[PATCH 0/4] Rework workaround init fn for BDW and CHV

[PATCH 0/4] Rework workaround init fn for BDW and CHV

[Arun Siluvery]

The patches that initialize workarounds for BDW and CHV using LRIs
are already merged in the tree but I received few more comments
from Chris and Damien.

I have reworked these patches as per their comments; it fixes
some issues and the code now looks clean. we can easily add
more workarounds with minimal changes.

I have tried to split BDW and CHV changes as separate patches but
it was getting ugly hence combined them also since it is a fixup
patch it should be ok.

In the previous implementation we were emitting each LRI individually
so the total number was not clear during init so a temporary array
was used to save w/a data (this is exported to debugfs) but if not
initialized we could potentially overrun array and also the condition
was not correct.
In this rework, w/a are organized as an array so we know the exact
count from the beginning and temporary array is no longer required.

The corresponding i-g-t is gem_workarounds.c and it is also updated.

Arun Siluvery (2):
  drm/i915: Rework workaround init functions for BDW and CHV
  drm/i915: Rework workaround data exporting to debugfs

Damien Lespiau (2):
  drm/i915: Rename intel_wa_registers with a i915_ prefix
  drm/i915: Don't restrict i915_wa_registers to BDW

 drivers/gpu/drm/i915/i915_debugfs.c     |  42 ++++++---
 drivers/gpu/drm/i915/i915_drv.h         |  14 ---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 162 ++++++++++++++------------------
 drivers/gpu/drm/i915/intel_ringbuffer.h |   8 ++
 4 files changed, 107 insertions(+), 119 deletions(-)

-- 
2.0.4

[PATCH 1/4] drm/i915: Rework workaround init functions for BDW and CHV

[Arun Siluvery]

This rework is based on suggestion from Chris.
Now w/a are organized in an array and all of them are emitted in
single fn instead of sending them individually. This approach is
very clean and new w/a can be added with minimal changes.
The same array can be used when exporting them to debugfs and the
temporary array in the current implementation is not required.

Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 149 +++++++++++++-------------------
 1 file changed, 58 insertions(+), 91 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index c5e4dc7..bae1527 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -650,87 +650,71 @@ err:
 	return ret;
 }
 
-static inline void intel_ring_emit_wa(struct intel_engine_cs *ring,
-				       u32 addr, u32 value)
+static int i915_request_emit_lri(struct intel_engine_cs *ring,
+				 int num_registers, const u32 *lri_list)
 {
-	struct drm_device *dev = ring->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
+	int i;
+	int ret;
 
-	if (dev_priv->num_wa_regs > I915_MAX_WA_REGS)
-		return;
+	ret = intel_ring_begin(ring, (2 * num_registers + 1));
+	if (ret)
+		return ret;
 
-	intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
-	intel_ring_emit(ring, addr);
-	intel_ring_emit(ring, value);
+	intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(num_registers));
+	for (i = 0; i < 2*num_registers; i += 2) {
+		intel_ring_emit(ring, *(lri_list + i));
+		intel_ring_emit(ring, *(lri_list + i + 1));
+	}
 
-	dev_priv->intel_wa_regs[dev_priv->num_wa_regs].addr = addr;
-	dev_priv->intel_wa_regs[dev_priv->num_wa_regs].mask = (value) & 0xFFFF;
-	/* value is updated with the status of remaining bits of this
-	 * register when it is read from debugfs file
-	 */
-	dev_priv->intel_wa_regs[dev_priv->num_wa_regs].value = value;
-	dev_priv->num_wa_regs++;
+	intel_ring_emit(ring, MI_NOOP);
+	intel_ring_advance(ring);
 
-	return;
+	return 0;
 }
 
-static int bdw8_init_workarounds(struct intel_engine_cs *ring)
-{
-	int ret;
-	struct drm_device *dev = ring->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
+static const u32 bdw_ring_init_context[] = {
 
 	/*
 	 * workarounds applied in this fn are part of register state context,
 	 * they need to be re-initialized followed by gpu reset, suspend/resume,
 	 * module reload.
 	 */
-	dev_priv->num_wa_regs = 0;
-	memset(dev_priv->intel_wa_regs, 0, sizeof(dev_priv->intel_wa_regs));
-
-	/*
-	 * update the number of dwords required based on the
-	 * actual number of workarounds applied
-	 */
-	ret = intel_ring_begin(ring, 24);
-	if (ret)
-		return ret;
 
 	/* WaDisablePartialInstShootdown:bdw */
 	/* WaDisableThreadStallDopClockGating:bdw */
 	/* FIXME: Unclear whether we really need this on production bdw. */
-	intel_ring_emit_wa(ring, GEN8_ROW_CHICKEN,
-			   _MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE
-					     | STALL_DOP_GATING_DISABLE));
+	GEN8_ROW_CHICKEN,
+	_MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE) |
+	_MASKED_BIT_ENABLE(STALL_DOP_GATING_DISABLE),
 
 	/* WaDisableDopClockGating:bdw May not be needed for production */
-	intel_ring_emit_wa(ring, GEN7_ROW_CHICKEN2,
-			   _MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE));
+	GEN7_ROW_CHICKEN2,
+	_MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE),
 
 	/*
 	 * This GEN8_CENTROID_PIXEL_OPT_DIS W/A is only needed for
 	 * pre-production hardware
 	 */
-	intel_ring_emit_wa(ring, HALF_SLICE_CHICKEN3,
-			   _MASKED_BIT_ENABLE(GEN8_CENTROID_PIXEL_OPT_DIS
-					      | GEN8_SAMPLER_POWER_BYPASS_DIS));
+	HALF_SLICE_CHICKEN3,
+	_MASKED_BIT_ENABLE(GEN8_CENTROID_PIXEL_OPT_DIS
+			   | GEN8_SAMPLER_POWER_BYPASS_DIS),
 
-	intel_ring_emit_wa(ring, GEN7_HALF_SLICE_CHICKEN1,
-			   _MASKED_BIT_ENABLE(GEN7_SINGLE_SUBSCAN_DISPATCH_ENABLE));
+	GEN7_HALF_SLICE_CHICKEN1,
+	_MASKED_BIT_ENABLE(GEN7_SINGLE_SUBSCAN_DISPATCH_ENABLE),
 
-	intel_ring_emit_wa(ring, COMMON_SLICE_CHICKEN2,
-			   _MASKED_BIT_ENABLE(GEN8_CSC2_SBE_VUE_CACHE_CONSERVATIVE));
+	COMMON_SLICE_CHICKEN2,
+	_MASKED_BIT_ENABLE(GEN8_CSC2_SBE_VUE_CACHE_CONSERVATIVE),
 
 	/* Use Force Non-Coherent whenever executing a 3D context. This is a
 	 * workaround for for a possible hang in the unlikely event a TLB
 	 * invalidation occurs during a PSD flush.
 	 */
-	intel_ring_emit_wa(ring, HDC_CHICKEN0,
-			   _MASKED_BIT_ENABLE(HDC_FORCE_NON_COHERENT));
+	HDC_CHICKEN0,
+	_MASKED_BIT_ENABLE(HDC_FORCE_NON_COHERENT),
 
