diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/media/video/Kconfig | 3 | ||||
| -rw-r--r-- | drivers/media/video/Makefile | 1 | ||||
| -rw-r--r-- | drivers/media/video/videobuf2-memops.c | 232 |
3 files changed, 236 insertions, 0 deletions
diff --git a/drivers/media/video/Kconfig b/drivers/media/video/Kconfig index a4a6aa703c26..aae5005cf86d 100644 --- a/drivers/media/video/Kconfig +++ b/drivers/media/video/Kconfig @@ -47,6 +47,9 @@ config V4L2_MEM2MEM_DEV config VIDEOBUF2_CORE tristate +config VIDEOBUF2_MEMOPS + tristate + # # Multimedia Video device configuration # diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile index 6a1feba87869..fca0444b66b1 100644 --- a/drivers/media/video/Makefile +++ b/drivers/media/video/Makefile @@ -112,6 +112,7 @@ obj-$(CONFIG_VIDEOBUF_DVB) += videobuf-dvb.o obj-$(CONFIG_VIDEO_BTCX) += btcx-risc.o obj-$(CONFIG_VIDEOBUF2_CORE) += videobuf2-core.o +obj-$(CONFIG_VIDEOBUF2_MEMOPS) += videobuf2-memops.o obj-$(CONFIG_V4L2_MEM2MEM_DEV) += v4l2-mem2mem.o diff --git a/drivers/media/video/videobuf2-memops.c b/drivers/media/video/videobuf2-memops.c new file mode 100644 index 000000000000..053c15794b8d --- /dev/null +++ b/drivers/media/video/videobuf2-memops.c @@ -0,0 +1,232 @@ +/* + * videobuf2-memops.c - generic memory handling routines for videobuf2 + * + * Copyright (C) 2010 Samsung Electronics + * + * Author: Pawel Osciak <p.osciak@samsung.com> + * Marek Szyprowski <m.szyprowski@samsung.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation. + */ + +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/dma-mapping.h> +#include <linux/vmalloc.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/file.h> +#include <linux/slab.h> + +#include <media/videobuf2-core.h> +#include <media/videobuf2-memops.h> + +/** + * vb2_get_vma() - acquire and lock the virtual memory area + * @vma: given virtual memory area + * + * This function attempts to acquire an area mapped in the userspace for + * the duration of a hardware operation. The area is "locked" by performing + * the same set of operation that are done when process calls fork() and + * memory areas are duplicated. + * + * Returns a copy of a virtual memory region on success or NULL. + */ +struct vm_area_struct *vb2_get_vma(struct vm_area_struct *vma) +{ + struct vm_area_struct *vma_copy; + + vma_copy = kmalloc(sizeof(*vma_copy), GFP_KERNEL); + if (vma_copy == NULL) + return NULL; + + if (vma->vm_ops && vma->vm_ops->open) + vma->vm_ops->open(vma); + + if (vma->vm_file) + get_file(vma->vm_file); + + memcpy(vma_copy, vma, sizeof(*vma)); + + vma_copy->vm_mm = NULL; + vma_copy->vm_next = NULL; + vma_copy->vm_prev = NULL; + + return vma_copy; +} + +/** + * vb2_put_userptr() - release a userspace virtual memory area + * @vma: virtual memory region associated with the area to be released + * + * This function releases the previously acquired memory area after a hardware + * operation. + */ +void vb2_put_vma(struct vm_area_struct *vma) +{ + if (!vma) + return; + + if (vma->vm_file) + fput(vma->vm_file); + + if (vma->vm_ops && vma->vm_ops->close) + vma->vm_ops->close(vma); + + kfree(vma); +} + +/** + * vb2_get_contig_userptr() - lock physically contiguous userspace mapped memory + * @vaddr: starting virtual address of the area to be verified + * @size: size of the area + * @res_paddr: will return physical address for the given vaddr + * @res_vma: will return locked copy of struct vm_area for the given area + * + * This function will go through memory area of size @size mapped at @vaddr and + * verify that the underlying physical pages are contiguous. If they are + * contiguous the virtual memory area is locked and a @res_vma is filled with + * the