Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
branch: master
Fetching contributors…

Cannot retrieve contributors at this time

482 lines (388 sloc) 11.605 kb
/*
* helper functions for physically contiguous capture buffers
*
* The functions support hardware lacking scatter gather support
* (i.e. the buffers must be linear in physical memory)
*
* Copyright (c) 2008 Magnus Damm
*
* Based on videobuf-vmalloc.c,
* (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
*
* 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; either version 2
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/dma-mapping.h>
#include <linux/sched.h>
#include <media/videobuf-dma-contig.h>
struct videobuf_dma_contig_memory {
u32 magic;
void *vaddr;
dma_addr_t dma_handle;
unsigned long size;
int is_userptr;
};
#define MAGIC_DC_MEM 0x0733ac61
#define MAGIC_CHECK(is, should) \
if (unlikely((is) != (should))) { \
pr_err("magic mismatch: %x expected %x\n", (is), (should)); \
BUG(); \
}
static void
videobuf_vm_open(struct vm_area_struct *vma)
{
struct videobuf_mapping *map = vma->vm_private_data;
dev_dbg(map->q->dev, "vm_open %p [count=%u,vma=%08lx-%08lx]\n",
map, map->count, vma->vm_start, vma->vm_end);
map->count++;
}
static void videobuf_vm_close(struct vm_area_struct *vma)
{
struct videobuf_mapping *map = vma->vm_private_data;
struct videobuf_queue *q = map->q;
int i;
dev_dbg(map->q->dev, "vm_close %p [count=%u,vma=%08lx-%08lx]\n",
map, map->count, vma->vm_start, vma->vm_end);
map->count--;
if (0 == map->count) {
struct videobuf_dma_contig_memory *mem;
dev_dbg(map->q->dev, "munmap %p q=%p\n", map, q);
mutex_lock(&q->vb_lock);
/* We need first to cancel streams, before unmapping */
if (q->streaming)
videobuf_queue_cancel(q);
for (i = 0; i < VIDEO_MAX_FRAME; i++) {
if (NULL == q->bufs[i])
continue;
if (q->bufs[i]->map != map)
continue;
mem = q->bufs[i]->priv;
if (mem) {
/* This callback is called only if kernel has
allocated memory and this memory is mmapped.
In this case, memory should be freed,
in order to do memory unmap.
*/
MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
/* vfree is not atomic - can't be
called with IRQ's disabled
*/
dev_dbg(map->q->dev, "buf[%d] freeing %p\n",
i, mem->vaddr);
dma_free_coherent(q->dev, mem->size,
mem->vaddr, mem->dma_handle);
mem->vaddr = NULL;
}
q->bufs[i]->map = NULL;
q->bufs[i]->baddr = 0;
}
kfree(map);
mutex_unlock(&q->vb_lock);
}
}
static struct vm_operations_struct videobuf_vm_ops = {
.open = videobuf_vm_open,
.close = videobuf_vm_close,
};
/**
* videobuf_dma_contig_user_put() - reset pointer to user space buffer
* @mem: per-buffer private videobuf-dma-contig data
*
* This function resets the user space pointer
*/
static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
{
mem->is_userptr = 0;
mem->dma_handle = 0;
mem->size = 0;
}
/**
* videobuf_dma_contig_user_get() - setup user space memory pointer
* @mem: per-buffer private videobuf-dma-contig data
* @vb: video buffer to map
*
* This function validates and sets up a pointer to user space memory.
* Only physically contiguous pfn-mapped memory is accepted.
*
* Returns 0 if successful.
