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Date:   Thu, 8 Aug 2019 12:37:29 +0300
From:   Sakari Ailus <sakari.ailus@linux.intel.com>
To:     Helen Koike <helen.koike@collabora.com>
Cc:     linux-rockchip@lists.infradead.org, devicetree@vger.kernel.org,
        eddie.cai.linux@gmail.com, mchehab@kernel.org, heiko@sntech.de,
        jacob2.chen@rock-chips.com, jeffy.chen@rock-chips.com,
        zyc@rock-chips.com, linux-kernel@vger.kernel.org,
        tfiga@chromium.org, hans.verkuil@cisco.com,
        laurent.pinchart@ideasonboard.com, kernel@collabora.com,
        ezequiel@collabora.com, linux-media@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, zhengsq@rock-chips.com,
        Jacob Chen <cc@rock-chips.com>,
        Allon Huang <allon.huang@rock-chips.com>
Subject: Re: [PATCH v8 06/14] media: rkisp1: add ISP1 statistics driver
Message-ID: <20190808093729.GR21370@paasikivi.fi.intel.com>
References: <20190730184256.30338-1-helen.koike@collabora.com>
 <20190730184256.30338-7-helen.koike@collabora.com>
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In-Reply-To: <20190730184256.30338-7-helen.koike@collabora.com>
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Hi Helen,

