mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 17:59:32 +00:00
418 lines
10 KiB
C
418 lines
10 KiB
C
![]() |
/*
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* helper functions for physically contiguous capture buffers
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*
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* The functions support hardware lacking scatter gather support
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* (i.e. the buffers must be linear in physical memory)
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*
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* Copyright (c) 2008 Magnus Damm
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*
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* Based on videobuf-vmalloc.c,
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* (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
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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; either version 2
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/dma-mapping.h>
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#include <media/videobuf-dma-contig.h>
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struct videobuf_dma_contig_memory {
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u32 magic;
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void *vaddr;
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dma_addr_t dma_handle;
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unsigned long size;
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};
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#define MAGIC_DC_MEM 0x0733ac61
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#define MAGIC_CHECK(is, should) \
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if (unlikely((is) != (should))) { \
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pr_err("magic mismatch: %x expected %x\n", is, should); \
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BUG(); \
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}
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static void
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videobuf_vm_open(struct vm_area_struct *vma)
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{
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struct videobuf_mapping *map = vma->vm_private_data;
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dev_dbg(map->q->dev, "vm_open %p [count=%u,vma=%08lx-%08lx]\n",
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map, map->count, vma->vm_start, vma->vm_end);
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map->count++;
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}
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static void videobuf_vm_close(struct vm_area_struct *vma)
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{
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struct videobuf_mapping *map = vma->vm_private_data;
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struct videobuf_queue *q = map->q;
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int i;
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dev_dbg(map->q->dev, "vm_close %p [count=%u,vma=%08lx-%08lx]\n",
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map, map->count, vma->vm_start, vma->vm_end);
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map->count--;
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if (0 == map->count) {
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struct videobuf_dma_contig_memory *mem;
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dev_dbg(map->q->dev, "munmap %p q=%p\n", map, q);
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mutex_lock(&q->vb_lock);
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/* We need first to cancel streams, before unmapping */
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if (q->streaming)
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videobuf_queue_cancel(q);
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for (i = 0; i < VIDEO_MAX_FRAME; i++) {
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if (NULL == q->bufs[i])
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continue;
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if (q->bufs[i]->map != map)
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continue;
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mem = q->bufs[i]->priv;
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if (mem) {
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/* This callback is called only if kernel has
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allocated memory and this memory is mmapped.
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In this case, memory should be freed,
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in order to do memory unmap.
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*/
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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/* vfree is not atomic - can't be
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called with IRQ's disabled
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*/
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dev_dbg(map->q->dev, "buf[%d] freeing %p\n",
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i, mem->vaddr);
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dma_free_coherent(q->dev, mem->size,
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mem->vaddr, mem->dma_handle);
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mem->vaddr = NULL;
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}
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q->bufs[i]->map = NULL;
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q->bufs[i]->baddr = 0;
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}
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kfree(map);
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mutex_unlock(&q->vb_lock);
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}
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}
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static struct vm_operations_struct videobuf_vm_ops = {
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.open = videobuf_vm_open,
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.close = videobuf_vm_close,
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};
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static void *__videobuf_alloc(size_t size)
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{
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struct videobuf_dma_contig_memory *mem;
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struct videobuf_buffer *vb;
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vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
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if (vb) {
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mem = vb->priv = ((char *)vb) + size;
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mem->magic = MAGIC_DC_MEM;
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}
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return vb;
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}
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static void *__videobuf_to_vmalloc(struct videobuf_buffer *buf)
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{
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struct videobuf_dma_contig_memory *mem = buf->priv;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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return mem->vaddr;
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}
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static int __videobuf_iolock(struct videobuf_queue *q,
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struct videobuf_buffer *vb,
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struct v4l2_framebuffer *fbuf)
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{
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struct videobuf_dma_contig_memory *mem = vb->priv;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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switch (vb->memory) {
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case V4L2_MEMORY_MMAP:
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dev_dbg(q->dev, "%s memory method MMAP\n", __func__);
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/* All handling should be done by __videobuf_mmap_mapper() */
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if (!mem->vaddr) {
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dev_err(q->dev, "memory is not alloced/mmapped.\n");
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return -EINVAL;
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}
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break;
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case V4L2_MEMORY_USERPTR:
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dev_dbg(q->dev, "%s memory method USERPTR\n", __func__);
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/* The only USERPTR currently supported is the one needed for
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read() method.
