diff options
Diffstat (limited to 'drivers/gpu/drm/i915/gt/intel_timeline.c')
| -rw-r--r-- | drivers/gpu/drm/i915/gt/intel_timeline.c | 629 |
1 files changed, 629 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.c b/drivers/gpu/drm/i915/gt/intel_timeline.c new file mode 100644 index 000000000..e25385ad2 --- /dev/null +++ b/drivers/gpu/drm/i915/gt/intel_timeline.c @@ -0,0 +1,629 @@ +/* + * SPDX-License-Identifier: MIT + * + * Copyright © 2016-2018 Intel Corporation + */ + +#include "i915_drv.h" + +#include "i915_active.h" +#include "i915_syncmap.h" +#include "intel_gt.h" +#include "intel_ring.h" +#include "intel_timeline.h" + +#define ptr_set_bit(ptr, bit) ((typeof(ptr))((unsigned long)(ptr) | BIT(bit))) +#define ptr_test_bit(ptr, bit) ((unsigned long)(ptr) & BIT(bit)) + +#define CACHELINE_BITS 6 +#define CACHELINE_FREE CACHELINE_BITS + +struct intel_timeline_hwsp { + struct intel_gt *gt; + struct intel_gt_timelines *gt_timelines; + struct list_head free_link; + struct i915_vma *vma; + u64 free_bitmap; +}; + +static struct i915_vma *__hwsp_alloc(struct intel_gt *gt) +{ + struct drm_i915_private *i915 = gt->i915; + struct drm_i915_gem_object *obj; + struct i915_vma *vma; + + obj = i915_gem_object_create_internal(i915, PAGE_SIZE); + if (IS_ERR(obj)) + return ERR_CAST(obj); + + i915_gem_object_set_cache_coherency(obj, I915_CACHE_LLC); + + vma = i915_vma_instance(obj, >->ggtt->vm, NULL); + if (IS_ERR(vma)) + i915_gem_object_put(obj); + + return vma; +} + +static struct i915_vma * +hwsp_alloc(struct intel_timeline *timeline, unsigned int *cacheline) +{ + struct intel_gt_timelines *gt = &timeline->gt->timelines; + struct intel_timeline_hwsp *hwsp; + + BUILD_BUG_ON(BITS_PER_TYPE(u64) * CACHELINE_BYTES > PAGE_SIZE); + + spin_lock_irq(>->hwsp_lock); + + /* hwsp_free_list only contains HWSP that have available cachelines */ + hwsp = list_first_entry_or_null(>->hwsp_free_list, + typeof(*hwsp), free_link); + if (!hwsp) { + struct i915_vma *vma; + + spin_unlock_irq(>->hwsp_lock); + + hwsp = kmalloc(sizeof(*hwsp), GFP_KERNEL); + if (!hwsp) + return ERR_PTR(-ENOMEM); + + vma = __hwsp_alloc(timeline->gt); + if (IS_ERR(vma)) { + kfree(hwsp); + return vma; + } + + GT_TRACE(timeline->gt, "new HWSP allocated\n"); + + vma->private = hwsp; + hwsp->gt = timeline->gt; + hwsp->vma = vma; + hwsp->free_bitmap = ~0ull; + hwsp->gt_timelines = gt; + + spin_lock_irq(>->hwsp_lock); + list_add(&hwsp->free_link, >->hwsp_free_list); + } + + GEM_BUG_ON(!hwsp->free_bitmap); + *cacheline = __ffs64(hwsp->free_bitmap); + hwsp->free_bitmap &= ~BIT_ULL(*cacheline); + if (!hwsp->free_bitmap) + list_del(&hwsp->free_link); + + spin_unlock_irq(>->hwsp_lock); + + GEM_BUG_ON(hwsp->vma->private != hwsp); + return hwsp->vma; +} + +static void __idle_hwsp_free(struct intel_timeline_hwsp *hwsp, int cacheline) +{ + struct intel_gt_timelines *gt = hwsp->gt_timelines; + unsigned long flags; + + spin_lock_irqsave(>->hwsp_lock, flags); + + /* As a cacheline becomes available, publish the HWSP on the freelist */ + if (!hwsp->free_bitmap) + list_add_tail(&hwsp->free_link, >->hwsp_free_list); + + GEM_BUG_ON(cacheline >= BITS_PER_TYPE(hwsp->free_bitmap)); + hwsp->free_bitmap |= BIT_ULL(cacheline); + + /* And if no one is left using it, give the page back to the system */ + if (hwsp->free_bitmap == ~0ull) { + i915_vma_put(hwsp->vma); + list_del(&hwsp->free_link); + kfree(hwsp); + } + + spin_unlock_irqrestore(>->hwsp_lock, flags); +} + +static void __rcu_cacheline_free(struct rcu_head *rcu) +{ + struct intel_timeline_cacheline *cl = + container_of(rcu, typeof(*cl), rcu); + + /* Must wait until after all *rq->hwsp are complete before removing */ + i915_gem_object_unpin_map(cl->hwsp->vma->obj); + __idle_hwsp_free(cl->hwsp, ptr_unmask_bits(cl->vaddr, CACHELINE_BITS)); + + i915_active_fini(&cl->active); + kfree(cl); +} + +static void __idle_cacheline_free(struct intel_timeline_cacheline *cl) +{ + GEM_BUG_ON(!i915_active_is_idle(&cl->active)); + call_rcu(&cl->rcu, __rcu_cacheline_free); +} + +__i915_active_call +static void __cacheline_retire(struct i915_active *active) +{ + struct intel_timeline_cacheline *cl = + container_of(active, typeof(*cl), active); + + i915_vma_unpin(cl->hwsp->vma); + if (ptr_test_bit(cl->vaddr, CACHELINE_FREE)) + __idle_cacheline_free(cl); +} + +static int __cacheline_active(struct i915_active *active) +{ + struct intel_timeline_cacheline *cl = + container_of(active, typeof(*cl), active); + + __i915_vma_pin(cl->hwsp->vma); + return 0; +} + +static struct intel_timeline_cacheline * +cacheline_alloc(struct intel_timeline_hwsp *hwsp, unsigned int cacheline) +{ + struct intel_timeline_cacheline *cl; + void *vaddr; + + GEM_BUG_ON(cacheline >= BIT(CACHELINE_BITS)); + + cl = kmalloc(sizeof(*cl), GFP_KERNEL); + if (!cl) + return ERR_PTR(-ENOMEM); + + vaddr = i915_gem_object_pin_map(hwsp->vma->obj, I915_MAP_WB); + if (IS_ERR(vaddr)) { + kfree(cl); + return ERR_CAST(vaddr); + } + + cl->hwsp = hwsp; + cl->vaddr = page_pack_bits(vaddr, cacheline); + + i915_active_init(&cl->active, __cacheline_active, __cacheline_retire); + + return cl; +} + +static void cacheline_acquire(struct intel_timeline_cacheline *cl, + u32 ggtt_offset) +{ + if (!cl) + return; + + cl->ggtt_offset = ggtt_offset; + i915_active_acquire(&cl->active); +} + +static void cacheline_release(struct intel_timeline_cacheline *cl) +{ + if (cl) + i915_active_release(&cl->active); +} + +static void cacheline_free(struct intel_timeline_cacheline *cl) +{ + if (!i915_active_acquire_if_busy(&cl->active)) { + __idle_cacheline_free(cl); + return; + } + + GEM_BUG_ON(ptr_test_bit(cl->vaddr, CACHELINE_FREE)); + cl->vaddr = ptr_set_bit(cl->vaddr, CACHELINE_FREE); + + i915_active_release(&cl->active); +} + +static int intel_timeline_init(struct intel_timeline *timeline, + struct intel_gt *gt, + struct i915_vma *hwsp, + unsigned int offset) +{ + void *vaddr; + + kref_init(&timeline->kref); + atomic_set(&timeline->pin_count, 0); + + timeline->gt = gt; + + timeline->has_initial_breadcrumb = !hwsp; + timeline->hwsp_cacheline = NULL; + + if (!hwsp) { + struct intel_timeline_cacheline *cl; + unsigned int cacheline; + + hwsp = hwsp_alloc(timeline, &cacheline); + if (IS_ERR(hwsp)) + return PTR_ERR(hwsp); + + cl = cacheline_alloc(hwsp->private, cacheline); + if (IS_ERR(cl)) { + __idle_hwsp_free(hwsp->private, cacheline); + return PTR_ERR(cl); + } + + timeline->hwsp_cacheline = cl; + timeline->hwsp_offset = cacheline * CACHELINE_BYTES; + + vaddr = page_mask_bits(cl->vaddr); + } else { + timeline->hwsp_offset = offset; + vaddr = i915_gem_object_pin_map(hwsp->obj, I915_MAP_WB); + if (IS_ERR(vaddr)) + return PTR_ERR(vaddr); + } + + timeline->hwsp_seqno = + memset(vaddr + timeline->hwsp_offset, 