staging: bcm2835-camera: Return early on errors

Fix several instances where it is easier to return
early on error conditions than handle it as an else
clause.
As requested by Mauro.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>

diff --git a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
index d8b43b7..0932969 100644 (file)
--- a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
@@ -335,7 +335,9 @@ static void buffer_cb(struct vchiq_mmal_instance *instance,
                        vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
                }
                return;
-       } else if (length == 0) {
+       }
+
+       if (length == 0) {
                /* stream ended */
                if (buf) {
                        /* this should only ever happen if the port is
@@ -358,71 +360,72 @@ static void buffer_cb(struct vchiq_mmal_instance *instance,
                        /* signal frame completion */
                        complete(&dev->capture.frame_cmplt);
                }
-       } else {
-               if (dev->capture.frame_count) {
-                       if (dev->capture.vc_start_timestamp == -1) {
-                               buf->vb.vb2_buf.timestamp = ktime_get_ns();
-                               v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev,
-                                        "Buffer time set as current time - %lld",
-                                        buf->vb.vb2_buf.timestamp);
-
-                       } else if (pts != 0) {
-                               ktime_t timestamp;
-                               s64 runtime_us = pts -
-                                   dev->capture.vc_start_timestamp;
-                               timestamp = ktime_add_us(dev->capture.kernel_start_ts,
-                                                        runtime_us);
-                               v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev,
-                                        "Convert start time %llu and %llu with offset %llu to %llu\n",
-                                        ktime_to_ns(dev->capture.kernel_start_ts),
-                                        dev->capture.vc_start_timestamp, pts,
-                                        ktime_to_ns(timestamp));
-                               buf->vb.vb2_buf.timestamp = ktime_to_ns(timestamp);
-                       } else {
-                               if (dev->capture.last_timestamp) {
-                                       buf->vb.vb2_buf.timestamp =
-                                               dev->capture.last_timestamp;
-                                       v4l2_dbg(1, bcm2835_v4l2_debug,
-                                                &dev->v4l2_dev,
-                                                "Buffer time set as last timestamp - %lld",
-                                                buf->vb.vb2_buf.timestamp);
-                               } else {
-                                       buf->vb.vb2_buf.timestamp =
-                                               ktime_to_ns(dev->capture.kernel_start_ts);
-                                       v4l2_dbg(1, bcm2835_v4l2_debug,
-                                                &dev->v4l2_dev,
-                                                "Buffer time set as start timestamp - %lld",
-                                                buf->vb.vb2_buf.timestamp);
-                               }
-                       }
-                       dev->capture.last_timestamp = buf->vb.vb2_buf.timestamp;
+               return;
+       }
 
-                       vb2_set_plane_payload(&buf->vb.vb2_buf, 0, length);
-                       if (mmal_flags & MMAL_BUFFER_HEADER_FLAG_KEYFRAME)
-                               buf->vb.flags |= V4L2_BUF_FLAG_KEYFRAME;
+       if (!dev->capture.frame_count) {
+               /* signal frame completion */
+               vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
+               complete(&dev->capture.frame_cmplt);
+               return;
+       }
 
+       if (dev->capture.vc_start_timestamp == -1) {
+               /*
+                * VPU doesn't support MMAL_PARAMETER_SYSTEM_TIME, rely on
+                * kernel time, and have no latency compensation.
+                */
+               buf->vb.vb2_buf.timestamp = ktime_get_ns();
+               v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev,
+                        "Buffer time set as current time - %lld",
+                        buf->vb.vb2_buf.timestamp);
+       } else if (pts != 0) {
+               ktime_t timestamp;
+               s64 runtime_us = pts -
+                   dev->capture.vc_start_timestamp;
+               timestamp = ktime_add_us(dev->capture.kernel_start_ts,
+                                        runtime_us);
+               v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev,
+                        "Convert start time %llu and %llu with offset %llu to %llu\n",
+                        ktime_to_ns(dev->capture.kernel_start_ts),
+                        dev->capture.vc_start_timestamp, pts,
+                        ktime_to_ns(timestamp));
+               buf->vb.vb2_buf.timestamp = ktime_to_ns(timestamp);
+       } else {
+               if (dev->capture.last_timestamp) {
+                       buf->vb.vb2_buf.timestamp = dev->capture.last_timestamp;
                        v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev,
-                                "Buffer has ts %llu",
-                                dev->capture.last_timestamp);
-                       vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
-
-                       if (mmal_flags & MMAL_BUFFER_HEADER_FLAG_EOS &&
-                           is_capturing(dev)) {
-                               v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev,
-                                        "Grab another frame as buffer has EOS");
-                               vchiq_mmal_port_parameter_set(
-                                       instance,
-                                       dev->capture.camera_port,
-                                       MMAL_PARAMETER_CAPTURE,
-                                       &dev->capture.frame_count,
-                                       sizeof(dev->capture.frame_count));
-                       }
+                                "Buffer time set as last timestamp - %lld",
+                                buf->vb.vb2_buf.timestamp);
                } else {
-                       /* signal frame completion */
-                       vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
-                       complete(&dev->capture.frame_cmplt);
+                       buf->vb.vb2_buf.timestamp =
+                               ktime_to_ns(dev->capture.kernel_start_ts);
+                       v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev,
+                                "Buffer time set as start timestamp - %lld",
+                                buf->vb.vb2_buf.timestamp);
                }
        }
+       dev->capture.last_timestamp = buf->vb.vb2_buf.timestamp;
+
+       vb2_set_plane_payload(&buf->vb.vb2_buf, 0, length);
+       if (mmal_flags & MMAL_BUFFER_HEADER_FLAG_KEYFRAME)
+               buf->vb.flags |= V4L2_BUF_FLAG_KEYFRAME;
+
+       v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev,
+                "Buffer has ts %llu",
+                dev->capture.last_timestamp);
+       vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
+
+       if (mmal_flags & MMAL_BUFFER_HEADER_FLAG_EOS &&
+           is_capturing(dev)) {
+               v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev,
+                        "Grab another frame as buffer has EOS");
+               vchiq_mmal_port_parameter_set(instance,
+                                             dev->capture.camera_port,
+                                             MMAL_PARAMETER_CAPTURE,
+                                             &dev->capture.frame_count,
+                                             sizeof(dev->capture.frame_count));
+       }
 }
 
 static int enable_camera(struct bm2835_mmal_dev *dev)
@@ -802,27 +805,29 @@ static int vidioc_overlay(struct file *file, void *f, unsigned int on)
 
        ret = vchiq_mmal_port_set_format(dev->instance, src);
        if (ret < 0)
-               goto error;
+               return ret;
 
        ret = set_overlay_params(dev, dst);
        if (ret < 0)
-               goto error;
+               return ret;
 
-       if (enable_camera(dev) < 0)
-               goto error;
+       if (enable_camera(dev) < 0) {
+               ret = -EINVAL;
+               return ret;
+       }
 
        ret = vchiq_mmal_component_enable(
                        dev->instance,
                        dev->component[MMAL_COMPONENT_PREVIEW]);
        if (ret < 0)
-               goto error;
+               return ret;
 
        v4l2_dbg(1, bcm2835_v4l2_debug, &dev->v4l2_dev, "connecting %p to %p\n",
                 src, dst);
        ret = vchiq_mmal_port_connect_tunnel(dev->instance, src, dst);
        if (!ret)
                ret = vchiq_mmal_port_enable(dev->instance, src, NULL);
-error:
+
        return ret;
 }