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*/
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if (vb->baddr)
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return -EINVAL;
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mem->size = PAGE_ALIGN(vb->size);
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mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
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&mem->dma_handle, GFP_KERNEL);
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if (!mem->vaddr) {
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dev_err(q->dev, "dma_alloc_coherent %ld failed\n",
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mem->size);
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return -ENOMEM;
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}
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dev_dbg(q->dev, "dma_alloc_coherent data is at %p (%ld)\n",
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mem->vaddr, mem->size);
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break;
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case V4L2_MEMORY_OVERLAY:
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default:
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dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n",
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__func__);
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return -EINVAL;
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}
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return 0;
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}
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static int __videobuf_sync(struct videobuf_queue *q,
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struct videobuf_buffer *buf)
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{
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struct videobuf_dma_contig_memory *mem = buf->priv;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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dma_sync_single_for_cpu(q->dev, mem->dma_handle, mem->size,
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DMA_FROM_DEVICE);
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return 0;
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}
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static int __videobuf_mmap_free(struct videobuf_queue *q)
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{
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unsigned int i;
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dev_dbg(q->dev, "%s\n", __func__);
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for (i = 0; i < VIDEO_MAX_FRAME; i++) {
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if (q->bufs[i] && q->bufs[i]->map)
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return -EBUSY;
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}
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return 0;
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}
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static int __videobuf_mmap_mapper(struct videobuf_queue *q,
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struct vm_area_struct *vma)
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{
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struct videobuf_dma_contig_memory *mem;
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struct videobuf_mapping *map;
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unsigned int first;
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int retval;
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unsigned long size, offset = vma->vm_pgoff << PAGE_SHIFT;
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dev_dbg(q->dev, "%s\n", __func__);
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if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED))
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return -EINVAL;
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/* look for first buffer to map */
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for (first = 0; first < VIDEO_MAX_FRAME; first++) {
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if (!q->bufs[first])
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continue;
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if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
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continue;
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if (q->bufs[first]->boff == offset)
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break;
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}
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if (VIDEO_MAX_FRAME == first) {
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dev_dbg(q->dev, "invalid user space offset [offset=0x%lx]\n",
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offset);
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return -EINVAL;
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}
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/* create mapping + update buffer list */
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map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
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if (!map)
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return -ENOMEM;
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q->bufs[first]->map = map;
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map->start = vma->vm_start;
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map->end = vma->vm_end;
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map->q = q;
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q->bufs[first]->baddr = vma->vm_start;
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mem = q->bufs[first]->priv;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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mem->size = PAGE_ALIGN(q->bufs[first]->bsize);
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mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
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&mem->dma_handle, GFP_KERNEL);
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if (!mem->vaddr) {
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dev_err(q->dev, "dma_alloc_coherent size %ld failed\n",
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mem->size);
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goto error;
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}
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dev_dbg(q->dev, "dma_alloc_coherent data is at addr %p (size %ld)\n",
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mem->vaddr, mem->size);
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/* Try to remap memory */
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size = vma->vm_end - vma->vm_start;
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size = (size < mem->size) ? size : mem->size;
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vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
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retval = remap_pfn_range(vma, vma->vm_start,
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mem->dma_handle >> PAGE_SHIFT,
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size, vma->vm_page_prot);
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if (retval) {
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dev_err(q->dev, "mmap: remap failed with error %d. ", retval);
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dma_free_coherent(q->dev, mem->size,
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mem->vaddr, mem->dma_handle);
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goto error;
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}
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vma->vm_ops = &videobuf_vm_ops;
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vma->vm_flags |= VM_DONTEXPAND;
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vma->vm_private_data = map;
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dev_dbg(q->dev, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
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map, q, vma->vm_start, vma->vm_end,
