Re: [PATCH v2 2/3] drm/panfrost: add amlogic reset quirk callback

Steven Price
2020-09-17T10:30:58Z

On 16/09/2020 16:01, Neil Armstrong wrote:
> The T820, G31 & G52 GPUs integratewd by Amlogic in the respective GXM, G12A/SM1 & G12B

NIT: s/integratewd/integrated/

> SoCs needs a quirk in the PWR registers at the GPU reset time.
>
> Since the Amlogic's integration of the GPU cores with the SoC is not
> publicly documented we do not know what does these
> values, but they permit having a fully functional GPU running with Panfrost.
>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

Reviewed-by: Steven Price <steven.price@arm.com>

> ---
> drivers/gpu/drm/panfrost/panfrost_gpu.c | 11 +++++++++++
> drivers/gpu/drm/panfrost/panfrost_gpu.h | 2 ++
> drivers/gpu/drm/panfrost/panfrost_regs.h | 4 ++++
> 3 files changed, 17 insertions(+)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
> index a6de78bc1fa8..e1b2a3376624 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
> @@ -76,6 +76,17 @@ int panfrost_gpu_soft_reset(struct panfrost_device *pfdev)
> return 0;
> }
>
> +void panfrost_gpu_amlogic_quirk(struct panfrost_device *pfdev)
> +{
> + /*
> + * The Amlogic integrated Mali-T820, Mali-G31 & Mali-G52 needs
> + * these undocumented bits in GPU_PWR_OVERRIDE1 to be set in order
> + * to operate correctly.
> + */
> + gpu_write(pfdev, GPU_PWR_KEY, GPU_PWR_KEY_UNLOCK);
> + gpu_write(pfdev, GPU_PWR_OVERRIDE1, 0xfff | (0x20 << 16));
> +}
> +
> static void panfrost_gpu_init_quirks(struct panfrost_device *pfdev)
> {
> u32 quirks = 0;
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.h b/drivers/gpu/drm/panfrost/panfrost_gpu.h
> index 4112412087b2..468c51e7e46d 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gpu.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_gpu.h
> @@ -16,4 +16,6 @@ int panfrost_gpu_soft_reset(struct panfrost_device *pfdev);
> void panfrost_gpu_power_on(struct panfrost_device *pfdev);
> void panfrost_gpu_power_off(struct panfrost_device *pfdev);
>
> +void panfrost_gpu_amlogic_quirk(struct panfrost_device *pfdev);
> +
> #endif
> diff --git a/drivers/gpu/drm/panfrost/panfrost_regs.h b/drivers/gpu/drm/panfrost/panfrost_regs.h
> index ea38ac60581c..eddaa62ad8b0 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_regs.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_regs.h
> @@ -51,6 +51,10 @@
> #define GPU_STATUS 0x34
> #define GPU_STATUS_PRFCNT_ACTIVE BIT(2)
> #define GPU_LATEST_FLUSH_ID 0x38
> +#define GPU_PWR_KEY 0x50 /* (WO) Power manager key register */
> +#define GPU_PWR_KEY_UNLOCK 0x2968A819
> +#define GPU_PWR_OVERRIDE0 0x54 /* (RW) Power manager override settings */
> +#define GPU_PWR_OVERRIDE1 0x58 /* (RW) Power manager override settings */
> #define GPU_FAULT_STATUS 0x3C
> #define GPU_FAULT_ADDRESS_LO 0x40
> #define GPU_FAULT_ADDRESS_HI 0x44