Re: [Intel-gfx] [PATCH 3/4] drm/i915/mtl: Define new PTE encode for MTL

["Das, Nirmoy" <nirmoy.das@linux.intel.com>]

Hi Aravind,

On 12/6/2022 8:37 AM, Aravind Iddamsetty wrote:
> Add a separate PTE encode function for MTL. The number of PAT registers
> have increased to 16 on MTL. All 16 PAT registers are available for
> PPGTT mapped pages, but only the lower 4 are available for GGTT mapped
> pages.
>
> BSPEC: 63884
>
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Cc: Matt Roper <matthew.d.roper@intel.com>
> Co-developed-by: Fei Yang <fei.yang@intel.com>
> Signed-off-by: Fei Yang <fei.yang@intel.com>
> Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
> ---
>   drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 33 +++++++++++++++++++++++++++-
>   drivers/gpu/drm/i915/gt/gen8_ppgtt.h |  4 ++++
>   drivers/gpu/drm/i915/gt/intel_ggtt.c | 32 ++++++++++++++++++++++++++-
>   drivers/gpu/drm/i915/gt/intel_gtt.h  | 13 +++++++++--
>   4 files changed, 78 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> index 31e838eee2ef..4197b43150cc 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> @@ -55,6 +55,34 @@ static u64 gen8_pte_encode(dma_addr_t addr,
>   	return pte;
>   }
>   
> +static u64 mtl_pte_encode(dma_addr_t addr,
> +			  enum i915_cache_level level,
> +			  u32 flags)
> +{
> +	gen8_pte_t pte = addr | GEN8_PAGE_PRESENT | GEN8_PAGE_RW;
> +
> +	if (unlikely(flags & PTE_READ_ONLY))
> +		pte &= ~GEN8_PAGE_RW;
> +
> +	if (flags & PTE_LM)

PTE_LM shouldn't be applicable for MTL, see below.

> +		pte |= GEN12_PPGTT_PTE_LM | GEN12_PPGTT_PTE_NC;
> +
> +	switch (level) {
> +	case I915_CACHE_NONE:
> +		pte |= GEN12_PPGTT_PTE_PAT1;
> +		break;
> +	case I915_CACHE_LLC:
> +	case I915_CACHE_L3_LLC:
> +		pte |= GEN12_PPGTT_PTE_PAT0 | GEN12_PPGTT_PTE_PAT1;
> +		break;
> +	case I915_CACHE_WT:
> +		pte |= GEN12_PPGTT_PTE_PAT0;
> +		break;
> +	}
> +
> +	return pte;
> +}
> +
>   static void gen8_ppgtt_notify_vgt(struct i915_ppgtt *ppgtt, bool create)
>   {
>   	struct drm_i915_private *i915 = ppgtt->vm.i915;
> @@ -963,7 +991,10 @@ struct i915_ppgtt *gen8_ppgtt_create(struct intel_gt *gt,
>   	 */
>   	ppgtt->vm.alloc_scratch_dma = alloc_pt_dma;
>   
> -	ppgtt->vm.pte_encode = gen8_pte_encode;
> +	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70))
> +		ppgtt->vm.pte_encode = mtl_pte_encode;

mtl_pte_encode() seems very specific for MTL but I assume it will be use for other platforms.
Please rename this function to a suitable one.