*/
static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
struct videobuf_buffer *vb)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long prev_pfn, this_pfn;
unsigned long pages_done, user_address;
int ret;
mem->size = PAGE_ALIGN(vb->size);
mem->is_userptr = 0;
ret = -EINVAL;
down_read(&mm->mmap_sem);
vma = find_vma(mm, vb->baddr);
if (!vma)
goto out_up;
if ((vb->baddr + mem->size) > vma->vm_end)
goto out_up;
pages_done = 0;
prev_pfn = 0; /* kill warning */
user_address = vb->baddr;
while (pages_done < (mem->size >> PAGE_SHIFT)) {
ret = follow_pfn(vma, user_address, &this_pfn);
if (ret)
break;
if (pages_done == 0)
mem->dma_handle = this_pfn << PAGE_SHIFT;
else if (this_pfn != (prev_pfn + 1))
ret = -EFAULT;
if (ret)
break;
prev_pfn = this_pfn;
user_address += PAGE_SIZE;
pages_done++;
}
if (!ret)
mem->is_userptr = 1;
out_up:
up_read(&current->mm->mmap_sem);
return ret;
}
static void *__videobuf_alloc(size_t size)
{
struct videobuf_dma_contig_memory *mem;
struct videobuf_buffer *vb;
vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
if (vb) {
mem = vb->priv = ((char *)vb) + size;
mem->magic = MAGIC_DC_MEM;
}
return vb;
}
static void *__videobuf_to_vmalloc(struct videobuf_buffer *buf)
{
struct videobuf_dma_contig_memory *mem = buf->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
return mem->vaddr;
}
static int __videobuf_iolock(struct videobuf_queue *q,
struct videobuf_buffer *vb,
struct v4l2_framebuffer *fbuf)
{
struct videobuf_dma_contig_memory *mem = vb->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
switch (vb->memory) {
case V4L2_MEMORY_MMAP:
dev_dbg(q->dev, "%s memory method MMAP\n", __func__);
/* All handling should be done by __videobuf_mmap_mapper() */
if (!mem->vaddr) {
dev_err(q->dev, "memory is not alloced/mmapped.\n");
return -EINVAL;
}
break;
case V4L2_MEMORY_USERPTR:
dev_dbg(q->dev, "%s memory method USERPTR\n", __func__);
/* handle pointer from user space */
if (vb->baddr)
return videobuf_dma_contig_user_get(mem, vb);
/* allocate memory for the read() method */
mem->size = PAGE_ALIGN(vb->size);
mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
&mem->dma_handle, GFP_ATOMIC);
if (!mem->vaddr) {
dev_err(q->dev, "dma_alloc_coherent %ld failed\n",
mem->size);
return -ENOMEM;
}
dev_dbg(q->dev, "dma_alloc_coherent data is at %p (%ld)\n",
mem->vaddr, mem->size);
break;
case V4L2_MEMORY_OVERLAY:
default:
dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n",
__func__);
return -EINVAL;
}
return 0;
}
static int __videobuf_mmap_free(struct videobuf_queue *q)
{
unsigned int i;
dev_dbg(q->dev, "%s\n", __func__);
for (i = 0; i < VIDEO_MAX_FRAME; i++) {
if (q->bufs[i] && q->bufs[i]->map)
return -EBUSY;
}
return 0;
}
static int __videobuf_mmap_mapper(struct videobuf_queue *q,
struct vm_area_struct *vma)
{
struct videobuf_dma_contig_memory *mem;
struct videobuf_mapping *map;
unsigned int first;
int retval;
unsigned long size, offset = vma->vm_pgoff << PAGE_SHIFT;
dev_dbg(q->dev, "%s\n", __func__);
if (!(vma->vm_flags & VM_WRITE) || !(vma->vm_flags & VM_SHARED))
return -EINVAL;
/* look for first buffer to map */
for (first = 0; first < VIDEO_MAX_FRAME; first++) {
if (!q->bufs[first])
continue;
if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
continue;
if (q->bufs[first]->boff == offset)
break;
}
if (VIDEO_MAX_FRAME == first) {
dev_dbg(q->dev, "invalid user space offset [offset=0x%lx]\n",
offset);
return -EINVAL;
}
/* create mapping + update buffer list */
map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
if (!map)
return -ENOMEM;
q->bufs[first]->map = map;
map->start = vma->vm_start;
map->end = vma->vm_end;
map->q = q;
q->bufs[first]->baddr = vma->vm_start;
mem = q->bufs[first]->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
mem->size = PAGE_ALIGN(q->bufs[first]->bsize);
mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
&mem->dma_handle, GFP_ATOMIC);
if (!mem->vaddr) {
dev_err(q->dev, "dma_alloc_coherent size %ld failed\n",
mem->size);
goto error;
}
dev_dbg(q->dev, "dma_alloc_coherent data is at addr %p (size %ld)\n",
mem->vaddr, mem->size);
/* Try to remap memory */
size = vma->vm_end - vma->vm_start;
size = (size < mem->size) ? size : mem->size;
retval = remap_pfn_range(vma, vma->vm_start,
mem->dma_handle >> PAGE_SHIFT,
size, vma->vm_page_prot);
if (retval) {
dev_err(q->dev, "mmap: remap failed with error %d. ", retval);
dma_free_coherent(q->dev, mem->size,
mem->vaddr, mem->dma_handle);
goto error;
}
vma->vm_ops = &videobuf_vm_ops;
vma->vm_flags |= VM_DONTEXPAND;
vma->vm_private_data = map;
dev_dbg(q->dev, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
map, q, vma->vm_start, vma->vm_end,
(long int) q->bufs[first]->bsize,
vma->vm_pgoff, first);
videobuf_vm_open(vma);
return 0;
error:
kfree(map);
return -ENOMEM;
}
static int __videobuf_copy_to_user(struct videobuf_queue *q,
char __user *data, size_t count,
int nonblocking)
{
struct videobuf_dma_contig_memory *mem = q->read_buf->priv;
void *vaddr;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
BUG_ON(!mem->vaddr);
/* copy to userspace */
if (count > q->read_buf->size - q->read_off)
count = q->read_buf->size - q->read_off;
vaddr = mem->vaddr;
if (copy_to_user(data, vaddr + q->read_off, count))
return -EFAULT;
return count;
}
static int __videobuf_copy_stream(struct videobuf_queue *q,
char __user *data, size_t count, size_t pos,
int vbihack, int nonblocking)
{
unsigned int *fc;
struct videobuf_dma_contig_memory *mem = q->read_buf->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
if (vbihack) {
/* dirty, undocumented hack -- pass the frame counter
* within the last four bytes of each vbi data block.
* We need that one to maintain backward compatibility
* to all vbi decoding software out there ... */
fc = (unsigned int *)mem->vaddr;
fc += (q->read_buf->size >> 2) - 1;
*fc = q->read_buf->field_count >> 1;
dev_dbg(q->dev, "vbihack: %d\n", *fc);
}
/* copy stuff using the common method */
count = __videobuf_copy_to_user(q, data, count, nonblocking);
if ((count == -EFAULT) && (pos == 0))
return -EFAULT;
return count;
}
static struct videobuf_qtype_ops qops = {
.magic = MAGIC_QTYPE_OPS,
.alloc = __videobuf_alloc,
.iolock = __videobuf_iolock,
.mmap_free = __videobuf_mmap_free,
.mmap_mapper = __videobuf_mmap_mapper,
.video_copy_to_user = __videobuf_copy_to_user,
.copy_stream = __videobuf_copy_stream,
.vmalloc = __videobuf_to_vmalloc,
};
void videobuf_queue_dma_contig_init(struct videobuf_queue *q,
struct videobuf_queue_ops *ops,
struct device *dev,
spinlock_t *irqlock,
enum v4l2_buf_type type,
enum v4l2_field field,
unsigned int msize,
void *priv)
{
videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
priv, &qops);
}
dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf)
{
struct videobuf_dma_contig_memory *mem = buf->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
return mem->dma_handle;
}
void videobuf_dma_contig_free(struct videobuf_queue *q,
struct videobuf_buffer *buf)
{
struct videobuf_dma_contig_memory *mem = buf->priv;
/* mmapped memory can't be freed here, otherwise mmapped region
would be released, while still needed. In this case, the memory
release should happen inside videobuf_vm_close().
So, it should free memory only if the memory were allocated for
read() operation.
*/
if (buf->memory != V4L2_MEMORY_USERPTR)
return;
if (!mem)
return;
MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
/* handle user space pointer case */
if (buf->baddr) {
videobuf_dma_contig_user_put(mem);
return;
}
/* read() method */
dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle);
mem->vaddr = NULL;
}
Jump to Line
Something went wrong with that request. Please try again.