diff options
| author | Jan Kara <jack@suse.cz> | 2015-07-13 11:55:46 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@osg.samsung.com> | 2015-08-16 13:10:42 -0300 |
| commit | 21fb0cb7ec65a40b9f5f7cda59eba0eb2ae76473 (patch) | |
| tree | e0cccb86717f351e3bc6c38811cb093c65837f07 /drivers/media/v4l2-core | |
| parent | 8a677b6eddfc3127ea36a710838ecd20502b1cb9 (diff) | |
| download | linux-21fb0cb7ec65a40b9f5f7cda59eba0eb2ae76473.tar.bz2 | |
[media] vb2: Provide helpers for mapping virtual addresses
Provide simple helper functions to map virtual address range into an
array of pfns / pages.
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Diffstat (limited to 'drivers/media/v4l2-core')
| -rw-r--r-- | drivers/media/v4l2-core/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/media/v4l2-core/videobuf2-memops.c | 58 |
2 files changed, 59 insertions, 0 deletions
diff --git a/drivers/media/v4l2-core/Kconfig b/drivers/media/v4l2-core/Kconfig index b4b022933e29..82876a67f144 100644 --- a/drivers/media/v4l2-core/Kconfig +++ b/drivers/media/v4l2-core/Kconfig @@ -84,6 +84,7 @@ config VIDEOBUF2_CORE config VIDEOBUF2_MEMOPS tristate + select FRAME_VECTOR config VIDEOBUF2_DMA_CONTIG tristate diff --git a/drivers/media/v4l2-core/videobuf2-memops.c b/drivers/media/v4l2-core/videobuf2-memops.c index 81c1ad8b2cf1..0ec186d41b9b 100644 --- a/drivers/media/v4l2-core/videobuf2-memops.c +++ b/drivers/media/v4l2-core/videobuf2-memops.c @@ -137,6 +137,64 @@ int vb2_get_contig_userptr(unsigned long vaddr, unsigned long size, EXPORT_SYMBOL_GPL(vb2_get_contig_userptr); /** + * vb2_create_framevec() - map virtual addresses to pfns + * @start: Virtual user address where we start mapping + * @length: Length of a range to map + * @write: Should we map for writing into the area + * + * This function allocates and fills in a vector with pfns corresponding to + * virtual address range passed in arguments. If pfns have corresponding pages, + * page references are also grabbed to pin pages in memory. The function + * returns pointer to the vector on success and error pointer in case of + * failure. Returned vector needs to be freed via vb2_destroy_pfnvec(). + */ +struct frame_vector *vb2_create_framevec(unsigned long start, + unsigned long length, + bool write) +{ + int ret; + unsigned long first, last; + unsigned long nr; + struct frame_vector *vec; + + first = start >> PAGE_SHIFT; + last = (start + length - 1) >> PAGE_SHIFT; + nr = last - first + 1; + vec = frame_vector_create(nr); + if (!vec) + return ERR_PTR(-ENOMEM); + ret = get_vaddr_frames(start, nr, write, 1, vec); + if (ret < 0) + goto out_destroy; + /* We accept only complete set of PFNs */ + if (ret != nr) { + ret = -EFAULT; + goto out_release; + } + return vec; +out_release: + put_vaddr_frames(vec); +out_destroy: + frame_vector_destroy(vec); + return ERR_PTR(ret); +} +EXPORT_SYMBOL(vb2_create_framevec); + +/** + * vb2_destroy_framevec() - release vector of mapped pfns + * @vec: vector of pfns / pages to release + * + * This releases references to all pages in the vector @vec (if corresponding + * pfns are backed by pages) and frees the passed vector. + */ +void vb2_destroy_framevec(struct frame_vector *vec) +{ + put_vaddr_frames(vec); + frame_vector_destroy(vec); +} +EXPORT_SYMBOL(vb2_destroy_framevec); + +/** * vb2_common_vm_open() - increase refcount of the vma * @vma: virtual memory region for the mapping * |