Re: [Intel-gfx] [PATCH] drm/i915: Introduce G12 subplatform of DG2

["Sripada, Radhakrishna" <radhakrishna.sripada@intel.com>]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Matt
> Roper
> Sent: Thursday, January 20, 2022 3:50 PM
> To: intel-gfx@lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH] drm/i915: Introduce G12 subplatform of DG2
> 
> Another fork of the DG2 design has appeared, known as "DG2-G12;" let's
> add it as a new subplatform.  As with G11, the GT stepping resets back
> to A0 (so a DG2-G12 A0 is similar, but not identical, to a DG2-G10 C0)
> but the display steppings continue to use the same numbering scheme as
> G10 and G11.
> 
> Some existing DG2 workarounds are starting to be extended to the DG2-G12
> subplatform.  So far only workarounds that were "permanent" for both
> DG2-G10 and DG2-G11 have been tagged for DG2-G12, but more
> stepping-specific workarounds are likely to show up in the future.
> 
> Bspec: 44477
Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>

> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_workarounds.c |  2 +-
>  drivers/gpu/drm/i915/i915_drv.h             | 19 +++++++++++--------
>  drivers/gpu/drm/i915/intel_device_info.h    |  3 ++-
>  drivers/gpu/drm/i915/intel_step.c           |  7 +++++++
>  4 files changed, 21 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c
> b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> index 6a4372c3a3c5..2d2e3ae9c997 100644
> --- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
> +++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> @@ -2077,7 +2077,7 @@ rcs_engine_wa_init(struct intel_engine_cs *engine,
> struct i915_wa_list *wal)
>  	}
> 
>  	if (IS_DG2_GRAPHICS_STEP(engine->i915, G10, STEP_B0,
> STEP_FOREVER) ||
> -	    IS_DG2_G11(engine->i915)) {
> +	    IS_DG2_G11(engine->i915) || IS_DG2_G12(engine->i915)) {
>  		/* Wa_22013037850:dg2 */
>  		wa_write_or(wal, LSC_CHICKEN_BIT_0_UDW,
>  			    DISABLE_128B_EVICTION_COMMAND_UDW);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 890f1f6fbc49..a2fe5a0a7acd 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1262,6 +1262,8 @@ IS_SUBPLATFORM(const struct drm_i915_private
> *i915,
>  	IS_SUBPLATFORM(dev_priv, INTEL_DG2, INTEL_SUBPLATFORM_G10)
>  #define IS_DG2_G11(dev_priv) \
>  	IS_SUBPLATFORM(dev_priv, INTEL_DG2, INTEL_SUBPLATFORM_G11)
> +#define IS_DG2_G12(dev_priv) \
> +	IS_SUBPLATFORM(dev_priv, INTEL_DG2, INTEL_SUBPLATFORM_G12)
>  #define IS_ADLS_RPLS(dev_priv) \
>  	IS_SUBPLATFORM(dev_priv, INTEL_ALDERLAKE_S,
> INTEL_SUBPLATFORM_RPL_S)
>  #define IS_ADLP_N(dev_priv) \
> @@ -1378,16 +1380,17 @@ IS_SUBPLATFORM(const struct drm_i915_private
> *i915,
>  	(IS_XEHPSDV(__i915) && IS_GRAPHICS_STEP(__i915, since, until))
> 
>  /*
> - * DG2 hardware steppings are a bit unusual.  The hardware design was forked
> - * to create two variants (G10 and G11) which have distinct workaround sets.
> - * The G11 fork of the DG2 design resets the GT stepping back to "A0" for its
> - * first iteration, even though it's more similar to a G10 B0 stepping in terms
> - * of functionality and workarounds.  However the display stepping does not
> - * reset in the same manner --- a specific stepping like "B0" has a consistent
> - * meaning regardless of whether it belongs to a G10 or G11 DG2.
> + * DG2 hardware steppings are a bit unusual.  The hardware design was forked
> to
> + * create three variants (G10, G11, and G12) which each have distinct
> + * workaround sets.  The G11 and G12 forks of the DG2 design reset the GT
> + * stepping back to "A0" for their first iterations, even though they're more
> + * similar to a G10 B0 stepping and G10 C0 stepping respectively in terms of
> + * functionality and workarounds.  However the display stepping does not reset
> + * in the same manner --- a specific stepping like "B0" has a consistent
> + * meaning regardless of whether it belongs to a G10, G11, or G12 DG2.
>   *
>   * TLDR:  All GT workarounds and stepping-specific logic must be applied in
> - * relation to a specific subplatform (G10 or G11), whereas display workarounds
> + * relation to a specific subplatform (G10/G11/G12), whereas display
> workarounds
>   * and stepping-specific logic will be applied with a general DG2-wide stepping
>   * number.
>   */
> diff --git a/drivers/gpu/drm/i915/intel_device_info.h
> b/drivers/gpu/drm/i915/intel_device_info.h
> index 3699b1c539ea..364abcc7aa54 100644
> --- a/drivers/gpu/drm/i915/intel_device_info.h
> +++ b/drivers/gpu/drm/i915/intel_device_info.h
> @@ -96,7 +96,7 @@ enum intel_platform {
>   * it is fine for the same bit to be used on multiple parent platforms.
>   */
> 
> -#define INTEL_SUBPLATFORM_BITS (2)
> +#define INTEL_SUBPLATFORM_BITS (3)
>  #define INTEL_SUBPLATFORM_MASK (BIT(INTEL_SUBPLATFORM_BITS) - 1)
> 
>  /* HSW/BDW/SKL/KBL/CFL */
> @@ -109,6 +109,7 @@ enum intel_platform {
>  /* DG2 */
>  #define INTEL_SUBPLATFORM_G10	0
>  #define INTEL_SUBPLATFORM_G11	1
> +#define INTEL_SUBPLATFORM_G12	2
> 
>  /* ADL-S */
>  #define INTEL_SUBPLATFORM_RPL_S	0
> diff --git a/drivers/gpu/drm/i915/intel_step.c
> b/drivers/gpu/drm/i915/intel_step.c
> index a4b16b9e2e55..46556883e93d 100644
> --- a/drivers/gpu/drm/i915/intel_step.c
> +++ b/drivers/gpu/drm/i915/intel_step.c
> @@ -122,6 +122,10 @@ static const struct intel_step_info
> dg2_g11_revid_step_tbl[] = {
>  	[0x5] = { COMMON_GT_MEDIA_STEP(B1), .display_step = STEP_C0 },
>  };
> 
> +static const struct intel_step_info dg2_g12_revid_step_tbl[] = {
> +	[0x0] = { COMMON_GT_MEDIA_STEP(A0), .display_step = STEP_C0 },
> +};
> +
>  void intel_step_init(struct drm_i915_private *i915)
>  {
>  	const struct intel_step_info *revids = NULL;
> @@ -135,6 +139,9 @@ void intel_step_init(struct drm_i915_private *i915)
>  	} else if (IS_DG2_G11(i915)) {
>  		revids = dg2_g11_revid_step_tbl;
>  		size = ARRAY_SIZE(dg2_g11_revid_step_tbl);
> +	} else if (IS_DG2_G12(i915)) {
> +		revids = dg2_g12_revid_step_tbl;
> +		size = ARRAY_SIZE(dg2_g12_revid_step_tbl);
>  	} else if (IS_XEHPSDV(i915)) {
>  		revids = xehpsdv_revids;
>  		size = ARRAY_SIZE(xehpsdv_revids);
> --
> 2.34.1