On Tue, Jul 30, 2019 at 03:42:48PM -0300, Helen Koike wrote:
> From: Jacob Chen <jacob2.chen@rock-chips.com>
> 
> Add the capture video driver for rockchip isp1 statistics block.
> 
> Signed-off-by: Jacob Chen <jacob2.chen@rock-chips.com>
> Signed-off-by: Shunqian Zheng <zhengsq@rock-chips.com>
> Signed-off-by: Yichong Zhong <zyc@rock-chips.com>
> Signed-off-by: Jacob Chen <cc@rock-chips.com>
> Signed-off-by: Eddie Cai <eddie.cai.linux@gmail.com>
> Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
> Signed-off-by: Allon Huang <allon.huang@rock-chips.com>
> Signed-off-by: Tomasz Figa <tfiga@chromium.org>
> [update for upstream]
> Signed-off-by: Helen Koike <helen.koike@collabora.com>
> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
> 
> ---
> 
> Changes in v8: None
> Changes in v7:
> - s/strlcpy/strscpy
> - sort out the locks in isp stats
> - code styling and checkpatch fixes
> 
>  .../media/platform/rockchip/isp1/isp_stats.c  | 508 ++++++++++++++++++
>  .../media/platform/rockchip/isp1/isp_stats.h  |  60 +++
>  2 files changed, 568 insertions(+)
>  create mode 100644 drivers/media/platform/rockchip/isp1/isp_stats.c
>  create mode 100644 drivers/media/platform/rockchip/isp1/isp_stats.h
> 
> diff --git a/drivers/media/platform/rockchip/isp1/isp_stats.c b/drivers/media/platform/rockchip/isp1/isp_stats.c
> new file mode 100644
> index 000000000000..01d947867c70
> --- /dev/null
> +++ b/drivers/media/platform/rockchip/isp1/isp_stats.c
> @@ -0,0 +1,508 @@
> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +/*
> + * Rockchip isp1 driver
> + *
> + * Copyright (C) 2017 Rockchip Electronics Co., Ltd.
> + */
> +
> +#include <media/v4l2-common.h>
> +#include <media/v4l2-event.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/videobuf2-core.h>
> +#include <media/videobuf2-vmalloc.h>	/* for ISP statistics */
> +
> +#include "dev.h"
> +#include "regs.h"
> +
> +#define RKISP1_ISP_STATS_REQ_BUFS_MIN 2
> +#define RKISP1_ISP_STATS_REQ_BUFS_MAX 8
> +
> +static int rkisp1_stats_enum_fmt_meta_cap(struct file *file, void *priv,
> +					  struct v4l2_fmtdesc *f)
> +{
> +	struct video_device *video = video_devdata(file);
> +	struct rkisp1_isp_stats_vdev *stats_vdev = video_get_drvdata(video);
> +
> +	if (f->index > 0 || f->type != video->queue->type)
> +		return -EINVAL;
> +
> +	f->pixelformat = stats_vdev->vdev_fmt.fmt.meta.dataformat;
> +	return 0;
> +}
> +
> +static int rkisp1_stats_g_fmt_meta_cap(struct file *file, void *priv,
> +				       struct v4l2_format *f)
> +{
> +	struct video_device *video = video_devdata(file);
> +	struct rkisp1_isp_stats_vdev *stats_vdev = video_get_drvdata(video);
> +	struct v4l2_meta_format *meta = &f->fmt.meta;
> +
> +	if (f->type != video->queue->type)
> +		return -EINVAL;
> +
> +	memset(meta, 0, sizeof(*meta));
> +	meta->dataformat = stats_vdev->vdev_fmt.fmt.meta.dataformat;
> +	meta->buffersize = stats_vdev->vdev_fmt.fmt.meta.buffersize;
> +
> +	return 0;
> +}
> +
> +static int rkisp1_stats_querycap(struct file *file,
> +				 void *priv, struct v4l2_capability *cap)
> +{
> +	struct video_device *vdev = video_devdata(file);
> +
> +	strscpy(cap->driver, DRIVER_NAME, sizeof(cap->driver));
> +	strscpy(cap->card, vdev->name, sizeof(cap->card));
> +	strscpy(cap->bus_info, "platform: " DRIVER_NAME, sizeof(cap->bus_info));
> +
> +	return 0;
> +}
> +
> +/* ISP video device IOCTLs */
> +static const struct v4l2_ioctl_ops rkisp1_stats_ioctl = {
> +	.vidioc_reqbufs = vb2_ioctl_reqbufs,
> +	.vidioc_querybuf = vb2_ioctl_querybuf,
> +	.vidioc_create_bufs = vb2_ioctl_create_bufs,
> +	.vidioc_qbuf = vb2_ioctl_qbuf,
> +	.vidioc_dqbuf = vb2_ioctl_dqbuf,
> +	.vidioc_prepare_buf = vb2_ioctl_prepare_buf,
> +	.vidioc_expbuf = vb2_ioctl_expbuf,
> +	.vidioc_streamon = vb2_ioctl_streamon,
> +	.vidioc_streamoff = vb2_ioctl_streamoff,
> +	.vidioc_enum_fmt_meta_cap = rkisp1_stats_enum_fmt_meta_cap,
> +	.vidioc_g_fmt_meta_cap = rkisp1_stats_g_fmt_meta_cap,
> +	.vidioc_s_fmt_meta_cap = rkisp1_stats_g_fmt_meta_cap,
> +	.vidioc_try_fmt_meta_cap = rkisp1_stats_g_fmt_meta_cap,
> +	.vidioc_querycap = rkisp1_stats_querycap,
> +	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
> +	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,

Do you have controls on the video nodes? If not, you can remove the two.

