[media] em28xx: clean up and unify functions em28xx_copy_vbi() em28xx_copy_video()

The code in em28xx_vbi_copy can be simplified a lot.
Also rename some variables to something more meaningful and fix+add the
function descriptions.

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c
index 133e6b0..4c1726d 100644 (file)
--- a/drivers/media/usb/em28xx/em28xx-video.c
+++ b/drivers/media/usb/em28xx/em28xx-video.c
@@ -168,28 +168,27 @@ static inline void finish_buffer(struct em28xx *dev,
 }
 
 /*
- * Identify the buffer header type and properly handles
+ * Copy picture data from USB buffer to videobuf buffer
  */
 static void em28xx_copy_video(struct em28xx *dev,
                              struct em28xx_buffer *buf,
-                             unsigned char *p,
+                             unsigned char *usb_buf,
                              unsigned long len)
 {
        void *fieldstart, *startwrite, *startread;
        int  linesdone, currlinedone, offset, lencopy, remain;
        int bytesperline = dev->width << 1;
-       unsigned char *outp = buf->vb_buf;
 
        if (buf->pos + len > buf->vb.size)
                len = buf->vb.size - buf->pos;
 
-       startread = p;
+       startread = usb_buf;
        remain = len;
 
        if (dev->progressive || buf->top_field)
-               fieldstart = outp;
+               fieldstart = buf->vb_buf;
        else /* interlaced mode, even nr. of lines */
-               fieldstart = outp + bytesperline;
+               fieldstart = buf->vb_buf + bytesperline;
 
        linesdone = buf->pos / bytesperline;
        currlinedone = buf->pos % bytesperline;
@@ -203,11 +202,12 @@ static void em28xx_copy_video(struct em28xx *dev,
        lencopy = bytesperline - currlinedone;
        lencopy = lencopy > remain ? remain : lencopy;
 
-       if ((char *)startwrite + lencopy > (char *)outp + buf->vb.size) {
+       if ((char *)startwrite + lencopy > (char *)buf->vb_buf + buf->vb.size) {
                em28xx_isocdbg("Overflow of %zi bytes past buffer end (1)\n",
-                              ((char *)startwrite + lencopy) -
-                              ((char *)outp + buf->vb.size));
-               remain = (char *)outp + buf->vb.size - (char *)startwrite;
+                             ((char *)startwrite + lencopy) -
+                             ((char *)buf->vb_buf + buf->vb.size));
+               remain = (char *)buf->vb_buf + buf->vb.size -
+                        (char *)startwrite;
                lencopy = remain;
        }
        if (lencopy <= 0)
@@ -227,13 +227,13 @@ static void em28xx_copy_video(struct em28xx *dev,
                else
                        lencopy = bytesperline;
 
-               if ((char *)startwrite + lencopy > (char *)outp +
+               if ((char *)startwrite + lencopy > (char *)buf->vb_buf +
                    buf->vb.size) {
                        em28xx_isocdbg("Overflow of %zi bytes past buffer end"
                                       "(2)\n",
                                       ((char *)startwrite + lencopy) -
-                                      ((char *)outp + buf->vb.size));
-                       lencopy = remain = (char *)outp + buf->vb.size -
+                                      ((char *)buf->vb_buf + buf->vb.size));
+                       lencopy = remain = (char *)buf->vb_buf + buf->vb.size -
                                           (char *)startwrite;
                }
                if (lencopy <= 0)
@@ -247,50 +247,25 @@ static void em28xx_copy_video(struct em28xx *dev,
        buf->pos += len;
 }
 
+/*
+ * Copy VBI data from USB buffer to videobuf buffer
+ */
 static void em28xx_copy_vbi(struct em28xx *dev,
                            struct em28xx_buffer *buf,
-                           unsigned char *p,
+                           unsigned char *usb_buf,
                            unsigned long len)
 {
-       void *startwrite, *startread;
-       int  offset;
-       int bytesperline;
-       unsigned char *outp;
-
-       if (dev == NULL) {
-               em28xx_isocdbg("dev is null\n");
-               return;
-       }
-       bytesperline = dev->vbi_width;
-
-       if (buf == NULL) {
-               return;
-       }
-       if (p == NULL) {
-               em28xx_isocdbg("p is null\n");
-               return;
-       }
-       outp = buf->vb_buf;
-       if (outp == NULL) {
-               em28xx_isocdbg("outp is null\n");
-               return;
-       }
+       unsigned int offset;
 
        if (buf->pos + len > buf->vb.size)
                len = buf->vb.size - buf->pos;
 
-       startread = p;
-
-       startwrite = outp + buf->pos;
        offset = buf->pos;
-
        /* Make sure the bottom field populates the second half of the frame */
-       if (buf->top_field == 0) {
-               startwrite += bytesperline * dev->vbi_height;
-               offset += bytesperline * dev->vbi_height;
-       }
+       if (buf->top_field == 0)
+               offset += dev->vbi_width * dev->vbi_height;
 
-       memcpy(startwrite, startread, len);
+       memcpy(buf->vb_buf + offset, usb_buf, len);
        buf->pos += len;
 }