isp: Add histogram supporthistogram

Support enabling the histogram statistics engine and retrieving
histogram data. Histogram data is currently ignored in the image quality
tuning implementation.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

9 files changed, 323 insertions, 34 deletions

diff --git a/iq.c b/iq.c
index dd85cfc..41fa90d 100644
--- a/iq.c
+++ b/iq.c
@@ -94,6 +94,12 @@ void iq_aewb_process(struct iq_tuning *iq,
 	omap3_isp_sensor_set_gain(iq->isp, iqp->gain);
 }
 
+void iq_histogram_process(struct iq_tuning *iq __attribute__((__unused__)),
+			  const struct omap3_isp_histogram_stats *stats __attribute__((__unused__)))
+{
+	printf("hist: data received\n");
+}
+
 /**
  * iq_params_init - Initialize IQ parameters
  * @params: IQ parameters
@@ -223,7 +229,8 @@ struct iq_tuning *iq_init(struct omap3_isp_device *isp,
 	window.height = params->window.height * format.height;
 
 	omap3_isp_aewb_configure(isp, &window, iq->pix_max - iq->params.black_level - 1);
-	omap3_isp_stats_enable(isp, true);
+	omap3_isp_histogram_configure(isp, &window);
+	omap3_isp_stats_enable(isp, OMAP3_ISP_STAT_AEWB | OMAP3_ISP_STAT_HIST);
 
 	return iq;
 }
diff --git a/iq.h b/iq.h
index be13a9f..5b5217a 100644
--- a/iq.h
+++ b/iq.h
@@ -69,6 +69,8 @@ struct iq_params {
 
 void iq_aewb_process(struct iq_tuning *iq,
 		     const struct omap3_isp_aewb_stats *stats);
+void iq_histogram_process(struct iq_tuning *iq,
+			  const struct omap3_isp_histogram_stats *stats);
 
 void iq_params_init(struct iq_params *params);
 int iq_params_parse(struct iq_params *params, const char *arg);
diff --git a/isp/omap3isp-priv.h b/isp/omap3isp-priv.h
index a31f943..3a3eee7 100644
--- a/isp/omap3isp-priv.h
+++ b/isp/omap3isp-priv.h
@@ -177,6 +177,7 @@ struct omap3_isp_device {
 		struct media_entity *entity;
 	} resizer;
 	struct omap3_isp_aewb aewb;
+	struct omap3_isp_histogram hist;
 
 	struct omap3_isp_pipeline viewfinder;
 	struct omap3_isp_pipeline snapshot;
diff --git a/isp/omap3isp.h b/isp/omap3isp.h
index 491dcdb..f31de3e 100644
--- a/isp/omap3isp.h
+++ b/isp/omap3isp.h
@@ -54,6 +54,8 @@ struct omap3_isp_operations {
 			     struct v4l2_video_buffer *buffer);
 	void (*aewb_ready)(struct omap3_isp_device *isp,
 			   const struct omap3_isp_aewb_stats *stats);
+	void (*histogram_ready)(struct omap3_isp_device *isp,
+				const struct omap3_isp_histogram_stats *hist);
 	void (*watch_fd)(int fd, enum omap3_isp_event_type type,
 			 void(*callback)(void *priv), void *priv);
 	void (*unwatch_fd)(int fd);
diff --git a/isp/stats-priv.h b/isp/stats-priv.h
index c3f084c..43b920a 100644
--- a/isp/stats-priv.h
+++ b/isp/stats-priv.h
@@ -66,6 +66,24 @@ struct omap3_isp_aewb {
 	bool enabled;
 };
 
+/*
+ * struct omap3_isp_histogram - OMAP3 ISP histogram statistics engine
+ * @entity: Histogram entity
+ * @size: buffer size
+ * @buffer: buffer memory
+ * @rect: histogram region of interest
+ * @enabled: statistics engine enabled
+ */
+struct omap3_isp_histogram {
+	struct media_entity *entity;
+	unsigned int size;
+	void *buffer;
+
+	struct v4l2_rect rect;
+
+	bool enabled;
+};
+
 int omap3_isp_stats_start(struct omap3_isp_device *isp);
 void omap3_isp_stats_stop(struct omap3_isp_device *isp);
 int omap3_isp_stats_init(struct omap3_isp_device *isp);
diff --git a/isp/stats.c b/isp/stats.c
index a96da5e..4ff11a9 100644
--- a/isp/stats.c
+++ b/isp/stats.c
@@ -278,32 +278,7 @@ int omap3_isp_aewb_configure(struct omap3_isp_device *isp, struct v4l2_rect *rec
 	return 0;
 }
 
