aboutsummaryrefslogtreecommitdiff
path: root/drivers
diff options
context:
space:
mode:
authorIan Armstrong <ian@iarmst.co.uk>2008-05-12 11:53:10 -0300
committerMauro Carvalho Chehab <mchehab@infradead.org>2008-07-20 07:05:57 -0300
commit4cbeb3711481a7e563fe4c61888986c4aa1cb22e (patch)
treeb672ed149fb8fe2544867f7d8b883df67814e7ac /drivers
parent5a4f5da6552e6c55eff6fbddfee3eab908325c63 (diff)
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/media/video/ivtv/ivtvfb.c82
1 files changed, 82 insertions, 0 deletions
diff --git a/drivers/media/video/ivtv/ivtvfb.c b/drivers/media/video/ivtv/ivtvfb.c
index 73be154f7f0..e8dbee44394 100644
--- a/drivers/media/video/ivtv/ivtvfb.c
+++ b/drivers/media/video/ivtv/ivtvfb.c
@@ -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,