kernel-ark/drivers/media/video/videobuf-dma-sg.c
Jonathan Corbet 38a54f35a0 V4L/DVB (13377): make struct videobuf_queue_ops constant
The videobuf_queue_ops function vector is not declared constant, but
there's no need for the videobuf layer to ever change it.  Make it const
so that videobuf users can make their operations const without warnings.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-12-05 18:41:35 -02:00

742 lines
18 KiB
C

/*
* helper functions for SG DMA video4linux capture buffers
*
* The functions expect the hardware being able to scatter gather
* (i.e. the buffers are not linear in physical memory, but fragmented
* into PAGE_SIZE chunks). They also assume the driver does not need
* to touch the video data.
*
* (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
*
* Highly based on video-buf written originally by:
* (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
* (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
* (c) 2006 Ted Walther and John Sokol
*
* 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/moduleparam.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/vmalloc.h>
#include <linux/pagemap.h>
#include <linux/scatterlist.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <media/videobuf-dma-sg.h>
#define MAGIC_DMABUF 0x19721112
#define MAGIC_SG_MEM 0x17890714
#define MAGIC_CHECK(is,should) if (unlikely((is) != (should))) \
{ printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); BUG(); }
static int debug;
module_param(debug, int, 0644);
MODULE_DESCRIPTION("helper module to manage video4linux dma sg buffers");
MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
MODULE_LICENSE("GPL");
#define dprintk(level, fmt, arg...) if (debug >= level) \
printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg)
/* --------------------------------------------------------------------- */
struct scatterlist*
videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages)
{
struct scatterlist *sglist;
struct page *pg;
int i;
sglist = vmalloc(nr_pages * sizeof(*sglist));
if (NULL == sglist)
return NULL;
memset(sglist, 0, nr_pages * sizeof(*sglist));
sg_init_table(sglist, nr_pages);
for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
pg = vmalloc_to_page(virt);
if (NULL == pg)
goto err;
BUG_ON(PageHighMem(pg));
sg_set_page(&sglist[i], pg, PAGE_SIZE, 0);
}
return sglist;
err:
vfree(sglist);
return NULL;
}
struct scatterlist*
videobuf_pages_to_sg(struct page **pages, int nr_pages, int offset)
{
struct scatterlist *sglist;
int i;
if (NULL == pages[0])
return NULL;
sglist = vmalloc(nr_pages * sizeof(*sglist));
if (NULL == sglist)
return NULL;
sg_init_table(sglist, nr_pages);
if (PageHighMem(pages[0]))
/* DMA to highmem pages might not work */
goto highmem;
sg_set_page(&sglist[0], pages[0], PAGE_SIZE - offset, offset);
for (i = 1; i < nr_pages; i++) {
if (NULL == pages[i])
goto nopage;
if (PageHighMem(pages[i]))
goto highmem;
sg_set_page(&sglist[i], pages[i], PAGE_SIZE, 0);
}
return sglist;
nopage:
dprintk(2,"sgl: oops - no page\n");
vfree(sglist);
return NULL;
highmem:
dprintk(2,"sgl: oops - highmem page\n");
vfree(sglist);
return NULL;
}
/* --------------------------------------------------------------------- */
struct videobuf_dmabuf *videobuf_to_dma (struct videobuf_buffer *buf)
{
struct videobuf_dma_sg_memory *mem = buf->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
return &mem->dma;
}
void videobuf_dma_init(struct videobuf_dmabuf *dma)
{
memset(dma,0,sizeof(*dma));
dma->magic = MAGIC_DMABUF;
}
static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
int direction, unsigned long data, unsigned long size)
{
unsigned long first,last;
int err, rw = 0;
dma->direction = direction;
switch (dma->direction) {
case DMA_FROM_DEVICE:
rw = READ;
break;
case DMA_TO_DEVICE:
rw = WRITE;
break;
default:
BUG();
}
first = (data & PAGE_MASK) >> PAGE_SHIFT;
last = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
dma->offset = data & ~PAGE_MASK;
dma->nr_pages = last-first+1;
dma->pages = kmalloc(dma->nr_pages * sizeof(struct page*),
GFP_KERNEL);
if (NULL == dma->pages)
return -ENOMEM;
dprintk(1,"init user [0x%lx+0x%lx => %d pages]\n",
data,size,dma->nr_pages);
err = get_user_pages(current,current->mm,
data & PAGE_MASK, dma->nr_pages,
rw == READ, 1, /* force */
dma->pages, NULL);
if (err != dma->nr_pages) {
dma->nr_pages = (err >= 0) ? err : 0;
dprintk(1,"get_user_pages: err=%d [%d]\n",err,dma->nr_pages);