-/* -----------------------------------------------------------------------------
- * Start/stop, init/cleanup
- */
-
-int omap3_isp_stats_get_format(struct omap3_isp_device *isp,
-			       struct v4l2_mbus_framefmt *format)
-{
-	struct omap3_isp_aewb *aewb = &isp->aewb;
-	struct media_entity_pad *source;
-
-	source = media_entity_remote_source(&aewb->entity->pads[0]);
-	if (source == NULL)
-		return -ENOENT;
-
-	return v4l2_subdev_get_format(source->entity, format, source->index,
-				      V4L2_SUBDEV_FORMAT_TRY);
-}
-
-void omap3_isp_stats_enable(struct omap3_isp_device *isp, bool enable)
-{
-	struct omap3_isp_aewb *aewb = &isp->aewb;
-
-	aewb->enabled = enable;
-}
-
-int omap3_isp_stats_start(struct omap3_isp_device *isp)
+static int omap3_isp_aewb_start(struct omap3_isp_device *isp)
 {
 	struct omap3_isp_aewb *aewb = &isp->aewb;
 	struct v4l2_event_subscription esub;
@@ -342,7 +317,7 @@ int omap3_isp_stats_start(struct omap3_isp_device *isp)
 	return 0;
 }
 
-void omap3_isp_stats_stop(struct omap3_isp_device *isp)
+static void omap3_isp_aewb_stop(struct omap3_isp_device *isp)
 {
 	struct omap3_isp_aewb *aewb = &isp->aewb;
 	struct v4l2_event_subscription esub;
@@ -359,7 +334,7 @@ void omap3_isp_stats_stop(struct omap3_isp_device *isp)
 	ioctl(aewb->entity->fd, VIDIOC_UNSUBSCRIBE_EVENT, &esub);
 }
 
-int omap3_isp_stats_init(struct omap3_isp_device *isp)
+static int omap3_isp_aewb_init(struct omap3_isp_device *isp)
 {
 	struct omap3_isp_aewb *aewb = &isp->aewb;
 
@@ -370,7 +345,250 @@ int omap3_isp_stats_init(struct omap3_isp_device *isp)
 	return v4l2_subdev_open(aewb->entity);
 }
 
