| /* |
| * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2 |
| * |
| * Copyright (C) 2010 Samsung Electronics |
| * |
| * Author: Andrzej Pietrasiewicz <andrzej.p@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/module.h> |
| #include <linux/mm.h> |
| #include <linux/scatterlist.h> |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/vmalloc.h> |
| |
| #include <media/videobuf2-core.h> |
| #include <media/videobuf2-memops.h> |
| #include <media/videobuf2-dma-sg.h> |
| |
| struct vb2_dma_sg_buf { |
| void *vaddr; |
| struct page **pages; |
| int write; |
| int offset; |
| struct vb2_dma_sg_desc sg_desc; |
| atomic_t refcount; |
| struct vb2_vmarea_handler handler; |
| }; |
| |
| static void vb2_dma_sg_put(void *buf_priv); |
| |
| static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size) |
| { |
| struct vb2_dma_sg_buf *buf; |
| int i; |
| |
| buf = kzalloc(sizeof *buf, GFP_KERNEL); |
| if (!buf) |
| return NULL; |
| |
| buf->vaddr = NULL; |
| buf->write = 0; |
| buf->offset = 0; |
| buf->sg_desc.size = size; |
| buf->sg_desc.num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| |
| buf->sg_desc.sglist = vzalloc(buf->sg_desc.num_pages * |
| sizeof(*buf->sg_desc.sglist)); |
| if (!buf->sg_desc.sglist) |
| goto fail_sglist_alloc; |
| sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages); |
| |
| buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *), |
| GFP_KERNEL); |
| if (!buf->pages) |
| goto fail_pages_array_alloc; |
| |
| for (i = 0; i < buf->sg_desc.num_pages; ++i) { |
| buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN); |
| if (NULL == buf->pages[i]) |
| goto fail_pages_alloc; |
| sg_set_page(&buf->sg_desc.sglist[i], |
| buf->pages[i], PAGE_SIZE, 0); |
| } |
| |
| buf->handler.refcount = &buf->refcount; |
| buf->handler.put = vb2_dma_sg_put; |
| buf->handler.arg = buf; |
| |
| atomic_inc(&buf->refcount); |
| |
| printk(KERN_DEBUG "%s: Allocated buffer of %d pages\n", |
| __func__, buf->sg_desc.num_pages); |
| |
| if (!buf->vaddr) |
| buf->vaddr = vm_map_ram(buf->pages, |
| buf->sg_desc.num_pages, |
| -1, |
| PAGE_KERNEL); |
| return buf; |
| |
| fail_pages_alloc: |
| while (--i >= 0) |
| __free_page(buf->pages[i]); |
| kfree(buf->pages); |
| |
| fail_pages_array_alloc: |
| vfree(buf->sg_desc.sglist); |
| |
| fail_sglist_alloc: |
| kfree(buf); |
| return NULL; |
| } |
| |
| static void vb2_dma_sg_put(void *buf_priv) |
| { |
| struct vb2_dma_sg_buf *buf = buf_priv; |
| int i = buf->sg_desc.num_pages; |
| |
| if (atomic_dec_and_test(&buf->refcount)) { |
| printk(KERN_DEBUG "%s: Freeing buffer of %d pages\n", __func__, |
| buf->sg_desc.num_pages); |
| if (buf->vaddr) |
| vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages); |
| vfree(buf->sg_desc.sglist); |
| while (--i >= 0) |
| __free_page(buf->pages[i]); |
| kfree(buf->pages); |
| kfree(buf); |
| } |
| } |
| |
| static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, |
| unsigned long size, int write) |
| { |
| struct vb2_dma_sg_buf *buf; |
| unsigned long first, last; |
| int num_pages_from_user, i; |
| |
| buf = kzalloc(sizeof *buf, GFP_KERNEL); |
| if (!buf) |
| return NULL; |
| |
| buf->vaddr = NULL; |
| buf->write = write; |
| buf->offset = vaddr & ~PAGE_MASK; |
| buf->sg_desc.size = size; |
| |
| first = (vaddr & PAGE_MASK) >> PAGE_SHIFT; |
| last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT; |
| buf->sg_desc.num_pages = last - first + 1; |
| |
| buf->sg_desc.sglist = vzalloc( |
| buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist)); |
| if (!buf->sg_desc.sglist) |
| goto userptr_fail_sglist_alloc; |
| |
| sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages); |
| |
| buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *), |
| GFP_KERNEL); |
| if (!buf->pages) |