> +};
> +
> +struct v4l2_file_operations rkisp1_stats_fops = {

static const

> +	.mmap = vb2_fop_mmap,
> +	.unlocked_ioctl = video_ioctl2,
> +	.poll = vb2_fop_poll,
> +	.open = v4l2_fh_open,
> +	.release = vb2_fop_release
> +};
> +
> +static int rkisp1_stats_vb2_queue_setup(struct vb2_queue *vq,
> +					unsigned int *num_buffers,
> +					unsigned int *num_planes,
> +					unsigned int sizes[],
> +					struct device *alloc_devs[])
> +{
> +	struct rkisp1_isp_stats_vdev *stats_vdev = vq->drv_priv;
> +
> +	*num_planes = 1;
> +
> +	*num_buffers = clamp_t(u32, *num_buffers, RKISP1_ISP_STATS_REQ_BUFS_MIN,
> +			       RKISP1_ISP_STATS_REQ_BUFS_MAX);
> +
> +	sizes[0] = sizeof(struct rkisp1_stat_buffer);
> +
> +	INIT_LIST_HEAD(&stats_vdev->stat);
> +
> +	return 0;
> +}
> +
> +static void rkisp1_stats_vb2_buf_queue(struct vb2_buffer *vb)
> +{
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +	struct rkisp1_buffer *stats_buf = to_rkisp1_buffer(vbuf);
> +	struct vb2_queue *vq = vb->vb2_queue;
> +	struct rkisp1_isp_stats_vdev *stats_dev = vq->drv_priv;
> +
> +	stats_buf->vaddr[0] = vb2_plane_vaddr(vb, 0);
> +
> +	mutex_lock(&stats_dev->wq_lock);
> +	list_add_tail(&stats_buf->queue, &stats_dev->stat);
> +	mutex_unlock(&stats_dev->wq_lock);
> +}
> +
> +static int rkisp1_stats_vb2_buf_prepare(struct vb2_buffer *vb)
> +{
> +	if (vb2_plane_size(vb, 0) < sizeof(struct rkisp1_stat_buffer))
> +		return -EINVAL;
> +
> +	vb2_set_plane_payload(vb, 0, sizeof(struct rkisp1_stat_buffer));
> +
> +	return 0;
> +}
> +
> +static void rkisp1_stats_vb2_stop_streaming(struct vb2_queue *vq)
> +{
> +	struct rkisp1_isp_stats_vdev *stats_vdev = vq->drv_priv;
> +	struct rkisp1_buffer *buf;
> +	unsigned long flags;
> +	unsigned int i;
> +
> +	/* Make sure no new work queued in isr before draining wq */
> +	spin_lock_irqsave(&stats_vdev->irq_lock, flags);
> +	stats_vdev->streamon = false;
> +	spin_unlock_irqrestore(&stats_vdev->irq_lock, flags);
> +
> +	drain_workqueue(stats_vdev->readout_wq);
> +
> +	mutex_lock(&stats_vdev->wq_lock);
> +	for (i = 0; i < RKISP1_ISP_STATS_REQ_BUFS_MAX; i++) {
> +		if (list_empty(&stats_vdev->stat))
> +			break;
> +		buf = list_first_entry(&stats_vdev->stat,
> +				       struct rkisp1_buffer, queue);
> +		list_del(&buf->queue);
> +		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
> +	}
> +	mutex_unlock(&stats_vdev->wq_lock);
> +}
> +
> +static int
> +rkisp1_stats_vb2_start_streaming(struct vb2_queue *queue,
> +				 unsigned int count)
> +{
> +	struct rkisp1_isp_stats_vdev *stats_vdev = queue->drv_priv;
> +
> +	stats_vdev->streamon = true;
> +
> +	return 0;
> +}
> +
> +static struct vb2_ops rkisp1_stats_vb2_ops = {