+/* -----------------------------------------------------------------------------
+ * Histogram
+ */
+
+static void omap3_isp_histogram_process(struct omap3_isp_device *isp,
+					void *buffer,
+					size_t size __attribute__((__unused__)))
+{
+	struct omap3_isp_histogram_stats stats;
+
+	memset(&stats, 0, sizeof stats);
+	stats.nbins = 256;
+	stats.bins = (uint32_t *)buffer;
+
+	isp->ops->histogram_ready(isp, &stats);
+}
+
+static void omap3_isp_histogram_event(void *priv)
+{
+	struct omap3_isp_device *isp = priv;
+	struct omap3_isp_histogram *hist = &isp->hist;
+	struct omap3isp_stat_data data;
+	struct v4l2_event event;
+	struct omap3isp_stat_event_status *status =
+		(struct omap3isp_stat_event_status *)event.u.data;
+	int ret;
+
+	memset(&event, 0, sizeof event);
+	ret = ioctl(hist->entity->fd, VIDIOC_DQEVENT, &event);
+	if (ret < 0) {
+		printf("unable to retrieve histogram event: %s (%d).\n",
+			strerror(errno), errno);
+		return;
+	}
+
+	if (status->buf_err) {
+		printf("histogram: stats error, skipping buffer.\n");
+		return;
+	}
+
+	memset(&data, 0, sizeof data);
+	data.buf = hist->buffer;
+	data.buf_size = hist->size;
+
+	ret = ioctl(hist->entity->fd, VIDIOC_OMAP3ISP_STAT_REQ, &data);
+	if (ret < 0) {
+		printf("unable to retrieve histogram data: %s (%d).\n",
+			strerror(errno), errno);
+		return;
+	}
+
+	omap3_isp_histogram_process(isp, data.buf, data.buf_size);
+}
+
+static int omap3_isp_histogram_setup(struct omap3_isp_device *isp)
+{
+	struct omap3_isp_histogram *hist = &isp->hist;
+	struct omap3isp_hist_config config;
+	unsigned int buf_size;
+	int ret;
+
+	memset(&config, 0, sizeof config);
+	config.num_acc_frames = 1;
+	config.hist_bins = OMAP3ISP_HIST_BINS_256;
+	config.cfa = OMAP3ISP_HIST_CFA_BAYER;
+	config.wg[0] = 1 << 5;
+	config.wg[1] = 1 << 5;
+	config.wg[2] = 1 << 5;
+	config.wg[3] = 1 << 5;
+	config.num_regions = 1;
+	config.region[0].h_start = hist->rect.left;
+	config.region[0].h_end = hist->rect.left + hist->rect.width - 1;
+	config.region[0].v_start = hist->rect.top;
+	config.region[0].v_end = hist->rect.top + hist->rect.height - 1;
+
+	buf_size = OMAP3ISP_HIST_MEM_SIZE_BINS(config.hist_bins)
+		 * config.num_regions;
+	config.buf_size = buf_size;
+
+	ret = ioctl(hist->entity->fd, VIDIOC_OMAP3ISP_HIST_CFG, &config);
+	if (ret < 0)
+		return -errno;
+
+	if (config.buf_size != buf_size)
+		printf("histogram: buf size was %u, is %u\n", buf_size,
+			config.buf_size);
+
+	hist->size = config.buf_size;
+	hist->buffer = malloc(config.buf_size);
+	if (hist->buffer == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+int omap3_isp_histogram_configure(struct omap3_isp_device *isp,
+				  struct v4l2_rect *rect)
+{
+	struct omap3_isp_histogram *hist = &isp->hist;
+	struct v4l2_mbus_framefmt format;
+	struct media_entity_pad *source;
+	int ret;
+
+	source = media_entity_remote_source(&hist->entity->pads[0]);
+	if (source == NULL)
+		return -ENOENT;
+
+	ret = v4l2_subdev_get_format(source->entity, &format, source->index,
+				     V4L2_SUBDEV_FORMAT_TRY);
+	if (ret < 0)
+		return ret;
+
+	/* Validate the requested rectangle. */
+	if (rect->left < 0 || rect->left + rect->width > (int)format.width ||
+	    rect->top < 0 || rect->top + rect->height > (int)format.height)
+		return -ERANGE;
+
+	hist->rect = *rect;
