diff options
| -rw-r--r-- | drivers/base/dma-buf.c | 124 | ||||
| -rw-r--r-- | include/linux/dma-buf.h | 59 |
2 files changed, 182 insertions, 1 deletions
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c index 5641b9c8d50c..07cbbc6fddb4 100644 --- a/drivers/base/dma-buf.c +++ b/drivers/base/dma-buf.c @@ -80,7 +80,9 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, if (WARN_ON(!priv || !ops || !ops->map_dma_buf || !ops->unmap_dma_buf - || !ops->release)) { + || !ops->release + || !ops->kmap_atomic + || !ops->kmap)) { return ERR_PTR(-EINVAL); } @@ -284,3 +286,123 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, direction); } EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); + + +/** + * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the + * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific + * preparations. Coherency is only guaranteed in the specified range for the + * specified access direction. + * @dma_buf: [in] buffer to prepare cpu access for. + * @start: [in] start of range for cpu access. + * @len: [in] length of range for cpu access. + * @direction: [in] length of range for cpu access. + * + * Can return negative error values, returns 0 on success. + */ +int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len, + enum dma_data_direction direction) +{ + int ret = 0; + + if (WARN_ON(!dmabuf)) + return -EINVAL; + + if (dmabuf->ops->begin_cpu_access) + ret = dmabuf->ops->begin_cpu_access(dmabuf, start, len, direction); + + return ret; +} +EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access); + +/** + * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the + * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific + * actions. Coherency is only guaranteed in the specified range for the + * specified access direction. + * @dma_buf: [in] buffer to complete cpu access for. + * @start: [in] start of range for cpu access. + * @len: [in] length of range for cpu access. + * @direction: [in] length of range for cpu access. + * + * This call must always succeed. + */ +void dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len, + enum dma_data_direction direction) +{ + WARN_ON(!dmabuf); + + if (dmabuf->ops->end_cpu_access) + dmabuf->ops->end_cpu_access(dmabuf, start, len, direction); +} +EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); + +/** + * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address + * space. The same restrictions as for kmap_atomic and friends apply. + * @dma_buf: [in] buffer to map page from. + * @page_num: [in] page in PAGE_SIZE units to map. + * + * This call must always succeed, any necessary preparations that might fail + * need to be done in begin_cpu_access. + */ +void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num) +{ + WARN_ON(!dmabuf); + + return dmabuf->ops->kmap_atomic(dmabuf, page_num); +} +EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic); + +/** + * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic. + * @dma_buf: [in] buffer to unmap page from. + * @page_num: [in] page in PAGE_SIZE units to unmap. + * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic. + * + * This call must always succeed. + */ +void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num, + void *vaddr) +{ + WARN_ON(!dmabuf); + + if (dmabuf->ops->kunmap_atomic) + dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr); +} +EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic); + +/** + * dma_buf_kmap - Map a page of the buffer object into kernel address space. The + * same restrictions as for kmap and friends apply. + * @dma_buf: [in] buffer to map page from. + * @page_num: [in] page in PAGE_SIZE units to map. + * + * This call must always succeed, any necessary preparations that might fail + * need to be done in begin_cpu_access. + */ +void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num) +{ + WARN_ON(!dmabuf); + + return dmabuf->ops->kmap(dmabuf, page_num); +} +EXPORT_SYMBOL_GPL(dma_buf_kmap); + +/** + * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap. + * @dma_buf: [in] buffer to unmap page from. + * @page_num: [in] page in PAGE_SIZE units to unmap. + * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap. + * + * This call must always succeed. + */ +void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num, + void *vaddr) +{ + WARN_ON(!dmabuf); + + if (dmabuf->ops->kunmap) + dmabuf->ops->kunmap(dmabuf, page_num, vaddr); +} +EXPORT_SYMBOL_GPL(dma_buf_kunmap); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 24e0f4828711..ee7ef9990d9a 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -50,6 +50,17 @@ struct dma_buf_attachment; * @unmap_dma_buf: decreases usecount of buffer, might deallocate scatter * pages. * @release: release this buffer; to be called after the last dma_buf_put. + * @begin_cpu_access: [optional] called before cpu access to invalidate cpu + * caches and allocate backing storage (if not yet done) + * respectively pin the objet into memory. + * @end_cpu_access: [optional] called after cpu access to flush cashes. + * @kmap_atomic: maps a page from the buffer into kernel address + * space, users may not block until the subsequent unmap call. + * This callback must not sleep. + * @kunmap_atomic: [optional] unmaps a atomically mapped page from the buffer. + * This Callback must not sleep. + * @kmap: maps a page from the buffer into kernel address space. + * @kunmap: [optional] unmaps a page from the buffer. */ struct dma_buf_ops { int (*attach)(struct dma_buf *, struct device *, @@ -73,6 +84,14 @@ struct dma_buf_ops { /* after final dma_buf_put() */ void (*release)(struct dma_buf *); + int (*begin_cpu_access)(struct dma_buf *, size_t, size_t, + enum dma_data_direction); + void (*end_cpu_access)(struct dma_buf *, size_t, size_t, + enum dma_data_direction); + void *(*kmap_atomic)(struct dma_buf *, unsigned long); + void (*kunmap_atomic)(struct dma_buf *, unsigned long, void *); + void *(*kmap)(struct dma_buf *, unsigned long); + void (*kunmap)(struct dma_buf *, unsigned long, void *); }; /** @@ -140,6 +159,14 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *, enum dma_data_direction); void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *, enum dma_data_direction); +int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len, + enum dma_data_direction dir); +void dma_buf_end_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len, + enum dma_data_direction dir); +void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long); +void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *); +void *dma_buf_kmap(struct dma_buf *, unsigned long); +void dma_buf_kunmap(struct dma_buf *, unsigned long, void *); #else static inline struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, @@ -188,6 +215,38 @@ static inline void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, return; } +static inline int dma_buf_begin_cpu_access(struct dma_buf *, + size_t, size_t, + enum dma_data_direction) +{ + return -ENODEV; +} + +static inline void dma_buf_end_cpu_access(struct dma_buf *, + size_t, size_t, + enum dma_data_direction) +{ +} + +static inline void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long) +{ + return NULL; +} + +static inline void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, + void *) +{ +} + +static inline void *dma_buf_kmap(struct dma_buf *, unsigned long) +{ + return NULL; +} + +static inline void dma_buf_kunmap(struct dma_buf *, unsigned long, + void *) +{ +} #endif /* CONFIG_DMA_SHARED_BUFFER */ #endif /* __DMA_BUF_H__ */ |