drm/msm/a2xx: Implement .gpu_busy

On Mon, Mar 13, 2023 at 9:54 AM Konrad Dybcio <konrad.dybcio@...aro.org> wrote:
>
>
>
> On 24.02.2023 16:04, Jonathan Marek wrote:
> > This won't work because a2xx freedreno userspace expects to own all the perfcounters.
> >
> > This will break perfcounters for userspace, and when userspace isn't using perfcounters, this won't count correctly because userspace writes 0 to CP_PERFMON_CNTL at the start of every submit.
>
> Rob, would you be willing to take this without the a2xx bits? It
> should still be fine, except without devfreq. Not that we had
> any significant sort of scaling on a2xx before.

Yup, sounds like a plan

BR,
-R

> Konrad
> >
> > On 2/23/23 5:52 AM, Konrad Dybcio wrote:
> >> Implement gpu_busy based on the downstream msm-3.4 code [1]. This
> >> allows us to use devfreq on this old old old hardware!
> >>
> >> [1] https://github.com/LineageOS/android_kernel_sony_apq8064/blob/lineage-16.0/drivers/gpu/msm/adreno_a2xx.c#L1975
> >>
> >> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> >> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
> >> ---
> >>   drivers/gpu/drm/msm/adreno/a2xx_gpu.c | 26 ++++++++++++++++++++++++++
> >>   1 file changed, 26 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/msm/adreno/a2xx_gpu.c b/drivers/gpu/drm/msm/adreno/a2xx_gpu.c
> >> index c67089a7ebc1..104bdf28cdaf 100644
> >> --- a/drivers/gpu/drm/msm/adreno/a2xx_gpu.c
> >> +++ b/drivers/gpu/drm/msm/adreno/a2xx_gpu.c
> >> @@ -481,6 +481,31 @@ a2xx_create_address_space(struct msm_gpu *gpu, struct platform_device *pdev)
> >>       return aspace;
> >>   }
> >>   +/* While the precise size of this field is unknown, it holds at least these three values.. */
> >> +static u64 a2xx_gpu_busy(struct msm_gpu *gpu, unsigned long *out_sample_rate)
> >> +{
> >> +    u64 busy_cycles;
> >> +
> >> +    /* Freeze the counter */
> >> +    gpu_write(gpu, REG_A2XX_CP_PERFMON_CNTL, PERF_STATE_FREEZE);
> >> +
> >> +    busy_cycles = gpu_read64(gpu, REG_A2XX_RBBM_PERFCOUNTER1_LO);
> >> +
> >> +    /* Reset the counter */
> >> +    gpu_write(gpu, REG_A2XX_CP_PERFMON_CNTL, PERF_STATE_RESET);
> >> +
> >> +    /* Re-enable the performance monitors */
> >> +    gpu_rmw(gpu, REG_A2XX_RBBM_PM_OVERRIDE2,
> >> +        A2XX_RBBM_PM_OVERRIDE2_DEBUG_PERF_SCLK_PM_OVERRIDE,
> >> +        A2XX_RBBM_PM_OVERRIDE2_DEBUG_PERF_SCLK_PM_OVERRIDE);
> >> +    gpu_write(gpu, REG_A2XX_RBBM_PERFCOUNTER1_SELECT, 1);
> >> +    gpu_write(gpu, REG_A2XX_CP_PERFMON_CNTL, PERF_STATE_ENABLE);
> >> +
> >> +    *out_sample_rate = clk_get_rate(gpu->core_clk);
> >> +
> >> +    return busy_cycles;
> >> +}
> >> +
> >>   static u32 a2xx_get_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> >>   {
> >>       ring->memptrs->rptr = gpu_read(gpu, REG_AXXX_CP_RB_RPTR);
> >> @@ -502,6 +527,7 @@ static const struct adreno_gpu_funcs funcs = {
> >>   #if defined(CONFIG_DEBUG_FS) || defined(CONFIG_DEV_COREDUMP)
> >>           .show = adreno_show,
> >>   #endif
> >> +        .gpu_busy = a2xx_gpu_busy,
> >>           .gpu_state_get = a2xx_gpu_state_get,
> >>           .gpu_state_put = adreno_gpu_state_put,
> >>           .create_address_space = a2xx_create_address_space,
> >>