drm/i915/execlists: Pull the w/a LRI emission into a helper

Having the w/a registers as an open-coded table leaves a trap for the
unwary; it would be easy to miss incrementing the LRI counter when
adding a new register to the list. Instead, pull the list of registers
into a table, so that we only need add new registers to that table
rather than try and remember important side-effects of earlier chunks of
GPU instructions.
Suggested-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180618094150.30895-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_reg.h

@@ -156,6 +156,7 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 #define _PHY3(phy, ...) _PICK(phy, __VA_ARGS__)
 #define _MMIO_PHY3(phy, a, b, c) _MMIO(_PHY3(phy, a, b, c))
 
+#define __MASKED_FIELD(mask, value) ((mask) << 16 | (value))
 #define _MASKED_FIELD(mask, value) ({					   \
 	if (__builtin_constant_p(mask))					   \
 		BUILD_BUG_ON_MSG(((mask) & 0xffff0000), "Incorrect mask"); \
@@ -164,7 +165,7 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 	if (__builtin_constant_p(mask) && __builtin_constant_p(value))	   \
 		BUILD_BUG_ON_MSG((value) & ~(mask),			   \
 				 "Incorrect value for mask");		   \
-	(mask) << 16 | (value); })
+	__MASKED_FIELD(mask, value); })
 #define _MASKED_BIT_ENABLE(a)	({ typeof(a) _a = (a); _MASKED_FIELD(_a, _a); })
 #define _MASKED_BIT_DISABLE(a)	(_MASKED_FIELD((a), 0))
 

drivers/gpu/drm/i915/intel_lrc.c

@@ -1566,29 +1566,56 @@ static u32 *gen8_init_indirectctx_bb(struct intel_engine_cs *engine, u32 *batch)
 	return batch;
 }
 
-static u32 *gen9_init_indirectctx_bb(struct intel_engine_cs *engine, u32 *batch)
+struct lri {
+	i915_reg_t reg;
+	u32 value;
+};
+
+static u32 *emit_lri(u32 *batch, const struct lri *lri, unsigned int count)
 {
-	*batch++ = MI_ARB_ON_OFF | MI_ARB_DISABLE;
+	GEM_BUG_ON(!count || count > 63);
 
-	/* WaFlushCoherentL3CacheLinesAtContextSwitch:skl,bxt,glk */
-	batch = gen8_emit_flush_coherentl3_wa(engine, batch);
+	*batch++ = MI_LOAD_REGISTER_IMM(count);
+	do {
+		*batch++ = i915_mmio_reg_offset(lri->reg);
+		*batch++ = lri->value;
+	} while (lri++, --count);
+	*batch++ = MI_NOOP;
 
-	*batch++ = MI_LOAD_REGISTER_IMM(3);
+	return batch;
+}
 
-	/* WaDisableGatherAtSetShaderCommonSlice:skl,bxt,kbl,glk */
-	*batch++ = i915_mmio_reg_offset(COMMON_SLICE_CHICKEN2);
-	*batch++ = _MASKED_BIT_DISABLE(
-			GEN9_DISABLE_GATHER_AT_SET_SHADER_COMMON_SLICE);
+static u32 *gen9_init_indirectctx_bb(struct intel_engine_cs *engine, u32 *batch)
+{
+	static const struct lri lri[] = {
+		/* WaDisableGatherAtSetShaderCommonSlice:skl,bxt,kbl,glk */
+		{
+			COMMON_SLICE_CHICKEN2,
+			__MASKED_FIELD(GEN9_DISABLE_GATHER_AT_SET_SHADER_COMMON_SLICE,
+				       0),
+		},
+
+		/* BSpec: 11391 */
+		{
+			FF_SLICE_CHICKEN,
+			__MASKED_FIELD(FF_SLICE_CHICKEN_CL_PROVOKING_VERTEX_FIX,
+				       FF_SLICE_CHICKEN_CL_PROVOKING_VERTEX_FIX),
+		},
+
+		/* BSpec: 11299 */
+		{
+			_3D_CHICKEN3,
+			__MASKED_FIELD(_3D_CHICKEN_SF_PROVOKING_VERTEX_FIX,
+				       _3D_CHICKEN_SF_PROVOKING_VERTEX_FIX),
+		}
+	};
 
-	/* BSpec: 11391 */
-	*batch++ = i915_mmio_reg_offset(FF_SLICE_CHICKEN);
-	*batch++ = _MASKED_BIT_ENABLE(FF_SLICE_CHICKEN_CL_PROVOKING_VERTEX_FIX);
+	*batch++ = MI_ARB_ON_OFF | MI_ARB_DISABLE;
 
-	/* BSpec: 11299 */
-	*batch++ = i915_mmio_reg_offset(_3D_CHICKEN3);
-	*batch++ = _MASKED_BIT_ENABLE(_3D_CHICKEN_SF_PROVOKING_VERTEX_FIX);
+	/* WaFlushCoherentL3CacheLinesAtContextSwitch:skl,bxt,glk */
+	batch = gen8_emit_flush_coherentl3_wa(engine, batch);
 
-	*batch++ = MI_NOOP;
+	batch = emit_lri(batch, lri, ARRAY_SIZE(lri));
 
 	/* WaClearSlmSpaceAtContextSwitch:kbl */
 	/* Actual scratch location is at 128 bytes offset */