[Intel-gfx] [PATCH] drm/i915: Remove 64b mmio write vfuncs

[Chris Wilson]

We don't have safe 64-bit mmio writes as they are really split into
2x32-bit writes. This tearing is dangerous as the hardware *will*
operate on the intermediate value, requiring great care when assigning.
(See, for example, i965_write_fence_reg.) As such we don't currently use
them and strongly advise not to us them. Go one step further and remove
the 64-bit write vfuncs.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_drv.h     | 3 ---
 drivers/gpu/drm/i915/intel_uncore.c | 9 ---------
 2 files changed, 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index b0ada4ac6e2d..687367c62ce8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -581,8 +581,6 @@ struct intel_uncore_funcs {
 				uint16_t val, bool trace);
 	void (*mmio_writel)(struct drm_i915_private *dev_priv, i915_reg_t r,
 				uint32_t val, bool trace);
-	void (*mmio_writeq)(struct drm_i915_private *dev_priv, i915_reg_t r,
-				uint64_t val, bool trace);
 };
 
 struct intel_uncore {
@@ -3725,7 +3723,6 @@ int intel_freq_opcode(struct drm_i915_private *dev_priv, int val);
  * act upon the intermediate value, possibly leading to corruption and
  * machine death. You have been warned.
  */
-#define I915_WRITE64(reg, val)	dev_priv->uncore.funcs.mmio_writeq(dev_priv, (reg), (val), true)
 #define I915_READ64(reg)	dev_priv->uncore.funcs.mmio_readq(dev_priv, (reg), true)
 
 #define I915_READ64_2x32(lower_reg, upper_reg) ({			\
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index e9f68cd56e32..a9b6c936aadd 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1018,11 +1018,9 @@ gen5_write##x(struct drm_i915_private *dev_priv, i915_reg_t reg, u##x val, bool
 __gen5_write(8)
 __gen5_write(16)
 __gen5_write(32)
-__gen5_write(64)
 __gen2_write(8)
 __gen2_write(16)
 __gen2_write(32)
-__gen2_write(64)
 
 #undef __gen5_write
 #undef __gen2_write
@@ -1112,23 +1110,18 @@ gen9_write##x(struct drm_i915_private *dev_priv, i915_reg_t reg, u##x val, \
 __gen9_write(8)
 __gen9_write(16)
 __gen9_write(32)
-__gen9_write(64)
 __chv_write(8)
 __chv_write(16)
 __chv_write(32)
-__chv_write(64)
 __gen8_write(8)
 __gen8_write(16)
 __gen8_write(32)
-__gen8_write(64)
 __hsw_write(8)
 __hsw_write(16)
 __hsw_write(32)
-__hsw_write(64)
 __gen6_write(8)
 __gen6_write(16)
 __gen6_write(32)
-__gen6_write(64)
 
 #undef __gen9_write
 #undef __chv_write
@@ -1158,7 +1151,6 @@ static void vgpu_write##x(struct drm_i915_private *dev_priv, \
 __vgpu_write(8)
 __vgpu_write(16)
 __vgpu_write(32)
-__vgpu_write(64)
 
 #undef __vgpu_write
 #undef VGPU_WRITE_FOOTER
@@ -1169,7 +1161,6 @@ do { \
 	dev_priv->uncore.funcs.mmio_writeb = x##_write8; \
 	dev_priv->uncore.funcs.mmio_writew = x##_write16; \
 	dev_priv->uncore.funcs.mmio_writel = x##_write32; \
-	dev_priv->uncore.funcs.mmio_writeq = x##_write64; \
 } while (0)
 
 #define ASSIGN_READ_MMIO_VFUNCS(x) \
-- 
2.9.3