V4L/DVB (11105): gspca - ov534: Adjust the packet scan function

- change max payload size to 2040 bytes (was 2048)
- optimize

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 57 insertions, 58 deletions

diff --git a/drivers/media/video/gspca/ov534.c b/drivers/media/video/gspca/ov534.c
index ea2245626d53..647c448f492f 100644
--- a/drivers/media/video/gspca/ov534.c
+++ b/drivers/media/video/gspca/ov534.c
@@ -46,9 +46,9 @@ MODULE_LICENSE("GPL");
 /* specific webcam descriptor */
 struct sd {
         struct gspca_dev gspca_dev;     /* !! must be the first item */
-        __u32 last_fid;
         __u32 last_pts;
-        int frame_rate;
+        u16 last_fid;
+        u8 frame_rate;
 };
 
 /* V4L2 controls supported by the driver */
@@ -428,76 +428,75 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev, struct gspca_frame *frame,
 {
         struct sd *sd = (struct sd *) gspca_dev;
         __u32 this_pts;
-        int this_fid;
+        u16 this_fid;
         int remaining_len = len;
-        __u8 *next_data = data;
 
-scan_next:
-        if (remaining_len <= 0)
-                return;
-
-        data = next_data;
-        len = min(remaining_len, 2048);
-        remaining_len -= len;
-        next_data += len;
-
-        /* Payloads are prefixed with a UVC-style header.  We
-           consider a frame to start when the FID toggles, or the PTS
-           changes.  A frame ends when EOF is set, and we've received
-           the correct number of bytes. */
-
-        /* Verify UVC header.  Header length is always 12 */
-        if (data[0] != 12 || len < 12) {
-                PDEBUG(D_PACK, "bad header");
-                goto discard;
-        }
+        do {
+                len = min(remaining_len, 2040);         /*fixme: was 2048*/
 
-        /* Check errors */
-        if (data[1] & UVC_STREAM_ERR) {
-                PDEBUG(D_PACK, "payload error");
-                goto discard;
-        }
+                /* Payloads are prefixed with a UVC-style header.  We
+                   consider a frame to start when the FID toggles, or the PTS
+                   changes.  A frame ends when EOF is set, and we've received
+                   the correct number of bytes. */
 
-        /* Extract PTS and FID */
-        if (!(data[1] & UVC_STREAM_PTS)) {
-                PDEBUG(D_PACK, "PTS not present");
-                goto discard;
-        }
-        this_pts = (data[5] << 24) | (data[4] << 16) | (data[3] << 8) | data[2];
-        this_fid = (data[1] & UVC_STREAM_FID) ? 1 : 0;
-
-        /* If PTS or FID has changed, start a new frame. */
-        if (this_pts != sd->last_pts || this_fid != sd->last_fid) {
-                gspca_frame_add(gspca_dev, FIRST_PACKET, frame, NULL, 0);
-                sd->last_pts = this_pts;
-                sd->last_fid = this_fid;
-        }
-
-        /* Add the data from this payload */
-        gspca_frame_add(gspca_dev, INTER_PACKET, frame,
-                                data + 12, len - 12);
+                /* Verify UVC header.  Header length is always 12 */
+                if (data[0] != 12 || len < 12) {
+                        PDEBUG(D_PACK, "bad header");
+                        goto discard;
+                }
 
-        /* If this packet is marked as EOF, end the frame */
-        if (data[1] & UVC_STREAM_EOF) {
-                sd->last_pts = 0;
+                /* Check errors */
+                if (data[1] & UVC_STREAM_ERR) {
+                        PDEBUG(D_PACK, "payload error");
+                        goto discard;
+                }
 
-                if ((frame->data_end - frame->data) !=
-                    (gspca_dev->width * gspca_dev->height * 2)) {
-                        PDEBUG(D_PACK, "short frame");
+                /* Extract PTS and FID */
+                if (!(data[1] & UVC_STREAM_PTS)) {
+                        PDEBUG(D_PACK, "PTS not present");
                         goto discard;
                 }
+                this_pts = (data[5] << 24) | (data[4] << 16)
+                                                | (data[3] << 8) | data[2];
+                this_fid = (data[1] & UVC_STREAM_FID) ? 1 : 0;
 
-                frame = gspca_frame_add(gspca_dev, LAST_PACKET, frame,
+                /* If PTS or FID has changed, start a new frame. */
+                if (this_pts != sd->last_pts || this_fid != sd->last_fid) {
+                        gspca_frame_add(gspca_dev, FIRST_PACKET, frame,
                                         NULL, 0);
+                        sd->last_pts = this_pts;
+                        sd->last_fid = this_fid;
+                }
+
+                /* Add the data from this payload */
+                gspca_frame_add(gspca_dev, INTER_PACKET, frame,
+                                        data + 12, len - 12);
+
+                /* If this packet is marked as EOF, end the frame */
+                if (data[1] & UVC_STREAM_EOF) {
+                        sd->last_pts = 0;
+
+                        if (frame->data_end - frame->data !=
+                            gspca_dev->width * gspca_dev->height * 2) {
+                                PDEBUG(D_PACK, "short frame");
+                                goto discard;
+                        }
+
+                        frame = gspca_frame_add(gspca_dev, LAST_PACKET, frame,
+                                                NULL, 0);
                 }
 
-        /* Done this payload */
-        goto scan_next;
+                /* Done this payload */
+                goto scan_next;
 
 discard:
-        /* Discard data until a new frame starts. */
-        gspca_frame_add(gspca_dev, DISCARD_PACKET, frame, NULL, 0);
-        goto scan_next;
+                /* Discard data until a new frame starts. */
+                gspca_frame_add(gspca_dev, DISCARD_PACKET, frame, NULL, 0);
+
+scan_next:
+                remaining_len -= len;
+                data += len;
+        } while (remaining_len > 0);
 }
 
 /* get stream parameters (framerate) */