+
+	return 0;
+}
+
+static int omap3_isp_histogram_start(struct omap3_isp_device *isp)
+{
+	struct omap3_isp_histogram *hist = &isp->hist;
+	struct v4l2_event_subscription esub;
+	unsigned long enable = 1;
+	int ret;
+
+	if (!hist->enabled)
+		return 0;
+
+	ret = omap3_isp_histogram_setup(isp);
+	if (ret < 0) {
+		printf("unable to configure histogram engine: %s (%d).\n",
+			strerror(errno), errno);
+		return ret;
+	}
+
+	memset(&esub, 0, sizeof esub);
+	esub.type = V4L2_EVENT_OMAP3ISP_HIST;
+	ret = ioctl(hist->entity->fd, VIDIOC_SUBSCRIBE_EVENT, &esub);
+	if (ret < 0) {
+		printf("unable to subscribe to histogram event: %s (%d).\n",
+			strerror(errno), errno);
+		return ret;
+	}
+
+	ret = ioctl(hist->entity->fd, VIDIOC_OMAP3ISP_STAT_EN, &enable);
+	if (ret < 0) {
+		printf("unable to start histogram engine: %s (%d).\n",
+			strerror(errno), errno);
+		return ret;
+	}
+
+	isp->ops->watch_fd(hist->entity->fd, OMAP3_ISP_EVENT_EXCEPTION,
+			   omap3_isp_histogram_event, isp);
+
+	return 0;
+}
+
+static void omap3_isp_histogram_stop(struct omap3_isp_device *isp)
+{
+	struct omap3_isp_histogram *hist = &isp->hist;
+	struct v4l2_event_subscription esub;
+	unsigned long enable = 0;
+
+	if (!hist->enabled)
+		return;
+
+	isp->ops->unwatch_fd(hist->entity->fd);
+	ioctl(hist->entity->fd, VIDIOC_OMAP3ISP_STAT_EN, &enable);
+
+	memset(&esub, 0, sizeof esub);
+	esub.type = V4L2_EVENT_OMAP3ISP_HIST;
+	ioctl(hist->entity->fd, VIDIOC_UNSUBSCRIBE_EVENT, &esub);
+}
+
+static int omap3_isp_histogram_init(struct omap3_isp_device *isp)
+{
+	struct omap3_isp_histogram *hist = &isp->hist;
+
+	hist->entity = media_get_entity_by_name(isp->mdev, "OMAP3 ISP histogram");
+	if (hist->entity == NULL)
+		return -ENOENT;
+
+	return v4l2_subdev_open(hist->entity);
+}
+
+/* -----------------------------------------------------------------------------
+ * Start/stop, init/cleanup
+ */
+
+int omap3_isp_stats_get_format(struct omap3_isp_device *isp,
+			       struct v4l2_mbus_framefmt *format)
+{
+	struct omap3_isp_aewb *aewb = &isp->aewb;
+	struct media_entity_pad *source;
+
+	source = media_entity_remote_source(&aewb->entity->pads[0]);
+	if (source == NULL)
+		return -ENOENT;
+
+	return v4l2_subdev_get_format(source->entity, format, source->index,
+				      V4L2_SUBDEV_FORMAT_TRY);
+}
+
+void omap3_isp_stats_enable(struct omap3_isp_device *isp,
+			    enum omap3_isp_stat_engine which)
+{
+	isp->aewb.enabled = !!(which & OMAP3_ISP_STAT_AEWB);
+	isp->hist.enabled = !!(which & OMAP3_ISP_STAT_HIST);
+}
+
+int omap3_isp_stats_start(struct omap3_isp_device *isp)
+{
+	int ret;
+
+	ret = omap3_isp_aewb_start(isp);
+	if (ret < 0)
+		return ret;
+
+	return omap3_isp_histogram_start(isp);
+}
+
+void omap3_isp_stats_stop(struct omap3_isp_device *isp)
+{
+	omap3_isp_aewb_stop(isp);
+	omap3_isp_histogram_stop(isp);
+}
+
+int omap3_isp_stats_init(struct omap3_isp_device *isp)
+{
+	int ret;
+
+	ret = omap3_isp_aewb_init(isp);
+	if (ret < 0)
+		return ret;
+
+	return omap3_isp_histogram_init(isp);
+}
+
 void omap3_isp_stats_cleanup(struct omap3_isp_device *isp)
 {
 	v4l2_subdev_close(isp->aewb.entity);
+	v4l2_subdev_close(isp->hist.entity);
 }
diff --git a/isp/stats.h b/isp/stats.h
index fb6c26a..f68d4fa 100644
--- a/isp/stats.h
+++ b/isp/stats.h
@@ -27,6 +27,11 @@
 