const

> +	.queue_setup = rkisp1_stats_vb2_queue_setup,
> +	.buf_queue = rkisp1_stats_vb2_buf_queue,
> +	.buf_prepare = rkisp1_stats_vb2_buf_prepare,
> +	.wait_prepare = vb2_ops_wait_prepare,
> +	.wait_finish = vb2_ops_wait_finish,
> +	.stop_streaming = rkisp1_stats_vb2_stop_streaming,
> +	.start_streaming = rkisp1_stats_vb2_start_streaming,
> +};
> +
> +static int rkisp1_stats_init_vb2_queue(struct vb2_queue *q,
> +				       struct rkisp1_isp_stats_vdev *stats_vdev)
> +{
> +	struct rkisp1_vdev_node *node;
> +
> +	node = queue_to_node(q);
> +
> +	q->type = V4L2_BUF_TYPE_META_CAPTURE;
> +	q->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
> +	q->drv_priv = stats_vdev;
> +	q->ops = &rkisp1_stats_vb2_ops;
> +	q->mem_ops = &vb2_vmalloc_memops;
> +	q->buf_struct_size = sizeof(struct rkisp1_buffer);
> +	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> +	q->lock = &node->vlock;
> +
> +	return vb2_queue_init(q);
> +}
> +
> +static void rkisp1_stats_get_awb_meas(struct rkisp1_isp_stats_vdev *stats_vdev,
> +				      struct rkisp1_stat_buffer *pbuf)
> +{
> +	/* Protect against concurrent access from ISR? */
> +	u32 reg_val;
> +
> +	pbuf->meas_type |= CIFISP_STAT_AWB;
> +	reg_val = readl(stats_vdev->dev->base_addr + CIF_ISP_AWB_WHITE_CNT);
> +	pbuf->params.awb.awb_mean[0].cnt = CIF_ISP_AWB_GET_PIXEL_CNT(reg_val);
> +	reg_val = readl(stats_vdev->dev->base_addr + CIF_ISP_AWB_MEAN);
> +
> +	pbuf->params.awb.awb_mean[0].mean_cr_or_r =
> +		CIF_ISP_AWB_GET_MEAN_CR_R(reg_val);
> +	pbuf->params.awb.awb_mean[0].mean_cb_or_b =
> +		CIF_ISP_AWB_GET_MEAN_CB_B(reg_val);
> +	pbuf->params.awb.awb_mean[0].mean_y_or_g =
> +		CIF_ISP_AWB_GET_MEAN_Y_G(reg_val);
> +}
> +
> +static void rkisp1_stats_get_aec_meas(struct rkisp1_isp_stats_vdev *stats_vdev,
> +				      struct rkisp1_stat_buffer *pbuf)
> +{
> +	void __iomem *addr = stats_vdev->dev->base_addr + CIF_ISP_EXP_MEAN_00;
> +	unsigned int i;
> +
> +	pbuf->meas_type |= CIFISP_STAT_AUTOEXP;
> +	for (i = 0; i < CIFISP_AE_MEAN_MAX; i++)
> +		pbuf->params.ae.exp_mean[i] = (u8)readl(addr + i * 4);
> +}
> +
> +static void rkisp1_stats_get_afc_meas(struct rkisp1_isp_stats_vdev *stats_vdev,
> +				      struct rkisp1_stat_buffer *pbuf)
> +{
> +	void __iomem *base_addr;
> +	struct cifisp_af_stat *af;
> +
> +	pbuf->meas_type = CIFISP_STAT_AFM_FIN;
> +
> +	af = &pbuf->params.af;
> +	base_addr = stats_vdev->dev->base_addr;
> +	af->window[0].sum = readl(base_addr + CIF_ISP_AFM_SUM_A);
> +	af->window[0].lum = readl(base_addr + CIF_ISP_AFM_LUM_A);
> +	af->window[1].sum = readl(base_addr + CIF_ISP_AFM_SUM_B);
> +	af->window[1].lum = readl(base_addr + CIF_ISP_AFM_LUM_B);
> +	af->window[2].sum = readl(base_addr + CIF_ISP_AFM_SUM_C);
> +	af->window[2].lum = readl(base_addr + CIF_ISP_AFM_LUM_C);
> +}
> +
> +static void rkisp1_stats_get_hst_meas(struct rkisp1_isp_stats_vdev *stats_vdev,
> +				      struct rkisp1_stat_buffer *pbuf)
> +{
> +	void __iomem *addr = stats_vdev->dev->base_addr + CIF_ISP_HIST_BIN_0;
> +	unsigned int i;
> +
> +	pbuf->meas_type |= CIFISP_STAT_HIST;
> +	for (i = 0; i < CIFISP_HIST_BIN_N_MAX; i++)
> +		pbuf->params.hist.hist_bins[i] = readl(addr + (i * 4));
> +}
> +
> +static void rkisp1_stats_get_bls_meas(struct rkisp1_isp_stats_vdev *stats_vdev,
> +				      struct rkisp1_stat_buffer *pbuf)
> +{
> +	struct rkisp1_device *dev = stats_vdev->dev;
