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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>
This commit is contained in:
Ian Armstrong 2008-05-12 11:53:10 -03:00 committed by Mauro Carvalho Chehab
parent 5a4f5da655
commit 4cbeb37114
1 changed files with 82 additions and 0 deletions
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82
drivers/media/video/ivtv/ivtvfb.c
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@ -367,6 +367,87 @@ static int ivtvfb_prep_frame(struct ivtv *itv, int cmd, void __user *source,
return ivtvfb_prep_dec_dma_to_device(itv, dest_offset, source, count);
}
static ssize_t ivtvfb_write(struct fb_info *info, const char __user *buf,
size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
void *dst;
int err = 0;
unsigned long total_size;
struct ivtv *itv = (struct ivtv *) info->par;
unsigned long dma_offset =
IVTV_DECODER_OFFSET + itv->osd_info->video_rbase;
unsigned long dma_size;
u16 lead = 0, tail = 0;
if (info->state != FBINFO_STATE_RUNNING)
return -EPERM;
total_size = info->screen_size;
if (total_size == 0)
total_size = info->fix.smem_len;
if (p > total_size)
return -EFBIG;
if (count > total_size) {
err = -EFBIG;
count = total_size;
}
if (count + p > total_size) {
if (!err)
err = -ENOSPC;
count = total_size - p;
}
dst = (void __force *) (info->screen_base + p);
if (info->fbops->fb_sync)
info->fbops->fb_sync(info);
if (!access_ok(VERIFY_READ, buf, count)) {
IVTVFB_WARN("Invalid userspace pointer 0x%08lx\n",
(unsigned long)buf);
err = -EFAULT;
}
if (!err) {
/* If transfer size > threshold and both src/dst
addresses are aligned, use DMA */
if (count >= 4096 && ((u32)buf & 3) == ((u32)dst & 3)) {
/* Odd address = can't DMA. Align */
if ((u32)dst & 3) {
lead = 4 - ((u32)dst & 3);
memcpy(dst, buf, lead);
buf += lead;
dst += lead;
}
/* DMA resolution is 32 bits */
if ((count - lead) & 3)
tail = (count - lead) & 3;
/* DMA the data */
dma_size = count - lead - tail;
err = ivtvfb_prep_dec_dma_to_device(itv,
p + lead + dma_offset, (void *)buf, dma_size);
dst += dma_size;
buf += dma_size;
/* Copy any leftover data */
if (tail)
memcpy(dst, buf, tail);
} else {
memcpy(dst, buf, count);
}
}
if (!err)
*ppos += count;
return (err) ? err : count;
}
static int ivtvfb_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
{
DEFINE_WAIT(wait);
@ -824,6 +905,7 @@ static int ivtvfb_blank(int blank_mode, struct fb_info *info)
static struct fb_ops ivtvfb_ops = {
.owner = THIS_MODULE,
.fb_write = ivtvfb_write,
.fb_check_var = ivtvfb_check_var,
.fb_set_par = ivtvfb_set_par,
.fb_setcolreg = ivtvfb_setcolreg,