[PATCH v6 12/25] drm/i915: Unify intel_ring_begin()

Chris Wilson
2016-04-26T20:06:47Z

Combine the near identical implementations of intel_logical_ring_begin()
and intel_ring_begin() - the only difference is that the logical wait
has to check for a matching ring (which is assumed by legacy).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
---
drivers/gpu/drm/i915/intel_lrc.c | 146 ++-----------------------
drivers/gpu/drm/i915/intel_lrc.h | 1 -
drivers/gpu/drm/i915/intel_mocs.c | 12 +--
drivers/gpu/drm/i915/intel_ringbuffer.c | 182 ++++++++++++--------------------
drivers/gpu/drm/i915/intel_ringbuffer.h | 3 -
5 files changed, 81 insertions(+), 263 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 2b7e6bbc017b..ba87c94928e7 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -721,48 +721,6 @@ int intel_logical_ring_alloc_request_extras(struct drm_i915_gem_request *request
return ret;
}

-static int logical_ring_wait_for_space(struct drm_i915_gem_request *req,
- int bytes)
-{
- struct intel_ringbuffer *ringbuf = req->ringbuf;
- struct intel_engine_cs *engine = req->engine;
- struct drm_i915_gem_request *target;
- unsigned space;
- int ret;
-
- if (intel_ring_space(ringbuf) >= bytes)
- return 0;
-
- /* The whole point of reserving space is to not wait! */
- WARN_ON(ringbuf->reserved_in_use);
-
- list_for_each_entry(target, &engine->request_list, list) {
- /*
- * The request queue is per-engine, so can contain requests
- * from multiple ringbuffers. Here, we must ignore any that
- * aren't from the ringbuffer we're considering.
- */
- if (target->ringbuf != ringbuf)
- continue;
-
- /* Would completion of this request free enough space? */
- space = __intel_ring_space(target->postfix, ringbuf->tail,
- ringbuf->size);
- if (space >= bytes)
- break;
- }
-
- if (WARN_ON(&target->list == &engine->request_list))
- return -ENOSPC;
-
- ret = i915_wait_request(target);
- if (ret)
- return ret;
-
- ringbuf->space = space;
- return 0;
-}
-
/*
* intel_logical_ring_advance_and_submit() - advance the tail and submit the workload
* @request: Request to advance the logical ringbuffer of.
@@ -814,92 +772,6 @@ intel_logical_ring_advance_and_submit(struct drm_i915_gem_request *request)
return 0;
}

-static void __wrap_ring_buffer(struct intel_ringbuffer *ringbuf)
-{
- uint32_t __iomem *virt;
- int rem = ringbuf->size - ringbuf->tail;
-
- virt = ringbuf->virtual_start + ringbuf->tail;
- rem /= 4;
- while (rem--)
- iowrite32(MI_NOOP, virt++);
-
- ringbuf->tail = 0;
- intel_ring_update_space(ringbuf);
-}
-
-static int logical_ring_prepare(struct drm_i915_gem_request *req, int bytes)
-{
- struct intel_ringbuffer *ringbuf = req->ringbuf;
- int remain_usable = ringbuf->effective_size - ringbuf->tail;
- int remain_actual = ringbuf->size - ringbuf->tail;
- int ret, total_bytes, wait_bytes = 0;
- bool need_wrap = false;
-
- if (ringbuf->reserved_in_use)
- total_bytes = bytes;
- else
- total_bytes = bytes + ringbuf->reserved_size;
-
- if (unlikely(bytes > remain_usable)) {
- /*
- * Not enough space for the basic request. So need to flush
- * out the remainder and then wait for base + reserved.
- */
- wait_bytes = remain_actual + total_bytes;
- need_wrap = true;
- } else {
- if (unlikely(total_bytes > remain_usable)) {
- /*
- * The base request will fit but the reserved space
- * falls off the end. So don't need an immediate wrap
- * and only need to effectively wait for the reserved
- * size space from the start of ringbuffer.
- */
- wait_bytes = remain_actual + ringbuf->reserved_size;
- } else if (total_bytes > ringbuf->space) {
- /* No wrapping required, just waiting. */
- wait_bytes = total_bytes;
- }
- }
-
- if (wait_bytes) {
- ret = logical_ring_wait_for_space(req, wait_bytes);
- if (unlikely(ret))
- return ret;
-
- if (need_wrap)
- __wrap_ring_buffer(ringbuf);
- }
-
- return 0;
-}
-
-/**
- * intel_logical_ring_begin() - prepare the logical ringbuffer to accept some commands
- *
- * @req: The request to start some new work for
- * @num_dwords: number of DWORDs that we plan to write to the ringbuffer.
- *
- * The ringbuffer might not be ready to accept the commands right away (maybe it needs to
- * be wrapped, or wait a bit for the tail to be updated). This function takes care of that
- * and also preallocates a request (every workload submission is still mediated through
- * requests, same as it did with legacy ringbuffer submission).
- *
- * Return: non-zero if the ringbuffer is not ready to be written to.
- */
-int intel_logical_ring_begin(struct drm_i915_gem_request *req, int num_dwords)
-{
- int ret;
-
- ret = logical_ring_prepare(req, num_dwords * sizeof(uint32_t));
- if (ret)
- return ret;
-
- req->ringbuf->space -= num_dwords * sizeof(uint32_t);
- return 0;
-}
-
int intel_logical_ring_reserve_space(struct drm_i915_gem_request *request)
{
/*
@@ -912,7 +784,7 @@ int intel_logical_ring_reserve_space(struct drm_i915_gem_request *request)
*/
intel_ring_reserved_space_reserve(request->ringbuf, MIN_SPACE_FOR_ADD_REQUEST);