 	/* Wa4x4STCOptimizationDisable:bdw */
-	intel_ring_emit_wa(ring, CACHE_MODE_1,
-			   _MASKED_BIT_ENABLE(GEN8_4x4_STC_OPTIMIZATION_DISABLE));
+	CACHE_MODE_1,
+	_MASKED_BIT_ENABLE(GEN8_4x4_STC_OPTIMIZATION_DISABLE),
 
 	/*
 	 * BSpec recommends 8x4 when MSAA is used,
@@ -740,54 +724,40 @@ static int bdw8_init_workarounds(struct intel_engine_cs *ring)
 	 * disable bit, which we don't touch here, but it's good
 	 * to keep in mind (see 3DSTATE_PS and 3DSTATE_WM).
 	 */
-	intel_ring_emit_wa(ring, GEN7_GT_MODE,
-			   GEN6_WIZ_HASHING_MASK | GEN6_WIZ_HASHING_16x4);
-
-	intel_ring_advance(ring);
-
-	DRM_DEBUG_DRIVER("Number of Workarounds applied: %d\n",
-			 dev_priv->num_wa_regs);
-
-	return 0;
-}
-
-static int chv_init_workarounds(struct intel_engine_cs *ring)
-{
-	int ret;
-	struct drm_device *dev = ring->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	/*
-	 * workarounds applied in this fn are part of register state context,
-	 * they need to be re-initialized followed by gpu reset, suspend/resume,
-	 * module reload.
-	 */
-	dev_priv->num_wa_regs = 0;
-	memset(dev_priv->intel_wa_regs, 0, sizeof(dev_priv->intel_wa_regs));
-
-	ret = intel_ring_begin(ring, 12);
-	if (ret)
-		return ret;
+	GEN7_GT_MODE,
+	_MASKED_BIT_ENABLE(GEN6_WIZ_HASHING_MASK | GEN6_WIZ_HASHING_16x4),
+};
 
+static const u32 chv_ring_init_context[] = {
 	/* WaDisablePartialInstShootdown:chv */
-	intel_ring_emit_wa(ring, GEN8_ROW_CHICKEN,
-			   _MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE));
-
 	/* WaDisableThreadStallDopClockGating:chv */
-	intel_ring_emit_wa(ring, GEN8_ROW_CHICKEN,
-			   _MASKED_BIT_ENABLE(STALL_DOP_GATING_DISABLE));
+	GEN8_ROW_CHICKEN,
+	_MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE) |
+	_MASKED_BIT_ENABLE(STALL_DOP_GATING_DISABLE),
 
 	/* WaDisableDopClockGating:chv (pre-production hw) */
-	intel_ring_emit_wa(ring, GEN7_ROW_CHICKEN2,
-			   _MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE));
+	GEN7_ROW_CHICKEN2,
+	_MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE),
 
 	/* WaDisableSamplerPowerBypass:chv (pre-production hw) */
-	intel_ring_emit_wa(ring, HALF_SLICE_CHICKEN3,
-			   _MASKED_BIT_ENABLE(GEN8_SAMPLER_POWER_BYPASS_DIS));
+	HALF_SLICE_CHICKEN3,
+	_MASKED_BIT_ENABLE(GEN8_SAMPLER_POWER_BYPASS_DIS),
+};
 
-	intel_ring_advance(ring);
+static int ring_init_context(struct intel_engine_cs *ring)
+{
+	int ret = -EINVAL;
 
-	return 0;
+	if (IS_CHERRYVIEW(ring->dev))
+		ret = i915_request_emit_lri(ring,
+					    ARRAY_SIZE(chv_ring_init_context)/2,
+					    chv_ring_init_context);
+	else
+		ret = i915_request_emit_lri(ring,
+					    ARRAY_SIZE(bdw_ring_init_context)/2,
+					    bdw_ring_init_context);
+
+	return ret;
 }
 
 static int init_render_ring(struct intel_engine_cs *ring)
@@ -2275,10 +2245,7 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
 					dev_priv->semaphore_obj = obj;
 			}
 		}
-		if (IS_CHERRYVIEW(dev))
-			ring->init_context = chv_init_workarounds;
-		else
-			ring->init_context = bdw_init_workarounds;
+		ring->init_context = ring_init_context;
 		ring->add_request = gen6_add_request;
 		ring->flush = gen8_render_ring_flush;
 		ring->irq_get = gen8_ring_get_irq;
-- 
2.0.4

[PATCH v2] drm/i915: Rework workaround init functions for BDW and CHV

[Arun Siluvery]

This rework is based on suggestion from Chris.
Now w/a are organized in an array and all of them are emitted in
single fn instead of sending them individually. This approach is
clean and new w/a can be added with minimal changes.
The same array can be used when exporting them to debugfs and the
temporary array in the current implementation is not required.

v2: As suggested by Damien a new w/a reg definition is added.
This helps in initializing w/a that are unmasked registers.

Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 158 ++++++++++++++------------------
 drivers/gpu/drm/i915/intel_ringbuffer.h |  26 ++++++
 2 files changed, 93 insertions(+), 91 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index c5e4dc7..3ed0ad5 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -650,87 +650,80 @@ err:
 	return ret;
 }
 
-static inline void intel_ring_emit_wa(struct intel_engine_cs *ring,
-				       u32 addr, u32 value)
+static int i915_request_emit_lri(struct intel_engine_cs *ring,
+				 int num_registers,
+				 const struct intel_wa_reg *lri_list)
 {
-	struct drm_device *dev = ring->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
+	int i;
+	int ret;
+	struct drm_i915_private *dev_priv = ring->dev->dev_private;
 
-	if (dev_priv->num_wa_regs > I915_MAX_WA_REGS)
-		return;
+	ret = intel_ring_begin(ring, (2 * num_registers + 1));
+	if (ret)
+		return ret;
 
-	intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
-	intel_ring_emit(ring, addr);
-	intel_ring_emit(ring, value);
+	intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(num_registers));
+	for (i = 0; i < num_registers; ++i) {
+		u32 value;
+		const struct intel_wa_reg *p = (lri_list + i);
 
-	dev_priv->intel_wa_regs[dev_priv->num_wa_regs].addr = addr;
-	dev_priv->intel_wa_regs[dev_priv->num_wa_regs].mask = (value) & 0xFFFF;
-	/* value is updated with the status of remaining bits of this
-	 * register when it is read from debugfs file
-	 */
-	dev_priv->intel_wa_regs[dev_priv->num_wa_regs].value = value;
-	dev_priv->num_wa_regs++;
+		if (p->masked_register)
+			value = (p->mask << 16) | p->value;
+		else
+			value = (I915_READ(p->addr) & ~p->mask) | p->value;
+		intel_ring_emit(ring, p->addr);
+		intel_ring_emit(ring, value);
+	}
 
-	return;
+	intel_ring_emit(ring, MI_NOOP);
+	intel_ring_advance(ring);
+
+	return 0;
 }
 
-static int bdw8_init_workarounds(struct intel_engine_cs *ring)
-{
-	int ret;
-	struct drm_device *dev = ring->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
+static const struct intel_wa_reg bdw_ring_init_context[] = {
 
