[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>

1 files changed, 21 insertions, 46 deletions

diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c
index 133e6b0a5c7d..4c1726d43374 100644
--- 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;
 }