- return intel_logical_ring_begin(request, 0);
+ return intel_ring_begin(request, 0);
}

/**
@@ -982,7 +854,7 @@ int intel_execlists_submission(struct i915_execbuffer_params *params,

if (engine == &dev_priv->engine[RCS] &&
instp_mode != dev_priv->relative_constants_mode) {
- ret = intel_logical_ring_begin(params->request, 4);
+ ret = intel_ring_begin(params->request, 4);
if (ret)
return ret;

@@ -1178,7 +1050,7 @@ static int intel_logical_ring_workarounds_emit(struct drm_i915_gem_request *req)
if (ret)
return ret;

- ret = intel_logical_ring_begin(req, w->count * 2 + 2);
+ ret = intel_ring_begin(req, w->count * 2 + 2);
if (ret)
return ret;

@@ -1669,7 +1541,7 @@ static int intel_logical_ring_emit_pdps(struct drm_i915_gem_request *req)
const int num_lri_cmds = GEN8_LEGACY_PDPES * 2;
int i, ret;

- ret = intel_logical_ring_begin(req, num_lri_cmds * 2 + 2);
+ ret = intel_ring_begin(req, num_lri_cmds * 2 + 2);
if (ret)
return ret;

@@ -1716,7 +1588,7 @@ static int gen8_emit_bb_start(struct drm_i915_gem_request *req,
req->ctx->ppgtt->pd_dirty_rings &= ~intel_engine_flag(req->engine);
}

- ret = intel_logical_ring_begin(req, 4);
+ ret = intel_ring_begin(req, 4);
if (ret)
return ret;

@@ -1778,7 +1650,7 @@ static int gen8_emit_flush(struct drm_i915_gem_request *request,
uint32_t cmd;
int ret;

- ret = intel_logical_ring_begin(request, 4);
+ ret = intel_ring_begin(request, 4);
if (ret)
return ret;

@@ -1846,7 +1718,7 @@ static int gen8_emit_flush_render(struct drm_i915_gem_request *request,
vf_flush_wa = true;
}

- ret = intel_logical_ring_begin(request, vf_flush_wa ? 12 : 6);
+ ret = intel_ring_begin(request, vf_flush_wa ? 12 : 6);
if (ret)
return ret;

@@ -1920,7 +1792,7 @@ static int gen8_emit_request(struct drm_i915_gem_request *request)
struct intel_ringbuffer *ringbuf = request->ringbuf;
int ret;