 	/*
 	 * workarounds applied in this fn are part of register state context,
 	 * they need to be re-initialized followed by gpu reset, suspend/resume,
 	 * module reload.
 	 */
-	dev_priv->num_wa_regs = 0;
-	memset(dev_priv->intel_wa_regs, 0, sizeof(dev_priv->intel_wa_regs));
-
-	/*
-	 * update the number of dwords required based on the
-	 * actual number of workarounds applied
-	 */
-	ret = intel_ring_begin(ring, 24);
-	if (ret)
-		return ret;
 
 	/* WaDisablePartialInstShootdown:bdw */
 	/* WaDisableThreadStallDopClockGating:bdw */
 	/* FIXME: Unclear whether we really need this on production bdw. */
-	intel_ring_emit_wa(ring, GEN8_ROW_CHICKEN,
-			   _MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE
-					     | STALL_DOP_GATING_DISABLE));
+	INIT_MASKED_WA(GEN8_ROW_CHICKEN,
+		       _MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE) |
+		       _MASKED_BIT_ENABLE(STALL_DOP_GATING_DISABLE)),
 
 	/* WaDisableDopClockGating:bdw May not be needed for production */
-	intel_ring_emit_wa(ring, GEN7_ROW_CHICKEN2,
-			   _MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE));
+	INIT_MASKED_WA(GEN7_ROW_CHICKEN2,
+		       _MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE)),
 
 	/*
 	 * This GEN8_CENTROID_PIXEL_OPT_DIS W/A is only needed for
 	 * pre-production hardware
 	 */
-	intel_ring_emit_wa(ring, HALF_SLICE_CHICKEN3,
-			   _MASKED_BIT_ENABLE(GEN8_CENTROID_PIXEL_OPT_DIS
-					      | GEN8_SAMPLER_POWER_BYPASS_DIS));
+	INIT_MASKED_WA(HALF_SLICE_CHICKEN3,
+		       _MASKED_BIT_ENABLE(GEN8_CENTROID_PIXEL_OPT_DIS) |
+		       _MASKED_BIT_ENABLE(GEN8_SAMPLER_POWER_BYPASS_DIS)),
 
-	intel_ring_emit_wa(ring, GEN7_HALF_SLICE_CHICKEN1,
-			   _MASKED_BIT_ENABLE(GEN7_SINGLE_SUBSCAN_DISPATCH_ENABLE));
+	INIT_MASKED_WA(GEN7_HALF_SLICE_CHICKEN1,
+		       _MASKED_BIT_ENABLE(GEN7_SINGLE_SUBSCAN_DISPATCH_ENABLE)),
 
-	intel_ring_emit_wa(ring, COMMON_SLICE_CHICKEN2,
-			   _MASKED_BIT_ENABLE(GEN8_CSC2_SBE_VUE_CACHE_CONSERVATIVE));
+	INIT_MASKED_WA(COMMON_SLICE_CHICKEN2,
+		       _MASKED_BIT_ENABLE(GEN8_CSC2_SBE_VUE_CACHE_CONSERVATIVE)),
 
 	/* Use Force Non-Coherent whenever executing a 3D context. This is a
 	 * workaround for for a possible hang in the unlikely event a TLB
 	 * invalidation occurs during a PSD flush.
 	 */
-	intel_ring_emit_wa(ring, HDC_CHICKEN0,
-			   _MASKED_BIT_ENABLE(HDC_FORCE_NON_COHERENT));
+	INIT_MASKED_WA(HDC_CHICKEN0,
+		       _MASKED_BIT_ENABLE(HDC_FORCE_NON_COHERENT)),
 
 	/* Wa4x4STCOptimizationDisable:bdw */
-	intel_ring_emit_wa(ring, CACHE_MODE_1,
-			   _MASKED_BIT_ENABLE(GEN8_4x4_STC_OPTIMIZATION_DISABLE));
+	INIT_MASKED_WA(CACHE_MODE_1,
+		       _MASKED_BIT_ENABLE(GEN8_4x4_STC_OPTIMIZATION_DISABLE)),
 
 	/*
 	 * BSpec recommends 8x4 when MSAA is used,
@@ -740,54 +733,40 @@ static int bdw8_init_workarounds(struct intel_engine_cs *ring)
 	 * disable bit, which we don't touch here, but it's good
 	 * to keep in mind (see 3DSTATE_PS and 3DSTATE_WM).
 	 */
-	intel_ring_emit_wa(ring, GEN7_GT_MODE,
-			   GEN6_WIZ_HASHING_MASK | GEN6_WIZ_HASHING_16x4);
-
-	intel_ring_advance(ring);
-
-	DRM_DEBUG_DRIVER("Number of Workarounds applied: %d\n",
-			 dev_priv->num_wa_regs);
-
-	return 0;
-}
-
-static int chv_init_workarounds(struct intel_engine_cs *ring)
-{
-	int ret;
-	struct drm_device *dev = ring->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	/*
-	 * workarounds applied in this fn are part of register state context,
-	 * they need to be re-initialized followed by gpu reset, suspend/resume,
-	 * module reload.
-	 */
-	dev_priv->num_wa_regs = 0;
-	memset(dev_priv->intel_wa_regs, 0, sizeof(dev_priv->intel_wa_regs));
-
-	ret = intel_ring_begin(ring, 12);
-	if (ret)
-		return ret;
+	INIT_MASKED_WA(GEN7_GT_MODE,
+		       (GEN6_WIZ_HASHING_MASK | GEN6_WIZ_HASHING_16x4)),
+};
 
+static const struct intel_wa_reg chv_ring_init_context[] = {
 	/* WaDisablePartialInstShootdown:chv */
-	intel_ring_emit_wa(ring, GEN8_ROW_CHICKEN,
-			   _MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE));
-
 	/* WaDisableThreadStallDopClockGating:chv */
-	intel_ring_emit_wa(ring, GEN8_ROW_CHICKEN,
-			   _MASKED_BIT_ENABLE(STALL_DOP_GATING_DISABLE));
+	INIT_MASKED_WA(GEN8_ROW_CHICKEN,
+		       _MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE) |
+		       _MASKED_BIT_ENABLE(STALL_DOP_GATING_DISABLE)),
 
 	/* WaDisableDopClockGating:chv (pre-production hw) */
-	intel_ring_emit_wa(ring, GEN7_ROW_CHICKEN2,
-			   _MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE));
+	INIT_MASKED_WA(GEN7_ROW_CHICKEN2,
+		       _MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE)),
 
 	/* WaDisableSamplerPowerBypass:chv (pre-production hw) */
-	intel_ring_emit_wa(ring, HALF_SLICE_CHICKEN3,
-			   _MASKED_BIT_ENABLE(GEN8_SAMPLER_POWER_BYPASS_DIS));
+	INIT_MASKED_WA(HALF_SLICE_CHICKEN3,
+		       _MASKED_BIT_ENABLE(GEN8_SAMPLER_POWER_BYPASS_DIS)),
+};
 
-	intel_ring_advance(ring);
+static int ring_init_context(struct intel_engine_cs *ring)
+{
+	int ret = -EINVAL;
 
