drm/i915/guc: local optimisations and updating comments

Tidying up guc_init_proc_desc() and adding commentary to the client
structure after the recent change in GuC page mapping strategy.

Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461078516-28678-1-git-send-email-david.s.gordon@intel.com
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
This commit is contained in:
Dave Gordon 2016-04-19 16:08:36 +01:00 committed by Tvrtko Ursulin
parent a5916e8f54
commit 86e06cc0c0
2 changed files with 41 additions and 20 deletions

View file

@ -358,12 +358,14 @@ static void guc_init_proc_desc(struct intel_guc *guc,
static void guc_init_ctx_desc(struct intel_guc *guc,
struct i915_guc_client *client)
{
struct drm_i915_gem_object *client_obj = client->client_obj;
struct drm_i915_private *dev_priv = guc_to_i915(guc);
struct intel_engine_cs *engine;
struct intel_context *ctx = client->owner;
struct guc_context_desc desc;
struct sg_table *sg;
enum intel_engine_id id;
u32 gfx_addr;
memset(&desc, 0, sizeof(desc));
@ -392,16 +394,17 @@ static void guc_init_ctx_desc(struct intel_guc *guc,
lrc->context_desc = (u32)ctx_desc;
/* The state page is after PPHWSP */
lrc->ring_lcra = i915_gem_obj_ggtt_offset(obj) +
LRC_STATE_PN * PAGE_SIZE;
gfx_addr = i915_gem_obj_ggtt_offset(obj);
lrc->ring_lcra = gfx_addr + LRC_STATE_PN * PAGE_SIZE;
lrc->context_id = (client->ctx_index << GUC_ELC_CTXID_OFFSET) |
(engine->guc_id << GUC_ELC_ENGINE_OFFSET);
obj = ctx->engine[id].ringbuf->obj;
gfx_addr = i915_gem_obj_ggtt_offset(obj);
lrc->ring_begin = i915_gem_obj_ggtt_offset(obj);
lrc->ring_end = lrc->ring_begin + obj->base.size - 1;
lrc->ring_next_free_location = lrc->ring_begin;
lrc->ring_begin = gfx_addr;
lrc->ring_end = gfx_addr + obj->base.size - 1;
lrc->ring_next_free_location = gfx_addr;
lrc->ring_current_tail_pointer_value = 0;
desc.engines_used |= (1 << engine->guc_id);
@ -410,22 +413,17 @@ static void guc_init_ctx_desc(struct intel_guc *guc,
WARN_ON(desc.engines_used == 0);
/*
* The CPU address is only needed at certain points, so kmap_atomic on
* demand instead of storing it in the ctx descriptor.
* XXX: May make debug easier to have it mapped
* The doorbell, process descriptor, and workqueue are all parts
* of the client object, which the GuC will reference via the GGTT
*/
desc.db_trigger_cpu = 0;
desc.db_trigger_uk = client->doorbell_offset +
i915_gem_obj_ggtt_offset(client->client_obj);
desc.db_trigger_phy = client->doorbell_offset +
sg_dma_address(client->client_obj->pages->sgl);
desc.process_desc = client->proc_desc_offset +
i915_gem_obj_ggtt_offset(client->client_obj);
desc.wq_addr = client->wq_offset +
i915_gem_obj_ggtt_offset(client->client_obj);
gfx_addr = i915_gem_obj_ggtt_offset(client_obj);
desc.db_trigger_phy = sg_dma_address(client_obj->pages->sgl) +
client->doorbell_offset;
desc.db_trigger_cpu = (uintptr_t)client->client_base +
client->doorbell_offset;
desc.db_trigger_uk = gfx_addr + client->doorbell_offset;
desc.process_desc = gfx_addr + client->proc_desc_offset;
desc.wq_addr = gfx_addr + client->wq_offset;
desc.wq_size = client->wq_size;
/*

View file

@ -29,6 +29,29 @@
struct drm_i915_gem_request;
/*
* This structure primarily describes the GEM object shared with the GuC.
* The GEM object is held for the entire lifetime of our interaction with
* the GuC, being allocated before the GuC is loaded with its firmware.
* Because there's no way to update the address used by the GuC after
* initialisation, the shared object must stay pinned into the GGTT as
* long as the GuC is in use. We also keep the first page (only) mapped
* into kernel address space, as it includes shared data that must be
* updated on every request submission.
*
* The single GEM object described here is actually made up of several
* separate areas, as far as the GuC is concerned. The first page (kept
* kmap'd) includes the "process decriptor" which holds sequence data for
* the doorbell, and one cacheline which actually *is* the doorbell; a
* write to this will "ring the doorbell" (i.e. send an interrupt to the
* GuC). The subsequent pages of the client object constitute the work
* queue (a circular array of work items), again described in the process
* descriptor. Work queue pages are mapped momentarily as required.
*
* Finally, we also keep a few statistics here, including the number of
* submissions to each engine, and a record of the last submission failure
* (if any).
*/
struct i915_guc_client {
struct drm_i915_gem_object *client_obj;
void *client_base; /* first page (only) of above */