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  1. /*
  2.  * Copyright © 2014 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 "i915_gem_batch_pool.h"
  27.  
  28. /**
  29.  * DOC: batch pool
  30.  *
  31.  * In order to submit batch buffers as 'secure', the software command parser
  32.  * must ensure that a batch buffer cannot be modified after parsing. It does
  33.  * this by copying the user provided batch buffer contents to a kernel owned
  34.  * buffer from which the hardware will actually execute, and by carefully
  35.  * managing the address space bindings for such buffers.
  36.  *
  37.  * The batch pool framework provides a mechanism for the driver to manage a
  38.  * set of scratch buffers to use for this purpose. The framework can be
  39.  * extended to support other uses cases should they arise.
  40.  */
  41.  
  42. /**
  43.  * i915_gem_batch_pool_init() - initialize a batch buffer pool
  44.  * @dev: the drm device
  45.  * @pool: the batch buffer pool
  46.  */
  47. void i915_gem_batch_pool_init(struct drm_device *dev,
  48.                               struct i915_gem_batch_pool *pool)
  49. {
  50.         int n;
  51.  
  52.         pool->dev = dev;
  53.  
  54.         for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++)
  55.                 INIT_LIST_HEAD(&pool->cache_list[n]);
  56. }
  57.  
  58. /**
  59.  * i915_gem_batch_pool_fini() - clean up a batch buffer pool
  60.  * @pool: the pool to clean up
  61.  *
  62.  * Note: Callers must hold the struct_mutex.
  63.  */
  64. void i915_gem_batch_pool_fini(struct i915_gem_batch_pool *pool)
  65. {
  66.         int n;
  67.  
  68.         WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
  69.  
  70.         for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) {
  71.                 while (!list_empty(&pool->cache_list[n])) {
  72.                         struct drm_i915_gem_object *obj =
  73.                                 list_first_entry(&pool->cache_list[n],
  74.                                                  struct drm_i915_gem_object,
  75.                                                  batch_pool_link);
  76.  
  77.                         list_del(&obj->batch_pool_link);
  78.                         drm_gem_object_unreference(&obj->base);
  79.                 }
  80.         }
  81. }
  82.  
  83. /**
  84.  * i915_gem_batch_pool_get() - allocate a buffer from the pool
  85.  * @pool: the batch buffer pool
  86.  * @size: the minimum desired size of the returned buffer
  87.  *
  88.  * Returns an inactive buffer from @pool with at least @size bytes,
  89.  * with the pages pinned. The caller must i915_gem_object_unpin_pages()
  90.  * on the returned object.
  91.  *
  92.  * Note: Callers must hold the struct_mutex
  93.  *
  94.  * Return: the buffer object or an error pointer
  95.  */
  96. struct drm_i915_gem_object *
  97. i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
  98.                         size_t size)
  99. {
  100.         struct drm_i915_gem_object *obj = NULL;
  101.         struct drm_i915_gem_object *tmp, *next;
  102.         struct list_head *list;
  103.         int n;
  104.  
  105.         WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
  106.  
  107.         /* Compute a power-of-two bucket, but throw everything greater than
  108.          * 16KiB into the same bucket: i.e. the the buckets hold objects of
  109.          * (1 page, 2 pages, 4 pages, 8+ pages).
  110.          */
  111.         n = fls(size >> PAGE_SHIFT) - 1;
  112.         if (n >= ARRAY_SIZE(pool->cache_list))
  113.                 n = ARRAY_SIZE(pool->cache_list) - 1;
  114.         list = &pool->cache_list[n];
  115.  
  116.         list_for_each_entry_safe(tmp, next, list, batch_pool_link) {
  117.                 /* The batches are strictly LRU ordered */
  118.                 if (tmp->active)
  119.                         break;
  120.  
  121.                 /* While we're looping, do some clean up */
  122.                 if (tmp->madv == __I915_MADV_PURGED) {
  123.                         list_del(&tmp->batch_pool_link);
  124.                         drm_gem_object_unreference(&tmp->base);
  125.                         continue;
  126.                 }
  127.  
  128.                 if (tmp->base.size >= size) {
  129.                         obj = tmp;
  130.                         break;
  131.                 }
  132.         }
  133.  
  134.         if (obj == NULL) {
  135.                 int ret;
  136.  
  137.                 obj = i915_gem_alloc_object(pool->dev, size);
  138.                 if (obj == NULL)
  139.                         return ERR_PTR(-ENOMEM);
  140.  
  141.                 ret = i915_gem_object_get_pages(obj);
  142.                 if (ret)
  143.                         return ERR_PTR(ret);
  144.  
  145.                 obj->madv = I915_MADV_DONTNEED;
  146.         }
  147.  
  148.         list_move_tail(&obj->batch_pool_link, list);
  149.         i915_gem_object_pin_pages(obj);
  150.         return obj;
  151. }
  152.