V4L/DVB (7886): ivtvfb: Use DMA for write()
write() operations to the ivtv framebuffer will now attempt to use DMA if the amount of data to copy is >= 4096 bytes. This change effectively depreciates the need for the proprietary IVTVFB_IOC_DMA_FRAME ioctl since a write() of sufficient size will do the same thing. Signed-off-by: Ian Armstrong <ian@iarmst.demon.co.uk> Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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@ -367,6 +367,87 @@ static int ivtvfb_prep_frame(struct ivtv *itv, int cmd, void __user *source,
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return ivtvfb_prep_dec_dma_to_device(itv, dest_offset, source, count);
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}
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static ssize_t ivtvfb_write(struct fb_info *info, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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unsigned long p = *ppos;
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void *dst;
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int err = 0;
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unsigned long total_size;
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struct ivtv *itv = (struct ivtv *) info->par;
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unsigned long dma_offset =
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IVTV_DECODER_OFFSET + itv->osd_info->video_rbase;
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unsigned long dma_size;
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u16 lead = 0, tail = 0;
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if (info->state != FBINFO_STATE_RUNNING)
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return -EPERM;
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total_size = info->screen_size;
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if (total_size == 0)
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total_size = info->fix.smem_len;
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if (p > total_size)
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return -EFBIG;
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if (count > total_size) {
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err = -EFBIG;
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count = total_size;
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}
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if (count + p > total_size) {
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if (!err)
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err = -ENOSPC;
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count = total_size - p;
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}
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dst = (void __force *) (info->screen_base + p);
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if (info->fbops->fb_sync)
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info->fbops->fb_sync(info);
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if (!access_ok(VERIFY_READ, buf, count)) {
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IVTVFB_WARN("Invalid userspace pointer 0x%08lx\n",
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(unsigned long)buf);
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err = -EFAULT;
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}
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if (!err) {
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/* If transfer size > threshold and both src/dst
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addresses are aligned, use DMA */
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if (count >= 4096 && ((u32)buf & 3) == ((u32)dst & 3)) {
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/* Odd address = can't DMA. Align */
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if ((u32)dst & 3) {
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lead = 4 - ((u32)dst & 3);
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memcpy(dst, buf, lead);
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buf += lead;
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dst += lead;
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}
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/* DMA resolution is 32 bits */
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if ((count - lead) & 3)
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tail = (count - lead) & 3;
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/* DMA the data */
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dma_size = count - lead - tail;
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err = ivtvfb_prep_dec_dma_to_device(itv,
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p + lead + dma_offset, (void *)buf, dma_size);
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dst += dma_size;
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buf += dma_size;
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/* Copy any leftover data */
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if (tail)
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memcpy(dst, buf, tail);
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} else {
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memcpy(dst, buf, count);
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}
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}
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if (!err)
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*ppos += count;
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return (err) ? err : count;
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}
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static int ivtvfb_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
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{
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DEFINE_WAIT(wait);
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@ -824,6 +905,7 @@ static int ivtvfb_blank(int blank_mode, struct fb_info *info)
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static struct fb_ops ivtvfb_ops = {
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.owner = THIS_MODULE,
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.fb_write = ivtvfb_write,
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.fb_check_var = ivtvfb_check_var,
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.fb_set_par = ivtvfb_set_par,
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.fb_setcolreg = ivtvfb_setcolreg,
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