0, CACHELINE_BYTES); + + timeline->hwsp_ggtt = i915_vma_get(hwsp); + GEM_BUG_ON(timeline->hwsp_offset >= hwsp->size); + + timeline->fence_context = dma_fence_context_alloc(1); + + mutex_init(&timeline->mutex); + + INIT_ACTIVE_FENCE(&timeline->last_request); + INIT_LIST_HEAD(&timeline->requests); + + i915_syncmap_init(&timeline->sync); + + return 0; +} + +void intel_gt_init_timelines(struct intel_gt *gt) +{ + struct intel_gt_timelines *timelines = >->timelines; + + spin_lock_init(&timelines->lock); + INIT_LIST_HEAD(&timelines->active_list); + + spin_lock_init(&timelines->hwsp_lock); + INIT_LIST_HEAD(&timelines->hwsp_free_list); +} + +static void intel_timeline_fini(struct intel_timeline *timeline) +{ + GEM_BUG_ON(atomic_read(&timeline->pin_count)); + GEM_BUG_ON(!list_empty(&timeline->requests)); + GEM_BUG_ON(timeline->retire); + + if (timeline->hwsp_cacheline) + cacheline_free(timeline->hwsp_cacheline); + else + i915_gem_object_unpin_map(timeline->hwsp_ggtt->obj); + + i915_vma_put(timeline->hwsp_ggtt); + + /* + * A small race exists between intel_gt_retire_requests_timeout and + * intel_timeline_exit which could result in the syncmap not getting + * free'd. Rather than work to hard to seal this race, simply cleanup + * the syncmap on fini. + */ + i915_syncmap_free(&timeline->sync); +} + +struct intel_timeline * +__intel_timeline_create(struct intel_gt *gt, + struct i915_vma *global_hwsp, + unsigned int offset) +{ + struct intel_timeline *timeline; + int err; + + timeline = kzalloc(sizeof(*timeline), GFP_KERNEL); + if (!timeline) + return ERR_PTR(-ENOMEM); + + err = intel_timeline_init(timeline, gt, global_hwsp, offset); + if (err) { + kfree(timeline); + return ERR_PTR(err); + } + + return timeline; +} + +void __intel_timeline_pin(struct intel_timeline *tl) +{ + GEM_BUG_ON(!atomic_read(&tl->pin_count)); + atomic_inc(&tl->pin_count); +} + +int intel_timeline_pin(struct intel_timeline *tl, struct i915_gem_ww_ctx *ww) +{ + int err; + + if (atomic_add_unless(&tl->pin_count, 1, 0)) + return 0; + + err = i915_ggtt_pin(tl->hwsp_ggtt, ww, 0, PIN_HIGH); + if (err) + return err; + + tl->hwsp_offset = + i915_ggtt_offset(tl->hwsp_ggtt) + + offset_in_page(tl->hwsp_offset); + GT_TRACE(tl->gt, "timeline:%llx using HWSP offset:%x\n", + tl->fence_context, tl->hwsp_offset); + + cacheline_acquire(tl->hwsp_cacheline, tl->hwsp_offset); + if (atomic_fetch_inc(&tl->pin_count)) { + cacheline_release(tl->hwsp_cacheline); + __i915_vma_unpin(tl->hwsp_ggtt); + } + + return 0; +} + +void intel_timeline_reset_seqno(const struct intel_timeline *tl) +{ + /* Must be pinned to be writable, and no requests in flight. */ + GEM_BUG_ON(!atomic_read(&tl->pin_count)); + WRITE_ONCE(*(u32 *)tl->hwsp_seqno, tl->seqno); +} + +void intel_timeline_enter(struct intel_timeline *tl) +{ + struct intel_gt_timelines *timelines = &tl->gt->timelines; + + /* + * Pretend we are serialised by the timeline->mutex. + * + * While generally true, there are a few exceptions to the rule + * for the engine->kernel_context being used to manage power + * transitions. As the engine_park may be called from under any + * timeline, it uses the power mutex as a global serialisation + * lock to prevent any other request entering its timeline. + * + * The rule is generally tl->mutex, otherwise engine->wakeref.mutex. + * + * However, intel_gt_retire_request() does