Nirmoy

> +	else
> +		ppgtt->vm.pte_encode = gen8_pte_encode;
>   
>   	ppgtt->vm.bind_async_flags = I915_VMA_LOCAL_BIND;
>   	ppgtt->vm.insert_entries = gen8_ppgtt_insert;
> diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.h b/drivers/gpu/drm/i915/gt/gen8_ppgtt.h
> index f541d19264b4..c48f1fc32909 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.h
> +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.h
> @@ -19,4 +19,8 @@ u64 gen8_ggtt_pte_encode(dma_addr_t addr,
>   			 enum i915_cache_level level,
>   			 u32 flags);
>   
> +u64 mtl_ggtt_pte_encode(dma_addr_t addr,
> +			enum i915_cache_level level,
> +			u32 flags);
> +
>   #endif
> diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
> index 82203ad85b0e..3b6f1f6f780a 100644
> --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
> @@ -246,6 +246,33 @@ static void guc_ggtt_invalidate(struct i915_ggtt *ggtt)
>   	}
>   }
>   
> +u64 mtl_ggtt_pte_encode(dma_addr_t addr,
> +			enum i915_cache_level level,
> +			u32 flags)
> +{
> +	gen8_pte_t pte = addr | GEN8_PAGE_PRESENT;
> +
> +	GEM_BUG_ON(addr & ~GEN12_GGTT_PTE_ADDR_MASK);
> +
> +	if (flags & PTE_LM)
> +		pte |= GEN12_GGTT_PTE_LM;
> +
> +	switch (level) {
> +	case I915_CACHE_NONE:
> +		pte |= MTL_GGTT_PTE_PAT1;
> +		break;
> +	case I915_CACHE_LLC:
> +	case I915_CACHE_L3_LLC:
> +		pte |= MTL_GGTT_PTE_PAT0 | MTL_GGTT_PTE_PAT1;
> +		break;
> +	case I915_CACHE_WT:
> +		pte |= MTL_GGTT_PTE_PAT0;
> +		break;
> +	}
> +
> +	return pte;
> +}
> +
>   u64 gen8_ggtt_pte_encode(dma_addr_t addr,
>   			 enum i915_cache_level level,
>   			 u32 flags)
> @@ -993,7 +1020,10 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt)
>   	ggtt->vm.vma_ops.bind_vma    = intel_ggtt_bind_vma;
>   	ggtt->vm.vma_ops.unbind_vma  = intel_ggtt_unbind_vma;
>   
> -	ggtt->vm.pte_encode = gen8_ggtt_pte_encode;
> +	if (GRAPHICS_VER_FULL(i915) >= IP_VER(12, 70))
> +		ggtt->vm.pte_encode = mtl_ggtt_pte_encode;
same here.
> +	else
> +		ggtt->vm.pte_encode = gen8_ggtt_pte_encode;
>   
>   	return ggtt_probe_common(ggtt, size);
>   }
> diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
> index 8a3e0a6793dd..4bb7a4005452 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gtt.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
> @@ -88,9 +88,18 @@ typedef u64 gen8_pte_t;
>   #define BYT_PTE_SNOOPED_BY_CPU_CACHES	REG_BIT(2)
>   #define BYT_PTE_WRITEABLE		REG_BIT(1)
>   
> +#define GEN12_PPGTT_PTE_PAT3    BIT_ULL(62)
>   #define GEN12_PPGTT_PTE_LM	BIT_ULL(11)
> -
> -#define GEN12_GGTT_PTE_LM	BIT_ULL(1)
> +#define GEN12_PPGTT_PTE_PAT2    BIT_ULL(7)
> +#define GEN12_PPGTT_PTE_NC      BIT_ULL(5)
> +#define GEN12_PPGTT_PTE_PAT1    BIT_ULL(4)
> +#define GEN12_PPGTT_PTE_PAT0    BIT_ULL(3)
> +
> +#define GEN12_GGTT_PTE_LM		BIT_ULL(1)
> +#define MTL_GGTT_PTE_PAT0		BIT_ULL(52)
> +#define MTL_GGTT_PTE_PAT1		BIT_ULL(53)
> +#define GEN12_GGTT_PTE_ADDR_MASK	GENMASK_ULL(45, 12)
> +#define MTL_GGTT_PTE_PAT_MASK		GENMASK_ULL(53, 52)
>   
>   #define GEN12_PDE_64K BIT(6)
>   #define GEN12_PTE_PS64 BIT(8)