[PATCH 07/61] drm/i915/gt: Pull ring submission resume under its caller forcewake
Mika Kuoppala
mika.kuoppala at linux.intel.com
Wed Jan 13 23:01:13 UTC 2021
Chris Wilson <chris at chris-wilson.co.uk> writes:
> Take advantage of calling xcs_resume under a forcewake by using direct
> mmio access. In particular, we can avoid the sleeping variants to allow
> resume to be called from softirq context, required for engine resets.
Yeah all call sites will grab forcewake.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
> .../gpu/drm/i915/gt/intel_ring_submission.c | 96 ++++++++-----------
> 1 file changed, 42 insertions(+), 54 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> index d7eabed01616..c57f34bdd178 100644
> --- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> @@ -122,31 +122,27 @@ static void set_hwsp(struct intel_engine_cs *engine, u32 offset)
> hwsp = RING_HWS_PGA(engine->mmio_base);
> }
>
> - intel_uncore_write(engine->uncore, hwsp, offset);
> - intel_uncore_posting_read(engine->uncore, hwsp);
> + intel_uncore_write_fw(engine->uncore, hwsp, offset);
> + intel_uncore_posting_read_fw(engine->uncore, hwsp);
> }
>
> static void flush_cs_tlb(struct intel_engine_cs *engine)
> {
> - struct drm_i915_private *dev_priv = engine->i915;
> -
> - if (!IS_GEN_RANGE(dev_priv, 6, 7))
> + if (!IS_GEN_RANGE(engine->i915, 6, 7))
> return;
>
> /* ring should be idle before issuing a sync flush*/
> - drm_WARN_ON(&dev_priv->drm,
> - (ENGINE_READ(engine, RING_MI_MODE) & MODE_IDLE) == 0);
> + GEM_DEBUG_WARN_ON((ENGINE_READ(engine, RING_MI_MODE) & MODE_IDLE) == 0);
>
> - ENGINE_WRITE(engine, RING_INSTPM,
> - _MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE |
> - INSTPM_SYNC_FLUSH));
> - if (intel_wait_for_register(engine->uncore,
> - RING_INSTPM(engine->mmio_base),
> - INSTPM_SYNC_FLUSH, 0,
> - 1000))
> - drm_err(&dev_priv->drm,
> - "%s: wait for SyncFlush to complete for TLB invalidation timed out\n",
> - engine->name);
> + ENGINE_WRITE_FW(engine, RING_INSTPM,
> + _MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE |
> + INSTPM_SYNC_FLUSH));
> + if (__intel_wait_for_register_fw(engine->uncore,
> + RING_INSTPM(engine->mmio_base),
> + INSTPM_SYNC_FLUSH, 0,
> + 2000, 0, NULL))
> + ENGINE_TRACE(engine,
> + "wait for SyncFlush to complete for TLB invalidation timed out\n");
> }
>
> static void ring_setup_status_page(struct intel_engine_cs *engine)
> @@ -177,13 +173,13 @@ static void set_pp_dir(struct intel_engine_cs *engine)
> if (!vm)
> return;
>
> - ENGINE_WRITE(engine, RING_PP_DIR_DCLV, PP_DIR_DCLV_2G);
> - ENGINE_WRITE(engine, RING_PP_DIR_BASE, pp_dir(vm));
> + ENGINE_WRITE_FW(engine, RING_PP_DIR_DCLV, PP_DIR_DCLV_2G);
> + ENGINE_WRITE_FW(engine, RING_PP_DIR_BASE, pp_dir(vm));
>
> if (INTEL_GEN(engine->i915) >= 7) {
> - ENGINE_WRITE(engine,
> - RING_MODE_GEN7,
> - _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
> + ENGINE_WRITE_FW(engine,
> + RING_MODE_GEN7,
> + _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
> }
> }
>
> @@ -191,13 +187,10 @@ static int xcs_resume(struct intel_engine_cs *engine)
> {
> struct drm_i915_private *dev_priv = engine->i915;
> struct intel_ring *ring = engine->legacy.ring;
> - int ret = 0;
>
> ENGINE_TRACE(engine, "ring:{HEAD:%04x, TAIL:%04x}\n",
> ring->head, ring->tail);
>
> - intel_uncore_forcewake_get(engine->uncore, FORCEWAKE_ALL);
> -
> if (HWS_NEEDS_PHYSICAL(dev_priv))
> ring_setup_phys_status_page(engine);
> else
> @@ -205,16 +198,13 @@ static int xcs_resume(struct intel_engine_cs *engine)
>
> intel_breadcrumbs_reset(engine->breadcrumbs);
>
> - /* Enforce ordering by reading HEAD register back */
> - ENGINE_POSTING_READ(engine, RING_HEAD);
> -
This raises worry, see
ece4a17d237a79f63fbfaf3f724a12b6d500555c
Do we introduce a another read as a post?
