[PATCH v1 5/5] [media] stm32-dcmi: g_/s_selection crop support

[Hugues Fruchet]

Implements g_/s_selection crop support by using DCMI crop
hardware feature.
User can first get the maximum supported resolution of the sensor
by calling g_selection(V4L2_SEL_TGT_CROP_BOUNDS).
Then user call to s_selection(V4L2_SEL_TGT_CROP) will reset sensor
to its maximum resolution and crop request is saved for later usage
in s_fmt().
Next call to s_fmt() will check if sensor can do frame size request
with crop request. If sensor supports only discrete frame sizes,
the frame size which is larger than user request is selected in
order to be able to match the crop request. Then s_fmt() resolution
user request is adjusted to match crop request resolution.

Signed-off-by: Hugues Fruchet <hugues.fruchet@xxxxxx>
---
 drivers/media/platform/stm32/stm32-dcmi.c | 367 +++++++++++++++++++++++++++++-
 1 file changed, 363 insertions(+), 4 deletions(-)

diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c
index 2be56b6..f1fb0b3 100644
--- a/drivers/media/platform/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/stm32/stm32-dcmi.c
@@ -33,6 +33,7 @@
 #include <media/v4l2-fwnode.h>
 #include <media/v4l2-image-sizes.h>
 #include <media/v4l2-ioctl.h>
+#include <media/v4l2-rect.h>
 #include <media/videobuf2-dma-contig.h>
 
 #define DRV_NAME "stm32-dcmi"
@@ -107,6 +108,11 @@ struct dcmi_format {
 	u8	bpp;
 };
 
+struct dcmi_framesize {
+	u32	width;
+	u32	height;
+};
+
 struct dcmi_buf {
 	struct vb2_v4l2_buffer	vb;
 	bool			prepared;
@@ -131,10 +137,16 @@ struct stm32_dcmi {
 	struct v4l2_async_notifier	notifier;
 	struct dcmi_graph_entity	entity;
 	struct v4l2_format		fmt;
+	struct v4l2_rect		crop;
+	bool				do_crop;
 
 	const struct dcmi_format	**sd_formats;
 	unsigned int			nb_of_sd_formats;
 	const struct dcmi_format	*sd_format;
+	struct dcmi_framesize		*sd_framesizes;
+	unsigned int			nb_of_sd_framesizes;
+	struct dcmi_framesize		sd_framesize;
+	struct v4l2_rect		sd_bounds;
 
 	/* Protect this data structure */
 	struct mutex			lock;
@@ -325,6 +337,28 @@ static int dcmi_start_capture(struct stm32_dcmi *dcmi)
 	return 0;
 }
 
+static void dcmi_set_crop(struct stm32_dcmi *dcmi)
+{
+	u32 size, start;
+
+	/* Crop resolution */
+	size = ((dcmi->crop.height - 1) << 16) |
+		((dcmi->crop.width << 1) - 1);
+	reg_write(dcmi->regs, DCMI_CWSIZE, size);
+
+	/* Crop start point */
+	start = ((dcmi->crop.top) << 16) |
+		 ((dcmi->crop.left << 1));
+	reg_write(dcmi->regs, DCMI_CWSTRT, start);
+
+	dev_dbg(dcmi->dev, "Cropping to %ux%u@%u:%u\n",
+		dcmi->crop.width, dcmi->crop.height,
+		dcmi->crop.left, dcmi->crop.top);
+
+	/* Enable crop */
+	reg_set(dcmi->regs, DCMI_CR, CR_CROP);
+}
+
 static irqreturn_t dcmi_irq_thread(int irq, void *arg)
 {
 	struct stm32_dcmi *dcmi = arg;
@@ -540,6 +574,10 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
 
 	reg_write(dcmi->regs, DCMI_CR, val);
 
+	/* Set crop */
+	if (dcmi->do_crop)
+		dcmi_set_crop(dcmi);
+
 	/* Enable dcmi */
 	reg_set(dcmi->regs, DCMI_CR, CR_ENABLE);
 
@@ -697,10 +735,37 @@ static const struct dcmi_format *find_format_by_fourcc(struct stm32_dcmi *dcmi,
 	return NULL;
 }
 
