[PATCH 7/8] drm/amdgpu: support memory power gating for lsdma

[Luben Tuikov]

On 2022-05-05 16:04, Alex Deucher wrote:
> From: Likun Gao <Likun.Gao at amd.com>
> 
> Support memory power gating control for LSDMA.
> 
> Signed-off-by: Likun Gao <Likun.Gao at amd.com>
> Reviewed-by: Hawking Zhang <Hawking.Zhang at amd.com>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_lsdma.h |  1 +
>  drivers/gpu/drm/amd/amdgpu/lsdma_v6_0.c   | 16 +++++++++++++++-
>  drivers/gpu/drm/amd/amdgpu/soc21.c        | 12 +++++++++++-
>  3 files changed, 27 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_lsdma.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_lsdma.h
> index 9a29f18407b8..7ec7598e7dec 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_lsdma.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_lsdma.h
> @@ -34,6 +34,7 @@ struct amdgpu_lsdma_funcs
>                      uint64_t dst_addr, uint64_t size);
>  	int (*fill_mem)(struct amdgpu_device *adev, uint64_t dst_addr,
>                      uint32_t data, uint64_t size);
> +	void (*update_memory_power_gating)(struct amdgpu_device *adev, bool enable);
>  };
>  
>  int amdgpu_lsdma_copy_mem(struct amdgpu_device *adev, uint64_t src_addr,
> diff --git a/drivers/gpu/drm/amd/amdgpu/lsdma_v6_0.c b/drivers/gpu/drm/amd/amdgpu/lsdma_v6_0.c
> index b4adb94a080b..1a285b531881 100644
> --- a/drivers/gpu/drm/amd/amdgpu/lsdma_v6_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/lsdma_v6_0.c
> @@ -101,7 +101,21 @@ static int lsdma_v6_0_fill_mem(struct amdgpu_device *adev,
>  	return ret;
>  }
>  
> +static void lsdma_v6_0_update_memory_power_gating(struct amdgpu_device *adev,
> +						 bool enable)
> +{
> +	uint32_t tmp;
> +
> +	tmp = RREG32_SOC15(LSDMA, 0, regLSDMA_MEM_POWER_CTRL);
> +	tmp = REG_SET_FIELD(tmp, LSDMA_MEM_POWER_CTRL, MEM_POWER_CTRL_EN, 0);
> +	WREG32_SOC15(LSDMA, 0, regLSDMA_MEM_POWER_CTRL, tmp);
> +
> +	tmp = REG_SET_FIELD(tmp, LSDMA_MEM_POWER_CTRL, MEM_POWER_CTRL_EN, enable);
> +	WREG32_SOC15(LSDMA, 0, regLSDMA_MEM_POWER_CTRL, tmp);
> +}
> +

Do we need to disable it first before updating?

What if we're updating it to the same value it currently is (on the first read)?
Shouldn't we just skip the subsequent writes?

>  const struct amdgpu_lsdma_funcs lsdma_v6_0_funcs = {
>  	.copy_mem = lsdma_v6_0_copy_mem,
> -	.fill_mem = lsdma_v6_0_fill_mem
> +	.fill_mem = lsdma_v6_0_fill_mem,
> +	.update_memory_power_gating = lsdma_v6_0_update_memory_power_gating
>  };
> diff --git a/drivers/gpu/drm/amd/amdgpu/soc21.c b/drivers/gpu/drm/amd/amdgpu/soc21.c
> index 741ed3ba84d6..3303e02f85d1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/soc21.c
> +++ b/drivers/gpu/drm/amd/amdgpu/soc21.c
> @@ -676,7 +676,17 @@ static int soc21_common_set_clockgating_state(void *handle,
>  static int soc21_common_set_powergating_state(void *handle,
>  					   enum amd_powergating_state state)
>  {
> -	/* TODO */
> +	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
> +
> +	switch (adev->ip_versions[LSDMA_HWIP][0]) {
> +	case IP_VERSION(6, 0, 0):
> +		adev->lsdma.funcs->update_memory_power_gating(adev,
> +				state == AMD_PG_STATE_GATE);
> +		break;
> +	default:
> +		break;
> +	}
> +
>  	return 0;
>  }
>  

Regards,
-- 
Luben