![Javier Martin](/assets/img/avatar_default.png)
Some video devices need to use contiguous memory which is not backed by pages as it happens with vmalloc. This patch provides USERPTR handling for those devices. Signed-off-by: Javier Martin <javier.martin@vista-silicon.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
223 lines
4.9 KiB
C
223 lines
4.9 KiB
C
/*
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* videobuf2-vmalloc.c - vmalloc memory allocator for videobuf2
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*
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* Copyright (C) 2010 Samsung Electronics
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*
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* Author: Pawel Osciak <pawel@osciak.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation.
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*/
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <media/videobuf2-core.h>
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#include <media/videobuf2-memops.h>
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struct vb2_vmalloc_buf {
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void *vaddr;
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struct page **pages;
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struct vm_area_struct *vma;
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int write;
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unsigned long size;
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unsigned int n_pages;
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atomic_t refcount;
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struct vb2_vmarea_handler handler;
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};
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static void vb2_vmalloc_put(void *buf_priv);
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static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size)
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{
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struct vb2_vmalloc_buf *buf;
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buf = kzalloc(sizeof(*buf), GFP_KERNEL);
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if (!buf)
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return NULL;
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buf->size = size;
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buf->vaddr = vmalloc_user(buf->size);
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buf->handler.refcount = &buf->refcount;
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buf->handler.put = vb2_vmalloc_put;
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buf->handler.arg = buf;
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if (!buf->vaddr) {
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pr_debug("vmalloc of size %ld failed\n", buf->size);
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kfree(buf);
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return NULL;
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}
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atomic_inc(&buf->refcount);
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return buf;
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}
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static void vb2_vmalloc_put(void *buf_priv)
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{
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struct vb2_vmalloc_buf *buf = buf_priv;
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if (atomic_dec_and_test(&buf->refcount)) {
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vfree(buf->vaddr);
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kfree(buf);
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}
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}
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static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
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unsigned long size, int write)
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{
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struct vb2_vmalloc_buf *buf;
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unsigned long first, last;
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int n_pages, offset;
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struct vm_area_struct *vma;
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dma_addr_t physp;
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buf = kzalloc(sizeof(*buf), GFP_KERNEL);
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if (!buf)
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return NULL;
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buf->write = write;
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offset = vaddr & ~PAGE_MASK;
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buf->size = size;
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vma = find_vma(current->mm, vaddr);
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if (vma && (vma->vm_flags & VM_PFNMAP) && (vma->vm_pgoff)) {
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if (vb2_get_contig_userptr(vaddr, size, &vma, &physp))
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goto fail_pages_array_alloc;
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buf->vma = vma;
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buf->vaddr = ioremap_nocache(physp, size);
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if (!buf->vaddr)
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goto fail_pages_array_alloc;
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} else {
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first = vaddr >> PAGE_SHIFT;
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last = (vaddr + size - 1) >> PAGE_SHIFT;
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buf->n_pages = last - first + 1;
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buf->pages = kzalloc(buf->n_pages * sizeof(struct page *),
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GFP_KERNEL);
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if (!buf->pages)
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goto fail_pages_array_alloc;
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/* current->mm->mmap_sem is taken by videobuf2 core */
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n_pages = get_user_pages(current, current->mm,
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vaddr & PAGE_MASK, buf->n_pages,
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write, 1, /* force */
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buf->pages, NULL);
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if (n_pages != buf->n_pages)
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goto fail_get_user_pages;
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buf->vaddr = vm_map_ram(buf->pages, buf->n_pages, -1,
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PAGE_KERNEL);
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if (!buf->vaddr)
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goto fail_get_user_pages;
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}
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buf->vaddr += offset;
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return buf;
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fail_get_user_pages:
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pr_debug("get_user_pages requested/got: %d/%d]\n", n_pages,
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buf->n_pages);
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while (--n_pages >= 0)
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put_page(buf->pages[n_pages]);
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kfree(buf->pages);
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fail_pages_array_alloc:
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kfree(buf);
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return NULL;
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}
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static void vb2_vmalloc_put_userptr(void *buf_priv)
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{
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struct vb2_vmalloc_buf *buf = buf_priv;
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unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
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unsigned int i;
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if (buf->pages) {
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if (vaddr)
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vm_unmap_ram((void *)vaddr, buf->n_pages);
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for (i = 0; i < buf->n_pages; ++i) {
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if (buf->write)
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set_page_dirty_lock(buf->pages[i]);
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put_page(buf->pages[i]);
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}
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kfree(buf->pages);
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} else {
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if (buf->vma)
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vb2_put_vma(buf->vma);
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iounmap(buf->vaddr);
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}
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kfree(buf);
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}
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static void *vb2_vmalloc_vaddr(void *buf_priv)
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{
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struct vb2_vmalloc_buf *buf = buf_priv;
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if (!buf->vaddr) {
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pr_err("Address of an unallocated plane requested "
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"or cannot map user pointer\n");
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return NULL;
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}
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return buf->vaddr;
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}
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static unsigned int vb2_vmalloc_num_users(void *buf_priv)
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{
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struct vb2_vmalloc_buf *buf = buf_priv;
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return atomic_read(&buf->refcount);
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}
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static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
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{
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struct vb2_vmalloc_buf *buf = buf_priv;
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int ret;
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if (!buf) {
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pr_err("No memory to map\n");
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return -EINVAL;
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}
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ret = remap_vmalloc_range(vma, buf->vaddr, 0);
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if (ret) {
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pr_err("Remapping vmalloc memory, error: %d\n", ret);
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return ret;
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}
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/*
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* Make sure that vm_areas for 2 buffers won't be merged together
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*/
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vma->vm_flags |= VM_DONTEXPAND;
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/*
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* Use common vm_area operations to track buffer refcount.
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*/
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vma->vm_private_data = &buf->handler;
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vma->vm_ops = &vb2_common_vm_ops;
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vma->vm_ops->open(vma);
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return 0;
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}
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const struct vb2_mem_ops vb2_vmalloc_memops = {
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.alloc = vb2_vmalloc_alloc,
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.put = vb2_vmalloc_put,
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.get_userptr = vb2_vmalloc_get_userptr,
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.put_userptr = vb2_vmalloc_put_userptr,
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.vaddr = vb2_vmalloc_vaddr,
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.mmap = vb2_vmalloc_mmap,
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.num_users = vb2_vmalloc_num_users,
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};
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EXPORT_SYMBOL_GPL(vb2_vmalloc_memops);
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MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
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MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
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MODULE_LICENSE("GPL");
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