- ret = intel_logical_ring_begin(request, 6 + WA_TAIL_DWORDS);
+ ret = intel_ring_begin(request, 6 + WA_TAIL_DWORDS);
if (ret)
return ret;

@@ -1944,7 +1816,7 @@ static int gen8_emit_request_render(struct drm_i915_gem_request *request)
struct intel_ringbuffer *ringbuf = request->ringbuf;
int ret;

- ret = intel_logical_ring_begin(request, 8 + WA_TAIL_DWORDS);
+ ret = intel_ring_begin(request, 8 + WA_TAIL_DWORDS);
if (ret)
return ret;

diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index 461f1ef9b5c1..60a7385bc531 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -63,7 +63,6 @@ int intel_logical_ring_reserve_space(struct drm_i915_gem_request *request);
void intel_logical_ring_stop(struct intel_engine_cs *engine);
void intel_logical_ring_cleanup(struct intel_engine_cs *engine);
int intel_logical_rings_init(struct drm_device *dev);
-int intel_logical_ring_begin(struct drm_i915_gem_request *req, int num_dwords);

int logical_ring_flush_all_caches(struct drm_i915_gem_request *req);
/**
diff --git a/drivers/gpu/drm/i915/intel_mocs.c b/drivers/gpu/drm/i915/intel_mocs.c
index 23b8545ad6b0..6ba4bf7f2a89 100644
--- a/drivers/gpu/drm/i915/intel_mocs.c
+++ b/drivers/gpu/drm/i915/intel_mocs.c
@@ -239,11 +239,9 @@ static int emit_mocs_control_table(struct drm_i915_gem_request *req,
if (WARN_ON(table->size > GEN9_NUM_MOCS_ENTRIES))
return -ENODEV;

- ret = intel_logical_ring_begin(req, 2 + 2 * GEN9_NUM_MOCS_ENTRIES);
- if (ret) {
- DRM_DEBUG("intel_logical_ring_begin failed %d\n", ret);
+ ret = intel_ring_begin(req, 2 + 2 * GEN9_NUM_MOCS_ENTRIES);
+ if (ret)
return ret;
- }

intel_logical_ring_emit(ringbuf,
MI_LOAD_REGISTER_IMM(GEN9_NUM_MOCS_ENTRIES));
@@ -305,11 +303,9 @@ static int emit_mocs_l3cc_table(struct drm_i915_gem_request *req,
if (WARN_ON(table->size > GEN9_NUM_MOCS_ENTRIES))
return -ENODEV;

- ret = intel_logical_ring_begin(req, 2 + GEN9_NUM_MOCS_ENTRIES);
- if (ret) {
- DRM_DEBUG("intel_logical_ring_begin failed %d\n", ret);
+ ret = intel_ring_begin(req, 2 + GEN9_NUM_MOCS_ENTRIES);
+ if (ret)
return ret;
- }

intel_logical_ring_emit(ringbuf,
MI_LOAD_REGISTER_IMM(GEN9_NUM_MOCS_ENTRIES / 2));
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 61c120aed11e..1d3d2ea3e9bc 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -53,12 +53,6 @@ void intel_ring_update_space(struct intel_ringbuffer *ringbuf)
ringbuf->tail, ringbuf->size);
}

-int intel_ring_space(struct intel_ringbuffer *ringbuf)
-{
- intel_ring_update_space(ringbuf);
- return ringbuf->space;
-}
-
bool intel_engine_stopped(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->dev->dev_private;
@@ -2318,51 +2312,6 @@ void intel_cleanup_engine(struct intel_engine_cs *engine)
engine->dev = NULL;
}

