ClabureDB: Classified Bug-Reports Database

  /*
   * 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/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 = 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 (!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_page(page_address(page), (unsigned long)vmf->virtual_address,
                        page);
        vmf->page = page;
        return 0;
}

static 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 += 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 += 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,
                         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:
 */