drm/i915: Add a mechanism for pipelining fence register updates

Not employed just yet...

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 2cfdee8..1e9cf2b 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2322,7 +2322,8 @@ i915_gpu_idle(struct drm_device *dev)
        return 0;
 }
 
-static void sandybridge_write_fence_reg(struct drm_i915_gem_object *obj)
+static int sandybridge_write_fence_reg(struct drm_i915_gem_object *obj,
+                                      struct intel_ring_buffer *pipelined)
 {
        struct drm_device *dev = obj->base.dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
@@ -2331,7 +2332,7 @@ static void sandybridge_write_fence_reg(struct drm_i915_gem_object *obj)
        uint64_t val;
 
        val = (uint64_t)((obj->gtt_offset + size - 4096) &
-                   0xfffff000) << 32;
+                        0xfffff000) << 32;
        val |= obj->gtt_offset & 0xfffff000;
        val |= (uint64_t)((obj->stride / 128) - 1) <<
                SANDYBRIDGE_FENCE_PITCH_SHIFT;
@@ -2340,10 +2341,26 @@ static void sandybridge_write_fence_reg(struct drm_i915_gem_object *obj)
                val |= 1 << I965_FENCE_TILING_Y_SHIFT;
        val |= I965_FENCE_REG_VALID;
 
-       I915_WRITE64(FENCE_REG_SANDYBRIDGE_0 + (regnum * 8), val);
+       if (pipelined) {
+               int ret = intel_ring_begin(pipelined, 6);
+               if (ret)
+                       return ret;
+
+               intel_ring_emit(pipelined, MI_NOOP);
+               intel_ring_emit(pipelined, MI_LOAD_REGISTER_IMM(2));
+               intel_ring_emit(pipelined, FENCE_REG_SANDYBRIDGE_0 + regnum*8);
+               intel_ring_emit(pipelined, (u32)val);
+               intel_ring_emit(pipelined, FENCE_REG_SANDYBRIDGE_0 + regnum*8 + 4);
+               intel_ring_emit(pipelined, (u32)(val >> 32));
+               intel_ring_advance(pipelined);
+       } else
+               I915_WRITE64(FENCE_REG_SANDYBRIDGE_0 + regnum * 8, val);
+
+       return 0;
 }
 
-static void i965_write_fence_reg(struct drm_i915_gem_object *obj)
+static int i965_write_fence_reg(struct drm_i915_gem_object *obj,
+                               struct intel_ring_buffer *pipelined)
 {
        struct drm_device *dev = obj->base.dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
@@ -2359,27 +2376,41 @@ static void i965_write_fence_reg(struct drm_i915_gem_object *obj)
                val |= 1 << I965_FENCE_TILING_Y_SHIFT;
        val |= I965_FENCE_REG_VALID;
 
-       I915_WRITE64(FENCE_REG_965_0 + (regnum * 8), val);
+       if (pipelined) {
+               int ret = intel_ring_begin(pipelined, 6);
+               if (ret)
+                       return ret;
+
+               intel_ring_emit(pipelined, MI_NOOP);
+               intel_ring_emit(pipelined, MI_LOAD_REGISTER_IMM(2));
+               intel_ring_emit(pipelined, FENCE_REG_965_0 + regnum*8);
+               intel_ring_emit(pipelined, (u32)val);
+               intel_ring_emit(pipelined, FENCE_REG_965_0 + regnum*8 + 4);
+               intel_ring_emit(pipelined, (u32)(val >> 32));
+               intel_ring_advance(pipelined);
+       } else
+               I915_WRITE64(FENCE_REG_965_0 + regnum * 8, val);
+
+       return 0;
 }
 
-static void i915_write_fence_reg(struct drm_i915_gem_object *obj)
+static int i915_write_fence_reg(struct drm_i915_gem_object *obj,
+                               struct intel_ring_buffer *pipelined)
 {
        struct drm_device *dev = obj->base.dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
        u32 size = obj->gtt_space->size;
-       uint32_t fence_reg, val, pitch_val;
+       u32 fence_reg, val, pitch_val;
        int tile_width;
 