copy and @res_pa set to the physical address of the buffer. + * + * Returns 0 on success. + */ +int vb2_get_contig_userptr(unsigned long vaddr, unsigned long size, + struct vm_area_struct **res_vma, dma_addr_t *res_pa) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long offset, start, end; + unsigned long this_pfn, prev_pfn; + dma_addr_t pa = 0; + int ret = -EFAULT; + + start = vaddr; + offset = start & ~PAGE_MASK; + end = start + size; + + down_read(&mm->mmap_sem); + vma = find_vma(mm, start); + + if (vma == NULL || vma->vm_end < end) + goto done; + + for (prev_pfn = 0; start < end; start += PAGE_SIZE) { + ret = follow_pfn(vma, start, &this_pfn); + if (ret) + goto done; + + if (prev_pfn == 0) + pa = this_pfn << PAGE_SHIFT; + else if (this_pfn != prev_pfn + 1) { + ret = -EFAULT; + goto done; + } + prev_pfn = this_pfn; + } + + /* + * Memory is contigous, lock vma and return to the caller + */ + *res_vma = vb2_get_vma(vma); + if (*res_vma == NULL) { + ret = -ENOMEM; + goto done; + } + *res_pa = pa + offset; + ret = 0; + +done: + up_read(&mm->mmap_sem); + return ret; +} + +/** + * vb2_mmap_pfn_range() - map physical pages to userspace + * @vma: virtual memory region for the mapping + * @paddr: starting physical address of the memory to be mapped + * @size: size of the memory to be mapped + * @vm_ops: vm operations to be assigned to the created area + * @priv: private data to be associated with the area + * + * Returns 0 on success. + */ +int vb2_mmap_pfn_range(struct vm_area_struct *vma, unsigned long paddr, + unsigned long size, + const struct vm_operations_struct *vm_ops, + void *priv) +{ + int ret; + + size = min_t(unsigned long, vma->vm_end - vma->vm_start, size); + + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + ret = remap_pfn_range(vma, vma->vm_start, paddr >> PAGE_SHIFT, + size, vma->vm_page_prot); + if (ret) { + printk(KERN_ERR "Remapping memory failed, error: %d\n", ret); + return ret; + } + + vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED; + vma->vm_private_data = priv; + vma->vm_ops = vm_ops; + + vma->vm_ops->open(vma); + + printk(KERN_DEBUG "%s: mapped paddr 0x%08lx at 0x%08lx, size %ld\n", + __func__, paddr, vma->vm_start, size); + + return 0; +} + +/** + * vb2_common_vm_open() - increase refcount of the vma + * @vma: virtual memory region for the mapping + * + * This function adds another user to the provided vma. It expects + * struct vb2_vmarea_handler pointer in vma->vm_private_data. + */ +static void vb2_common_vm_open(struct vm_area_struct *vma) +{ + struct vb2_vmarea_handler *h = vma->vm_private_data; + + printk(KERN_DEBUG "%s: %p, refcount: %d, vma: %08lx-%08lx\n", + __func__, h, atomic_read(h->refcount), vma->vm_start, + vma->vm_end); + + atomic_inc(h->refcount); +} + +/** + * vb2_common_vm_close() - decrease refcount of the vma + * @vma: virtual memory region for the mapping + * + * This function releases the user from the provided vma. It expects + * struct vb2_vmarea_handler pointer in vma->vm_private_data. + */ +static void vb2_common_vm_close(struct vm_area_struct *vma) +{ + struct vb2_vmarea_handler *h = vma->vm_private_data; + + printk(KERN_DEBUG "%s: %p, refcount: %d, vma: %08lx-%08lx\n", + __func__, h, atomic_read(h->refcount), vma->vm_start, + vma->vm_end); + + h->put(h->arg); +} + +/** + * vb2_common_vm_ops - common vm_ops used for tracking refcount of mmaped + * video buffers + */ +const struct vm_operations_struct vb2_common_vm_ops = { + .open = vb2_common_vm_open, + .close = vb2_common_vm_close, +}; +EXPORT_SYMBOL_GPL(vb2_common_vm_ops); + +MODULE_DESCRIPTION("common memory handling routines for videobuf2"); +MODULE_AUTHOR("Pawel Osciak"); +MODULE_LICENSE("GPL"); |
