V4L/DVB (5147): Make vivi driver to use vmalloced pointers

Before this patch, vivi were simulating a scatter gather DMA transfer.
While this is academic, showing how stuff really works on a real PCI
device, this means a non-optimized code.
There are only two memory models that vivi implements:
1) kernel alloced memory. This is also used by read() method.
On this case, a vmalloc32 buffer is allocated at kernel;
2) userspace allocated memory. This is used by most userspace apps.
video-buf will store this pointer.
a simple copy_to_user is enough to transfer data.
The third memory model scenario supported by video-buf is overlay mode.
This model is not implemented on vivi and unlikely to be implemented on
newer drivers, since now, most userspace apps do some post-processing
(like de-interlacing).
After this patch, some cleanups may be done at video-buf.c to avoid
allocating pages, when the driver doesn't need a PCI buffer. This is the
case of vivi and usb drivers.

Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/video/video-buf.c

···
 	dprintk(1,"init user [0x%lx+0x%lx => %d pages]\n",
 		data,size,dma->nr_pages);
 
+	dma->varea = (void *) data;
+
 	down_read(&current->mm->mmap_sem);
 	err = get_user_pages(current,current->mm,
 			     data & PAGE_MASK, dma->nr_pages,
···
 
 	vfree(dma->vmalloc);
 	dma->vmalloc = NULL;
+	dma->varea = NULL;
 
 	if (dma->bus_addr) {
 		dma->bus_addr = 0;

drivers/media/video/vivi.c

···
 
 	struct vivi_fmt        *fmt;
 
+#ifdef CONFIG_VIVI_SCATTER
 	struct sg_to_addr      *to_addr;
+#endif
 };
 
 struct vivi_dmaqueue {
···
 #define TSTAMP_MAX_Y TSTAMP_MIN_Y+15
 #define TSTAMP_MIN_X 64
 
+#ifdef CONFIG_VIVI_SCATTER
 static void prep_to_addr(struct sg_to_addr to_addr[],
 			 struct videobuf_buffer *vb)
 {
···
 
 	return (p1);
 }
+#endif
 
+#ifdef CONFIG_VIVI_SCATTER
 static void gen_line(struct sg_to_addr to_addr[],int inipos,int pages,int wmax,
 		     int hmax, int line, char *timestr)
+#else
+static void gen_line(char *basep,int inipos,int wmax,
+		     int hmax, int line, char *timestr)
+#endif
 {
-	int  w,i,j,pos=inipos,pgpos,oldpg,y;
-	char *p,*s,*basep;
-	struct page *pg;
+	int  w,i,j,pos=inipos,y;
+	char *p,*s;
 	u8   chr,r,g,b,color;
+#ifdef CONFIG_VIVI_SCATTER
+	int pgpos,oldpg;
+	char *basep;
+	struct page *pg;
+
 	unsigned long flags;
 	spinlock_t spinlock;
 
···
 	pg=pfn_to_page(sg_dma_address(to_addr[oldpg].sg) >> PAGE_SHIFT);
 	spin_lock_irqsave(&spinlock,flags);
 	basep = kmap_atomic(pg, KM_BOUNCE_READ)+to_addr[oldpg].sg->offset;
+#endif
 
 	/* We will just duplicate the second pixel at the packet */
 	wmax/=2;
···
 		b=bars[w*7/wmax][2];
 
 		for (color=0;color<4;color++) {
+#ifdef CONFIG_VIVI_SCATTER
 			pgpos=get_addr_pos(pos,pages,to_addr);
 			if (pgpos!=oldpg) {
 				pg=pfn_to_page(sg_dma_address(to_addr[pgpos].sg) >> PAGE_SHIFT);
···
 				oldpg=pgpos;
 			}
 			p=basep+pos-to_addr[pgpos].pos;
+#else
+			p=basep+pos;
+#endif
 
 			switch (color) {
 				case 0:
···
 
 				pos=inipos+j*2;
 				for (color=0;color<4;color++) {
+#ifdef CONFIG_VIVI_SCATTER
 					pgpos=get_addr_pos(pos,pages,to_addr);
 					if (pgpos!=oldpg) {
 						pg=pfn_to_page(sg_dma_address(
···
 						oldpg=pgpos;
 					}
 					p=basep+pos-to_addr[pgpos].pos;
+#else
+					p=basep+pos;
+#endif
 
 					y=TO_Y(r,g,b);
 
···
 
 
 end:
+#ifdef CONFIG_VIVI_SCATTER
 	kunmap_atomic(basep, KM_BOUNCE_READ);
 	spin_unlock_irqrestore(&spinlock,flags);
-
+#else
+	return;
+#endif
 }
 static void vivi_fillbuff(struct vivi_dev *dev,struct vivi_buffer *buf)
 {
 	int h,pos=0;
 	int hmax  = buf->vb.height;
 	int wmax  = buf->vb.width;
-	struct videobuf_buffer *vb=&buf->vb;
-	struct sg_to_addr *to_addr=buf->to_addr;
 	struct timeval ts;
+#ifdef CONFIG_VIVI_SCATTER
+	struct sg_to_addr *to_addr=buf->to_addr;
+	struct videobuf_buffer *vb=&buf->vb;
+#else
+	char *tmpbuf;
+#endif
 
