[PATCH 1/1] drm/msm: Expose uche trap base via uapi

Dmitry Baryshkov dmitry.baryshkov at linaro.org
Tue Dec 3 13:34:40 UTC 2024


On Tue, Dec 03, 2024 at 02:09:59PM +0100, Danylo wrote:
> 
> 
> 
> On 12/3/24 13:52, Dmitry Baryshkov wrote:
> > On Tue, Dec 03, 2024 at 10:59:20AM +0100, Danylo Piliaiev wrote:
> > > This adds MSM_PARAM_UCHE_TRAP_BASE that will be used by Mesa
> > > implementation for VK_KHR_shader_clock and GL_ARB_shader_clock.
> > Could you please spend more words, describing what it is and why is it
> > necessary for those extensions. For a5xx+ it looks like some kind of an
> > internal address (what kind of?). For a4xx I'm completely lost.
> Yes, my bad. On at least a6xx+, shader could read 64b ALWAYSON counter
> from UCHE_TRAP_BASE+0 address. We use it to implement VK_KHR_shader_clock:
>  "This extension advertises the SPIR-V ShaderClockKHR capability for Vulkan,
> which
>   allows a shader to query a real-time or monotonically incrementing counter
> at
>   the subgroup level or across the device level."
> And there is no other proper way to get such counter. Same with
> GL_ARB_shader_clock.

Yes, please add this to the commit message.

> 
> Not sure what's there on older gens, I exposed the value on them for the
> completeness sake. But I don't know whether it is desired or not (I don't
> expect
> the value being read and used on a4xx/a5xx in Mesa).

Do you know if there is anything interesting in that region on a4xx /
a5xx (or at least if it's a region on a4xx?) Also how will that
GET_PARAM behave on a2xx-a3xx? Will it return 0 or some -EINVAL?