return err < 0 ? err : -EINVAL;
}
return 0;
}
int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
unsigned long data, unsigned long size)
{
int ret;
down_read(&current->mm->mmap_sem);
ret = videobuf_dma_init_user_locked(dma, direction, data, size);
up_read(&current->mm->mmap_sem);
return ret;
}
int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
int nr_pages)
{
dprintk(1,"init kernel [%d pages]\n",nr_pages);
dma->direction = direction;
dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
if (NULL == dma->vmalloc) {
dprintk(1,"vmalloc_32(%d pages) failed\n",nr_pages);
return -ENOMEM;
}
dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
(unsigned long)dma->vmalloc,
nr_pages << PAGE_SHIFT);
memset(dma->vmalloc,0,nr_pages << PAGE_SHIFT);
dma->nr_pages = nr_pages;
return 0;
}
int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
dma_addr_t addr, int nr_pages)
{
dprintk(1,"init overlay [%d pages @ bus 0x%lx]\n",
nr_pages,(unsigned long)addr);
dma->direction = direction;
if (0 == addr)
return -EINVAL;
dma->bus_addr = addr;
dma->nr_pages = nr_pages;
return 0;
}
int videobuf_dma_map(struct videobuf_queue* q, struct videobuf_dmabuf *dma)
{
MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
BUG_ON(0 == dma->nr_pages);
if (dma->pages) {
dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
dma->offset);
}
if (dma->vmalloc) {
dma->sglist = videobuf_vmalloc_to_sg
(dma->vmalloc,dma->nr_pages);
}
if (dma->bus_addr) {
dma->sglist = vmalloc(sizeof(*dma->sglist));
if (NULL != dma->sglist) {
dma->sglen = 1;
sg_dma_address(&dma->sglist[0]) = dma->bus_addr & PAGE_MASK;
dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
}
}
if (NULL == dma->sglist) {
dprintk(1,"scatterlist is NULL\n");
return -ENOMEM;
}
if (!dma->bus_addr) {
dma->sglen = dma_map_sg(q->dev, dma->sglist,
dma->nr_pages, dma->direction);
if (0 == dma->sglen) {
printk(KERN_WARNING
"%s: videobuf_map_sg failed\n",__func__);
vfree(dma->sglist);
dma->sglist = NULL;
dma->sglen = 0;
return -ENOMEM;
}
}
return 0;
}
int videobuf_dma_sync(struct videobuf_queue *q, struct videobuf_dmabuf *dma)
{
MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
BUG_ON(!dma->sglen);
dma_sync_sg_for_cpu(q->dev, dma->sglist, dma->nr_pages, dma->direction);
return 0;
}
int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma)
{
MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
if (!dma->sglen)
return 0;
dma_unmap_sg(q->dev, dma->sglist, dma->nr_pages, dma->direction);
vfree(dma->sglist);
dma->sglist = NULL;
dma->sglen = 0;
return 0;
}
int videobuf_dma_free(struct videobuf_dmabuf *dma)
{
MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
BUG_ON(dma->sglen);
if (dma->pages) {
int i;
for (i=0; i < dma->nr_pages; i++)
page_cache_release(dma->pages[i]);
kfree(dma->pages);
dma->pages = NULL;
}
vfree(dma->vmalloc);
dma->vmalloc = NULL;
if (dma->bus_addr) {
dma->bus_addr = 0;
}
dma->direction = DMA_NONE;
return 0;
}
/* --------------------------------------------------------------------- */
int videobuf_sg_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
{
struct videobuf_queue q;
q.dev = dev;
return videobuf_dma_map(&q, dma);
}
int videobuf_sg_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
{
struct videobuf_queue q;
q.dev = dev;
return videobuf_dma_unmap(&q, dma);
}
/* --------------------------------------------------------------------- */
static void
videobuf_vm_open(struct vm_area_struct *vma)
{
struct videobuf_mapping *map = vma->vm_private_data;
dprintk(2,"vm_open %p [count=%d,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;
struct videobuf_dma_sg_memory *mem;
int i;
dprintk(2,"vm_close %p [count=%d,vma=%08lx-%08lx]\n",map,
map->count,vma->vm_start,vma->vm_end);
map->count--;
if (0 == map->count) {
dprintk(1,"munmap %p q=%p\n",map,q);
mutex_lock(&q->vb_lock);
for (i = 0; i < VIDEO_MAX_FRAME; i++) {
if (NULL == q->bufs[i])
continue;
mem=q->bufs[i]->priv;
if (!mem)
continue;
MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
if (q->bufs[i]->map != map)
continue;
q->bufs[i]->map = NULL;
q->bufs[i]->baddr = 0;
q->ops->buf_release(q,q->bufs[i]);
}
mutex_unlock(&q->vb_lock);
kfree(map);
}
return;
}
/*
* Get a anonymous page for the mapping. Make sure we can DMA to that
* memory location with 32bit PCI devices (i.e. don't use highmem for
* now ...). Bounce buffers don't work very well for the data rates
* video capture has.
