133 lines
2.9 KiB
C
133 lines
2.9 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/module.h>
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#include <linux/mm.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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unsigned long size;
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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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printk(KERN_ERR "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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printk(KERN_DEBUG "Allocated vmalloc buffer of size %ld at vaddr=%p\n",
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buf->size, buf->vaddr);
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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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printk(KERN_DEBUG "%s: Freeing vmalloc mem at vaddr=%p\n",
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__func__, buf->vaddr);
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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_vaddr(void *buf_priv)
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{
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struct vb2_vmalloc_buf *buf = buf_priv;
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BUG_ON(!buf);
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if (!buf->vaddr) {
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printk(KERN_ERR "Address of an unallocated plane requested\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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printk(KERN_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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printk(KERN_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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.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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