-	return 0;
+	if (IS_CHERRYVIEW(ring->dev))
+		ret = i915_request_emit_lri(ring,
+					    ARRAY_SIZE(chv_ring_init_context),
+					    chv_ring_init_context);
+	else
+		ret = i915_request_emit_lri(ring,
+					    ARRAY_SIZE(bdw_ring_init_context),
+					    bdw_ring_init_context);
+
+	return ret;
 }
 
 static int init_render_ring(struct intel_engine_cs *ring)
@@ -2275,10 +2254,7 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
 					dev_priv->semaphore_obj = obj;
 			}
 		}
-		if (IS_CHERRYVIEW(dev))
-			ring->init_context = chv_init_workarounds;
-		else
-			ring->init_context = bdw_init_workarounds;
+		ring->init_context = ring_init_context;
 		ring->add_request = gen6_add_request;
 		ring->flush = gen8_render_ring_flush;
 		ring->irq_get = gen8_ring_get_irq;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 96479c8..c9ed06c 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -317,6 +317,32 @@ struct  intel_engine_cs {
 	u32 (*get_cmd_length_mask)(u32 cmd_header);
 };
 
+/*
+ * Workaround register definition
+ * mask: bits correponding to the w/a
+ * value: represents reference values of w/a bits
+ */
+struct intel_wa_reg {
+	u32 masked_register : 1;
+	u32 addr;
+	u32 mask;
+	u32 value;
+};
+
+#define INIT_WA_REG(_masked, _addr, _mask, _value)	\
+{					\
+	.masked_register = _masked,	\
+	.addr = _addr,	\
+	.mask = _mask,	\
+	.value = _value,\
+}
+
+#define INIT_MASKED_WA(_addr, _value) \
+	INIT_WA_REG(1, _addr, ((_value) >> 16), ((_value) & 0xFFFF))
+
+#define INIT_UNMASKED_WA(_addr, _value) \
+	INIT_WA_REG(0, _addr, ~(_value), _value)
+
 bool intel_ring_initialized(struct intel_engine_cs *ring);
 
 static inline unsigned
-- 
2.0.4

Re: [PATCH v2] drm/i915: Rework workaround init functions for BDW and CHV

[Damien Lespiau]

On Tue, Sep 02, 2014 at 10:14:17AM +0100, Arun Siluvery wrote:
> This rework is based on suggestion from Chris.
> Now w/a are organized in an array and all of them are emitted in
> single fn instead of sending them individually. This approach is
> clean and new w/a can be added with minimal changes.
> The same array can be used when exporting them to debugfs and the
> temporary array in the current implementation is not required.
> 
> v2: As suggested by Damien a new w/a reg definition is added.
> This helps in initializing w/a that are unmasked registers.
> 
> Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_ringbuffer.c | 158 ++++++++++++++------------------
>  drivers/gpu/drm/i915/intel_ringbuffer.h |  26 ++++++
>  2 files changed, 93 insertions(+), 91 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index c5e4dc7..3ed0ad5 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -650,87 +650,80 @@ err:
>  	return ret;
>  }
>  
> -static inline void intel_ring_emit_wa(struct intel_engine_cs *ring,
> -				       u32 addr, u32 value)
> +static int i915_request_emit_lri(struct intel_engine_cs *ring,
> +				 int num_registers,
> +				 const struct intel_wa_reg *lri_list)
>  {

[...]

> +	for (i = 0; i < num_registers; ++i) {
> +		u32 value;
> +		const struct intel_wa_reg *p = (lri_list + i);
>
> +		if (p->masked_register)
> +			value = (p->mask << 16) | p->value;
> +		else
> +			value = (I915_READ(p->addr) & ~p->mask) | p->value;

There's one case when this won't work, when several WAs for a single
'normal' register are defined. The read done here means only the last of
those W/As will end up being applied (because the last LRI to that
register will be the value that ends up in the register. We'll probably
need to coalesce all W/A defined for a single normal register into one
write.

Considering that, and the comment about the define, maybe the simplest
way to go forward with the patch is to forget the non-masked case for
the moment, especially as it's not used in this patch.

> +#define INIT_MASKED_WA(_addr, _value) \
> +	INIT_WA_REG(1, _addr, ((_value) >> 16), ((_value) & 0xFFFF))

Those outer '()' look unnecessary

> +#define INIT_UNMASKED_WA(_addr, _value) \
> +	INIT_WA_REG(0, _addr, ~(_value), _value)
> +

~value is not a mask. Consider values with one or more bits defined to 0.

-- 
Damien

Re: [PATCH v2] drm/i915: Rework workaround init functions for BDW and CHV

[Damien Lespiau]

On Tue, Sep 02, 2014 at 10:45:45AM +0100, Damien Lespiau wrote:
> There's one case when this won't work, when several WAs for a single
> 'normal' register are defined. The read done here means only the last of
> those W/As will end up being applied (because the last LRI to that
> register will be the value that ends up in the register. We'll probably
> need to coalesce all W/A defined for a single normal register into one
> write.

To more correct/clear, it's not the read that's the problem, in the case
where a normal register has several W/A, the last write will override
the previous ones.

-- 
Damien

Re: [PATCH v2] drm/i915: Rework workaround init functions for BDW and CHV

[Chris Wilson]

On Tue, Sep 02, 2014 at 10:45:45AM +0100, Damien Lespiau wrote:
> On Tue, Sep 02, 2014 at 10:14:17AM +0100, Arun Siluvery wrote:
> > This rework is based on suggestion from Chris.
> > Now w/a are organized in an array and all of them are emitted in
> > single fn instead of sending them individually. This approach is
> > clean and new w/a can be added with minimal changes.
> > The same array can be used when exporting them to debugfs and the
> > temporary array in the current implementation is not required.
> > 
> > v2: As suggested by Damien a new w/a reg definition is added.
> > This helps in initializing w/a that are unmasked registers.
> > 
> > Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_ringbuffer.c | 158 ++++++++++++++------------------
> >  drivers/gpu/drm/i915/intel_ringbuffer.h |  26 ++++++
> >  2 files changed, 93 insertions(+), 91 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > index c5e4dc7..3ed0ad5 100644
> > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > @@ -650,87 +650,80 @@ err:
> >  	return ret;
> >  }
> >  
> > -static inline void intel_ring_emit_wa(struct intel_engine_cs *ring,
> > -				       u32 addr, u32 value)
> > +static int i915_request_emit_lri(struct intel_engine_cs *ring,
> > +				 int num_registers,
> > +				 const struct intel_wa_reg *lri_list)
> >  {
> 
> [...]
> 
> > +	for (i = 0; i < num_registers; ++i) {
> > +		u32 value;
> > +		const struct intel_wa_reg *p = (lri_list + i);
> >
> > +		if (p->masked_register)
> > +			value = (p->mask << 16) | p->value;
> > +		else
> > +			value = (I915_READ(p->addr) & ~p->mask) | p->value;
> 
> There's one case when this won't work, when several WAs for a single
> 'normal' register are defined. The read done here means only the last of
> those W/As will end up being applied (because the last LRI to that
> register will be the value that ends up in the register. We'll probably
> need to coalesce all W/A defined for a single normal register into one
> write.
> 
> Considering that, and the comment about the define, maybe the simplest
> way to go forward with the patch is to forget the non-masked case for
> the moment, especially as it's not used in this patch.

