[PATCH 2/2] drm/amdgpu: add reset register trace function on GPU reset

[Alex Deucher]

On Tue, Feb 8, 2022 at 3:17 AM Somalapuram Amaranath
<Amaranath.Somalapuram at amd.com> wrote:
>
> Dump the list of register values to trace event on GPU reset.
>
> Signed-off-by: Somalapuram Amaranath <Amaranath.Somalapuram at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 21 ++++++++++++++++++++-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h  | 19 +++++++++++++++++++
>  2 files changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 1e651b959141..057922fb7e37 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -4534,6 +4534,23 @@ int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev,
>         return r;
>  }
>
> +static int amdgpu_reset_reg_dumps(struct amdgpu_device *adev)
> +{
> +       int i;
> +       uint32_t reg_value[128];
> +
> +       for (i = 0; adev->reset_dump_reg_list[i] != 0; i++) {
> +               if (adev->asic_type >= CHIP_NAVI10)

This check should be against CHIP_VEGA10.  Also, this only allows for
GC registers.  If we wanted to dump other registers, we'd need a
different macro.  Might be better to just use RREG32 here for
everything and then encode the full offset using
SOC15_REG_ENTRY_OFFSET() or a similar macro.  Also, we need to think
about how to handle gfxoff in this case.  gfxoff needs to be disabled
or we'll hang the chip if we try and read GC or SDMA registers via
MMIO which will adversely affect the hang signature.

Alex

> +                       reg_value[i] = RREG32_SOC15_IP(GC, adev->reset_dump_reg_list[i]);
> +               else
> +                       reg_value[i] = RREG32(adev->reset_dump_reg_list[i]);
> +       }
> +
> +       trace_amdgpu_reset_reg_dumps(adev->reset_dump_reg_list, reg_value, i);
> +
> +       return 0;
> +}
> +
>  int amdgpu_do_asic_reset(struct list_head *device_list_handle,
>                          struct amdgpu_reset_context *reset_context)
>  {
> @@ -4567,8 +4584,10 @@ int amdgpu_do_asic_reset(struct list_head *device_list_handle,
>                                 tmp_adev->gmc.xgmi.pending_reset = false;
>                                 if (!queue_work(system_unbound_wq, &tmp_adev->xgmi_reset_work))
>                                         r = -EALREADY;
> -                       } else
> +                       } else {
> +                               amdgpu_reset_reg_dumps(tmp_adev);
>                                 r = amdgpu_asic_reset(tmp_adev);
> +                       }
>
>                         if (r) {
>                                 dev_err(tmp_adev->dev, "ASIC reset failed with error, %d for drm dev, %s",
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
> index d855cb53c7e0..3fe33de3564a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
> @@ -537,6 +537,25 @@ TRACE_EVENT(amdgpu_ib_pipe_sync,
>                       __entry->seqno)
>  );
>
> +TRACE_EVENT(amdgpu_reset_reg_dumps,
> +           TP_PROTO(long *address, uint32_t *value, int length),
> +           TP_ARGS(address, value, length),
> +           TP_STRUCT__entry(
> +                            __array(long, address, 128)
> +                            __array(uint32_t, value, 128)
> +                            __field(int, len)
> +                            ),
> +           TP_fast_assign(
> +                          memcpy(__entry->address, address, 128);
> +                          memcpy(__entry->value,  value, 128);
> +                          __entry->len = length;
> +                          ),
> +           TP_printk("amdgpu register dump offset: %s value: %s ",
> +                     __print_array(__entry->address, __entry->len, 8),
> +                     __print_array(__entry->value, __entry->len, 8)
> +                    )
> +);
> +
>  #undef AMDGPU_JOB_GET_TIMELINE_NAME
>  #endif
>
> --
> 2.25.1
>