/*
* Copyright © 2014 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
*/
#include "i915_drv.h"
/**
* DOC: batch pool
*
* In order to submit batch buffers as 'secure', the software command parser
* must ensure that a batch buffer cannot be modified after parsing. It does
* this by copying the user provided batch buffer contents to a kernel owned
* buffer from which the hardware will actually execute, and by carefully
* managing the address space bindings for such buffers.
*
* The batch pool framework provides a mechanism for the driver to manage a
* set of scratch buffers to use for this purpose. The framework can be
* extended to support other uses cases should they arise.
*/
/**
* i915_gem_batch_pool_init() - initialize a batch buffer pool
* @dev: the drm device
* @pool: the batch buffer pool
*/
void i915_gem_batch_pool_init(struct drm_device *dev,
struct i915_gem_batch_pool *pool)
{
pool->dev = dev;
INIT_LIST_HEAD(&pool->cache_list);
}
/**
* i915_gem_batch_pool_fini() - clean up a batch buffer pool
* @pool: the pool to clean up
*
* Note: Callers must hold the struct_mutex.
*/
void i915_gem_batch_pool_fini(struct i915_gem_batch_pool *pool)
{
WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
while (!list_empty(&pool->cache_list)) {
struct drm_i915_gem_object *obj =
list_first_entry(&pool->cache_list,
struct drm_i915_gem_object,
batch_pool_list);
WARN_ON(obj->active);
list_del_init(&obj->batch_pool_list);
drm_gem_object_unreference(&obj->base);
}
}
/**
* i915_gem_batch_pool_get() - select a buffer from the pool
* @pool: the batch buffer pool
* @size: the minimum desired size of the returned buffer
*
* Finds or allocates a batch buffer in the pool with at least the requested
* size. The caller is responsible for any domain, active/inactive, or
* purgeability management for the returned buffer.
*
* Note: Callers must hold the struct_mutex
*
* Return: the selected batch buffer object
*/
struct drm_i915_gem_object *
i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
size_t size)
{
struct drm_i915_gem_object *obj = NULL;
struct drm_i915_gem_object *tmp, *next;
WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
list_for_each_entry_safe(tmp, next,
&pool->cache_list, batch_pool_list) {
if (tmp->active)
continue;
/* While we're looping, do some clean up */
if (tmp->madv == __I915_MADV_PURGED) {
list_del(&tmp->batch_pool_list);
drm_gem_object_unreference(&tmp->base);
continue;
}
/*
* Select a buffer that is at least as big as needed
* but not 'too much' bigger. A better way to do this
* might be to bucket the pool objects based on size.
*/
if (tmp->base.size >= size &&
tmp->base.size <= (2 * size)) {
obj = tmp;
break;
}
}
if (!obj) {
obj = i915_gem_alloc_object(pool->dev, size);
if (!obj)
return ERR_PTR(-ENOMEM);
list_add_tail(&obj->batch_pool_list, &pool->cache_list);
}
else
/* Keep list in LRU order */
list_move_tail(&obj->batch_pool_list, &pool->cache_list);
obj->madv = I915_MADV_WILLNEED;
return obj;
}