If you are still considering an in-kernel table, despite that it can be
done in userspace, design it to track all w/a and not just the ring
specific fixups.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

[PATCH 2/4] drm/i915: Rename intel_wa_registers with a i915_ prefix

[Arun Siluvery]

From: Damien Lespiau <damien.lespiau@intel.com>

Those debugfs files are prefixed by i915, the name of the kernel module,
presumably to make the difference with files exposed by core DRM.

Also, add a ',' at the end of the last entry. This is to ease the
conflict resolution when rebasing internal patches that add a member at
the end of the array. Without it, wiggle can't do its job as we need to
modify an existing line (appending the ',').

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index f0d63f6..f09ba8c 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2458,7 +2458,7 @@ static int i915_shared_dplls_info(struct seq_file *m, void *unused)
 	return 0;
 }
 
-static int intel_wa_registers(struct seq_file *m, void *unused)
+static int i915_wa_registers(struct seq_file *m, void *unused)
 {
 	int i;
 	int ret;
@@ -4026,7 +4026,7 @@ static const struct drm_info_list i915_debugfs_list[] = {
 	{"i915_semaphore_status", i915_semaphore_status, 0},
 	{"i915_shared_dplls_info", i915_shared_dplls_info, 0},
 	{"i915_dp_mst_info", i915_dp_mst_info, 0},
-	{"intel_wa_registers", intel_wa_registers, 0}
+	{"i915_wa_registers", i915_wa_registers, 0},
 };
 #define I915_DEBUGFS_ENTRIES ARRAY_SIZE(i915_debugfs_list)
 
-- 
2.0.4

[PATCH 3/4] drm/i915: Don't restrict i915_wa_registers to BDW

[Arun Siluvery]

From: Damien Lespiau <damien.lespiau@intel.com>

We have CHV code that already makes the test obsolete. Besides, when
num_wa_regs is 0 (platforms not gathering that W/A data), we expose
something sensible already.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Arun Siluvery <arun.siluvery@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index f09ba8c..2727bda 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2466,11 +2466,6 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
 	struct drm_device *dev = node->minor->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	if (!IS_BROADWELL(dev)) {
-		DRM_DEBUG_DRIVER("Workaround table not available !!\n");
-		return -EINVAL;
-	}
-
 	ret = mutex_lock_interruptible(&dev->struct_mutex);
 	if (ret)
 		return ret;
-- 
2.0.4

[PATCH 4/4] drm/i915: Rework workaround data exporting to debugfs

[Arun Siluvery]

Now w/a are organized in an array so we know exactly how many of them
are applied; use the same array while exporting data to debugfs and
remove the temporary array we currently have in driver priv structure.

Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c     | 41 +++++++++++++++++++++++----------
 drivers/gpu/drm/i915/i915_drv.h         | 14 -----------
 drivers/gpu/drm/i915/intel_ringbuffer.c | 15 ++++++++++++
 drivers/gpu/drm/i915/intel_ringbuffer.h |  8 +++++++
 4 files changed, 52 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 2727bda..bab0408 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2465,6 +2465,14 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
 	struct drm_device *dev = node->minor->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_ring_context_rodata ro_data;
+
+	ret = ring_context_rodata(dev, &ro_data);
+	if (ret) {
+		seq_printf(m, "Workarounds applied: 0\n");
+		DRM_DEBUG_DRIVER("Workaround table not available !!\n");
+		return -EINVAL;
+	}
 
 	ret = mutex_lock_interruptible(&dev->struct_mutex);
 	if (ret)
@@ -2472,18 +2480,27 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
 
 	intel_runtime_pm_get(dev_priv);
 
-	seq_printf(m, "Workarounds applied: %d\n", dev_priv->num_wa_regs);
-	for (i = 0; i < dev_priv->num_wa_regs; ++i) {
-		u32 addr, mask;
-
-		addr = dev_priv->intel_wa_regs[i].addr;
-		mask = dev_priv->intel_wa_regs[i].mask;
-		dev_priv->intel_wa_regs[i].value = I915_READ(addr) | mask;
-		if (dev_priv->intel_wa_regs[i].addr)
-			seq_printf(m, "0x%X: 0x%08X, mask: 0x%08X\n",
-				   dev_priv->intel_wa_regs[i].addr,
-				   dev_priv->intel_wa_regs[i].value,
-				   dev_priv->intel_wa_regs[i].mask);
+	seq_printf(m, "Workarounds applied: %d\n", ro_data.num_items/2);
+	for (i = 0; i < ro_data.num_items; i += 2) {
+		u32 addr, mask, value;
+
+		addr = ro_data.init_context[i];
+		/*
+		 * Most of workarounds are  masked registers;
+		 * to set a bit in lower 16-bits we set a mask bit in
+		 * upper 16-bits so we can take either of them as mask but
+		 * it doesn't work if the w/a is about clearing a bit so
+		 * use upper 16-bits to cover both cases.
+		 */
+		mask = ro_data.init_context[i+1] >> 16;
+
+		/*
+		 * value represents the status of other bits in the
+		 * register besides w/a bits
+		 */
+		value  = I915_READ(addr) | mask;
+		seq_printf(m, "0x%X: 0x%08X, mask: 0x%08X\n",
+			   addr, value, mask);
 	}
 
 	intel_runtime_pm_put(dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 49b7be7..bcf79f0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1553,20 +1553,6 @@ struct drm_i915_private {
 	struct intel_shared_dpll shared_dplls[I915_NUM_PLLS];
 	int dpio_phy_iosf_port[I915_NUM_PHYS_VLV];
 
-	/*
-	 * workarounds are currently applied at different places and
-	 * changes are being done to consolidate them so exact count is
-	 * not clear at this point, use a max value for now.
-	 */
-#define I915_MAX_WA_REGS  16
-	struct {
-		u32 addr;
-		u32 value;
-		/* bitmask representing WA bits */
-		u32 mask;
-	} intel_wa_regs[I915_MAX_WA_REGS];
-	u32 num_wa_regs;
-
 	/* Reclocking support */
 	bool render_reclock_avail;
 	bool lvds_downclock_avail;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index bae1527..6c07e69 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -760,6 +760,21 @@ static int ring_init_context(struct intel_engine_cs *ring)
 	return ret;
 }
 
+int ring_context_rodata(struct drm_device *dev,
+			struct intel_ring_context_rodata *ro_data)
+{
+	if (IS_CHERRYVIEW(dev)) {
+		ro_data->init_context = chv_ring_init_context;
+		ro_data->num_items = ARRAY_SIZE(chv_ring_init_context);
+	} else if (IS_BROADWELL(dev)) {
+		ro_data->init_context = bdw_ring_init_context;
+		ro_data->num_items = ARRAY_SIZE(bdw_ring_init_context);
+	} else
+		return -EINVAL;
+
+	return 0;
+}
+
 static int init_render_ring(struct intel_engine_cs *ring)
 {
 	struct drm_device *dev = ring->dev;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 96479c8..f555505 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -317,6 +317,14 @@ struct  intel_engine_cs {
 	u32 (*get_cmd_length_mask)(u32 cmd_header);
 };
 