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(long int) q->bufs[first]->bsize,
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vma->vm_pgoff, first);
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videobuf_vm_open(vma);
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return 0;
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error:
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kfree(map);
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return -ENOMEM;
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}
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static int __videobuf_copy_to_user(struct videobuf_queue *q,
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char __user *data, size_t count,
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int nonblocking)
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{
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struct videobuf_dma_contig_memory *mem = q->read_buf->priv;
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void *vaddr;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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BUG_ON(!mem->vaddr);
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/* copy to userspace */
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if (count > q->read_buf->size - q->read_off)
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count = q->read_buf->size - q->read_off;
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vaddr = mem->vaddr;
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if (copy_to_user(data, vaddr + q->read_off, count))
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return -EFAULT;
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return count;
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}
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static int __videobuf_copy_stream(struct videobuf_queue *q,
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char __user *data, size_t count, size_t pos,
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int vbihack, int nonblocking)
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{
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unsigned int *fc;
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struct videobuf_dma_contig_memory *mem = q->read_buf->priv;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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if (vbihack) {
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/* dirty, undocumented hack -- pass the frame counter
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* within the last four bytes of each vbi data block.
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* We need that one to maintain backward compatibility
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* to all vbi decoding software out there ... */
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fc = (unsigned int *)mem->vaddr;
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fc += (q->read_buf->size >> 2) - 1;
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*fc = q->read_buf->field_count >> 1;
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dev_dbg(q->dev, "vbihack: %d\n", *fc);
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}
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/* copy stuff using the common method */
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count = __videobuf_copy_to_user(q, data, count, nonblocking);
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if ((count == -EFAULT) && (pos == 0))
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return -EFAULT;
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return count;
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}
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static struct videobuf_qtype_ops qops = {
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.magic = MAGIC_QTYPE_OPS,
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.alloc = __videobuf_alloc,
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.iolock = __videobuf_iolock,
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.sync = __videobuf_sync,
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.mmap_free = __videobuf_mmap_free,
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.mmap_mapper = __videobuf_mmap_mapper,
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.video_copy_to_user = __videobuf_copy_to_user,
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.copy_stream = __videobuf_copy_stream,
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.vmalloc = __videobuf_to_vmalloc,
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};
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void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
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struct videobuf_queue_ops *ops,
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struct device *dev,
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spinlock_t *irqlock,
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enum v4l2_buf_type type,
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enum v4l2_field field,
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unsigned int msize,
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void *priv)
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{
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videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
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priv, &qops);
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}
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EXPORT_SYMBOL_GPL(videobuf_queue_dma_contig_init);
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dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf)
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{
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struct videobuf_dma_contig_memory *mem = buf->priv;
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BUG_ON(!mem);
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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return mem->dma_handle;
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}
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EXPORT_SYMBOL_GPL(videobuf_to_dma_contig);
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void videobuf_dma_contig_free(struct videobuf_queue *q,
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struct videobuf_buffer *buf)
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{
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struct videobuf_dma_contig_memory *mem = buf->priv;
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/* mmapped memory can't be freed here, otherwise mmapped region
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would be released, while still needed. In this case, the memory
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release should happen inside videobuf_vm_close().
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So, it should free memory only if the memory were allocated for
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read() operation.
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*/
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if ((buf->memory != V4L2_MEMORY_USERPTR) || !buf->baddr)
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return;
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if (!mem)
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return;
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MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
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dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle);
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mem->vaddr = NULL;
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}
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EXPORT_SYMBOL_GPL(videobuf_dma_contig_free);
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MODULE_DESCRIPTION("helper module to manage video4linux dma contig buffers");
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MODULE_AUTHOR("Magnus Damm");
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MODULE_LICENSE("GPL");
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