| goto userptr_fail_pages_array_alloc; |
| |
| down_read(¤t->mm->mmap_sem); |
| num_pages_from_user = get_user_pages(current, current->mm, |
| vaddr & PAGE_MASK, |
| buf->sg_desc.num_pages, |
| write, |
| 1, /* force */ |
| buf->pages, |
| NULL); |
| up_read(¤t->mm->mmap_sem); |
| if (num_pages_from_user != buf->sg_desc.num_pages) |
| goto userptr_fail_get_user_pages; |
| |
| sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0], |
| PAGE_SIZE - buf->offset, buf->offset); |
| size -= PAGE_SIZE - buf->offset; |
| for (i = 1; i < buf->sg_desc.num_pages; ++i) { |
| sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i], |
| min_t(size_t, PAGE_SIZE, size), 0); |
| size -= min_t(size_t, PAGE_SIZE, size); |
| } |
| return buf; |
| |
| userptr_fail_get_user_pages: |
| printk(KERN_DEBUG "get_user_pages requested/got: %d/%d]\n", |
| num_pages_from_user, buf->sg_desc.num_pages); |
| while (--num_pages_from_user >= 0) |
| put_page(buf->pages[num_pages_from_user]); |
| kfree(buf->pages); |
| |
| userptr_fail_pages_array_alloc: |
| vfree(buf->sg_desc.sglist); |
| |
| userptr_fail_sglist_alloc: |
| kfree(buf); |
| return NULL; |
| } |
| |
| /* |
| * @put_userptr: inform the allocator that a USERPTR buffer will no longer |
| * be used |
| */ |
| static void vb2_dma_sg_put_userptr(void *buf_priv) |
| { |
| struct vb2_dma_sg_buf *buf = buf_priv; |
| int i = buf->sg_desc.num_pages; |
| |
| printk(KERN_DEBUG "%s: Releasing userspace buffer of %d pages\n", |
| __func__, buf->sg_desc.num_pages); |
| if (buf->vaddr) |
| vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages); |
| while (--i >= 0) { |
| if (buf->write) |
| set_page_dirty_lock(buf->pages[i]); |
| put_page(buf->pages[i]); |
| } |
| vfree(buf->sg_desc.sglist); |
| kfree(buf->pages); |
| kfree(buf); |
| } |
| |
| static void *vb2_dma_sg_vaddr(void *buf_priv) |
| { |
| struct vb2_dma_sg_buf *buf = buf_priv; |
| |
| BUG_ON(!buf); |
| |
| if (!buf->vaddr) |
| buf->vaddr = vm_map_ram(buf->pages, |
| buf->sg_desc.num_pages, |
| -1, |
| PAGE_KERNEL); |
| |
| /* add offset in case userptr is not page-aligned */ |
| return buf->vaddr + buf->offset; |
| } |
| |
| static unsigned int vb2_dma_sg_num_users(void *buf_priv) |
| { |
| struct vb2_dma_sg_buf *buf = buf_priv; |
| |
| return atomic_read(&buf->refcount); |
| } |
| |
| static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) |
| { |
| struct vb2_dma_sg_buf *buf = buf_priv; |
| unsigned long uaddr = vma->vm_start; |
| unsigned long usize = vma->vm_end - vma->vm_start; |
| int i = 0; |
| |
| if (!buf) { |
| printk(KERN_ERR "No memory to map\n"); |
| return -EINVAL; |
| } |
| |
| do { |
| int ret; |
| |
| ret = vm_insert_page(vma, uaddr, buf->pages[i++]); |
| if (ret) { |
| printk(KERN_ERR "Remapping memory, error: %d\n", ret); |
| return ret; |
| } |
| |
| uaddr += PAGE_SIZE; |
| usize -= PAGE_SIZE; |
| } while (usize > 0); |
| |
| |
| /* |
| * Use common vm_area operations to track buffer refcount. |
| */ |
| vma->vm_private_data = &buf->handler; |
| vma->vm_ops = &vb2_common_vm_ops; |
| |
| vma->vm_ops->open(vma); |
| |
| return 0; |
| } |
| |
| static void *vb2_dma_sg_cookie(void *buf_priv) |
| { |
| struct vb2_dma_sg_buf *buf = buf_priv; |
| |
| return &buf->sg_desc; |
| } |
| |
| const struct vb2_mem_ops vb2_dma_sg_memops = { |
| .alloc = vb2_dma_sg_alloc, |
| .put = vb2_dma_sg_put, |
| .get_userptr = vb2_dma_sg_get_userptr, |
| .put_userptr = vb2_dma_sg_put_userptr, |
| .vaddr = vb2_dma_sg_vaddr, |
| .mmap = vb2_dma_sg_mmap, |
| .num_users = vb2_dma_sg_num_users, |
| .cookie = vb2_dma_sg_cookie, |
| }; |
| EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); |
| |
| MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); |
| MODULE_AUTHOR("Andrzej Pietrasiewicz"); |
| MODULE_LICENSE("GPL"); |