[PATCH v3 6/6] drm/i915/gen8: Add WaRsRestoreWithPerCtxtBb workaround

[Arun Siluvery <arun.siluvery@linux.intel.com>]

In Per context w/a batch buffer,
WaRsRestoreWithPerCtxtBb

v2: This patches modifies definitions of MI_LOAD_REGISTER_MEM and
MI_LOAD_REGISTER_REG; Add GEN8 specific defines for these instructions
so as to not break any future users of existing definitions (Michel)

Signed-off-by: Rafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h  | 26 ++++++++++++++++++
 drivers/gpu/drm/i915/intel_lrc.c | 59 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 33b0ff1..6928162 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -347,6 +347,26 @@
 #define   MI_INVALIDATE_BSD		(1<<7)
 #define   MI_FLUSH_DW_USE_GTT		(1<<2)
 #define   MI_FLUSH_DW_USE_PPGTT		(0<<2)
+#define MI_ATOMIC(len)	MI_INSTR(0x2F, (len-2))
+#define   MI_ATOMIC_MEMORY_TYPE_GGTT	(1<<22)
+#define   MI_ATOMIC_INLINE_DATA		(1<<18)
+#define   MI_ATOMIC_CS_STALL		(1<<17)
+#define   MI_ATOMIC_RETURN_DATA_CTL	(1<<16)
+#define MI_ATOMIC_OP_MASK(op)  ((op) << 8)
+#define MI_ATOMIC_AND	MI_ATOMIC_OP_MASK(0x01)
+#define MI_ATOMIC_OR	MI_ATOMIC_OP_MASK(0x02)
+#define MI_ATOMIC_XOR	MI_ATOMIC_OP_MASK(0x03)
+#define MI_ATOMIC_MOVE	MI_ATOMIC_OP_MASK(0x04)
+#define MI_ATOMIC_INC	MI_ATOMIC_OP_MASK(0x05)
+#define MI_ATOMIC_DEC	MI_ATOMIC_OP_MASK(0x06)
+#define MI_ATOMIC_ADD	MI_ATOMIC_OP_MASK(0x07)
+#define MI_ATOMIC_SUB	MI_ATOMIC_OP_MASK(0x08)
+#define MI_ATOMIC_RSUB	MI_ATOMIC_OP_MASK(0x09)
+#define MI_ATOMIC_IMAX	MI_ATOMIC_OP_MASK(0x0A)
+#define MI_ATOMIC_IMIN	MI_ATOMIC_OP_MASK(0x0B)
+#define MI_ATOMIC_UMAX	MI_ATOMIC_OP_MASK(0x0C)
+#define MI_ATOMIC_UMIN	MI_ATOMIC_OP_MASK(0x0D)
+
 #define MI_BATCH_BUFFER		MI_INSTR(0x30, 1)
 #define   MI_BATCH_NON_SECURE		(1)
 /* for snb/ivb/vlv this also means "batch in ppgtt" when ppgtt is enabled. */
@@ -453,6 +473,10 @@
 #define   MI_REPORT_PERF_COUNT_GGTT (1<<0)
 #define MI_LOAD_REGISTER_MEM    MI_INSTR(0x29, 0)
 #define MI_LOAD_REGISTER_REG    MI_INSTR(0x2A, 0)
+#define MI_LOAD_REGISTER_MEM_GEN8 MI_INSTR(0x29, 2)
+#define   MI_LRM_USE_GLOBAL_GTT (1<<22)
+#define   MI_LRM_ASYNC_MODE_ENABLE (1<<21)
+#define MI_LOAD_REGISTER_REG_GEN8 MI_INSTR(0x2A, 1)
 #define MI_RS_STORE_DATA_IMM    MI_INSTR(0x2B, 0)
 #define MI_LOAD_URB_MEM         MI_INSTR(0x2C, 0)
 #define MI_STORE_URB_MEM        MI_INSTR(0x2D, 0)
@@ -1799,6 +1823,8 @@ enum skl_disp_power_wells {
 #define   GEN8_RC_SEMA_IDLE_MSG_DISABLE	(1 << 12)
 #define   GEN8_FF_DOP_CLOCK_GATE_DISABLE	(1<<10)
 