> +	const struct ispsd_in_fmt *in_fmt =
> +			rkisp1_get_ispsd_in_fmt(&dev->isp_sdev);
> +	void __iomem *base = stats_vdev->dev->base_addr;
> +	struct cifisp_bls_meas_val *bls_val;
> +
> +	bls_val = &pbuf->params.ae.bls_val;
> +	if (in_fmt->bayer_pat == RAW_BGGR) {
> +		bls_val->meas_b = readl(base + CIF_ISP_BLS_A_MEASURED);
> +		bls_val->meas_gb = readl(base + CIF_ISP_BLS_B_MEASURED);
> +		bls_val->meas_gr = readl(base + CIF_ISP_BLS_C_MEASURED);
> +		bls_val->meas_r = readl(base + CIF_ISP_BLS_D_MEASURED);
> +	} else if (in_fmt->bayer_pat == RAW_GBRG) {
> +		bls_val->meas_gb = readl(base + CIF_ISP_BLS_A_MEASURED);
> +		bls_val->meas_b = readl(base + CIF_ISP_BLS_B_MEASURED);
> +		bls_val->meas_r = readl(base + CIF_ISP_BLS_C_MEASURED);
> +		bls_val->meas_gr = readl(base + CIF_ISP_BLS_D_MEASURED);
> +	} else if (in_fmt->bayer_pat == RAW_GRBG) {
> +		bls_val->meas_gr = readl(base + CIF_ISP_BLS_A_MEASURED);
> +		bls_val->meas_r = readl(base + CIF_ISP_BLS_B_MEASURED);
> +		bls_val->meas_b = readl(base + CIF_ISP_BLS_C_MEASURED);
> +		bls_val->meas_gb = readl(base + CIF_ISP_BLS_D_MEASURED);
> +	} else if (in_fmt->bayer_pat == RAW_RGGB) {
> +		bls_val->meas_r = readl(base + CIF_ISP_BLS_A_MEASURED);
> +		bls_val->meas_gr = readl(base + CIF_ISP_BLS_B_MEASURED);
> +		bls_val->meas_gb = readl(base + CIF_ISP_BLS_C_MEASURED);
> +		bls_val->meas_b = readl(base + CIF_ISP_BLS_D_MEASURED);
> +	}
> +}
> +
> +static void
> +rkisp1_stats_send_measurement(struct rkisp1_isp_stats_vdev *stats_vdev,
> +			      struct rkisp1_isp_readout_work *meas_work)
> +{
> +	struct rkisp1_stat_buffer *cur_stat_buf;
> +	struct rkisp1_buffer *cur_buf = NULL;
> +	unsigned int cur_frame_id = -1;
> +
> +	cur_frame_id = atomic_read(&stats_vdev->dev->isp_sdev.frm_sync_seq) - 1;
> +	if (cur_frame_id != meas_work->frame_id) {
> +		v4l2_warn(stats_vdev->vnode.vdev.v4l2_dev,
> +			  "Measurement late(%d, %d)\n",
> +			  cur_frame_id, meas_work->frame_id);
> +		cur_frame_id = meas_work->frame_id;
> +	}
> +
> +	mutex_lock(&stats_vdev->wq_lock);
> +	/* get one empty buffer */
> +	if (!list_empty(&stats_vdev->stat)) {
> +		cur_buf = list_first_entry(&stats_vdev->stat,
> +					   struct rkisp1_buffer, queue);
> +		list_del(&cur_buf->queue);
> +	}
> +	mutex_unlock(&stats_vdev->wq_lock);
> +
> +	if (!cur_buf)
> +		return;
> +
> +	cur_stat_buf =
> +		(struct rkisp1_stat_buffer *)(cur_buf->vaddr[0]);
> +
> +	if (meas_work->isp_ris & CIF_ISP_AWB_DONE) {
> +		rkisp1_stats_get_awb_meas(stats_vdev, cur_stat_buf);
> +		cur_stat_buf->meas_type |= CIFISP_STAT_AWB;
> +	}
> +
> +	if (meas_work->isp_ris & CIF_ISP_AFM_FIN) {
> +		rkisp1_stats_get_afc_meas(stats_vdev, cur_stat_buf);
> +		cur_stat_buf->meas_type |= CIFISP_STAT_AFM_FIN;
> +	}
> +
> +	if (meas_work->isp_ris & CIF_ISP_EXP_END) {
> +		rkisp1_stats_get_aec_meas(stats_vdev, cur_stat_buf);
> +		rkisp1_stats_get_bls_meas(stats_vdev, cur_stat_buf);
> +		cur_stat_buf->meas_type |= CIFISP_STAT_AUTOEXP;
> +	}
> +
> +	if (meas_work->isp_ris & CIF_ISP_HIST_MEASURE_RDY) {
> +		rkisp1_stats_get_hst_meas(stats_vdev, cur_stat_buf);
> +		cur_stat_buf->meas_type |= CIFISP_STAT_HIST;
> +	}
> +
> +	vb2_set_plane_payload(&cur_buf->vb.vb2_buf, 0,
> +			      sizeof(struct rkisp1_stat_buffer));
> +	cur_buf->vb.sequence = cur_frame_id;
> +	cur_buf->vb.vb2_buf.timestamp = ktime_get_ns();