*/
static int
videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct page *page;
dprintk(3,"fault: fault @ %08lx [vma %08lx-%08lx]\n",
(unsigned long)vmf->virtual_address,vma->vm_start,vma->vm_end);
page = alloc_page(GFP_USER | __GFP_DMA32);
if (!page)
return VM_FAULT_OOM;
clear_user_highpage(page, (unsigned long)vmf->virtual_address);
vmf->page = page;
return 0;
}
static const struct vm_operations_struct videobuf_vm_ops =
{
.open = videobuf_vm_open,
.close = videobuf_vm_close,
.fault = videobuf_vm_fault,
};
/* ---------------------------------------------------------------------
* SG handlers for the generic methods
*/
/* Allocated area consists on 3 parts:
struct video_buffer
struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
struct videobuf_dma_sg_memory
*/
static void *__videobuf_alloc(size_t size)
{
struct videobuf_dma_sg_memory *mem;
struct videobuf_buffer *vb;
vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
mem = vb->priv = ((char *)vb)+size;
mem->magic=MAGIC_SG_MEM;
videobuf_dma_init(&mem->dma);
dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
__func__,vb,(long)sizeof(*vb),(long)size-sizeof(*vb),
mem,(long)sizeof(*mem));
return vb;
}
static void *__videobuf_to_vmalloc (struct videobuf_buffer *buf)
{
struct videobuf_dma_sg_memory *mem = buf->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
return mem->dma.vmalloc;
}
static int __videobuf_iolock (struct videobuf_queue* q,
struct videobuf_buffer *vb,
struct v4l2_framebuffer *fbuf)
{
int err,pages;
dma_addr_t bus;
struct videobuf_dma_sg_memory *mem = vb->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
switch (vb->memory) {
case V4L2_MEMORY_MMAP:
case V4L2_MEMORY_USERPTR:
if (0 == vb->baddr) {
/* no userspace addr -- kernel bounce buffer */
pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
err = videobuf_dma_init_kernel( &mem->dma,
DMA_FROM_DEVICE,
pages );
if (0 != err)
return err;
} else if (vb->memory == V4L2_MEMORY_USERPTR) {
/* dma directly to userspace */
err = videobuf_dma_init_user( &mem->dma,
DMA_FROM_DEVICE,
vb->baddr,vb->bsize );
if (0 != err)
return err;
} else {
/* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
buffers can only be called from videobuf_qbuf
we take current->mm->mmap_sem there, to prevent
locking inversion, so don't take it here */
err = videobuf_dma_init_user_locked(&mem->dma,
DMA_FROM_DEVICE,
vb->baddr, vb->bsize);
if (0 != err)
return err;
}
break;
case V4L2_MEMORY_OVERLAY:
if (NULL == fbuf)
return -EINVAL;
/* FIXME: need sanity checks for vb->boff */
/*
* Using a double cast to avoid compiler warnings when
* building for PAE. Compiler doesn't like direct casting
* of a 32 bit ptr to 64 bit integer.