not know which engine + * it is retiring along and so cannot partake in the engine-pm + * barrier, and there we use the tl->active_count as a means to + * pin the timeline in the active_list while the locks are dropped. + * Ergo, as that is outside of the engine-pm barrier, we need to + * use atomic to manipulate tl->active_count. + */ + lockdep_assert_held(&tl->mutex); + + if (atomic_add_unless(&tl->active_count, 1, 0)) + return; + + spin_lock(&timelines->lock); + if (!atomic_fetch_inc(&tl->active_count)) { + /* + * The HWSP is volatile, and may have been lost while inactive, + * e.g. across suspend/resume. Be paranoid, and ensure that + * the HWSP value matches our seqno so we don't proclaim + * the next request as already complete. + */ + intel_timeline_reset_seqno(tl); + list_add_tail(&tl->link, &timelines->active_list); + } + spin_unlock(&timelines->lock); +} + +void intel_timeline_exit(struct intel_timeline *tl) +{ + struct intel_gt_timelines *timelines = &tl->gt->timelines; + + /* See intel_timeline_enter() */ + lockdep_assert_held(&tl->mutex); + + GEM_BUG_ON(!atomic_read(&tl->active_count)); + if (atomic_add_unless(&tl->active_count, -1, 1)) + return; + + spin_lock(&timelines->lock); + if (atomic_dec_and_test(&tl->active_count)) + list_del(&tl->link); + spin_unlock(&timelines->lock); + + /* + * Since this timeline is idle, all bariers upon which we were waiting + * must also be complete and so we can discard the last used barriers + * without loss of information. + */ + i915_syncmap_free(&tl->sync); +} + +static u32 timeline_advance(struct intel_timeline *tl) +{ + GEM_BUG_ON(!atomic_read(&tl->pin_count)); + GEM_BUG_ON(tl->seqno & tl->has_initial_breadcrumb); + + return tl->seqno += 1 + tl->has_initial_breadcrumb; +} + +static void timeline_rollback(struct intel_timeline *tl) +{ + tl->seqno -= 1 + tl->has_initial_breadcrumb; +} + +static noinline int +__intel_timeline_get_seqno(struct intel_timeline *tl, + struct i915_request *rq, + u32 *seqno) +{ + struct intel_timeline_cacheline *cl; + unsigned int cacheline; + struct i915_vma *vma; + void *vaddr; + int err; + + might_lock(&tl->gt->ggtt->vm.mutex); + GT_TRACE(tl->gt, "timeline:%llx wrapped\n", tl->fence_context); + + /* + * If there is an outstanding GPU reference to this cacheline, + * such as it being sampled by a HW semaphore on another timeline, + * we cannot wraparound our seqno value (the HW semaphore does + * a strict greater-than-or-equals compare, not i915_seqno_passed). + * So if the cacheline is still busy, we must detach ourselves + * from it and leave it inflight alongside its users. + * + * However, if nobody is watching and we can guarantee that nobody + * will, we could simply reuse the same cacheline. + * + * if (i915_active_request_is_signaled(&tl->last_request) && + * i915_active_is_signaled(&tl->hwsp_cacheline->active)) + * return 0; + * + * That seems unlikely for a busy timeline that needed to wrap in + * the first place, so just replace the cacheline. + */ + + vma = hwsp_alloc(tl, &cacheline); + if (IS_ERR(vma)) { + err = PTR_ERR(vma); + goto err_rollback; + } + + err = i915_ggtt_pin(vma, NULL, 0, PIN_HIGH); + if (err) { + __idle_hwsp_free(vma->private, cacheline); + goto err_rollback; + } + + cl = cacheline_alloc(vma->private, cacheline); + if (IS_ERR(cl)) { + err = PTR_ERR(cl); + __idle_hwsp_free(vma->private, cacheline); + goto