> 
> > > Signed-off-by: Danylo Piliaiev <dpiliaiev at igalia.com>
> > > ---
> > >   drivers/gpu/drm/msm/adreno/a4xx_gpu.c   |  6 ++++--
> > >   drivers/gpu/drm/msm/adreno/a5xx_gpu.c   | 10 ++++++----
> > >   drivers/gpu/drm/msm/adreno/a6xx_gpu.c   | 12 +++++++-----
> > >   drivers/gpu/drm/msm/adreno/adreno_gpu.c |  3 +++
> > >   drivers/gpu/drm/msm/adreno/adreno_gpu.h |  2 ++
> > >   include/uapi/drm/msm_drm.h              |  1 +
> > >   6 files changed, 23 insertions(+), 11 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/msm/adreno/a4xx_gpu.c b/drivers/gpu/drm/msm/adreno/a4xx_gpu.c
> > > index 50c490b492f0..f1b18a6663f7 100644
> > > --- a/drivers/gpu/drm/msm/adreno/a4xx_gpu.c
> > > +++ b/drivers/gpu/drm/msm/adreno/a4xx_gpu.c
> > > @@ -251,8 +251,8 @@ static int a4xx_hw_init(struct msm_gpu *gpu)
> > >   		gpu_write(gpu, REG_A4XX_UCHE_CACHE_WAYS_VFD, 0x07);
> > >   	/* Disable L2 bypass to avoid UCHE out of bounds errors */
> > > -	gpu_write(gpu, REG_A4XX_UCHE_TRAP_BASE_LO, 0xffff0000);
> > > -	gpu_write(gpu, REG_A4XX_UCHE_TRAP_BASE_HI, 0xffff0000);
> > > +	gpu_write(gpu, REG_A4XX_UCHE_TRAP_BASE_LO, lower_32_bits(adreno_gpu->uche_trap_base));
> > > +	gpu_write(gpu, REG_A4XX_UCHE_TRAP_BASE_HI, upper_32_bits(adreno_gpu->uche_trap_base));
> > >   	gpu_write(gpu, REG_A4XX_CP_DEBUG, (1 << 25) |
> > >   			(adreno_is_a420(adreno_gpu) ? (1 << 29) : 0));
> > > @@ -693,6 +693,8 @@ struct msm_gpu *a4xx_gpu_init(struct drm_device *dev)
> > >   	if (ret)
> > >   		goto fail;
> > > +	adreno_gpu->uche_trap_base = 0xffff0000ffff0000ull;
> > > +
> > >   	if (!gpu->aspace) {
> > >   		/* TODO we think it is possible to configure the GPU to
> > >   		 * restrict access to VRAM carveout.  But the required
> > > diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> > > index ee89db72e36e..caf2c0a7a29f 100644
> > > --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> > > +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> > > @@ -750,10 +750,10 @@ static int a5xx_hw_init(struct msm_gpu *gpu)
> > >   	gpu_write(gpu, REG_A5XX_UCHE_CACHE_WAYS, 0x02);
> > >   	/* Disable L2 bypass in the UCHE */
> > > -	gpu_write(gpu, REG_A5XX_UCHE_TRAP_BASE_LO, 0xFFFF0000);
> > > -	gpu_write(gpu, REG_A5XX_UCHE_TRAP_BASE_HI, 0x0001FFFF);
> > > -	gpu_write(gpu, REG_A5XX_UCHE_WRITE_THRU_BASE_LO, 0xFFFF0000);
> > > -	gpu_write(gpu, REG_A5XX_UCHE_WRITE_THRU_BASE_HI, 0x0001FFFF);
> > > +	gpu_write(gpu, REG_A5XX_UCHE_TRAP_BASE_LO, lower_32_bits(adreno_gpu->uche_trap_base));
> > > +	gpu_write(gpu, REG_A5XX_UCHE_TRAP_BASE_HI, upper_32_bits(adreno_gpu->uche_trap_base));
> > > +	gpu_write(gpu, REG_A5XX_UCHE_WRITE_THRU_BASE_LO, lower_32_bits(adreno_gpu->uche_trap_base));
> > > +	gpu_write(gpu, REG_A5XX_UCHE_WRITE_THRU_BASE_HI, upper_32_bits(adreno_gpu->uche_trap_base));
> > >   	/* Set the GMEM VA range (0 to gpu->gmem) */
> > >   	gpu_write(gpu, REG_A5XX_UCHE_GMEM_RANGE_MIN_LO, 0x00100000);
> > > @@ -1805,5 +1805,7 @@ struct msm_gpu *a5xx_gpu_init(struct drm_device *dev)
> > >   	adreno_gpu->ubwc_config.macrotile_mode = 0;
> > >   	adreno_gpu->ubwc_config.ubwc_swizzle = 0x7;
> > > +	adreno_gpu->uche_trap_base = 0x0001ffffffff0000ull;
> > > +
> > >   	return gpu;
> > >   }
> > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > index 019610341df1..0ae29a7c8a4d 100644
> > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > @@ -1123,12 +1123,12 @@ static int hw_init(struct msm_gpu *gpu)
> > >   	/* Disable L2 bypass in the UCHE */
> > >   	if (adreno_is_a7xx(adreno_gpu)) {
> > > -		gpu_write64(gpu, REG_A6XX_UCHE_TRAP_BASE, 0x0001fffffffff000llu);
> > > -		gpu_write64(gpu, REG_A6XX_UCHE_WRITE_THRU_BASE, 0x0001fffffffff000llu);
> > > +		gpu_write64(gpu, REG_A6XX_UCHE_TRAP_BASE, adreno_gpu->uche_trap_base);
> > > +		gpu_write64(gpu, REG_A6XX_UCHE_WRITE_THRU_BASE, adreno_gpu->uche_trap_base);
> > >   	} else {
> > > -		gpu_write64(gpu, REG_A6XX_UCHE_WRITE_RANGE_MAX, 0x0001ffffffffffc0llu);
> > > -		gpu_write64(gpu, REG_A6XX_UCHE_TRAP_BASE, 0x0001fffffffff000llu);
> > > -		gpu_write64(gpu, REG_A6XX_UCHE_WRITE_THRU_BASE, 0x0001fffffffff000llu);
> > > +		gpu_write64(gpu, REG_A6XX_UCHE_WRITE_RANGE_MAX, adreno_gpu->uche_trap_base + 0xfc0);
> > > +		gpu_write64(gpu, REG_A6XX_UCHE_TRAP_BASE, adreno_gpu->uche_trap_base);
> > > +		gpu_write64(gpu, REG_A6XX_UCHE_WRITE_THRU_BASE, adreno_gpu->uche_trap_base);
> > >   	}
> > >   	if (!(adreno_is_a650_family(adreno_gpu) ||
> > > @@ -2533,6 +2533,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
> > >   		}
> > >   	}
> > > +	adreno_gpu->uche_trap_base = 0x1fffffffff000ull;
> > > +
> > >   	if (gpu->aspace)
> > >   		msm_mmu_set_fault_handler(gpu->aspace->mmu, gpu,
> > >   				a6xx_fault_handler);
> > > diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > > index 076be0473eb5..774ff6eacb9f 100644
> > > --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > > +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > > @@ -385,6 +385,9 @@ int adreno_get_param(struct msm_gpu *gpu, struct msm_file_private *ctx,
> > >   	case MSM_PARAM_MACROTILE_MODE:
> > >   		*value = adreno_gpu->ubwc_config.macrotile_mode;
> > >   		return 0;
> > > +	case MSM_PARAM_UCHE_TRAP_BASE:
> > > +		*value = adreno_gpu->uche_trap_base;
> > > +		return 0;
> > >   	default:
> > >   		DBG("%s: invalid param: %u", gpu->name, param);
> > >   		return -EINVAL;
> > > diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> > > index e71f420f8b3a..9bd38dda4308 100644
> > > --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> > > +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> > > @@ -253,6 +253,8 @@ struct adreno_gpu {
> > >   	bool gmu_is_wrapper;
> > >   	bool has_ray_tracing;
> > > +
> > > +	u64 uche_trap_base;
> > >   };
> > >   #define to_adreno_gpu(x) container_of(x, struct adreno_gpu, base)
> > > diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
> > > index b916aab80dde..2342cb90857e 100644
> > > --- a/include/uapi/drm/msm_drm.h
> > > +++ b/include/uapi/drm/msm_drm.h
> > > @@ -90,6 +90,7 @@ struct drm_msm_timespec {
> > >   #define MSM_PARAM_RAYTRACING 0x11 /* RO */
> > >   #define MSM_PARAM_UBWC_SWIZZLE 0x12 /* RO */
> > >   #define MSM_PARAM_MACROTILE_MODE 0x13 /* RO */
> > > +#define MSM_PARAM_UCHE_TRAP_BASE 0x14 /* RO */
> > >   /* For backwards compat.  The original support for preemption was based on
> > >    * a single ring per priority level so # of priority levels equals the #
> > > -- 
> > > 2.46.2
> > > 
> 

-- 
With best wishes
Dmitry


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