*/
bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE,
bus, pages);
if (0 != err)
return err;
break;
default:
BUG();
}
err = videobuf_dma_map(q, &mem->dma);
if (0 != err)
return err;
return 0;
}
static int __videobuf_sync(struct videobuf_queue *q,
struct videobuf_buffer *buf)
{
struct videobuf_dma_sg_memory *mem = buf->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
return videobuf_dma_sync(q,&mem->dma);
}
static int __videobuf_mmap_free(struct videobuf_queue *q)
{
int i;
for (i = 0; i < VIDEO_MAX_FRAME; i++) {
if (q->bufs[i]) {
if (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_sg_memory *mem;
struct videobuf_mapping *map;
unsigned int first,last,size,i;
int retval;
retval = -EINVAL;
if (!(vma->vm_flags & VM_WRITE)) {
dprintk(1,"mmap app bug: PROT_WRITE please\n");
goto done;
}
if (!(vma->vm_flags & VM_SHARED)) {
dprintk(1,"mmap app bug: MAP_SHARED please\n");
goto done;
}
/* This function maintains backwards compatibility with V4L1 and will
* map more than one buffer if the vma length is equal to the combined
* size of multiple buffers than it will map them together. See
* VIDIOCGMBUF in the v4l spec
*
* TODO: Allow drivers to specify if they support this mode
*/
/* look for first buffer to map */
for (first = 0; first < VIDEO_MAX_FRAME; first++) {
if (NULL == q->bufs[first])
continue;
mem=q->bufs[first]->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
continue;
if (q->bufs[first]->boff == (vma->vm_pgoff << PAGE_SHIFT))
break;
}
if (VIDEO_MAX_FRAME == first) {
dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
(vma->vm_pgoff << PAGE_SHIFT));
goto done;
}
/* look for last buffer to map */
for (size = 0, last = first; last < VIDEO_MAX_FRAME; last++) {
if (NULL == q->bufs[last])
continue;
if (V4L2_MEMORY_MMAP != q->bufs[last]->memory)
continue;
if (q->bufs[last]->map) {
retval = -EBUSY;
goto done;
}
size += PAGE_ALIGN(q->bufs[last]->bsize);
if (size == (vma->vm_end - vma->vm_start))
break;
}
if (VIDEO_MAX_FRAME == last) {
dprintk(1,"mmap app bug: size invalid [size=0x%lx]\n",
(vma->vm_end - vma->vm_start));
goto done;
}
/* create mapping + update buffer list */
retval = -ENOMEM;
map = kmalloc(sizeof(struct videobuf_mapping),GFP_KERNEL);
if (NULL == map)
goto done;
size = 0;
for (i = first; i <= last; i++) {
if (NULL == q->bufs[i])
continue;
q->bufs[i]->map = map;
q->bufs[i]->baddr = vma->vm_start + size;
size += PAGE_ALIGN(q->bufs[i]->bsize);
}
map->count = 1;
map->start = vma->vm_start;
map->end = vma->vm_end;
map->q = q;
vma->vm_ops = &videobuf_vm_ops;
vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
vma->vm_private_data = map;
dprintk(1,"mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
map,q,vma->vm_start,vma->vm_end,vma->vm_pgoff,first,last);
retval = 0;
done:
return retval;
}
static int __videobuf_copy_to_user ( struct videobuf_queue *q,
char __user *data, size_t count,
int nonblocking )
{
struct videobuf_dma_sg_memory *mem = q->read_buf->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
/* copy to userspace */
if (count > q->read_buf->size - q->read_off)
count = q->read_buf->size - q->read_off;
if (copy_to_user(data, mem->dma.vmalloc+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_sg_memory *mem = q->read_buf->priv;
BUG_ON(!mem);
MAGIC_CHECK(mem->magic,MAGIC_SG_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->dma.vmalloc;
fc += (q->read_buf->size>>2) -1;
*fc = q->read_buf->field_count >> 1;
dprintk(1,"vbihack: %d\n",*fc);
}
/* copy stuff using the common method */
count = __videobuf_copy_to_user (q,data,count,nonblocking);
if ( (count==-EFAULT) && (0 == pos) )
return -EFAULT;
return count;
}
static struct videobuf_qtype_ops sg_ops = {
.magic = MAGIC_QTYPE_OPS,
.alloc = __videobuf_alloc,
.iolock = __videobuf_iolock,
.sync = __videobuf_sync,
.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_sg_alloc(size_t size)
{
struct videobuf_queue q;
/* Required to make generic handler to call __videobuf_alloc */
q.int_ops = &sg_ops;
q.msize = size;
return videobuf_alloc(&q);
}
void videobuf_queue_sg_init(struct videobuf_queue* q,
const 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, &sg_ops);
}
/* --------------------------------------------------------------------- */
EXPORT_SYMBOL_GPL(videobuf_vmalloc_to_sg);
EXPORT_SYMBOL_GPL(videobuf_to_dma);
EXPORT_SYMBOL_GPL(videobuf_dma_init);
EXPORT_SYMBOL_GPL(videobuf_dma_init_user);
EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel);
EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay);
EXPORT_SYMBOL_GPL(videobuf_dma_map);
EXPORT_SYMBOL_GPL(videobuf_dma_sync);
EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
EXPORT_SYMBOL_GPL(videobuf_dma_free);
EXPORT_SYMBOL_GPL(videobuf_sg_dma_map);
EXPORT_SYMBOL_GPL(videobuf_sg_dma_unmap);
EXPORT_SYMBOL_GPL(videobuf_sg_alloc);
EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);
/*
* Local variables:
* c-basic-offset: 8
* End:
*/