diff options
| -rw-r--r-- | drivers/media/video/videobuf-dma-contig.c | 94 |
1 files changed, 89 insertions, 5 deletions
diff --git a/drivers/media/video/videobuf-dma-contig.c b/drivers/media/video/videobuf-dma-contig.c index 6109fb5f34e2..0c29a019bc89 100644 --- a/drivers/media/video/videobuf-dma-contig.c +++ b/drivers/media/video/videobuf-dma-contig.c @@ -17,6 +17,7 @@ #include <linux/init.h> #include <linux/module.h> #include <linux/mm.h> +#include <linux/pagemap.h> #include <linux/dma-mapping.h> #include <media/videobuf-dma-contig.h> @@ -25,6 +26,7 @@ struct videobuf_dma_contig_memory { void *vaddr; dma_addr_t dma_handle; unsigned long size; + int is_userptr; }; #define MAGIC_DC_MEM 0x0733ac61 @@ -108,6 +110,82 @@ static struct vm_operations_struct videobuf_vm_ops = { .close = videobuf_vm_close, }; +/** + * videobuf_dma_contig_user_put() - reset pointer to user space buffer + * @mem: per-buffer private videobuf-dma-contig data + * + * This function resets the user space pointer + */ +static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem) +{ + mem->is_userptr = 0; + mem->dma_handle = 0; + mem->size = 0; +} + +/** + * videobuf_dma_contig_user_get() - setup user space memory pointer + * @mem: per-buffer private videobuf-dma-contig data + * @vb: video buffer to map + * + * This function validates and sets up a pointer to user space memory. + * Only physically contiguous pfn-mapped memory is accepted. + * + * Returns 0 if successful. + */ +static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem, + struct videobuf_buffer *vb) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long prev_pfn, this_pfn; + unsigned long pages_done, user_address; + int ret; + + mem->size = PAGE_ALIGN(vb->size); + mem->is_userptr = 0; + ret = -EINVAL; + + down_read(&mm->mmap_sem); + + vma = find_vma(mm, vb->baddr); + if (!vma) + goto out_up; + + if ((vb->baddr + mem->size) > vma->vm_end) + goto out_up; + + pages_done = 0; + prev_pfn = 0; /* kill warning */ + user_address = vb->baddr; + + while (pages_done < (mem->size >> PAGE_SHIFT)) { + ret = follow_pfn(vma, user_address, &this_pfn); + if (ret) + break; + + if (pages_done == 0) + mem->dma_handle = this_pfn << PAGE_SHIFT; + else if (this_pfn != (prev_pfn + 1)) + ret = -EFAULT; + + if (ret) + break; + + prev_pfn = this_pfn; + user_address += PAGE_SIZE; + pages_done++; + } + + if (!ret) + mem->is_userptr = 1; + + out_up: + up_read(¤t->mm->mmap_sem); + + return ret; +} + static void *__videobuf_alloc(size_t size) { struct videobuf_dma_contig_memory *mem; @@ -154,12 +232,11 @@ static int __videobuf_iolock(struct videobuf_queue *q, case V4L2_MEMORY_USERPTR: dev_dbg(q->dev, "%s memory method USERPTR\n", __func__); - /* The only USERPTR currently supported is the one needed for - read() method. - */ + /* handle pointer from user space */ if (vb->baddr) - return -EINVAL; + return videobuf_dma_contig_user_get(mem, vb); + /* allocate memory for the read() method */ mem->size = PAGE_ALIGN(vb->size); mem->vaddr = dma_alloc_coherent(q->dev, mem->size, &mem->dma_handle, GFP_KERNEL); @@ -400,7 +477,7 @@ void videobuf_dma_contig_free(struct videobuf_queue *q, So, it should free memory only if the memory were allocated for read() operation. */ - if ((buf->memory != V4L2_MEMORY_USERPTR) || buf->baddr) + if (buf->memory != V4L2_MEMORY_USERPTR) return; if (!mem) @@ -408,6 +485,13 @@ void videobuf_dma_contig_free(struct videobuf_queue *q, MAGIC_CHECK(mem->magic, MAGIC_DC_MEM); + /* handle user space pointer case */ + if (buf->baddr) { + videobuf_dma_contig_user_put(mem); + return; + } + + /* read() method */ dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle); mem->vaddr = NULL; } |