videobuf-dma-sg.c

trident tm5600的linux驱动

/*
 * 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, <[e-mail]>
 *
 * Highly based on video-buf written originally by:
 * (c) 2001,02 Gerd Knorr <[e-mail]>
 * (c) 2006 Mauro Carvalho Chehab, <[e-mail]>
 * (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/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>
#include "compat.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 <[e-mail]>");
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 = kcalloc(nr_pages, sizeof(struct scatterlist), GFP_KERNEL);
	if (NULL == sglist)
		return NULL;
	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:
	kfree(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 = kmalloc(nr_pages * sizeof(*sglist), GFP_KERNEL);
	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");
	kfree(sglist);
	return NULL;

 highmem:
	dprintk(2,"sgl: oops - highmem page\n");
	kfree(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 = kmalloc(sizeof(struct scatterlist), GFP_KERNEL);
		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__);
			kfree(dma->sglist);
			dma->sglist = NULL;
			dma->sglen = 0;
			return -EIO;
		}
	}
	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);

	kfree(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 0
			/* FIXME: this seems to be a hack!!!  */
			if (q->bufs[i])
				;
#endif
			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.
 */