err_unpin; + } + GEM_BUG_ON(cl->hwsp->vma != vma); + + /* + * Attach the old cacheline to the current request, so that we only + * free it after the current request is retired, which ensures that + * all writes into the cacheline from previous requests are complete. + */ + err = i915_active_ref(&tl->hwsp_cacheline->active, + tl->fence_context, + &rq->fence); + if (err) + goto err_cacheline; + + cacheline_release(tl->hwsp_cacheline); /* ownership now xfered to rq */ + cacheline_free(tl->hwsp_cacheline); + + i915_vma_unpin(tl->hwsp_ggtt); /* binding kept alive by old cacheline */ + i915_vma_put(tl->hwsp_ggtt); + + tl->hwsp_ggtt = i915_vma_get(vma); + + vaddr = page_mask_bits(cl->vaddr); + tl->hwsp_offset = cacheline * CACHELINE_BYTES; + tl->hwsp_seqno = + memset(vaddr + tl->hwsp_offset, 0, CACHELINE_BYTES); + + tl->hwsp_offset += i915_ggtt_offset(vma); + GT_TRACE(tl->gt, "timeline:%llx using HWSP offset:%x\n", + tl->fence_context, tl->hwsp_offset); + + cacheline_acquire(cl, tl->hwsp_offset); + tl->hwsp_cacheline = cl; + + *seqno = timeline_advance(tl); + GEM_BUG_ON(i915_seqno_passed(*tl->hwsp_seqno, *seqno)); + return 0; + +err_cacheline: + cacheline_free(cl); +err_unpin: + i915_vma_unpin(vma); +err_rollback: + timeline_rollback(tl); + return err; +} + +int intel_timeline_get_seqno(struct intel_timeline *tl, + struct i915_request *rq, + u32 *seqno) +{ + *seqno = timeline_advance(tl); + + /* Replace the HWSP on wraparound for HW semaphores */ + if (unlikely(!*seqno && tl->hwsp_cacheline)) + return __intel_timeline_get_seqno(tl, rq, seqno); + + return 0; +} + +static int cacheline_ref(struct intel_timeline_cacheline *cl, + struct i915_request *rq) +{ + return i915_active_add_request(&cl->active, rq); +} + +int intel_timeline_read_hwsp(struct i915_request *from, + struct i915_request *to, + u32 *hwsp) +{ + struct intel_timeline_cacheline *cl; + int err; + + GEM_BUG_ON(!rcu_access_pointer(from->hwsp_cacheline)); + + rcu_read_lock(); + cl = rcu_dereference(from->hwsp_cacheline); + if (i915_request_completed(from)) /* confirm cacheline is valid */ + goto unlock; + if (unlikely(!i915_active_acquire_if_busy(&cl->active))) + goto unlock; /* seqno wrapped and completed! */ + if (unlikely(i915_request_completed(from))) + goto release; + rcu_read_unlock(); + + err = cacheline_ref(cl, to); + if (err) + goto out; + + *hwsp = cl->ggtt_offset; +out: + i915_active_release(&cl->active); + return err; + +release: + i915_active_release(&cl->active); +unlock: + rcu_read_unlock(); + return 1; +} + +void intel_timeline_unpin(struct intel_timeline *tl) +{ + GEM_BUG_ON(!atomic_read(&tl->pin_count)); + if (!atomic_dec_and_test(&tl->pin_count)) + return; + + cacheline_release(tl->hwsp_cacheline); + + __i915_vma_unpin(tl->hwsp_ggtt); +} + +void __intel_timeline_free(struct kref *kref) +{ + struct intel_timeline *timeline = + container_of(kref, typeof(*timeline), kref); + + intel_timeline_fini(timeline); + kfree_rcu(timeline, rcu); +} + +void intel_gt_fini_timelines(struct intel_gt *gt) +{ + struct intel_gt_timelines *timelines = >->timelines; + + GEM_BUG_ON(!list_empty(&timelines->active_list)); + GEM_BUG_ON(!list_empty(&timelines->hwsp_free_list)); +} + +#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) +#include "gt/selftests/mock_timeline.c" +#include "gt/selftest_timeline.c" +#endif |