+struct intel_ring_context_rodata {
+	u32 num_items;
+	const u32 *init_context;
+};
+
+int ring_context_rodata(struct drm_device *dev,
+			struct intel_ring_context_rodata *ro_data);
+
 bool intel_ring_initialized(struct intel_engine_cs *ring);
 
 static inline unsigned
-- 
2.0.4

Re: [PATCH 4/4] drm/i915: Rework workaround data exporting to debugfs

[Damien Lespiau]

On Mon, Sep 01, 2014 at 02:28:53PM +0100, Arun Siluvery wrote:
> Now w/a are organized in an array so we know exactly how many of them
> are applied; use the same array while exporting data to debugfs and
> remove the temporary array we currently have in driver priv structure.
> 
> Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c     | 41 +++++++++++++++++++++++----------
>  drivers/gpu/drm/i915/i915_drv.h         | 14 -----------
>  drivers/gpu/drm/i915/intel_ringbuffer.c | 15 ++++++++++++
>  drivers/gpu/drm/i915/intel_ringbuffer.h |  8 +++++++
>  4 files changed, 52 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 2727bda..bab0408 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -2465,6 +2465,14 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
>  	struct drm_info_node *node = (struct drm_info_node *) m->private;
>  	struct drm_device *dev = node->minor->dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_ring_context_rodata ro_data;
> +
> +	ret = ring_context_rodata(dev, &ro_data);
> +	if (ret) {
> +		seq_printf(m, "Workarounds applied: 0\n");

seq_puts()

> +		DRM_DEBUG_DRIVER("Workaround table not available !!\n");
> +		return -EINVAL;
> +	}
>  
>  	ret = mutex_lock_interruptible(&dev->struct_mutex);
>  	if (ret)
> @@ -2472,18 +2480,27 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
>  
>  	intel_runtime_pm_get(dev_priv);
>  
> -	seq_printf(m, "Workarounds applied: %d\n", dev_priv->num_wa_regs);
> -	for (i = 0; i < dev_priv->num_wa_regs; ++i) {
> -		u32 addr, mask;
> -
> -		addr = dev_priv->intel_wa_regs[i].addr;
> -		mask = dev_priv->intel_wa_regs[i].mask;
> -		dev_priv->intel_wa_regs[i].value = I915_READ(addr) | mask;
> -		if (dev_priv->intel_wa_regs[i].addr)
> -			seq_printf(m, "0x%X: 0x%08X, mask: 0x%08X\n",
> -				   dev_priv->intel_wa_regs[i].addr,
> -				   dev_priv->intel_wa_regs[i].value,
> -				   dev_priv->intel_wa_regs[i].mask);
> +	seq_printf(m, "Workarounds applied: %d\n", ro_data.num_items/2);
> +	for (i = 0; i < ro_data.num_items; i += 2) {
> +		u32 addr, mask, value;
> +
> +		addr = ro_data.init_context[i];
> +		/*
> +		 * Most of workarounds are  masked registers;
> +		 * to set a bit in lower 16-bits we set a mask bit in
> +		 * upper 16-bits so we can take either of them as mask but
> +		 * it doesn't work if the w/a is about clearing a bit so
> +		 * use upper 16-bits to cover both cases.
> +		 */
> +		mask = ro_data.init_context[i+1] >> 16;

"Most" doesn't seem good here. Either it's "all" and we're happy, or we
need a generic way to describe the W/A (masked register or not). value +
mask is generic enough to code for both cases.

> +
> +		/*
> +		 * value represents the status of other bits in the
> +		 * register besides w/a bits
> +		 */
> +		value  = I915_READ(addr) | mask;
> +		seq_printf(m, "0x%X: 0x%08X, mask: 0x%08X\n",
> +			   addr, value, mask);
>  	}

I still don't get it. 'value' is supposed to be the reference value for
the W/A, but you're or'ing the mask here, so you treat the mask as if it
were the reference value. This won't work if the W/A is about setting
multi-bits fields or about clearing a bit.

The comment is still not clear enough. You're saying "other bits besides
the w/a bits", but or'ing the mask doesn't do that.

Why do we care about the "other bits" in the reference value? they don't
matter. Why use something else than (ro_data.init_context[i+1] & 0xffff)
for the value here (as long we're talking about masked registers)?

-- 
Damien

Re: [PATCH 4/4] drm/i915: Rework workaround data exporting to debugfs

[Siluvery, Arun]

On 01/09/2014 15:06, Damien Lespiau wrote:
> On Mon, Sep 01, 2014 at 02:28:53PM +0100, Arun Siluvery wrote:
>> Now w/a are organized in an array so we know exactly how many of them
>> are applied; use the same array while exporting data to debugfs and
>> remove the temporary array we currently have in driver priv structure.
>>
>> Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_debugfs.c     | 41 +++++++++++++++++++++++----------
>>   drivers/gpu/drm/i915/i915_drv.h         | 14 -----------
>>   drivers/gpu/drm/i915/intel_ringbuffer.c | 15 ++++++++++++
>>   drivers/gpu/drm/i915/intel_ringbuffer.h |  8 +++++++
>>   4 files changed, 52 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
>> index 2727bda..bab0408 100644
>> --- a/drivers/gpu/drm/i915/i915_debugfs.c
>> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
>> @@ -2465,6 +2465,14 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
>>   	struct drm_info_node *node = (struct drm_info_node *) m->private;
>>   	struct drm_device *dev = node->minor->dev;
>>   	struct drm_i915_private *dev_priv = dev->dev_private;
>> +	struct intel_ring_context_rodata ro_data;
>> +
>> +	ret = ring_context_rodata(dev, &ro_data);
>> +	if (ret) {
>> +		seq_printf(m, "Workarounds applied: 0\n");
>
> seq_puts()
>
>> +		DRM_DEBUG_DRIVER("Workaround table not available !!\n");
>> +		return -EINVAL;
>> +	}
>>
>>   	ret = mutex_lock_interruptible(&dev->struct_mutex);
>>   	if (ret)
>> @@ -2472,18 +2480,27 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
>>
>>   	intel_runtime_pm_get(dev_priv);
>>
>> -	seq_printf(m, "Workarounds applied: %d\n", dev_priv->num_wa_regs);
>> -	for (i = 0; i < dev_priv->num_wa_regs; ++i) {
>> -		u32 addr, mask;
>> -
>> -		addr = dev_priv->intel_wa_regs[i].addr;
>> -		mask = dev_priv->intel_wa_regs[i].mask;
>> -		dev_priv->intel_wa_regs[i].value = I915_READ(addr) | mask;
>> -		if (dev_priv->intel_wa_regs[i].addr)
>> -			seq_printf(m, "0x%X: 0x%08X, mask: 0x%08X\n",
>> -				   dev_priv->intel_wa_regs[i].addr,
>> -				   dev_priv->intel_wa_regs[i].value,
>> -				   dev_priv->intel_wa_regs[i].mask);
>> +	seq_printf(m, "Workarounds applied: %d\n", ro_data.num_items/2);
>> +	for (i = 0; i < ro_data.num_items; i += 2) {
>> +		u32 addr, mask, value;
>> +
>> +		addr = ro_data.init_context[i];
>> +		/*
>> +		 * Most of workarounds are  masked registers;
>> +		 * to set a bit in lower 16-bits we set a mask bit in
>> +		 * upper 16-bits so we can take either of them as mask but
>> +		 * it doesn't work if the w/a is about clearing a bit so
>> +		 * use upper 16-bits to cover both cases.
>> +		 */
>> +		mask = ro_data.init_context[i+1] >> 16;
>
> "Most" doesn't seem good here. Either it's "all" and we're happy, or we
> need a generic way to describe the W/A (masked register or not). value +
> mask is generic enough to code for both cases.
>
It seems some of them could be unmasked registers.
We can use 'mask' itself to determine whether it is a masked/unmasked 
register. mask == 0 if it is an unmasked register.
>> +
>> +		/*
>> +		 * value represents the status of other bits in the
>> +		 * register besides w/a bits
>> +		 */
>> +		value  = I915_READ(addr) | mask;
>> +		seq_printf(m, "0x%X: 0x%08X, mask: 0x%08X\n",
>> +			   addr, value, mask);
>>   	}
>
> I still don't get it. 'value' is supposed to be the reference value for
> the W/A, but you're or'ing the mask here, so you treat the mask as if it
> were the reference value. This won't work if the W/A is about setting
> multi-bits fields or about clearing a bit.
>
> The comment is still not clear enough. You're saying "other bits besides
> the w/a bits", but or'ing the mask doesn't do that.
>
> Why do we care about the "other bits" in the reference value? they don't
> matter. Why use something else than (ro_data.init_context[i+1] & 0xffff)
> for the value here (as long we're talking about masked registers)?
>
I have always considered value as the register value (remaining bits of 
the register and w/a bits) and now I see your point.
Yes lower 16-bits can be used as reference value, depending on whether 
it is a masked/unmasked we can use/not use the mask in conjunction with 
value in the test.