-static int ring_wait_for_space(struct intel_engine_cs *engine, int n)
-{
- struct intel_ringbuffer *ringbuf = engine->buffer;
- struct drm_i915_gem_request *request;
- unsigned space;
- int ret;
-
- if (intel_ring_space(ringbuf) >= n)
- return 0;
-
- /* The whole point of reserving space is to not wait! */
- WARN_ON(ringbuf->reserved_in_use);
-
- list_for_each_entry(request, &engine->request_list, list) {
- space = __intel_ring_space(request->postfix, ringbuf->tail,
- ringbuf->size);
- if (space >= n)
- break;
- }
-
- if (WARN_ON(&request->list == &engine->request_list))
- return -ENOSPC;
-
- ret = i915_wait_request(request);
- if (ret)
- return ret;
-
- ringbuf->space = space;
- return 0;
-}
-
-static void __wrap_ring_buffer(struct intel_ringbuffer *ringbuf)
-{
- uint32_t __iomem *virt;
- int rem = ringbuf->size - ringbuf->tail;
-
- virt = ringbuf->virtual_start + ringbuf->tail;
- rem /= 4;
- while (rem--)
- iowrite32(MI_NOOP, virt++);
-
- ringbuf->tail = 0;
- intel_ring_update_space(ringbuf);
-}
-
int intel_engine_idle(struct intel_engine_cs *engine)
{
struct drm_i915_gem_request *req;
@@ -2404,63 +2353,74 @@ int intel_ring_reserve_space(struct drm_i915_gem_request *request)

void intel_ring_reserved_space_reserve(struct intel_ringbuffer *ringbuf, int size)
{
- WARN_ON(ringbuf->reserved_size);
- WARN_ON(ringbuf->reserved_in_use);
-
+ GEM_BUG_ON(ringbuf->reserved_size);
ringbuf->reserved_size = size;
}

void intel_ring_reserved_space_cancel(struct intel_ringbuffer *ringbuf)
{
- WARN_ON(ringbuf->reserved_in_use);
-
+ GEM_BUG_ON(!ringbuf->reserved_size);
ringbuf->reserved_size = 0;
- ringbuf->reserved_in_use = false;
}

void intel_ring_reserved_space_use(struct intel_ringbuffer *ringbuf)
{
- WARN_ON(ringbuf->reserved_in_use);
-
- ringbuf->reserved_in_use = true;
- ringbuf->reserved_tail = ringbuf->tail;
+ GEM_BUG_ON(!ringbuf->reserved_size);
+ ringbuf->reserved_size = 0;
}

void intel_ring_reserved_space_end(struct intel_ringbuffer *ringbuf)
{
- WARN_ON(!ringbuf->reserved_in_use);
- if (ringbuf->tail > ringbuf->reserved_tail) {
- WARN(ringbuf->tail > ringbuf->reserved_tail + ringbuf->reserved_size,
- "request reserved size too small: %d vs %d!\n",
- ringbuf->tail - ringbuf->reserved_tail, ringbuf->reserved_size);
- } else {
+ GEM_BUG_ON(ringbuf->reserved_size);
+}
+
+static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
+{
+ struct intel_ringbuffer *ringbuf = req->ringbuf;
+ struct intel_engine_cs *engine = req->engine;
+ struct drm_i915_gem_request *target;
+
+ intel_ring_update_space(ringbuf);
+ if (ringbuf->space >= bytes)
+ return 0;
+
+ /* The whole point of reserving space is to not wait! */
+ GEM_BUG_ON(!ringbuf->reserved_size);
+
+ list_for_each_entry(target, &engine->request_list, list) {
+ unsigned space;
+
/*
- * The ring was wrapped while the reserved space was in use.
- * That means that some unknown amount of the ring tail was
- * no-op filled and skipped. Thus simply adding the ring size
- * to the tail and doing the above space check will not work.
- * Rather than attempt to track how much tail was skipped,
- * it is much simpler to say that also skipping the sanity
- * check every once in a while is not a big issue.
+ * The request queue is per-engine, so can contain requests
+ * from multiple ringbuffers. Here, we must ignore any that
+ * aren't from the ringbuffer we're considering.
*/
+ if (target->ringbuf != ringbuf)
+ continue;
+
+ /* Would completion of this request free enough space? */
+ space = __intel_ring_space(target->postfix, ringbuf->tail,
+ ringbuf->size);
+ if (space >= bytes)
+ break;
}

- ringbuf->reserved_size = 0;
- ringbuf->reserved_in_use = false;
+ if (WARN_ON(&target->list == &engine->request_list))
+ return -ENOSPC;
+
+ return i915_wait_request(target);
}