It might be better to get the timestamp in the beginning of the function
before acquiring the mutex which can take a relatively long time.

> +	vb2_buffer_done(&cur_buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
> +}
> +
> +static void rkisp1_stats_readout_work(struct work_struct *work)
> +{
> +	struct rkisp1_isp_readout_work *readout_work = container_of(work,
> +						struct rkisp1_isp_readout_work,
> +						work);
> +	struct rkisp1_isp_stats_vdev *stats_vdev = readout_work->stats_vdev;
> +
> +	if (readout_work->readout == RKISP1_ISP_READOUT_MEAS)
> +		rkisp1_stats_send_measurement(stats_vdev, readout_work);
> +
> +	kfree(readout_work);
> +}
> +
> +int rkisp1_stats_isr(struct rkisp1_isp_stats_vdev *stats_vdev, u32 isp_ris)
> +{
> +	unsigned int cur_frame_id =
> +		atomic_read(&stats_vdev->dev->isp_sdev.frm_sync_seq) - 1;
> +	struct rkisp1_isp_readout_work *work;
> +	unsigned int isp_mis_tmp = 0;
> +#ifdef LOG_ISR_EXE_TIME
> +	ktime_t in_t = ktime_get();
> +#endif
> +
> +	spin_lock(&stats_vdev->irq_lock);
> +
> +	writel((CIF_ISP_AWB_DONE | CIF_ISP_AFM_FIN | CIF_ISP_EXP_END |
> +		CIF_ISP_HIST_MEASURE_RDY),
> +		stats_vdev->dev->base_addr + CIF_ISP_ICR);
> +
> +	isp_mis_tmp = readl(stats_vdev->dev->base_addr + CIF_ISP_MIS);
> +	if (isp_mis_tmp &
> +		(CIF_ISP_AWB_DONE | CIF_ISP_AFM_FIN |
> +		 CIF_ISP_EXP_END | CIF_ISP_HIST_MEASURE_RDY))
> +		v4l2_err(stats_vdev->vnode.vdev.v4l2_dev,
> +			 "isp icr 3A info err: 0x%x\n",
> +			 isp_mis_tmp);
> +
> +	if (!stats_vdev->streamon)
> +		goto unlock;
> +	if (isp_ris & (CIF_ISP_AWB_DONE | CIF_ISP_AFM_FIN | CIF_ISP_EXP_END |
> +		CIF_ISP_HIST_MEASURE_RDY)) {
> +		work = (struct rkisp1_isp_readout_work *)
> +			kzalloc(sizeof(struct rkisp1_isp_readout_work),
> +				GFP_ATOMIC);
> +		if (work) {
> +			INIT_WORK(&work->work,
> +				  rkisp1_stats_readout_work);
> +			work->readout = RKISP1_ISP_READOUT_MEAS;
> +			work->stats_vdev = stats_vdev;
> +			work->frame_id = cur_frame_id;
> +			work->isp_ris = isp_ris;
> +			if (!queue_work(stats_vdev->readout_wq,
> +					&work->work))

Please use threaded interrupt handling instead.