regards
Arun

Re: [PATCH 4/4] drm/i915: Rework workaround data exporting to debugfs

[Damien Lespiau]

On Mon, Sep 01, 2014 at 03:45:29PM +0100, Siluvery, Arun wrote:
> >>+		/*
> >>+		 * Most of workarounds are  masked registers;
> >>+		 * to set a bit in lower 16-bits we set a mask bit in
> >>+		 * upper 16-bits so we can take either of them as mask but
> >>+		 * it doesn't work if the w/a is about clearing a bit so
> >>+		 * use upper 16-bits to cover both cases.
> >>+		 */
> >>+		mask = ro_data.init_context[i+1] >> 16;
> >
> >"Most" doesn't seem good here. Either it's "all" and we're happy, or we
> >need a generic way to describe the W/A (masked register or not). value +
> >mask is generic enough to code for both cases.
> >
> It seems some of them could be unmasked registers.
> We can use 'mask' itself to determine whether it is a
> masked/unmasked register. mask == 0 if it is an unmasked register.

I don't think we can use mask == 0 when it's an unmasked register. In
this case, we still need to be able to have a mask that tells us which
are the interesting bits in the value. If we want something generic that
can be applied to masked and unmasked register, we'll something like:

struct reg_wa {
	unsigned int masked_register : 1;
	u32 addr;
	u32 mask;
	u32 value;
};

So:

1. masked register case:

  - masked_register = 1
  - addr
  - mask (selects the lower 16 bits that are coding for the W/A value)
  - value (it only makes sense to some of the lower 16 bits set here)

2. 'normal' register case

  - masked_register = 0
  - addr
  - mask
  - value

>From that generic description you can cover all cases, eg.

1. the write for masked registers becomes: mask << 16 | value
2. the write for normal registers becomes: (read(addr) & ~mask) | value
2. check a W/A has been applied (both normal and masked register):
	read(addr) & mask == value

We seem to have only masked registers atm, so it's fine to handle just
that case, but if you envision that we'll need more than masked
registers, we need a better W/A definition.
  
-- 
Damien

[PATCH v2] drm/i915: Rework workaround data exporting to debugfs

[Arun Siluvery]

Now w/a are organized in an array so we know exactly how many of them
are applied; use the same array while exporting data to debugfs and
remove the temporary array we currently have in driver priv structure.

Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c     | 29 +++++++++++++++++------------
 drivers/gpu/drm/i915/i915_drv.h         | 14 --------------
 drivers/gpu/drm/i915/intel_ringbuffer.c | 15 +++++++++++++++
 drivers/gpu/drm/i915/intel_ringbuffer.h |  8 ++++++++
 4 files changed, 40 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 2727bda..0c1e294 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2465,6 +2465,14 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
 	struct drm_device *dev = node->minor->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_ring_context_rodata ro_data;
+
+	ret = ring_context_rodata(dev, &ro_data);
+	if (ret) {
+		seq_puts(m, "Workarounds applied: 0\n");
+		DRM_DEBUG_DRIVER("Workaround table not available !!\n");
+		return -EINVAL;
+	}
 
 	ret = mutex_lock_interruptible(&dev->struct_mutex);
 	if (ret)
@@ -2472,18 +2480,15 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
 
 	intel_runtime_pm_get(dev_priv);
 
-	seq_printf(m, "Workarounds applied: %d\n", dev_priv->num_wa_regs);
-	for (i = 0; i < dev_priv->num_wa_regs; ++i) {
-		u32 addr, mask;
-
-		addr = dev_priv->intel_wa_regs[i].addr;
-		mask = dev_priv->intel_wa_regs[i].mask;
-		dev_priv->intel_wa_regs[i].value = I915_READ(addr) | mask;
-		if (dev_priv->intel_wa_regs[i].addr)
-			seq_printf(m, "0x%X: 0x%08X, mask: 0x%08X\n",
-				   dev_priv->intel_wa_regs[i].addr,
-				   dev_priv->intel_wa_regs[i].value,
-				   dev_priv->intel_wa_regs[i].mask);
+	seq_printf(m, "Workarounds applied: %d\n", ro_data.num_items);
+	for (i = 0; i < ro_data.num_items; ++i) {
+		u32 addr, mask, value;
+
+		addr = ro_data.init_context[i].addr;
+		mask = ro_data.init_context[i].mask;
+		value  = ro_data.init_context[i].value;
+		seq_printf(m, "0x%X: 0x%08X, mask: 0x%08X\n",
+			   addr, value, mask);
 	}
 
 	intel_runtime_pm_put(dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 49b7be7..bcf79f0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1553,20 +1553,6 @@ struct drm_i915_private {
 	struct intel_shared_dpll shared_dplls[I915_NUM_PLLS];
 	int dpio_phy_iosf_port[I915_NUM_PHYS_VLV];
 
-	/*
-	 * workarounds are currently applied at different places and
-	 * changes are being done to consolidate them so exact count is
-	 * not clear at this point, use a max value for now.
-	 */
-#define I915_MAX_WA_REGS  16
-	struct {
-		u32 addr;
-		u32 value;
-		/* bitmask representing WA bits */
-		u32 mask;
-	} intel_wa_regs[I915_MAX_WA_REGS];
-	u32 num_wa_regs;
-
 	/* Reclocking support */
 	bool render_reclock_avail;
 	bool lvds_downclock_avail;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 3ed0ad5..7262c10 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -769,6 +769,21 @@ static int ring_init_context(struct intel_engine_cs *ring)
 	return ret;
 }
 