 struct omap3_isp_device;
 
+enum omap3_isp_stat_engine {
+	OMAP3_ISP_STAT_AEWB = 1 << 0,
+	OMAP3_ISP_STAT_HIST = 1 << 1,
+};
+
 /*
  * struct omap3_isp_aewb_stats - OMAP3 ISP AEWB statistics
  * @npix: Total number of accumulated pixels
@@ -52,15 +57,28 @@ struct omap3_isp_aewb_stats {
 };
 
 /*
+ * struct omap3_isp_histogram_stats - OMAP3 ISP histogram statistics
+ * @nbins: Number of bins in the histogram
+ * @bins: Array of histogram frequency data
+ *
+ * Each bin entry is stored on 32 bits but limited to 20 bits.
+ */
+struct omap3_isp_histogram_stats {
+	unsigned int nbins;
+	uint32_t *bins;
+};
+
+/*
  * omap3_isp_stats_enable - Enable or disable the statistics engine
  * @isp: The ISP device
- * @enable: Whether to enable to disable the statistics engine
+ * @which: The statistics engine(s) to enable
  *
- * The statistics engine must be enabled prior to starting the video stream.
- * When enabled, it statistics will be computed for every frame and delivered
- * through the ISP aewb_ready() callback.
+ * The statistics engines must be enabled prior to starting the video stream.
+ * When enabled, statistics will be computed for every frame and delivered
+ * through the ISP aewb_ready() and histogram_ready() callbacks.
  */
-void omap3_isp_stats_enable(struct omap3_isp_device *isp, bool enable);
+void omap3_isp_stats_enable(struct omap3_isp_device *isp,
+			    enum omap3_isp_stat_engine which);
 
 /*
  * omap3_isp_stats_get_format - Get frame format at the statistics engine input
@@ -72,6 +90,7 @@ void omap3_isp_stats_enable(struct omap3_isp_device *isp, bool enable);
  */
 int omap3_isp_stats_get_format(struct omap3_isp_device *isp,
 			       struct v4l2_mbus_framefmt *format);
+
 /*
  * omap3_isp_aewb_configure - Configure the AEWB statistics engine
  * @isp: The ISP device
@@ -81,4 +100,12 @@ int omap3_isp_stats_get_format(struct omap3_isp_device *isp,
 int omap3_isp_aewb_configure(struct omap3_isp_device *isp, struct v4l2_rect *rect,
 			     unsigned int saturation);
 
+/*
+ * omap3_isp_histogram_configure - Configure the histogram statistics engine
+ * @isp: The ISP device
+ * @rect: The region of interest, relative to the sensor output frame size
+ */
+int omap3_isp_histogram_configure(struct omap3_isp_device *isp,
+				  struct v4l2_rect *rect);
+
 #endif
diff --git a/live.c b/live.c
index 47e04d2..d4d14dc 100644
--- a/live.c
+++ b/live.c
@@ -103,6 +103,12 @@ static void __iq_aewb_process(struct omap3_isp_device *isp __attribute__((__unus
 	iq_aewb_process(iq, stats);
 }
 
+static void __iq_histogram_process(struct omap3_isp_device *isp __attribute__((__unused__)),
+				   const struct omap3_isp_histogram_stats *stats)
+{
+	iq_histogram_process(iq, stats);
+}
+
 /* -----------------------------------------------------------------------------
  * Events
  */
@@ -286,6 +292,7 @@ static struct omap3_isp_operations isp_ops = {
 	.watch_fd = __events_watch_fd,
 	.unwatch_fd = __events_unwatch_fd,
 	.aewb_ready = __iq_aewb_process,
+	.histogram_ready = __iq_histogram_process,
 };
 
 static int viewfinder_init(struct omap3_isp_device *isp,
diff --git a/snapshot.c b/snapshot.c
index 878d4bf..61e297f 100644
--- a/snapshot.c
+++ b/snapshot.c
@@ -119,6 +119,12 @@ static void __iq_aewb_process(struct omap3_isp_device *isp __attribute__((__unus
 	iq_aewb_process(iq, stats);
 }
 
+static void __iq_histogram_process(struct omap3_isp_device *isp __attribute__((__unused__)),
+				   const struct omap3_isp_histogram_stats *stats)
+{
+	iq_histogram_process(iq, stats);
+}
+
 /* -----------------------------------------------------------------------------
  * Events
  */
@@ -617,6 +623,7 @@ int main(int argc __attribute__((__unused__)), char *argv[] __attribute__((__unu
 	ops.watch_fd = __events_watch_fd;
 	ops.unwatch_fd = __events_unwatch_fd;
 	ops.aewb_ready = __iq_aewb_process;
+	ops.histogram_ready = __iq_histogram_process,
 
 	isp = omap3_isp_open(MEDIA_DEVICE, &ops);
 	if (isp == NULL) {