diff options
Diffstat (limited to 'kernel/include/linux/dma-buf.h')
| -rw-r--r-- | kernel/include/linux/dma-buf.h | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/kernel/include/linux/dma-buf.h b/kernel/include/linux/dma-buf.h new file mode 100644 index 000000000..2f0b431b7 --- /dev/null +++ b/kernel/include/linux/dma-buf.h @@ -0,0 +1,236 @@ +/* + * Header file for dma buffer sharing framework. + * + * Copyright(C) 2011 Linaro Limited. All rights reserved. + * Author: Sumit Semwal <sumit.semwal@ti.com> + * + * Many thanks to linaro-mm-sig list, and specially + * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and + * Daniel Vetter <daniel@ffwll.ch> for their support in creation and + * refining of this idea. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ +#ifndef __DMA_BUF_H__ +#define __DMA_BUF_H__ + +#include <linux/file.h> +#include <linux/err.h> +#include <linux/scatterlist.h> +#include <linux/list.h> +#include <linux/dma-mapping.h> +#include <linux/fs.h> +#include <linux/fence.h> +#include <linux/wait.h> + +struct device; +struct dma_buf; +struct dma_buf_attachment; + +/** + * struct dma_buf_ops - operations possible on struct dma_buf + * @attach: [optional] allows different devices to 'attach' themselves to the + * given buffer. It might return -EBUSY to signal that backing storage + * is already allocated and incompatible with the requirements + * of requesting device. + * @detach: [optional] detach a given device from this buffer. + * @map_dma_buf: returns list of scatter pages allocated, increases usecount + * of the buffer. Requires atleast one attach to be called + * before. Returned sg list should already be mapped into + * _device_ address space. This call may sleep. May also return + * -EINTR. Should return -EINVAL if attach hasn't been called yet. + * @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 caches. + * @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. + * @mmap: used to expose the backing storage to userspace. Note that the + * mapping needs to be coherent - if the exporter doesn't directly + * support this, it needs to fake coherency by shooting down any ptes + * when transitioning away from the cpu domain. + * @vmap: [optional] creates a virtual mapping for the buffer into kernel + * address space. Same restrictions as for vmap and friends apply. + * @vunmap: [optional] unmaps a vmap from the buffer + */ +struct dma_buf_ops { + int (*attach)(struct dma_buf *, struct device *, + struct dma_buf_attachment *); + + void (*detach)(struct dma_buf *, struct dma_buf_attachment *); + + /* For {map,unmap}_dma_buf below, any specific buffer attributes + * required should get added to device_dma_parameters accessible + * via dev->dma_params. + */ + struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *, + enum dma_data_direction); + void (*unmap_dma_buf)(struct dma_buf_attachment *, + struct sg_table *, + enum dma_data_direction); + /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY + * if the call would block. + */ + + /* 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 *); + + int (*mmap)(struct dma_buf *, struct vm_area_struct *vma); + + void *(*vmap)(struct dma_buf *); + void (*vunmap)(struct dma_buf *, void *vaddr); +}; + +/** + * struct dma_buf - shared buffer object + * @size: size of the buffer + * @file: file pointer used for sharing buffers across, and for refcounting. + * @attachments: list of dma_buf_attachment that denotes all devices attached. + * @ops: dma_buf_ops associated with this buffer object. + * @exp_name: name of the exporter; useful for debugging. + * @list_node: node for dma_buf accounting and debugging. + * @priv: exporter specific private data for this buffer object. + * @resv: reservation object linked to this dma-buf + */ +struct dma_buf { + size_t size; + struct file *file; + struct list_head attachments; + const struct dma_buf_ops *ops; + /* mutex to serialize list manipulation, attach/detach and vmap/unmap */ + struct mutex lock; + unsigned vmapping_counter; + void *vmap_ptr; + const char *exp_name; + struct list_head list_node; + void *priv; + struct reservation_object *resv; + + /* poll support */ + wait_queue_head_t poll; + + struct dma_buf_poll_cb_t { + struct fence_cb cb; + wait_queue_head_t *poll; + + unsigned long active; + } cb_excl, cb_shared; +}; + +/** + * struct dma_buf_attachment - holds device-buffer attachment data + * @dmabuf: buffer for this attachment. + * @dev: device attached to the buffer. + * @node: list of dma_buf_attachment. + * @priv: exporter specific attachment data. + * + * This structure holds the attachment information between the dma_buf buffer + * and its user device(s). The list contains one attachment struct per device + * attached to the buffer. + */ +struct dma_buf_attachment { + struct dma_buf *dmabuf; + struct device *dev; + struct list_head node; + void *priv; +}; + +/** + * struct dma_buf_export_info - holds information needed to export a dma_buf + * @exp_name: name of the exporting module - useful for debugging. + * @ops: Attach allocator-defined dma buf ops to the new buffer + * @size: Size of the buffer + * @flags: mode flags for the file + * @resv: reservation-object, NULL to allocate default one + * @priv: Attach private data of allocator to this buffer + * + * This structure holds the information required to export the buffer. Used + * with dma_buf_export() only. + */ +struct dma_buf_export_info { + const char *exp_name; + const struct dma_buf_ops *ops; + size_t size; + int flags; + struct reservation_object *resv; + void *priv; +}; + +/** + * helper macro for exporters; zeros and fills in most common values + */ +#define DEFINE_DMA_BUF_EXPORT_INFO(a) \ + struct dma_buf_export_info a = { .exp_name = KBUILD_MODNAME } + +/** + * get_dma_buf - convenience wrapper for get_file. + * @dmabuf: [in] pointer to dma_buf + * + * Increments the reference count on the dma-buf, needed in case of drivers + * that either need to create additional references to the dmabuf on the + * kernel side. For example, an exporter that needs to keep a dmabuf ptr + * so that subsequent exports don't create a new dmabuf. + */ +static inline void get_dma_buf(struct dma_buf *dmabuf) +{ + get_file(dmabuf->file); +} + +struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, + struct device *dev); +void dma_buf_detach(struct dma_buf *dmabuf, + struct dma_buf_attachment *dmabuf_attach); + +struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info); + +int dma_buf_fd(struct dma_buf *dmabuf, int flags); +struct dma_buf *dma_buf_get(int fd); +void dma_buf_put(struct dma_buf *dmabuf); + +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 *); + +int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *, + unsigned long); +void *dma_buf_vmap(struct dma_buf *); +void dma_buf_vunmap(struct dma_buf *, void *vaddr); +int dma_buf_debugfs_create_file(const char *name, + int (*write)(struct seq_file *)); +#endif /* __DMA_BUF_H__ */ |