+static void __find_outer_frame_size(struct stm32_dcmi *dcmi,
+				    struct v4l2_pix_format *pix,
+				    struct dcmi_framesize *framesize)
+{
+	struct dcmi_framesize *match = NULL;
+	unsigned int i;
+	unsigned int min_err = UINT_MAX;
+
+	for (i = 0; i < dcmi->nb_of_sd_framesizes; i++) {
+		struct dcmi_framesize *fsize = &dcmi->sd_framesizes[i];
+		int w_err = (fsize->width - pix->width);
+		int h_err = (fsize->height - pix->height);
+		int err = w_err + h_err;
+
+		if ((w_err >= 0) && (h_err >= 0) && (err < min_err)) {
+			min_err = err;
+			match = fsize;
+		}
+	}
+	if (!match)
+		match = &dcmi->sd_framesizes[0];
+
+	*framesize = *match;
+}
+
 static int dcmi_try_fmt(struct stm32_dcmi *dcmi, struct v4l2_format *f,
-			const struct dcmi_format **sd_format)
+			const struct dcmi_format **sd_format,
+			struct dcmi_framesize *sd_framesize)
 {
 	const struct dcmi_format *sd_fmt;
+	struct dcmi_framesize sd_fsize;
 	struct v4l2_pix_format *pix = &f->fmt.pix;
 	struct v4l2_subdev_pad_config pad_cfg;
 	struct v4l2_subdev_format format = {
@@ -718,6 +783,17 @@ static int dcmi_try_fmt(struct stm32_dcmi *dcmi, struct v4l2_format *f,
 	pix->width = clamp(pix->width, MIN_WIDTH, MAX_WIDTH);
 	pix->height = clamp(pix->height, MIN_HEIGHT, MAX_HEIGHT);
 
+	if (dcmi->do_crop && dcmi->nb_of_sd_framesizes) {
+		struct dcmi_framesize outer_sd_fsize;
+		/*
+		 * If crop is requested and sensor have discrete frame sizes,
+		 * select the frame size that is just larger than request
+		 */
+		__find_outer_frame_size(dcmi, pix, &outer_sd_fsize);
+		pix->width = outer_sd_fsize.width;
+		pix->height = outer_sd_fsize.height;
+	}
+
 	v4l2_fill_mbus_format(&format.format, pix, sd_fmt->mbus_code);
 	ret = v4l2_subdev_call(dcmi->entity.subdev, pad, set_fmt,
 			       &pad_cfg, &format);
@@ -727,6 +803,31 @@ static int dcmi_try_fmt(struct stm32_dcmi *dcmi, struct v4l2_format *f,
 	/* Update pix regarding to what sensor can do */
 	v4l2_fill_pix_format(pix, &format.format);
 
+	/* Save resolution that sensor can actually do */
+	sd_fsize.width = pix->width;
+	sd_fsize.height = pix->height;
+
+	if (dcmi->do_crop) {
+		struct v4l2_rect c = dcmi->crop;
+		struct v4l2_rect max_rect;
+
+		/*
+		 * Adjust crop by making the intersection between
+		 * format resolution request and crop request
+		 */
+		max_rect.top = 0;
+		max_rect.left = 0;
+		max_rect.width = pix->width;
+		max_rect.height = pix->height;
+		v4l2_rect_map_inside(&c, &max_rect);
+		c.top  = clamp_t(s32, c.top, 0, pix->height - c.height);
+		c.left = clamp_t(s32, c.left, 0, pix->width - c.width);
+		dcmi->crop = c;
+
+		/* Adjust format resolution request to crop */
+		pix->width = dcmi->crop.width;
+		pix->height = dcmi->crop.height;
+	}
 
 	pix->field = V4L2_FIELD_NONE;
 	pix->bytesperline = pix->width * sd_fmt->bpp;
@@ -734,6 +835,8 @@ static int dcmi_try_fmt(struct stm32_dcmi *dcmi, struct v4l2_format *f,
 
 	if (sd_format)
 		*sd_format = sd_fmt;
+	if (sd_framesize)
+		*sd_framesize = sd_fsize;
 
 	return 0;
 }
@@ -744,24 +847,41 @@ static int dcmi_set_fmt(struct stm32_dcmi *dcmi, struct v4l2_format *f)
 		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
 	};
 	const struct dcmi_format *sd_format;
+	struct dcmi_framesize sd_framesize;
 	struct v4l2_mbus_framefmt *mf = &format.format;
 	struct v4l2_pix_format *pix = &f->fmt.pix;
 	int ret;
 
