drivers/gpu/drm/i915/i915_gem_clflush.c

   1 /*
   2  * Copyright © 2016 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  */
  24
  25 #include "i915_drv.h"
  26 #include "intel_frontbuffer.h"
  27 #include "i915_gem_clflush.h"
  28
  29 static DEFINE_SPINLOCK(clflush_lock);
  30
  31 struct clflush {
  32         struct dma_fence dma; /* Must be first for dma_fence_free() */
  33         struct i915_sw_fence wait;
  34         struct work_struct work;
  35         struct drm_i915_gem_object *obj;
  36 };
  37
  38 static const char *i915_clflush_get_driver_name(struct dma_fence *fence)
  39 {
  40         return DRIVER_NAME;
  41 }
  42
  43 static const char *i915_clflush_get_timeline_name(struct dma_fence *fence)
  44 {
  45         return "clflush";
  46 }
  47
  48 static void i915_clflush_release(struct dma_fence *fence)
  49 {
  50         struct clflush *clflush = container_of(fence, typeof(*clflush), dma);
  51
  52         i915_sw_fence_fini(&clflush->wait);
  53
  54         BUILD_BUG_ON(offsetof(typeof(*clflush), dma));
  55         dma_fence_free(&clflush->dma);
  56 }
  57
  58 static const struct dma_fence_ops i915_clflush_ops = {
  59         .get_driver_name = i915_clflush_get_driver_name,
  60         .get_timeline_name = i915_clflush_get_timeline_name,
  61         .release = i915_clflush_release,
  62 };
  63
  64 static void __i915_do_clflush(struct drm_i915_gem_object *obj)
  65 {
  66         GEM_BUG_ON(!i915_gem_object_has_pages(obj));
  67         drm_clflush_sg(obj->mm.pages);
  68         intel_fb_obj_flush(obj, ORIGIN_CPU);
  69 }
  70
  71 static void i915_clflush_work(struct work_struct *work)
  72 {
  73         struct clflush *clflush = container_of(work, typeof(*clflush), work);
  74         struct drm_i915_gem_object *obj = clflush->obj;
  75
  76         if (i915_gem_object_pin_pages(obj)) {
  77                 DRM_ERROR("Failed to acquire obj->pages for clflushing\n");
  78                 goto out;
  79         }
  80
  81         __i915_do_clflush(obj);
  82
  83         i915_gem_object_unpin_pages(obj);
  84
  85 out:
  86         i915_gem_object_put(obj);
  87
  88         dma_fence_signal(&clflush->dma);
  89         dma_fence_put(&clflush->dma);
  90 }
  91
  92 static int __i915_sw_fence_call
  93 i915_clflush_notify(struct i915_sw_fence *fence,
  94                     enum i915_sw_fence_notify state)
  95 {
  96         struct clflush *clflush = container_of(fence, typeof(*clflush), wait);
  97
  98         switch (state) {
  99         case FENCE_COMPLETE:
 100                 schedule_work(&clflush->work);
 101                 break;
 102
 103         case FENCE_FREE:
 104                 dma_fence_put(&clflush->dma);
 105                 break;
 106         }
 107
 108         return NOTIFY_DONE;
 109 }
 110
 111 bool i915_gem_clflush_object(struct drm_i915_gem_object *obj,
 112                              unsigned int flags)
 113 {
 114         struct clflush *clflush;
 115
 116         /*
 117          * Stolen memory is always coherent with the GPU as it is explicitly
 118          * marked as wc by the system, or the system is cache-coherent.
 119          * Similarly, we only access struct pages through the CPU cache, so
 120          * anything not backed by physical memory we consider to be always
 121          * coherent and not need clflushing.
 122          */
 123         if (!i915_gem_object_has_struct_page(obj)) {
 124                 obj->cache_dirty = false;
 125                 return false;
 126         }
 127
 128         /* If the GPU is snooping the contents of the CPU cache,
 129          * we do not need to manually clear the CPU cache lines.  However,
 130          * the caches are only snooped when the render cache is
 131          * flushed/invalidated.  As we always have to emit invalidations
 132          * and flushes when moving into and out of the RENDER domain, correct
 133          * snooping behaviour occurs naturally as the result of our domain
 134          * tracking.
 135          */
 136         if (!(flags & I915_CLFLUSH_FORCE) &&
 137             obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_READ)
 138                 return false;
 139
 140         trace_i915_gem_object_clflush(obj);
 141
 142         clflush = NULL;
 143         if (!(flags & I915_CLFLUSH_SYNC))
 144                 clflush = kmalloc(sizeof(*clflush), GFP_KERNEL);
 145         if (clflush) {
 146                 GEM_BUG_ON(!obj->cache_dirty);
 147
 148                 dma_fence_init(&clflush->dma,
 149                                &i915_clflush_ops,
 150                                &clflush_lock,
 151                                to_i915(obj->base.dev)->mm.unordered_timeline,
 152                                0);
 153                 i915_sw_fence_init(&clflush->wait, i915_clflush_notify);
 154
 155                 clflush->obj = i915_gem_object_get(obj);
 156                 INIT_WORK(&clflush->work, i915_clflush_work);
 157
 158                 dma_fence_get(&clflush->dma);
 159
 160                 i915_sw_fence_await_reservation(&clflush->wait,
 161                                                 obj->resv, NULL,
 162                                                 true, I915_FENCE_TIMEOUT,
 163                                                 I915_FENCE_GFP);
 164
 165                 reservation_object_lock(obj->resv, NULL);
 166                 reservation_object_add_excl_fence(obj->resv, &clflush->dma);
 167                 reservation_object_unlock(obj->resv);
 168
 169                 i915_sw_fence_commit(&clflush->wait);
 170         } else if (obj->mm.pages) {
 171                 __i915_do_clflush(obj);
 172         } else {
 173                 GEM_BUG_ON(obj->write_domain != I915_GEM_DOMAIN_CPU);
 174         }
 175
 176         obj->cache_dirty = false;
 177         return true;
 178 }