-       if ((obj->gtt_offset & ~I915_FENCE_START_MASK) ||
-           (obj->gtt_offset & (size - 1))) {
-               WARN(1, "%s: object 0x%08x [fenceable? %d] not 1M or size (0x%08x) aligned [gtt_space offset=%lx, size=%lx]\n",
-                    __func__, obj->gtt_offset, obj->map_and_fenceable, size,
-                    obj->gtt_space->start, obj->gtt_space->size);
-               return;
-       }
+       if (WARN((obj->gtt_offset & ~I915_FENCE_START_MASK) ||
+                (size & -size) != size ||
+                (obj->gtt_offset & (size - 1)),
+                "object 0x%08x [fenceable? %d] not 1M or pot-size (0x%08x) aligned\n",
+                obj->gtt_offset, obj->map_and_fenceable, size))
+               return -EINVAL;
 
-       if (obj->tiling_mode == I915_TILING_Y &&
-           HAS_128_BYTE_Y_TILING(dev))
+       if (obj->tiling_mode == I915_TILING_Y && HAS_128_BYTE_Y_TILING(dev))
                tile_width = 128;
        else
                tile_width = 512;
@@ -2388,12 +2419,6 @@ static void i915_write_fence_reg(struct drm_i915_gem_object *obj)
        pitch_val = obj->stride / tile_width;
        pitch_val = ffs(pitch_val) - 1;
 
-       if (obj->tiling_mode == I915_TILING_Y &&
-           HAS_128_BYTE_Y_TILING(dev))
-               WARN_ON(pitch_val > I830_FENCE_MAX_PITCH_VAL);
-       else
-               WARN_ON(pitch_val > I915_FENCE_MAX_PITCH_VAL);
-
        val = obj->gtt_offset;
        if (obj->tiling_mode == I915_TILING_Y)
                val |= 1 << I830_FENCE_TILING_Y_SHIFT;
@@ -2406,10 +2431,25 @@ static void i915_write_fence_reg(struct drm_i915_gem_object *obj)
                fence_reg = FENCE_REG_830_0 + fence_reg * 4;
        else
                fence_reg = FENCE_REG_945_8 + (fence_reg - 8) * 4;
-       I915_WRITE(fence_reg, val);
+
+       if (pipelined) {
+               int ret = intel_ring_begin(pipelined, 4);
+               if (ret)
+                       return ret;
+
+               intel_ring_emit(pipelined, MI_NOOP);
+               intel_ring_emit(pipelined, MI_LOAD_REGISTER_IMM(1));
+               intel_ring_emit(pipelined, fence_reg);
+               intel_ring_emit(pipelined, val);
+               intel_ring_advance(pipelined);
+       } else
+               I915_WRITE(fence_reg, val);
+
+       return 0;
 }
 
-static void i830_write_fence_reg(struct drm_i915_gem_object *obj)
+static int i830_write_fence_reg(struct drm_i915_gem_object *obj,
+                               struct intel_ring_buffer *pipelined)
 {
        struct drm_device *dev = obj->base.dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
@@ -2417,29 +2457,38 @@ static void i830_write_fence_reg(struct drm_i915_gem_object *obj)
        int regnum = obj->fence_reg;
        uint32_t val;
        uint32_t pitch_val;
-       uint32_t fence_size_bits;
 
-       if ((obj->gtt_offset & ~I830_FENCE_START_MASK) ||
-           (obj->gtt_offset & (obj->base.size - 1))) {
-               WARN(1, "%s: object 0x%08x not 512K or size aligned\n",
-                    __func__, obj->gtt_offset);
-               return;
-       }
+       if (WARN((obj->gtt_offset & ~I830_FENCE_START_MASK) ||
+                (size & -size) != size ||
+                (obj->gtt_offset & (size - 1)),
+                "object 0x%08x not 512K or pot-size 0x%08x aligned\n",
+                obj->gtt_offset, size))
+               return -EINVAL;
 