-	ret = dcmi_try_fmt(dcmi, f, &sd_format);
+	/*
+	 * Try format, fmt.width/height could have been changed
+	 * to match sensor capability or crop request
+	 * sd_format & sd_framesize will contain what subdev
+	 * can do for this request.
+	 */
+	ret = dcmi_try_fmt(dcmi, f, &sd_format, &sd_framesize);
 	if (ret)
 		return ret;
 
 	/* pix to mbus format */
 	v4l2_fill_mbus_format(mf, pix,
 			      sd_format->mbus_code);
+	mf->width = sd_framesize.width;
+	mf->height = sd_framesize.height;
+
 	ret = v4l2_subdev_call(dcmi->entity.subdev, pad,
 			       set_fmt, NULL, &format);
 	if (ret < 0)
 		return ret;
 
+	dev_dbg(dcmi->dev, "Sensor format set to 0x%x %ux%u\n",
+		mf->code, mf->width, mf->height);
+	dev_dbg(dcmi->dev, "Buffer format set to %4.4s %ux%u\n",
+		(char *)&pix->pixelformat,
+		pix->width, pix->height);
+
 	dcmi->fmt = *f;
 	dcmi->sd_format = sd_format;
+	dcmi->sd_framesize = sd_framesize;
 
 	return 0;
 }
@@ -782,7 +902,7 @@ static int dcmi_try_fmt_vid_cap(struct file *file, void *priv,
 {
 	struct stm32_dcmi *dcmi = video_drvdata(file);
 
-	return dcmi_try_fmt(dcmi, f, NULL);
+	return dcmi_try_fmt(dcmi, f, NULL, NULL);
 }
 
 static int dcmi_enum_fmt_vid_cap(struct file *file, void  *priv,
@@ -797,6 +917,186 @@ static int dcmi_enum_fmt_vid_cap(struct file *file, void  *priv,
 	return 0;
 }
 
