[media] uvcvideo: Extract video stream statistics

Export the statistics through debugfs.

Signed-off-by: Alexey Fisher <bug-track@fisher-privat.net>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 199 insertions, 5 deletions

diff --git a/drivers/media/video/uvc/uvc_debugfs.c b/drivers/media/video/uvc/uvc_debugfs.c
index 39fd43b3e1d2..14561a5abb79 100644
--- a/drivers/media/video/uvc/uvc_debugfs.c
+++ b/drivers/media/video/uvc/uvc_debugfs.c
@@ -19,6 +19,57 @@
 #include "uvcvideo.h"
 
 /* -----------------------------------------------------------------------------
+ * Statistics
+ */
+
+#define UVC_DEBUGFS_BUF_SIZE    1024
+
+struct uvc_debugfs_buffer {
+        size_t count;
+        char data[UVC_DEBUGFS_BUF_SIZE];
+};
+
+static int uvc_debugfs_stats_open(struct inode *inode, struct file *file)
+{
+        struct uvc_streaming *stream = inode->i_private;
+        struct uvc_debugfs_buffer *buf;
+
+        buf = kmalloc(sizeof(*buf), GFP_KERNEL);
+        if (buf == NULL)
+                return -ENOMEM;
+
+        buf->count = uvc_video_stats_dump(stream, buf->data, sizeof(buf->data));
+
+        file->private_data = buf;
+        return 0;
+}
+
+static ssize_t uvc_debugfs_stats_read(struct file *file, char __user *user_buf,
+                                      size_t nbytes, loff_t *ppos)
+{
+        struct uvc_debugfs_buffer *buf = file->private_data;
+
+        return simple_read_from_buffer(user_buf, nbytes, ppos, buf->data,
+                                       buf->count);
+}
+
+static int uvc_debugfs_stats_release(struct inode *inode, struct file *file)
+{
+        kfree(file->private_data);
+        file->private_data = NULL;
+
+        return 0;
+}
+
+static const struct file_operations uvc_debugfs_stats_fops = {
+        .owner = THIS_MODULE,
+        .open = uvc_debugfs_stats_open,
+        .llseek = no_llseek,
+        .read = uvc_debugfs_stats_read,
+        .release = uvc_debugfs_stats_release,
+};
+
+/* -----------------------------------------------------------------------------
  * Global and stream initialization/cleanup
  */
 
@@ -37,13 +88,21 @@ int uvc_debugfs_init_stream(struct uvc_streaming *stream)
 
         dent = debugfs_create_dir(dir_name, uvc_debugfs_root_dir);
         if (IS_ERR_OR_NULL(dent)) {
-                uvc_printk(KERN_INFO, "Unable to create debugfs %s directory.\n",
-                           dir_name);
+                uvc_printk(KERN_INFO, "Unable to create debugfs %s "
+                           "directory.\n", dir_name);
                 return -ENODEV;
         }
 
         stream->debugfs_dir = dent;
 
+        dent = debugfs_create_file("stats", 0444, stream->debugfs_dir,
+                                   stream, &uvc_debugfs_stats_fops);
+        if (IS_ERR_OR_NULL(dent)) {
+                uvc_printk(KERN_INFO, "Unable to create debugfs stats file.\n");
+                uvc_debugfs_cleanup_stream(stream);
+                return -ENODEV;
+        }
+
         return 0;
 }
 
diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c
index a57f81341849..1908dd859433 100644
--- a/drivers/media/video/uvc/uvc_video.c
+++ b/drivers/media/video/uvc/uvc_video.c
@@ -358,6 +358,100 @@ static int uvc_commit_video(struct uvc_streaming *stream,
 }
 
 /* ------------------------------------------------------------------------
+ * Stream statistics
+ */
+
+static void uvc_video_stats_decode(struct uvc_streaming *stream,
+                const __u8 *data, int len)
+{
+        unsigned int header_size;
+
+        if (stream->stats.stream.nb_frames == 0 &&
+            stream->stats.frame.nb_packets == 0)
+                ktime_get_ts(&stream->stats.stream.start_ts);
+
+        switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {
+        case UVC_STREAM_PTS | UVC_STREAM_SCR:
+                header_size = 12;
+                break;
+        case UVC_STREAM_PTS:
+                header_size = 6;
+                break;
+        case UVC_STREAM_SCR:
+                header_size = 8;
+                break;
+        default:
+                header_size = 2;
+                break;
+        }
+
+        /* Check for invalid headers. */
+        if (len < header_size || data[0] < header_size) {
+                stream->stats.frame.nb_invalid++;
+                return;
+        }
+
+        /* Record the first non-empty packet number. */
+        if (stream->stats.frame.size == 0 && len > header_size)
+                stream->stats.frame.first_data = stream->stats.frame.nb_packets;
+
+        /* Update the frame size. */
+        stream->stats.frame.size += len - header_size;
+
+        /* Update the packets counters. */
+        stream->stats.frame.nb_packets++;
+        if (len > header_size)
+                stream->stats.frame.nb_empty++;
+
+        if (data[1] & UVC_STREAM_ERR)
+                stream->stats.frame.nb_errors++;
+}
+
+static void uvc_video_stats_update(struct uvc_streaming *stream)
+{
+        struct uvc_stats_frame *frame = &stream->stats.frame;
+
+        uvc_trace(UVC_TRACE_STATS, "frame %u stats: %u/%u/%u packets\n",
+                  stream->sequence, frame->first_data,
+                  frame->nb_packets - frame->nb_empty, frame->nb_packets);
+
+        stream->stats.stream.nb_frames++;
+        stream->stats.stream.nb_packets += stream->stats.frame.nb_packets;
+        stream->stats.stream.nb_empty += stream->stats.frame.nb_empty;
+        stream->stats.stream.nb_errors += stream->stats.frame.nb_errors;
+        stream->stats.stream.nb_invalid += stream->stats.frame.nb_invalid;
+
+        memset(&stream->stats.frame, 0, sizeof(stream->stats.frame));
+}
+
+size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
+                            size_t size)
+{
+        size_t count = 0;
+
+        count += scnprintf(buf + count, size - count,
+                           "frames:  %u\npackets: %u\nempty:   %u\n"
+                           "errors:  %u\ninvalid: %u\n",
+                           stream->stats.stream.nb_frames,
+                           stream->stats.stream.nb_packets,
+                           stream->stats.stream.nb_empty,
+                           stream->stats.stream.nb_errors,
+                           stream->stats.stream.nb_invalid);
+
+        return count;
+}
+
+static void uvc_video_stats_start(struct uvc_streaming *stream)
+{
+        memset(&stream->stats, 0, sizeof(stream->stats));
+}
+
+static void uvc_video_stats_stop(struct uvc_streaming *stream)
+{
+        ktime_get_ts(&stream->stats.stream.stop_ts);
+}
+
+/* ------------------------------------------------------------------------
  * Video codecs
  */
 
