[Intel-gfx] [PATCH v2 03/12] drm/i915/skl: Use revid->stepping tables

[Lucas De Marchi]

On Fri, Jul 09, 2021 at 08:37:15PM -0700, Matt Roper wrote:
>Switch SKL to use a revid->stepping table as we're trying to do on all
>platforms going forward.  Also drop the preproduction revisions and add
>the newer steppings we hadn't already handled.
>
>Note that SKL has a case where a newer revision ID corresponds to an
>older GT/disp stepping (0x9 -> STEP_J0, 0xA -> STEP_I1).  Also, the lack
>of a revision ID 0x8 in the table is intentional and not an oversight.
>We'll re-write the KBL-specific comment to make it clear that these kind
>of quirks are expected.
>
>v2:
> - Since GT and display steppings are always identical on SKL use a
>   macro to set both values at once in a more readable manner.  (Anusha)
> - Drop preproduction steppings.
>
>Bspec: 13626
>Cc: Anusha Srivatsa <anusha.srivatsa at intel.com>
>Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
>---
> drivers/gpu/drm/i915/gt/intel_workarounds.c |  2 +-
> drivers/gpu/drm/i915/i915_drv.h             | 11 +-------
> drivers/gpu/drm/i915/intel_step.c           | 30 +++++++++++++++++----
> drivers/gpu/drm/i915/intel_step.h           |  4 +++
> 4 files changed, 31 insertions(+), 16 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
>index d9a5a445ceec..6dfd564e078f 100644
>--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
>+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
>@@ -883,7 +883,7 @@ skl_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
> 		    GEN8_EU_GAUNIT_CLOCK_GATE_DISABLE);
>
> 	/* WaInPlaceDecompressionHang:skl */
>-	if (IS_SKL_REVID(i915, SKL_REVID_H0, REVID_FOREVER))
>+	if (IS_SKL_GT_STEP(i915, STEP_H0, STEP_FOREVER))
> 		wa_write_or(wal,
> 			    GEN9_GAMT_ECO_REG_RW_IA,
> 			    GAMT_ECO_ENABLE_IN_PLACE_DECOMPRESS);
>diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>index c4747f4407ef..f30499ed6787 100644
>--- a/drivers/gpu/drm/i915/i915_drv.h
>+++ b/drivers/gpu/drm/i915/i915_drv.h
>@@ -1515,16 +1515,7 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
> #define IS_TGL_Y(dev_priv) \
> 	IS_SUBPLATFORM(dev_priv, INTEL_TIGERLAKE, INTEL_SUBPLATFORM_ULX)
>
>-#define SKL_REVID_A0		0x0
>-#define SKL_REVID_B0		0x1
>-#define SKL_REVID_C0		0x2
>-#define SKL_REVID_D0		0x3
>-#define SKL_REVID_E0		0x4
>-#define SKL_REVID_F0		0x5
>-#define SKL_REVID_G0		0x6
>-#define SKL_REVID_H0		0x7
>-
>-#define IS_SKL_REVID(p, since, until) (IS_SKYLAKE(p) && IS_REVID(p, since, until))
>+#define IS_SKL_GT_STEP(p, since, until) (IS_SKYLAKE(p) && IS_GT_STEP(p, since, until))
>
> #define BXT_REVID_A0		0x0
> #define BXT_REVID_A1		0x1
>diff --git a/drivers/gpu/drm/i915/intel_step.c b/drivers/gpu/drm/i915/intel_step.c
>index 93ccd42f2514..69c928b046e8 100644
>--- a/drivers/gpu/drm/i915/intel_step.c
>+++ b/drivers/gpu/drm/i915/intel_step.c
>@@ -7,14 +7,31 @@
> #include "intel_step.h"
>
> /*
>- * KBL revision ID ordering is bizarre; higher revision ID's map to lower
>- * steppings in some cases.  So rather than test against the revision ID
>- * directly, let's map that into our own range of increasing ID's that we
>- * can test against in a regular manner.
>+ * Some platforms have unusual ways of mapping PCI revision ID to GT/display
>+ * steppings.  E.g., in some cases a higher PCI revision may translate to a
>+ * lower stepping of the GT and/or display IP.  This file provides lookup
>+ * tables to map the PCI revision into a standard set of stepping values that
>+ * can be compared numerically.
>+ *
>+ * Also note that some revisions/steppings may have been set aside as
>+ * placeholders but never materialized in real hardware; in those cases there
>+ * may be jumps in the revision IDs or stepping values in the tables below.
>  */
>
>+/*
>+ * Some platforms always have the same stepping value for GT and display;
>+ * use a macro to define these to make it easier to identify the platforms
>+ * where the two steppings can deviate.
>+ */
>+#define COMMON_STEPPING(x)  .gt_step = STEP_##x, .display_step = STEP_##x

nitpick:

"stepping" is the proper word, but we settled on "step"
everyhere: functions, macros, tables, filename etc. Can we
continue doing that?  For the comments I think it's ok to
continue using the proper word, but for real code I think it
would be better to keep it consistent

thanks
Lucas De Marchi