        pitch_val = obj->stride / 128;
        pitch_val = ffs(pitch_val) - 1;
-       WARN_ON(pitch_val > I830_FENCE_MAX_PITCH_VAL);
 
        val = obj->gtt_offset;
        if (obj->tiling_mode == I915_TILING_Y)
                val |= 1 << I830_FENCE_TILING_Y_SHIFT;
-       fence_size_bits = I830_FENCE_SIZE_BITS(size);
-       WARN_ON(fence_size_bits & ~0x00000f00);
-       val |= fence_size_bits;
+       val |= I830_FENCE_SIZE_BITS(size);
        val |= pitch_val << I830_FENCE_PITCH_SHIFT;
        val |= I830_FENCE_REG_VALID;
 
-       I915_WRITE(FENCE_REG_830_0 + (regnum * 4), val);
+       if (pipelined) {
+               int ret = intel_ring_begin(pipelined, 4);
+               if (ret)
+                       return ret;
+
+               intel_ring_emit(pipelined, MI_NOOP);
+               intel_ring_emit(pipelined, MI_LOAD_REGISTER_IMM(1));
+               intel_ring_emit(pipelined, FENCE_REG_830_0 + regnum*4);
+               intel_ring_emit(pipelined, val);
+               intel_ring_advance(pipelined);
+       } else
+               I915_WRITE(FENCE_REG_830_0 + regnum * 4, val);
+
+       return 0;
 }
 
 static int i915_find_fence_reg(struct drm_device *dev,
@@ -2512,6 +2561,7 @@ i915_gem_object_get_fence_reg(struct drm_i915_gem_object *obj,
        struct drm_device *dev = obj->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_i915_fence_reg *reg = NULL;
+       struct intel_ring_buffer *pipelined = NULL;
        int ret;
 
        /* Just update our place in the LRU if our fence is getting used. */
@@ -2553,25 +2603,24 @@ i915_gem_object_get_fence_reg(struct drm_i915_gem_object *obj,
 
        switch (INTEL_INFO(dev)->gen) {
        case 6:
-               sandybridge_write_fence_reg(obj);
+               ret = sandybridge_write_fence_reg(obj, pipelined);
                break;
        case 5:
        case 4:
-               i965_write_fence_reg(obj);
+               ret = i965_write_fence_reg(obj, pipelined);
                break;
        case 3:
-               i915_write_fence_reg(obj);
+               ret = i915_write_fence_reg(obj, pipelined);
                break;
        case 2:
-               i830_write_fence_reg(obj);
+               ret = i830_write_fence_reg(obj, pipelined);
                break;
        }
 
        trace_i915_gem_object_get_fence(obj,
                                        obj->fence_reg,
                                        obj->tiling_mode);
-
-       return 0;
+       return ret;
 }
 
 /**

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index c668b2f..ce97471 100644 (file)
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -164,7 +164,13 @@
 #define   MI_MEM_VIRTUAL       (1 << 22) /* 965+ only */
 #define MI_STORE_DWORD_INDEX   MI_INSTR(0x21, 1)
 #define   MI_STORE_DWORD_INDEX_SHIFT 2
-#define MI_LOAD_REGISTER_IMM   MI_INSTR(0x22, 1)
+/* Official intel docs are somewhat sloppy concerning MI_LOAD_REGISTER_IMM:
+ * - Always issue a MI_NOOP _before_ the MI_LOAD_REGISTER_IMM - otherwise hw
+ *   simply ignores the register load under certain conditions.
+ * - One can actually load arbitrary many arbitrary registers: Simply issue x
+ *   address/value pairs. Don't overdue it, though, x <= 2^4 must hold!
+ */
+#define MI_LOAD_REGISTER_IMM(x)        MI_INSTR(0x22, 2*x-1)
 #define MI_FLUSH_DW            MI_INSTR(0x26, 2) /* for GEN6 */
 #define MI_BATCH_BUFFER                MI_INSTR(0x30, 1)
 #define   MI_BATCH_NON_SECURE  (1)