+static int dcmi_get_sensor_format(struct stm32_dcmi *dcmi,
+				  struct v4l2_pix_format *pix)
+{
+	struct v4l2_subdev_format fmt = {
+		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
+	};
+	int ret;
+
+	ret = v4l2_subdev_call(dcmi->entity.subdev, pad, get_fmt, NULL, &fmt);
+	if (ret)
+		return ret;
+
+	v4l2_fill_pix_format(pix, &fmt.format);
+
+	return 0;
+}
+
+static int dcmi_set_sensor_format(struct stm32_dcmi *dcmi,
+				  struct v4l2_pix_format *pix)
+{
+	const struct dcmi_format *sd_fmt;
+	struct v4l2_subdev_format format = {
+		.which = V4L2_SUBDEV_FORMAT_TRY,
+	};
+	struct v4l2_subdev_pad_config pad_cfg;
+	int ret;
+
+	sd_fmt = find_format_by_fourcc(dcmi, pix->pixelformat);
+	if (!sd_fmt) {
+		sd_fmt = dcmi->sd_formats[dcmi->nb_of_sd_formats - 1];
+		pix->pixelformat = sd_fmt->fourcc;
+	}
+
+	v4l2_fill_mbus_format(&format.format, pix, sd_fmt->mbus_code);
+	ret = v4l2_subdev_call(dcmi->entity.subdev, pad, set_fmt,
+			       &pad_cfg, &format);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int dcmi_get_sensor_bounds(struct stm32_dcmi *dcmi,
+				  struct v4l2_rect *r)
+{
+	struct v4l2_subdev_selection bounds = {
+		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
+		.target = V4L2_SEL_TGT_CROP_BOUNDS,
+	};
+	unsigned int max_width, max_height, max_pixsize;
+	struct v4l2_pix_format pix;
+	unsigned int i;
+	int ret;
+
+	/*
+	 * Get sensor bounds first
+	 */
+	ret = v4l2_subdev_call(dcmi->entity.subdev, pad, get_selection,
+			       NULL, &bounds);
+	if (!ret)
+		*r = bounds.r;
+	if (ret != -ENOIOCTLCMD)
+		return ret;
+
+	/*
+	 * If selection is not implemented,
+	 * fallback by enumerating sensor frame sizes
+	 * and take the largest one
+	 */
+	max_width = 0;
+	max_height = 0;
+	max_pixsize = 0;
+	for (i = 0; i < dcmi->nb_of_sd_framesizes; i++) {
+		struct dcmi_framesize *fsize = &dcmi->sd_framesizes[i];
+		unsigned int pixsize = fsize->width * fsize->height;
+
+		if (pixsize > max_pixsize) {
+			max_pixsize = pixsize;
+			max_width = fsize->width;
+			max_height = fsize->height;
+		}
+	}
+	if (max_pixsize > 0) {
+		r->top = 0;
+		r->left = 0;
+		r->width = max_width;
+		r->height = max_height;
+		return 0;
+	}
+
+	/*
+	 * If frame sizes enumeration is not implemented,
+	 * fallback by getting current sensor frame size
+	 */
+	ret = dcmi_get_sensor_format(dcmi, &pix);
+	if (ret)
+		return ret;
+
+	r->top = 0;
+	r->left = 0;
+	r->width = pix.width;
+	r->height = pix.height;
+
+	return 0;
+}
+
+static int dcmi_g_selection(struct file *file, void *fh,
+			    struct v4l2_selection *s)
+{
+	struct stm32_dcmi *dcmi = video_drvdata(file);
+	struct v4l2_rect crop;
+
+	if (s->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	if (dcmi->do_crop) {
+		crop = dcmi->crop;
+	} else {
+		crop.top = 0;
+		crop.left = 0;
+		crop.width = dcmi->fmt.fmt.pix.width;
+		crop.height = dcmi->fmt.fmt.pix.height;
+	}
+
+	switch (s->target) {
+	case V4L2_SEL_TGT_CROP_DEFAULT:
+	case V4L2_SEL_TGT_CROP_BOUNDS:
+		s->r = dcmi->sd_bounds;
+		return 0;
+	case V4L2_SEL_TGT_CROP:
+		s->r = crop;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int dcmi_s_selection(struct file *file, void *priv,
+			    struct v4l2_selection *s)
+{
+	struct stm32_dcmi *dcmi = video_drvdata(file);
+	struct v4l2_rect r = s->r;
+	struct v4l2_rect max_rect;
+	struct v4l2_pix_format pix;
+
+	if (s->type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
+	    s->target != V4L2_SEL_TGT_CROP)
+		return -EINVAL;
+
+	/* Reset sensor resolution to max resolution */
+	pix.pixelformat = dcmi->fmt.fmt.pix.pixelformat;
+	pix.width = dcmi->sd_bounds.width;
+	pix.height = dcmi->sd_bounds.height;
+	dcmi_set_sensor_format(dcmi, &pix);
+
+	/*
+	 * Make the intersection between
+	 * sensor resolution
+	 * and crop request
+	 */
+	max_rect.top = 0;
+	max_rect.left = 0;
+	max_rect.width = pix.width;
+	max_rect.height = pix.height;
+	v4l2_rect_map_inside(&r, &max_rect);
+	r.top  = clamp_t(s32, r.top, 0, pix.height - r.height);
+	r.left = clamp_t(s32, r.left, 0, pix.width - r.width);
+
+	dcmi->crop = r;
+	s->r = r;
+	dcmi->do_crop = true;
+
+	dev_dbg(dcmi->dev, "s_selection: crop %ux%u@(%u,%u) from %ux%u\n",
+		r.width, r.height, r.left, r.top, pix.width, pix.height);
+
+	return 0;
+}
+
 static int dcmi_querycap(struct file *file, void *priv,
 			 struct v4l2_capability *cap)
 {
@@ -903,7 +1203,7 @@ static int dcmi_set_default_fmt(struct stm32_dcmi *dcmi)
 	};
 	int ret;
 