@@ -406,16 +500,23 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,
          * - bHeaderLength value must be at least 2 bytes (see above)
          * - bHeaderLength value can't be larger than the packet size.
          */
-        if (len < 2 || data[0] < 2 || data[0] > len)
+        if (len < 2 || data[0] < 2 || data[0] > len) {
+                stream->stats.frame.nb_invalid++;
                 return -EINVAL;
+        }
 
         fid = data[1] & UVC_STREAM_FID;
 
         /* Increase the sequence number regardless of any buffer states, so
          * that discontinuous sequence numbers always indicate lost frames.
          */
-        if (stream->last_fid != fid)
+        if (stream->last_fid != fid) {
                 stream->sequence++;
+                if (stream->sequence)
+                        uvc_video_stats_update(stream);
+        }
+
+        uvc_video_stats_decode(stream, data, len);
 
         /* Store the payload FID bit and return immediately when the buffer is
          * NULL.
@@ -860,6 +961,8 @@ static void uvc_uninit_video(struct uvc_streaming *stream, int free_buffers)
         struct urb *urb;
         unsigned int i;
 
+        uvc_video_stats_stop(stream);
+
         for (i = 0; i < UVC_URBS; ++i) {
                 urb = stream->urb[i];
                 if (urb == NULL)
@@ -999,6 +1102,8 @@ static int uvc_init_video(struct uvc_streaming *stream, gfp_t gfp_flags)
         stream->bulk.skip_payload = 0;
         stream->bulk.payload_size = 0;
 
+        uvc_video_stats_start(stream);
+
         if (intf->num_altsetting > 1) {
                 struct usb_host_endpoint *best_ep = NULL;
                 unsigned int best_psize = 3 * 1024;
diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h
index d975636cbb10..f9ee62ed0150 100644
--- a/drivers/media/video/uvc/uvcvideo.h
+++ b/drivers/media/video/uvc/uvcvideo.h
@@ -356,6 +356,28 @@ struct uvc_video_chain {
         struct mutex ctrl_mutex;                /* Protects ctrl.info */
 };
 
+struct uvc_stats_frame {
+        unsigned int size;              /* Number of bytes captured */
+        unsigned int first_data;        /* Index of the first non-empty packet */
+
+        unsigned int nb_packets;        /* Number of packets */
+        unsigned int nb_empty;          /* Number of empty packets */
+        unsigned int nb_invalid;        /* Number of packets with an invalid header */
+        unsigned int nb_errors;         /* Number of packets with the error bit set */
+};
+
+struct uvc_stats_stream {
+        struct timespec start_ts;       /* Stream start timestamp */
+        struct timespec stop_ts;        /* Stream stop timestamp */
+
+        unsigned int nb_frames;         /* Number of frames */
+
+        unsigned int nb_packets;        /* Number of packets */
+        unsigned int nb_empty;          /* Number of empty packets */
+        unsigned int nb_invalid;        /* Number of packets with an invalid header */
+        unsigned int nb_errors;         /* Number of packets with the error bit set */
+};
+
 struct uvc_streaming {
         struct list_head list;
         struct uvc_device *dev;
@@ -406,6 +428,10 @@ struct uvc_streaming {
 
         /* debugfs */
         struct dentry *debugfs_dir;
+        struct {
+                struct uvc_stats_frame frame;
+                struct uvc_stats_stream stream;
+        } stats;
 };
 
 enum uvc_device_state {
@@ -477,6 +503,7 @@ struct uvc_driver {
 #define UVC_TRACE_SUSPEND       (1 << 8)
 #define UVC_TRACE_STATUS        (1 << 9)
 #define UVC_TRACE_VIDEO         (1 << 10)
+#define UVC_TRACE_STATS         (1 << 11)
 
 #define UVC_WARN_MINMAX         0
 #define UVC_WARN_PROBE_DEF      1
@@ -609,10 +636,13 @@ extern struct usb_host_endpoint *uvc_find_endpoint(
 void uvc_video_decode_isight(struct urb *urb, struct uvc_streaming *stream,
                 struct uvc_buffer *buf);
 
-/* debugfs */
+/* debugfs and statistics */
 int uvc_debugfs_init(void);
 void uvc_debugfs_cleanup(void);
 int uvc_debugfs_init_stream(struct uvc_streaming *stream);
 void uvc_debugfs_cleanup_stream(struct uvc_streaming *stream);
 
+size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
+                            size_t size);
+
 #endif