+int ring_context_rodata(struct drm_device *dev,
+			struct intel_ring_context_rodata *ro_data)
+{
+	if (IS_CHERRYVIEW(dev)) {
+		ro_data->init_context = chv_ring_init_context;
+		ro_data->num_items = ARRAY_SIZE(chv_ring_init_context);
+	} else if (IS_BROADWELL(dev)) {
+		ro_data->init_context = bdw_ring_init_context;
+		ro_data->num_items = ARRAY_SIZE(bdw_ring_init_context);
+	} else
+		return -EINVAL;
+
+	return 0;
+}
+
 static int init_render_ring(struct intel_engine_cs *ring)
 {
 	struct drm_device *dev = ring->dev;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index c9ed06c..33454ce 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -343,6 +343,14 @@ struct intel_wa_reg {
 #define INIT_UNMASKED_WA(_addr, _value) \
 	INIT_WA_REG(0, _addr, ~(_value), _value)
 
+struct intel_ring_context_rodata {
+	u32 num_items;
+	const struct intel_wa_reg *init_context;
+};
+
+int ring_context_rodata(struct drm_device *dev,
+			struct intel_ring_context_rodata *ro_data);
+
 bool intel_ring_initialized(struct intel_engine_cs *ring);
 
 static inline unsigned
-- 
2.0.4

Re: [PATCH v2] drm/i915: Rework workaround data exporting to debugfs

[Daniel Vetter]

On Tue, Sep 02, 2014 at 10:15:31AM +0100, Arun Siluvery wrote:
> Now w/a are organized in an array so we know exactly how many of them
> are applied; use the same array while exporting data to debugfs and
> remove the temporary array we currently have in driver priv structure.
> 
> Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c     | 29 +++++++++++++++++------------
>  drivers/gpu/drm/i915/i915_drv.h         | 14 --------------
>  drivers/gpu/drm/i915/intel_ringbuffer.c | 15 +++++++++++++++
>  drivers/gpu/drm/i915/intel_ringbuffer.h |  8 ++++++++
>  4 files changed, 40 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 2727bda..0c1e294 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -2465,6 +2465,14 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
>  	struct drm_info_node *node = (struct drm_info_node *) m->private;
>  	struct drm_device *dev = node->minor->dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_ring_context_rodata ro_data;
> +
> +	ret = ring_context_rodata(dev, &ro_data);
> +	if (ret) {
> +		seq_puts(m, "Workarounds applied: 0\n");
> +		DRM_DEBUG_DRIVER("Workaround table not available !!\n");
> +		return -EINVAL;
> +	}
>  
>  	ret = mutex_lock_interruptible(&dev->struct_mutex);
>  	if (ret)
> @@ -2472,18 +2480,15 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
>  
>  	intel_runtime_pm_get(dev_priv);
>  
> -	seq_printf(m, "Workarounds applied: %d\n", dev_priv->num_wa_regs);
> -	for (i = 0; i < dev_priv->num_wa_regs; ++i) {
> -		u32 addr, mask;
> -
> -		addr = dev_priv->intel_wa_regs[i].addr;
> -		mask = dev_priv->intel_wa_regs[i].mask;
> -		dev_priv->intel_wa_regs[i].value = I915_READ(addr) | mask;
> -		if (dev_priv->intel_wa_regs[i].addr)
> -			seq_printf(m, "0x%X: 0x%08X, mask: 0x%08X\n",
> -				   dev_priv->intel_wa_regs[i].addr,
> -				   dev_priv->intel_wa_regs[i].value,
> -				   dev_priv->intel_wa_regs[i].mask);
> +	seq_printf(m, "Workarounds applied: %d\n", ro_data.num_items);
> +	for (i = 0; i < ro_data.num_items; ++i) {
> +		u32 addr, mask, value;
> +
> +		addr = ro_data.init_context[i].addr;
> +		mask = ro_data.init_context[i].mask;
> +		value  = ro_data.init_context[i].value;
> +		seq_printf(m, "0x%X: 0x%08X, mask: 0x%08X\n",
> +			   addr, value, mask);
>  	}
>  
>  	intel_runtime_pm_put(dev_priv);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 49b7be7..bcf79f0 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1553,20 +1553,6 @@ struct drm_i915_private {
>  	struct intel_shared_dpll shared_dplls[I915_NUM_PLLS];
>  	int dpio_phy_iosf_port[I915_NUM_PHYS_VLV];
>  
> -	/*
> -	 * workarounds are currently applied at different places and
> -	 * changes are being done to consolidate them so exact count is
> -	 * not clear at this point, use a max value for now.
> -	 */
> -#define I915_MAX_WA_REGS  16
> -	struct {
> -		u32 addr;
> -		u32 value;
> -		/* bitmask representing WA bits */
> -		u32 mask;
> -	} intel_wa_regs[I915_MAX_WA_REGS];
> -	u32 num_wa_regs;
> -
>  	/* Reclocking support */
>  	bool render_reclock_avail;
>  	bool lvds_downclock_avail;
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 3ed0ad5..7262c10 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -769,6 +769,21 @@ static int ring_init_context(struct intel_engine_cs *ring)
>  	return ret;
>  }
>  
> +int ring_context_rodata(struct drm_device *dev,
> +			struct intel_ring_context_rodata *ro_data)
> +{
> +	if (IS_CHERRYVIEW(dev)) {
> +		ro_data->init_context = chv_ring_init_context;
> +		ro_data->num_items = ARRAY_SIZE(chv_ring_init_context);
> +	} else if (IS_BROADWELL(dev)) {
> +		ro_data->init_context = bdw_ring_init_context;
> +		ro_data->num_items = ARRAY_SIZE(bdw_ring_init_context);

This will kinda break my idea that we could put _all_ static register
w/a into these schem, so also everything that's in the various init_clock
gating functions.

The goal of the test is after all to make sure that we set the w/a bits in
the right place, so if you only check the w/a emitted in the context init
(and this change here kinda bakes this in) then it will not be really
useful.

Maybe you should (just as a prove of concept of these refactorings)
convert the chv or bdw w/a in the init_clock_gating to this infrastructure
too?

Thanks, Daniel

> +	} else
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>  static int init_render_ring(struct intel_engine_cs *ring)
>  {
>  	struct drm_device *dev = ring->dev;
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index c9ed06c..33454ce 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -343,6 +343,14 @@ struct intel_wa_reg {
>  #define INIT_UNMASKED_WA(_addr, _value) \
>  	INIT_WA_REG(0, _addr, ~(_value), _value)
>  
> +struct intel_ring_context_rodata {
> +	u32 num_items;
> +	const struct intel_wa_reg *init_context;
> +};
> +
> +int ring_context_rodata(struct drm_device *dev,
> +			struct intel_ring_context_rodata *ro_data);
> +
>  bool intel_ring_initialized(struct intel_engine_cs *ring);
>  
>  static inline unsigned
> -- 
> 2.0.4
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch