drivers/gpu/drm/ttm/ttm_execbuf_util.c

   1 /**************************************************************************
   2  *
   3  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28 #include "ttm/ttm_execbuf_util.h"
  29 #include "ttm/ttm_bo_driver.h"
  30 #include "ttm/ttm_placement.h"
  31 #include <linux/wait.h>
  32 #include <linux/sched.h>
  33 #include <linux/module.h>
  34
  35 void ttm_eu_backoff_reservation(struct list_head *list)
  36 {
  37         struct ttm_validate_buffer *entry;
  38
  39         list_for_each_entry(entry, list, head) {
  40                 struct ttm_buffer_object *bo = entry->bo;
  41                 if (!entry->reserved)
  42                         continue;
  43
  44                 entry->reserved = false;
  45                 ttm_bo_unreserve(bo);
  46         }
  47 }
  48 EXPORT_SYMBOL(ttm_eu_backoff_reservation);
  49
  50 /*
  51  * Reserve buffers for validation.
  52  *
  53  * If a buffer in the list is marked for CPU access, we back off and
  54  * wait for that buffer to become free for GPU access.
  55  *
  56  * If a buffer is reserved for another validation, the validator with
  57  * the highest validation sequence backs off and waits for that buffer
  58  * to become unreserved. This prevents deadlocks when validating multiple
  59  * buffers in different orders.
  60  */
  61
  62 int ttm_eu_reserve_buffers(struct list_head *list, uint32_t val_seq)
  63 {
  64         struct ttm_validate_buffer *entry;
  65         int ret;
  66
  67 retry:
  68         list_for_each_entry(entry, list, head) {
  69                 struct ttm_buffer_object *bo = entry->bo;
  70
  71                 entry->reserved = false;
  72                 ret = ttm_bo_reserve(bo, true, false, true, val_seq);
  73                 if (ret != 0) {
  74                         ttm_eu_backoff_reservation(list);
  75                         if (ret == -EAGAIN) {
  76                                 ret = ttm_bo_wait_unreserved(bo, true);
  77                                 if (unlikely(ret != 0))
  78                                         return ret;
  79                                 goto retry;
  80                         } else
  81                                 return ret;
  82                 }
  83
  84                 entry->reserved = true;
  85                 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
  86                         ttm_eu_backoff_reservation(list);
  87                         ret = ttm_bo_wait_cpu(bo, false);
  88                         if (ret)
  89                                 return ret;
  90                         goto retry;
  91                 }
  92         }
  93         return 0;
  94 }
  95 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
  96
  97 void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
  98 {
  99         struct ttm_validate_buffer *entry;
 100
 101         list_for_each_entry(entry, list, head) {
 102                 struct ttm_buffer_object *bo = entry->bo;
 103                 struct ttm_bo_driver *driver = bo->bdev->driver;
 104                 void *old_sync_obj;
 105
 106                 spin_lock(&bo->lock);
 107                 old_sync_obj = bo->sync_obj;
 108                 bo->sync_obj = driver->sync_obj_ref(sync_obj);
 109                 bo->sync_obj_arg = entry->new_sync_obj_arg;
 110                 spin_unlock(&bo->lock);
 111                 ttm_bo_unreserve(bo);
 112                 entry->reserved = false;
 113                 if (old_sync_obj)
 114                         driver->sync_obj_unref(&old_sync_obj);
 115         }
 116 }
 117 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);