[Intel-gfx] [PATCH v2 3/4] drm/i915/gem: Extra pages in ttm_tt for ccs data

Ramalingam C
2022-03-01T21:53:33Z

On Xe-HP and later devices, we use dedicated compression control
state (CCS) stored in local memory for each surface, to support the
3D and media compression formats.

The memory required for the CCS of the entire local memory is 1/256 of
the local memory size. So before the kernel boot, the required memory
is reserved for the CCS data and a secure register will be programmed
with the CCS base address

So when we allocate a object in local memory we dont need to explicitly
allocate the space for ccs data. But when we evict the obj into the
smem to hold the compression related data along with the obj we need
smem space of obj_size + (obj_size/256).

Hence when we create smem for an obj with lmem placement possibility we
create with the extra space.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
cc: Christian Koenig <christian.koenig@amd.com>
cc: Hellstrom Thomas <thomas.hellstrom@intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 1a8262f5f692..c7a36861c38d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -20,6 +20,7 @@
#include "gem/i915_gem_ttm.h"
#include "gem/i915_gem_ttm_move.h"
#include "gem/i915_gem_ttm_pm.h"
+#include "gt/intel_gpu_commands.h"

#define I915_TTM_PRIO_PURGE 0
#define I915_TTM_PRIO_NO_PAGES 1
@@ -255,12 +256,27 @@ static const struct i915_refct_sgt_ops tt_rsgt_ops = {
.release = i915_ttm_tt_release
};

+static inline bool
+i915_gem_object_has_lmem_placement(struct drm_i915_gem_object *obj)
+{
+ int i;
+
+ for (i = 0; i < obj->mm.n_placements; i++)
+ if (obj->mm.placements[i]->type == INTEL_MEMORY_LOCAL)
+ return true;
+
+ return false;
+}
+
static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
uint32_t page_flags)
{
+ struct drm_i915_private *i915 = container_of(bo->bdev, typeof(*i915),
+ bdev);
struct ttm_resource_manager *man =
ttm_manager_type(bo->bdev, bo->resource->mem_type);
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
+ unsigned long ccs_pages = 0;
enum ttm_caching caching;
struct i915_ttm_tt *i915_tt;
int ret;
@@ -283,7 +299,12 @@ static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
i915_tt->is_shmem = true;
}

- ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching, 0);
+ if (HAS_FLAT_CCS(i915) && i915_gem_object_has_lmem_placement(obj))
+ ccs_pages = DIV_ROUND_UP(DIV_ROUND_UP(bo->base.size,
+ NUM_BYTES_PER_CCS_BYTE),
+ PAGE_SIZE);
+
+ ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching, ccs_pages);
if (ret)
goto err_free;

--
2.20.1