drm/i915: add new helpers for accessing stepping info

Add new runtime info field for stepping. Add new helpers for accessing
them. As we'll be switching platforms over to the new scheme
incrementally, check for non-initialized steppings.

In case a platform does not have separate display and gt steppings, it's
okay to use a common shorthand. However, in this case the display
stepping must not be initialized, and gt stepping is the single point of
truth.

v3: Remove IS_STEP() (José)

v2: Rename stepping->step

Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/bb4275733fa390ea3dbf6f62794d55b616665230.1616764798.git.jani.nikula@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -1269,6 +1269,17 @@ static inline struct drm_i915_private *pdev_to_i915(struct pci_dev *pdev)
 #define IS_REVID(p, since, until) \
 	(INTEL_REVID(p) >= (since) && INTEL_REVID(p) <= (until))
 
+#define INTEL_DISPLAY_STEP(__i915) (RUNTIME_INFO(__i915)->step.disp_stepping)
+#define INTEL_GT_STEP(__i915) (RUNTIME_INFO(__i915)->step.gt_stepping)
+
+#define IS_DISPLAY_STEP(__i915, since, until) \
+	(drm_WARN_ON(&(__i915)->drm, INTEL_DISPLAY_STEP(__i915) == STEP_NONE), \
+	 INTEL_DISPLAY_STEP(__i915) >= (since) && INTEL_DISPLAY_STEP(__i915) <= (until))
+
+#define IS_GT_STEP(__i915, since, until) \
+	(drm_WARN_ON(&(__i915)->drm, INTEL_GT_STEP(__i915) == STEP_NONE), \
+	 INTEL_GT_STEP(__i915) >= (since) && INTEL_GT_STEP(__i915) <= (until))
+
 static __always_inline unsigned int
 __platform_mask_index(const struct intel_runtime_info *info,
 		      enum intel_platform p)
@@ -1507,15 +1518,6 @@ enum {
 #define IS_JSL_EHL_REVID(p, since, until) \
 	(IS_JSL_EHL(p) && IS_REVID(p, since, until))
 
-enum {
-	STEP_A0,
-	STEP_A2,
-	STEP_B0,
-	STEP_B1,
-	STEP_C0,
-	STEP_D0,
-};
-
 static inline const struct i915_rev_steppings *
 tgl_stepping_get(struct drm_i915_private *dev_priv)
 {

drivers/gpu/drm/i915/intel_device_info.h

@@ -27,6 +27,8 @@
 
 #include <uapi/drm/i915_drm.h>
 
+#include "intel_step.h"
+
 #include "display/intel_display.h"
 
 #include "gt/intel_engine_types.h"
@@ -226,6 +228,8 @@ struct intel_runtime_info {
 	u8 num_scalers[I915_MAX_PIPES];
 
 	u32 rawclk_freq;
+
+	struct i915_rev_steppings step;
 };
 
 struct intel_driver_caps {

drivers/gpu/drm/i915/intel_step.h

@@ -22,4 +22,18 @@ extern const struct i915_rev_steppings tgl_uy_revid_step_tbl[TGL_UY_REVID_STEP_T
 extern const struct i915_rev_steppings tgl_revid_step_tbl[TGL_REVID_STEP_TBL_SIZE];
 extern const struct i915_rev_steppings adls_revid_step_tbl[ADLS_REVID_STEP_TBL_SIZE];
 
+/*
+ * Symbolic steppings that do not match the hardware. These are valid both as gt
+ * and display steppings as symbolic names.
+ */
+enum intel_step {
+	STEP_NONE = 0,
+	STEP_A0,
+	STEP_A2,
+	STEP_B0,
+	STEP_B1,
+	STEP_C0,
+	STEP_D0,
+};
+
 #endif /* __INTEL_STEP_H__ */