+#ifdef CONFIG_VIVI_SCATTER
 	/* Test if DMA mapping is ready */
 	if (!sg_dma_address(&vb->dma.sglist[0]))
 		return;
···
 
 	/* Check if there is enough memory */
 	BUG_ON(buf->vb.dma.nr_pages << PAGE_SHIFT < (buf->vb.width*buf->vb.height)*2);
+#else
+	if (buf->vb.dma.varea) {
+		tmpbuf=kmalloc (wmax*2, GFP_KERNEL);
+	} else {
+		tmpbuf=buf->vb.dma.vmalloc;
+	}
+
+#endif
 
 	for (h=0;h<hmax;h++) {
+#ifdef CONFIG_VIVI_SCATTER
 		gen_line(to_addr,pos,vb->dma.nr_pages,wmax,hmax,h,dev->timestr);
+#else
+		if (buf->vb.dma.varea) {
+			gen_line(tmpbuf,0,wmax,hmax,h,dev->timestr);
+			/* FIXME: replacing to __copy_to_user */
+			copy_to_user(buf->vb.dma.varea+pos,tmpbuf,wmax*2);
+		} else {
+			gen_line(tmpbuf,pos,wmax,hmax,h,dev->timestr);
+		}
+#endif
 		pos += wmax*2;
 	}
 
···
 			dev->h,dev->m,dev->s,(dev->us+500)/1000);
 
 	dprintk(2,"vivifill at %s: Buffer 0x%08lx size= %d\n",dev->timestr,
-			(unsigned long)buf->vb.dma.vmalloc,pos);
+			(unsigned long)buf->vb.dma.varea,pos);
 
 	/* Advice that buffer was filled */
 	buf->vb.state = STATE_DONE;
···
 	if (in_interrupt())
 		BUG();
 
+#ifdef CONFIG_VIVI_SCATTER
 	/*FIXME: Maybe a spinlock is required here */
 	kfree(buf->to_addr);
 	buf->to_addr=NULL;
+#endif
 
 	videobuf_waiton(&buf->vb,0,0);
 	videobuf_dma_unmap(vq, &buf->vb.dma);
···
 
 	buf->vb.state = STATE_PREPARED;
 
+#ifdef CONFIG_VIVI_SCATTER
 	if (NULL == (buf->to_addr = kmalloc(sizeof(*buf->to_addr) * vb->dma.nr_pages,GFP_KERNEL))) {
 		rc=-ENOMEM;
 		goto fail;
 	}
-
+#endif
 	return 0;
 
 fail:
···
 	free_buffer(vq,buf);
 }
 
+#ifdef CONFIG_VIVI_SCATTER
 static int vivi_map_sg(void *dev, struct scatterlist *sg, int nents,
 		       int direction)
 {
···
 //	flush_write_buffers();
 	return 0;
 }
+#endif
 
 static struct videobuf_queue_ops vivi_video_qops = {
 	.buf_setup      = buffer_setup,
···
 	.buf_release    = buffer_release,
 
 	/* Non-pci handling routines */
-	.vb_map_sg      = vivi_map_sg,
-	.vb_dma_sync_sg = vivi_dma_sync_sg,
-	.vb_unmap_sg    = vivi_unmap_sg,
+//	.vb_map_sg      = vivi_map_sg,
+//	.vb_dma_sync_sg = vivi_dma_sync_sg,
+//	.vb_unmap_sg    = vivi_unmap_sg,
 };
 
 /* ------------------------------------------------------------------
···
 	sprintf(dev->timestr,"%02d:%02d:%02d:%03d",
 			dev->h,dev->m,dev->s,(dev->us+500)/1000);
 
+#ifdef CONFIG_VIVI_SCATTER
+	videobuf_queue_init(&fh->vb_vidq,VIDEOBUF_DMA_SCATTER, &vivi_video_qops,
+			NULL, NULL,
+			fh->type,
+			V4L2_FIELD_INTERLACED,
+			sizeof(struct vivi_buffer),fh);
+#else
 	videobuf_queue_init(&fh->vb_vidq, &vivi_video_qops,
 			NULL, NULL,
 			fh->type,
 			V4L2_FIELD_INTERLACED,
 			sizeof(struct vivi_buffer),fh);
+#endif
 
 	return 0;
 }

include/media/video-buf.h

···
 	/* for kernel buffers */
 	void                *vmalloc;
 
+	/* Stores the userspace pointer to vmalloc area */
+	void                *varea;
+
 	/* for overlay buffers (pci-pci dma) */
 	dma_addr_t          bus_addr;