-static int __intel_ring_prepare(struct intel_engine_cs *engine, int bytes)
+int intel_ring_begin(struct drm_i915_gem_request *req, int num_dwords)
{
- struct intel_ringbuffer *ringbuf = engine->buffer;
- int remain_usable = ringbuf->effective_size - ringbuf->tail;
+ struct intel_ringbuffer *ringbuf = req->ringbuf;
int remain_actual = ringbuf->size - ringbuf->tail;
- int ret, total_bytes, wait_bytes = 0;
+ int remain_usable = ringbuf->effective_size - ringbuf->tail;
+ int bytes = num_dwords * sizeof(u32);
+ int total_bytes, wait_bytes;
bool need_wrap = false;

- if (ringbuf->reserved_in_use)
- total_bytes = bytes;
- else
- total_bytes = bytes + ringbuf->reserved_size;
+ total_bytes = bytes + ringbuf->reserved_size;

if (unlikely(bytes > remain_usable)) {
/*
@@ -2469,44 +2429,38 @@ static int __intel_ring_prepare(struct intel_engine_cs *engine, int bytes)
*/
wait_bytes = remain_actual + total_bytes;
need_wrap = true;
- } else {
- if (unlikely(total_bytes > remain_usable)) {
- /*
- * The base request will fit but the reserved space
- * falls off the end. So don't need an immediate wrap
- * and only need to effectively wait for the reserved
- * size space from the start of ringbuffer.
- */
- wait_bytes = remain_actual + ringbuf->reserved_size;
- } else if (total_bytes > ringbuf->space) {
- /* No wrapping required, just waiting. */
- wait_bytes = total_bytes;
- }
- }
+ } else if (unlikely(total_bytes > remain_usable)) {
+ /*
+ * The base request will fit but the reserved space
+ * falls off the end. So we don't need an immediate wrap
+ * and only need to effectively wait for the reserved
+ * size space from the start of ringbuffer.
+ */
+ wait_bytes = remain_actual + ringbuf->reserved_size;
+ } else
+ /* No wrapping required, just waiting. */
+ wait_bytes = total_bytes;

- if (wait_bytes) {
- ret = ring_wait_for_space(engine, wait_bytes);
+ if (wait_bytes > ringbuf->space) {
+ int ret = wait_for_space(req, wait_bytes);
if (unlikely(ret))
return ret;

- if (need_wrap)
- __wrap_ring_buffer(ringbuf);
+ intel_ring_update_space(ringbuf);
}

- return 0;
-}
+ if (unlikely(need_wrap)) {
+ GEM_BUG_ON(remain_actual > ringbuf->space);
+ GEM_BUG_ON(ringbuf->tail + remain_actual > ringbuf->size);

-int intel_ring_begin(struct drm_i915_gem_request *req,
- int num_dwords)
-{
- struct intel_engine_cs *engine = req->engine;
- int ret;
-
- ret = __intel_ring_prepare(engine, num_dwords * sizeof(uint32_t));
- if (ret)
- return ret;
+ memset(ringbuf->virtual_start + ringbuf->tail,
+ 0, remain_actual);
+ ringbuf->tail = 0;
+ ringbuf->space -= remain_actual;
+ }

- engine->buffer->space -= num_dwords * sizeof(uint32_t);
+ ringbuf->space -= bytes;
+ GEM_BUG_ON(ringbuf->space < 0);
return 0;
}

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 2ade194bbea9..201e7752d765 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -108,8 +108,6 @@ struct intel_ringbuffer {
int size;
int effective_size;
int reserved_size;
- int reserved_tail;
- bool reserved_in_use;

/** We track the position of the requests in the ring buffer, and
* when each is retired we increment last_retired_head as the GPU
@@ -459,7 +457,6 @@ static inline void intel_ring_advance(struct intel_engine_cs *engine)
}
int __intel_ring_space(int head, int tail, int size);
void intel_ring_update_space(struct intel_ringbuffer *ringbuf);
-int intel_ring_space(struct intel_ringbuffer *ringbuf);
bool intel_engine_stopped(struct intel_engine_cs *engine);

int __must_check intel_engine_idle(struct intel_engine_cs *engine);