> +				kfree(work);
> +		} else {
> +			v4l2_err(stats_vdev->vnode.vdev.v4l2_dev,
> +				 "Could not allocate work\n");
> +		}
> +	}
> +
> +#ifdef LOG_ISR_EXE_TIME
> +	if (isp_ris & (CIF_ISP_EXP_END | CIF_ISP_AWB_DONE |
> +		       CIF_ISP_FRAME | CIF_ISP_HIST_MEASURE_RDY)) {
> +		unsigned int diff_us =
> +				ktime_to_us(ktime_sub(ktime_get(), in_t));
> +
> +		if (diff_us > g_longest_isr_time)
> +			g_longest_isr_time = diff_us;
> +
> +		v4l2_info(stats_vdev->vnode.vdev.v4l2_dev,
> +			  "isp_isr time %d %d\n", diff_us, g_longest_isr_time);
> +	}
> +#endif

I'd remove this; it could be useful during development time but hardly any
longer.

> +
> +unlock:
> +	spin_unlock(&stats_vdev->irq_lock);
> +
> +	return 0;
> +}
> +
> +static void rkisp1_init_stats_vdev(struct rkisp1_isp_stats_vdev *stats_vdev)
> +{
> +	stats_vdev->vdev_fmt.fmt.meta.dataformat =
> +		V4L2_META_FMT_RK_ISP1_STAT_3A;
> +	stats_vdev->vdev_fmt.fmt.meta.buffersize =
> +		sizeof(struct rkisp1_stat_buffer);
> +}
> +
> +int rkisp1_register_stats_vdev(struct rkisp1_isp_stats_vdev *stats_vdev,
> +			       struct v4l2_device *v4l2_dev,
> +			       struct rkisp1_device *dev)
> +{
> +	struct rkisp1_vdev_node *node = &stats_vdev->vnode;
> +	struct video_device *vdev = &node->vdev;
> +	unsigned int ret;
> +
> +	stats_vdev->dev = dev;
> +	mutex_init(&stats_vdev->wq_lock);
> +	mutex_init(&node->vlock);
> +	INIT_LIST_HEAD(&stats_vdev->stat);
> +	spin_lock_init(&stats_vdev->irq_lock);
> +
> +	strlcpy(vdev->name, "rkisp1-statistics", sizeof(vdev->name));

strscpy()?

> +
> +	video_set_drvdata(vdev, stats_vdev);
> +	vdev->ioctl_ops = &rkisp1_stats_ioctl;
> +	vdev->fops = &rkisp1_stats_fops;
> +	vdev->release = video_device_release_empty;
> +	vdev->lock = &node->vlock;
> +	vdev->v4l2_dev = v4l2_dev;
> +	vdev->queue = &node->buf_queue;
> +	vdev->device_caps = V4L2_CAP_META_CAPTURE | V4L2_CAP_STREAMING;
> +	vdev->vfl_dir =  VFL_DIR_RX;
> +	rkisp1_stats_init_vb2_queue(vdev->queue, stats_vdev);
> +	rkisp1_init_stats_vdev(stats_vdev);
> +	video_set_drvdata(vdev, stats_vdev);
> +
> +	node->pad.flags = MEDIA_PAD_FL_SINK;
> +	ret = media_entity_pads_init(&vdev->entity, 1, &node->pad);
> +	if (ret < 0)
> +		goto err_release_queue;
> +
> +	ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
> +	if (ret < 0) {
> +		dev_err(&vdev->dev,
> +			"could not register Video for Linux device\n");
> +		goto err_cleanup_media_entity;
> +	}
> +
> +	stats_vdev->readout_wq =
> +	    alloc_workqueue("measurement_queue",

Indentation.

