// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2021 Rockchip Electronics Co. Ltd.
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*/
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#include <linux/slab.h>
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#include <linux/dma-buf.h>
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#undef CONFIG_DMABUF_CACHE
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#include <linux/dma-buf-cache.h>
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/* NOTE: dma-buf-cache APIs are not irq safe, please DO NOT run in irq context !! */
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struct dma_buf_cache_list {
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struct list_head head;
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};
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struct dma_buf_cache {
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struct list_head list;
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struct dma_buf_attachment *attach;
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enum dma_data_direction direction;
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struct sg_table *sg_table;
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};
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static int dma_buf_cache_destructor(struct dma_buf *dmabuf, void *dtor_data)
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{
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struct dma_buf_cache_list *data;
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struct dma_buf_cache *cache, *tmp;
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mutex_lock(&dmabuf->cache_lock);
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data = dmabuf->dtor_data;
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list_for_each_entry_safe(cache, tmp, &data->head, list) {
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if (!IS_ERR_OR_NULL(cache->sg_table))
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dma_buf_unmap_attachment(cache->attach,
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cache->sg_table,
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cache->direction);
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dma_buf_detach(dmabuf, cache->attach);
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list_del(&cache->list);
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kfree(cache);
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}
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mutex_unlock(&dmabuf->cache_lock);
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kfree(data);
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return 0;
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}
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static struct dma_buf_cache *
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dma_buf_cache_get_cache(struct dma_buf_attachment *attach)
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{
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struct dma_buf_cache_list *data;
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struct dma_buf_cache *cache;
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struct dma_buf *dmabuf = attach->dmabuf;
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if (dmabuf->dtor != dma_buf_cache_destructor)
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return NULL;
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data = dmabuf->dtor_data;
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list_for_each_entry(cache, &data->head, list) {
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if (cache->attach == attach)
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return cache;
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}
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return NULL;
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}
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void dma_buf_cache_detach(struct dma_buf *dmabuf,
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struct dma_buf_attachment *attach)
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{
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struct dma_buf_cache *cache;
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mutex_lock(&dmabuf->cache_lock);
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cache = dma_buf_cache_get_cache(attach);
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if (!cache)
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dma_buf_detach(dmabuf, attach);
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mutex_unlock(&dmabuf->cache_lock);
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}
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EXPORT_SYMBOL(dma_buf_cache_detach);
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struct dma_buf_attachment *dma_buf_cache_attach(struct dma_buf *dmabuf,
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struct device *dev)
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{
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struct dma_buf_attachment *attach;
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struct dma_buf_cache_list *data;
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struct dma_buf_cache *cache;
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mutex_lock(&dmabuf->cache_lock);
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if (!dmabuf->dtor) {
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data = kzalloc(sizeof(*data), GFP_KERNEL);
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if (!data) {
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attach = ERR_PTR(-ENOMEM);
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goto err_data;
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}
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INIT_LIST_HEAD(&data->head);
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dma_buf_set_destructor(dmabuf, dma_buf_cache_destructor, data);
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}
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if (dmabuf->dtor && dmabuf->dtor != dma_buf_cache_destructor) {
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attach = dma_buf_attach(dmabuf, dev);
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goto attach_done;
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}
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data = dmabuf->dtor_data;
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list_for_each_entry(cache, &data->head, list) {
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if (cache->attach->dev == dev) {
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/* Already attached */
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attach = cache->attach;
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goto attach_done;
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}
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}
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cache = kzalloc(sizeof(*cache), GFP_KERNEL);
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if (!cache) {
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attach = ERR_PTR(-ENOMEM);
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goto err_cache;
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}
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/* Cache attachment */
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attach = dma_buf_attach(dmabuf, dev);
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if (IS_ERR_OR_NULL(attach))
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goto err_attach;
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cache->attach = attach;
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list_add(&cache->list, &data->head);
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attach_done:
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mutex_unlock(&dmabuf->cache_lock);
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return attach;
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err_attach:
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kfree(cache);
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err_cache:
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kfree(data);
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dma_buf_set_destructor(dmabuf, NULL, NULL);
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err_data:
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mutex_unlock(&dmabuf->cache_lock);
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return attach;
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}
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EXPORT_SYMBOL(dma_buf_cache_attach);
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void dma_buf_cache_unmap_attachment(struct dma_buf_attachment *attach,
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struct sg_table *sg_table,
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enum dma_data_direction direction)
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{
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struct dma_buf *dmabuf = attach->dmabuf;
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struct dma_buf_cache *cache;
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mutex_lock(&dmabuf->cache_lock);
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cache = dma_buf_cache_get_cache(attach);
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if (!cache)
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dma_buf_unmap_attachment(attach, sg_table, direction);
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mutex_unlock(&dmabuf->cache_lock);
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}
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EXPORT_SYMBOL(dma_buf_cache_unmap_attachment);
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struct sg_table *dma_buf_cache_map_attachment(struct dma_buf_attachment *attach,
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enum dma_data_direction direction)
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{
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struct dma_buf *dmabuf = attach->dmabuf;
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struct dma_buf_cache *cache;
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struct sg_table *sg_table;
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mutex_lock(&dmabuf->cache_lock);
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cache = dma_buf_cache_get_cache(attach);
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if (!cache) {
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sg_table = dma_buf_map_attachment(attach, direction);
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goto map_done;
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}
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if (cache->sg_table) {
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/* Already mapped */
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if (cache->direction == direction) {
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sg_table = cache->sg_table;
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goto map_done;
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}
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/* Different directions */
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dma_buf_unmap_attachment(attach, cache->sg_table,
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cache->direction);
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}
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/* Cache map */
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sg_table = dma_buf_map_attachment(attach, direction);
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cache->sg_table = sg_table;
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cache->direction = direction;
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map_done:
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mutex_unlock(&dmabuf->cache_lock);
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return sg_table;
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}
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EXPORT_SYMBOL(dma_buf_cache_map_attachment);
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