+#define GEN8_RS_PREEMPT_STATUS		0x215C
+
 /* Fuse readout registers for GT */
 #define CHV_FUSE_GT			(VLV_DISPLAY_BASE + 0x2168)
 #define   CHV_FGT_DISABLE_SS0		(1 << 10)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index bca137e..61b1e22 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1155,6 +1155,13 @@ static int gen8_init_perctx_bb(struct intel_engine_cs *ring)
 	int end;
 	struct page *page;
 	uint32_t *reg_state;
+	u32 scratch_addr;
+	unsigned long flags = 0;
+
+	if (ring->scratch.obj == NULL) {
+		DRM_ERROR("scratch page not allocated for %s\n", ring->name);
+		return -EINVAL;
+	}
 
 	page = i915_gem_object_get_page(ring->ctx_wa.obj, 0);
 	reg_state = kmap_atomic(page);
@@ -1169,9 +1176,61 @@ static int gen8_init_perctx_bb(struct intel_engine_cs *ring)
 		return -EINVAL;
 	}
 
+	/* Actual scratch location is at 128 bytes offset */
+	scratch_addr = ring->scratch.gtt_offset + 2*CACHELINE_BYTES;
+	scratch_addr |= PIPE_CONTROL_GLOBAL_GTT;
+
 	/* WaDisableCtxRestoreArbitration:bdw,chv */
 	reg_state[index++] = MI_ARB_ON_OFF | MI_ARB_ENABLE;
 
+	/*
+	 * As per Bspec, to workaround a known HW issue, SW must perform the
+	 * below programming sequence prior to programming MI_BATCH_BUFFER_END.
+	 *
+	 * This is only applicable for Gen8.
+	 */
+
+	/* WaRsRestoreWithPerCtxtBb:bdw,chv */
+	reg_state[index++] = MI_LOAD_REGISTER_IMM(1);
+	reg_state[index++] = INSTPM;
+	reg_state[index++] = _MASKED_BIT_DISABLE(INSTPM_FORCE_ORDERING);
+
+	flags = MI_ATOMIC_MEMORY_TYPE_GGTT |
+		MI_ATOMIC_INLINE_DATA |
+		MI_ATOMIC_CS_STALL |
+		MI_ATOMIC_RETURN_DATA_CTL |
+		MI_ATOMIC_MOVE;
+
+	reg_state[index++] = MI_ATOMIC(5) | flags;
+	reg_state[index++] = scratch_addr;
+	reg_state[index++] = 0;
+	reg_state[index++] = _MASKED_BIT_ENABLE(INSTPM_FORCE_ORDERING);
+	reg_state[index++] = _MASKED_BIT_ENABLE(INSTPM_FORCE_ORDERING);
+
+	/*
+	 * BSpec says MI_LOAD_REGISTER_MEM, MI_LOAD_REGISTER_REG and
+	 * MI_BATCH_BUFFER_END instructions in this sequence need to be
+	 * in the same cacheline.
+	 */
+	while (((unsigned long) (reg_state + index) % CACHELINE_BYTES) != 0)
+		reg_state[index++] = MI_NOOP;
+
+	reg_state[index++] = MI_LOAD_REGISTER_MEM_GEN8 |
+		MI_LRM_USE_GLOBAL_GTT |
+		MI_LRM_ASYNC_MODE_ENABLE;
+	reg_state[index++] = INSTPM;
+	reg_state[index++] = scratch_addr;
+	reg_state[index++] = 0;
+
+	/*
+	 * BSpec says there should not be any commands programmed
+	 * between MI_LOAD_REGISTER_REG and MI_BATCH_BUFFER_END so
+	 * do not add any new commands
+	 */
+	reg_state[index++] = MI_LOAD_REGISTER_REG_GEN8;
+	reg_state[index++] = GEN8_RS_PREEMPT_STATUS;
+	reg_state[index++] = GEN8_RS_PREEMPT_STATUS;
+
 	/* padding */
         while (index < end)
 		reg_state[index++] = MI_NOOP;
-- 
2.3.0

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