-	ret = dcmi_try_fmt(dcmi, &f, NULL);
+	ret = dcmi_try_fmt(dcmi, &f, NULL, NULL);
 	if (ret)
 		return ret;
 	dcmi->sd_format = dcmi->sd_formats[0];
@@ -938,6 +1238,8 @@ static int dcmi_open(struct file *file)
 	if (ret < 0 && ret != -ENOIOCTLCMD)
 		goto fh_rel;
 
+	dcmi->do_crop = false;
+
 	ret = dcmi_set_default_fmt(dcmi);
 	if (ret)
 		goto power_off;
@@ -983,6 +1285,8 @@ static int dcmi_release(struct file *file)
 	.vidioc_g_fmt_vid_cap		= dcmi_g_fmt_vid_cap,
 	.vidioc_s_fmt_vid_cap		= dcmi_s_fmt_vid_cap,
 	.vidioc_enum_fmt_vid_cap	= dcmi_enum_fmt_vid_cap,
+	.vidioc_g_selection		= dcmi_g_selection,
+	.vidioc_s_selection		= dcmi_s_selection,
 
 	.vidioc_enum_input		= dcmi_enum_input,
 	.vidioc_g_input			= dcmi_g_input,
@@ -1082,6 +1386,49 @@ static int dcmi_formats_init(struct stm32_dcmi *dcmi)
 	return 0;
 }
 
+static int dcmi_framesizes_init(struct stm32_dcmi *dcmi)
+{
+	unsigned int num_fsize = 0;
+	struct v4l2_subdev *subdev = dcmi->entity.subdev;
+	struct v4l2_subdev_frame_size_enum fse = {
+		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
+		.code = dcmi->sd_format->mbus_code,
+	};
+	unsigned int ret;
+	unsigned int i;
+
+	/* Allocate discrete framesizes array */
+	while (!v4l2_subdev_call(subdev, pad, enum_frame_size,
+				 NULL, &fse))
+		fse.index++;
+
+	num_fsize = fse.index;
+	if (!num_fsize)
+		return 0;
+
+	dcmi->nb_of_sd_framesizes = num_fsize;
+	dcmi->sd_framesizes = devm_kcalloc(dcmi->dev, num_fsize,
+					   sizeof(struct dcmi_framesize),
+					   GFP_KERNEL);
+	if (!dcmi->sd_framesizes) {
+		dev_err(dcmi->dev, "Could not allocate memory\n");
+		return -ENOMEM;
+	}
+
+	/* Fill array with sensor supported framesizes */
+	dev_dbg(dcmi->dev, "Sensor supports %u frame sizes:\n", num_fsize);
+	for (i = 0; i < dcmi->nb_of_sd_framesizes; i++) {
+		fse.index = i;
+		if (v4l2_subdev_call(subdev, pad, enum_frame_size, NULL, &fse))
+			return ret;
+		dcmi->sd_framesizes[fse.index].width = fse.max_width;
+		dcmi->sd_framesizes[fse.index].height = fse.max_height;
+		dev_dbg(dcmi->dev, "%ux%u\n", fse.max_width, fse.max_height);
+	}
+
+	return 0;
+}
+
 static int dcmi_graph_notify_complete(struct v4l2_async_notifier *notifier)
 {
 	struct stm32_dcmi *dcmi = notifier_to_dcmi(notifier);
@@ -1094,6 +1441,18 @@ static int dcmi_graph_notify_complete(struct v4l2_async_notifier *notifier)
 		return ret;
 	}
 
+	ret = dcmi_framesizes_init(dcmi);
+	if (ret) {
+		dev_err(dcmi->dev, "Could not initialize framesizes\n");
+		return ret;
+	}
+
+	ret = dcmi_get_sensor_bounds(dcmi, &dcmi->sd_bounds);
+	if (ret) {
+		dev_err(dcmi->dev, "Could not get sensor bounds\n");
+		return ret;
+	}
+
 	ret = dcmi_set_default_fmt(dcmi);
 	if (ret) {
 		dev_err(dcmi->dev, "Could not set default format\n");
-- 
1.9.1