[PATCH 20/62] drm/i915/bdw: Add GTT functions

Ben Widawsky
2013-11-03T04:08:13Z

With the PTE clarifications, the bind and clear functions can now be
added for gen8.

v2: Use for_each_sg_pages in gen8_ggtt_insert_entries.

v3: Drop dev argument to pte encode functions, upstream lost it. Also
rebase on top of the scratch page movement.

v4: Rebase on top of the new address space vfuncs.

v5: Add the bool use_scratch argument to clear_range and the bool valid argument
to the PTE encode function to follow upstream changes.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net> (v1)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 88 +++++++++++++++++++++++++++++++++++--
1 file changed, 85 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 8bf2184..df992dc 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -58,6 +58,15 @@ typedef uint64_t gen8_gtt_pte_t;
#define HSW_WB_ELLC_LLC_AGE0 HSW_CACHEABILITY_CONTROL(0xb)
#define HSW_WT_ELLC_LLC_AGE0 HSW_CACHEABILITY_CONTROL(0x6)

+static inline gen8_gtt_pte_t gen8_pte_encode(dma_addr_t addr,
+ enum i915_cache_level level,
+ bool valid)
+{
+ gen8_gtt_pte_t pte = valid ? _PAGE_PRESENT | _PAGE_RW : 0;
+ pte |= addr;
+ return pte;
+}
+
static gen6_gtt_pte_t snb_pte_encode(dma_addr_t addr,
enum i915_cache_level level,
bool valid)
@@ -576,6 +585,56 @@ int i915_gem_gtt_prepare_object(struct drm_i915_gem_object *obj)
return 0;
}

+static inline void gen8_set_pte(void __iomem *addr, gen8_gtt_pte_t pte)
+{
+#ifdef writeq
+ writeq(pte, addr);
+#else
+ iowrite32((u32)pte, addr);
+ iowrite32(pte >> 32, addr + 4);
+#endif
+}
+
+static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
+ struct sg_table *st,
+ unsigned int first_entry,
+ enum i915_cache_level level)
+{
+ struct drm_i915_private *dev_priv = vm->dev->dev_private;
+ gen8_gtt_pte_t __iomem *gtt_entries =
+ (gen8_gtt_pte_t __iomem *)dev_priv->gtt.gsm + first_entry;
+ int i = 0;
+ struct sg_page_iter sg_iter;
+ dma_addr_t addr;
+
+ for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) {
+ addr = sg_dma_address(sg_iter.sg) +
+ (sg_iter.sg_pgoffset << PAGE_SHIFT);
+ gen8_set_pte(&gtt_entries[i],
+ gen8_pte_encode(addr, level, true));
+ i++;
+ }
+
+ /* XXX: This serves as a posting read to make sure that the PTE has
+ * actually been updated. There is some concern that even though
+ * registers and PTEs are within the same BAR that they are potentially
+ * of NUMA access patterns. Therefore, even with the way we assume
+ * hardware should work, we must keep this posting read for paranoia.
+ */
+ if (i != 0)
+ WARN_ON(readl(&gtt_entries[i-1])
+ != gen8_pte_encode(addr, level, true));
+
+#if 0 /* TODO: Still needed on GEN8? */
+ /* This next bit makes the above posting read even more important. We
+ * want to flush the TLBs only after we're certain all the PTE updates
+ * have finished.
+ */
+ I915_WRITE(GFX_FLSH_CNTL_GEN6, GFX_FLSH_CNTL_EN);
+ POSTING_READ(GFX_FLSH_CNTL_GEN6);
+#endif
+}
+
/*
* Binds an object into the global gtt with the specified cache level. The object
* will be accessible to the GPU via commands whose operands reference offsets
@@ -618,6 +677,30 @@ static void gen6_ggtt_insert_entries(struct i915_address_space *vm,
POSTING_READ(GFX_FLSH_CNTL_GEN6);
}

+static void gen8_ggtt_clear_range(struct i915_address_space *vm,
+ unsigned int first_entry,
+ unsigned int num_entries,
+ bool use_scratch)
+{
+ struct drm_i915_private *dev_priv = vm->dev->dev_private;
+ gen8_gtt_pte_t scratch_pte, __iomem *gtt_base =
+ (gen8_gtt_pte_t __iomem *) dev_priv->gtt.gsm + first_entry;
+ const int max_entries = gtt_total_entries(dev_priv->gtt) - first_entry;
+ int i;
+
+ if (WARN(num_entries > max_entries,
+ "First entry = %d; Num entries = %d (max=%d)\n",
+ first_entry, num_entries, max_entries))
+ num_entries = max_entries;
+
+ scratch_pte = gen8_pte_encode(vm->scratch.addr,
+ I915_CACHE_LLC,
+ use_scratch);
+ for (i = 0; i < num_entries; i++)
+ gen8_set_pte(&gtt_base[i], scratch_pte);
+ readl(gtt_base);
+}
+
static void gen6_ggtt_clear_range(struct i915_address_space *vm,
unsigned int first_entry,
unsigned int num_entries,
@@ -641,7 +724,6 @@ static void gen6_ggtt_clear_range(struct i915_address_space *vm,
readl(gtt_base);
}

-
static void i915_ggtt_insert_entries(struct i915_address_space *vm,
struct sg_table *st,
unsigned int pg_start,
@@ -947,8 +1029,8 @@ static int gen8_gmch_probe(struct drm_device *dev,

ret = ggtt_probe_common(dev, gtt_size);

- dev_priv->gtt.base.clear_range = NULL;
- dev_priv->gtt.base.insert_entries = NULL;
+ dev_priv->gtt.base.clear_range = gen8_ggtt_clear_range;
+ dev_priv->gtt.base.insert_entries = gen8_ggtt_insert_entries;

return ret;
}
--
1.8.4.2