linux/drivers/media/video/videobuf-dma-sg.c

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/*
* 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:
*/