-Mika
> /*
> * Initialize the ring. This must happen _after_ we've cleared the ring
> * registers with the above sequence (the readback of the HEAD registers
> * also enforces ordering), otherwise the hw might lose the new ring
> * register values.
> */
> - ENGINE_WRITE(engine, RING_START, i915_ggtt_offset(ring->vma));
> + ENGINE_WRITE_FW(engine, RING_START, i915_ggtt_offset(ring->vma));
>
> /* Check that the ring offsets point within the ring! */
> GEM_BUG_ON(!intel_ring_offset_valid(ring, ring->head));
> @@ -224,46 +214,44 @@ static int xcs_resume(struct intel_engine_cs *engine)
> set_pp_dir(engine);
>
> /* First wake the ring up to an empty/idle ring */
> - ENGINE_WRITE(engine, RING_HEAD, ring->head);
> - ENGINE_WRITE(engine, RING_TAIL, ring->head);
> + ENGINE_WRITE_FW(engine, RING_HEAD, ring->head);
> + ENGINE_WRITE_FW(engine, RING_TAIL, ring->head);
> ENGINE_POSTING_READ(engine, RING_TAIL);
>
> - ENGINE_WRITE(engine, RING_CTL, RING_CTL_SIZE(ring->size) | RING_VALID);
> + ENGINE_WRITE_FW(engine, RING_CTL,
> + RING_CTL_SIZE(ring->size) | RING_VALID);
>
> /* If the head is still not zero, the ring is dead */
> - if (intel_wait_for_register(engine->uncore,
> - RING_CTL(engine->mmio_base),
> - RING_VALID, RING_VALID,
> - 50)) {
> - drm_err(&dev_priv->drm, "%s initialization failed "
> - "ctl %08x (valid? %d) head %08x [%08x] tail %08x [%08x] start %08x [expected %08x]\n",
> - engine->name,
> - ENGINE_READ(engine, RING_CTL),
> - ENGINE_READ(engine, RING_CTL) & RING_VALID,
> - ENGINE_READ(engine, RING_HEAD), ring->head,
> - ENGINE_READ(engine, RING_TAIL), ring->tail,
> - ENGINE_READ(engine, RING_START),
> - i915_ggtt_offset(ring->vma));
> - ret = -EIO;
> - goto out;
> + if (__intel_wait_for_register_fw(engine->uncore,
> + RING_CTL(engine->mmio_base),
> + RING_VALID, RING_VALID,
> + 5000, 0, NULL)) {
> + drm_err(&dev_priv->drm,
> + "%s initialization failed; "
> + "ctl %08x (valid? %d) head %08x [%08x] tail %08x [%08x] start %08x [expected %08x]\n",
> + engine->name,
> + ENGINE_READ(engine, RING_CTL),
> + ENGINE_READ(engine, RING_CTL) & RING_VALID,
> + ENGINE_READ(engine, RING_HEAD), ring->head,
> + ENGINE_READ(engine, RING_TAIL), ring->tail,
> + ENGINE_READ(engine, RING_START),
> + i915_ggtt_offset(ring->vma));
> + return -EIO;
> }
>
> if (INTEL_GEN(dev_priv) > 2)
> - ENGINE_WRITE(engine,
> - RING_MI_MODE, _MASKED_BIT_DISABLE(STOP_RING));
> + ENGINE_WRITE_FW(engine,
> + RING_MI_MODE, _MASKED_BIT_DISABLE(STOP_RING));
>
> /* Now awake, let it get started */
> if (ring->tail != ring->head) {
> - ENGINE_WRITE(engine, RING_TAIL, ring->tail);
> + ENGINE_WRITE_FW(engine, RING_TAIL, ring->tail);
> ENGINE_POSTING_READ(engine, RING_TAIL);
> }
>
> /* Papering over lost _interrupts_ immediately following the restart */
> intel_engine_signal_breadcrumbs(engine);
> -out:
> - intel_uncore_forcewake_put(engine->uncore, FORCEWAKE_ALL);
> -
> - return ret;
> + return 0;
> }
>
> static void sanitize_hwsp(struct intel_engine_cs *engine)
> --
> 2.20.1
>
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