> +			    WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
> +
> +	if (!stats_vdev->readout_wq) {
> +		ret = -ENOMEM;
> +			goto err_unreg_vdev;

Same here.

> +	}
> +
> +	return 0;

Please leave an extra newline before the labels below, as well as before
return.

> +err_unreg_vdev:
> +	video_unregister_device(vdev);
> +err_cleanup_media_entity:
> +	media_entity_cleanup(&vdev->entity);
> +err_release_queue:
> +	vb2_queue_release(vdev->queue);

Also remember mutex_destroy() for the two mutexes.

> +	return ret;
> +}
> +
> +void rkisp1_unregister_stats_vdev(struct rkisp1_isp_stats_vdev *stats_vdev)
> +{
> +	struct rkisp1_vdev_node *node = &stats_vdev->vnode;
> +	struct video_device *vdev = &node->vdev;
> +
> +	destroy_workqueue(stats_vdev->readout_wq);
> +	video_unregister_device(vdev);
> +	media_entity_cleanup(&vdev->entity);
> +	vb2_queue_release(vdev->queue);

mutex_destroy() here, too.

> +}
> diff --git a/drivers/media/platform/rockchip/isp1/isp_stats.h b/drivers/media/platform/rockchip/isp1/isp_stats.h
> new file mode 100644
> index 000000000000..b46c8537e1c7
> --- /dev/null
> +++ b/drivers/media/platform/rockchip/isp1/isp_stats.h
> @@ -0,0 +1,60 @@
> +/* SPDX-License-Identifier: (GPL-2.0+ OR MIT) */
> +/*
> + * Rockchip isp1 driver
> + *
> + * Copyright (C) 2017 Rockchip Electronics Co., Ltd.
> + */
> +
> +#ifndef _RKISP1_ISP_STATS_H
> +#define _RKISP1_ISP_STATS_H
> +
> +#include <linux/rkisp1-config.h>
> +
> +#include "common.h"
> +
> +struct rkisp1_isp_stats_vdev;
> +
> +enum rkisp1_isp_readout_cmd {
> +	RKISP1_ISP_READOUT_MEAS,
> +	RKISP1_ISP_READOUT_META,
> +};
> +
> +struct rkisp1_isp_readout_work {
> +	struct work_struct work;
> +	struct rkisp1_isp_stats_vdev *stats_vdev;
> +
> +	unsigned int frame_id;
> +	unsigned int isp_ris;
> +	enum rkisp1_isp_readout_cmd readout;
> +	struct vb2_buffer *vb;
> +};
> +
> +/*
> + * struct rkisp1_isp_stats_vdev - ISP Statistics device
> + *
> + * @irq_lock: buffer queue lock
> + * @stat: stats buffer list
> + * @readout_wq: workqueue for statistics information read
> + */
> +struct rkisp1_isp_stats_vdev {
> +	struct rkisp1_vdev_node vnode;
> +	struct rkisp1_device *dev;
> +
> +	spinlock_t irq_lock;
> +	struct list_head stat;
> +	struct v4l2_format vdev_fmt;
> +	bool streamon;
> +
> +	struct workqueue_struct *readout_wq;
> +	struct mutex wq_lock;
> +};
> +
> +int rkisp1_stats_isr(struct rkisp1_isp_stats_vdev *stats_vdev, u32 isp_ris);
> +
> +int rkisp1_register_stats_vdev(struct rkisp1_isp_stats_vdev *stats_vdev,
> +			       struct v4l2_device *v4l2_dev,
> +			       struct rkisp1_device *dev);
> +
> +void rkisp1_unregister_stats_vdev(struct rkisp1_isp_stats_vdev *stats_vdev);
> +
> +#endif /* _RKISP1_ISP_STATS_H */

-- 
Kind regards,

Sakari Ailus
sakari.ailus@linux.intel.com