/*
 * V4L2 Capture CSI Subdev for Freescale i.MX5/6 SOC
 *
 * Copyright (c) 2014-2017 Mentor Graphics Inc.
 * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */
#include <linux/delay.h>
#include <linux/gcd.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of_graph.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-device.h>
#include <media/v4l2-event.h>
#include <media/v4l2-fwnode.h>
#include <media/v4l2-mc.h>
#include <media/v4l2-subdev.h>
#include <media/videobuf2-dma-contig.h>
#include <video/imx-ipu-v3.h>
#include <media/imx.h>
#include "imx-media.h"

/*
 * Min/Max supported width and heights.
 *
 * We allow planar output, so we have to align width by 16 pixels
 * to meet IDMAC alignment requirements.
 *
 * TODO: move this into pad format negotiation, if capture device
 * has not requested planar formats, we should allow 8 pixel
 * alignment.
 */
#define MIN_W       176
#define MIN_H       144
#define MAX_W      4096
#define MAX_H      4096
#define W_ALIGN    4 /* multiple of 16 pixels */
#define H_ALIGN    1 /* multiple of 2 lines */
#define S_ALIGN    1 /* multiple of 2 */

/*
 * struct csi_skip_desc - CSI frame skipping descriptor
 * @keep - number of frames kept per max_ratio frames
 * @max_ratio - width of skip_smfc, written to MAX_RATIO bitfield
 * @skip_smfc - skip pattern written to the SKIP_SMFC bitfield
 */
struct csi_skip_desc {
        u8 keep;
        u8 max_ratio;
        u8 skip_smfc;
};

struct csi_priv {
        struct device *dev;
        struct ipu_soc *ipu;
        struct imx_media_dev *md;
        struct v4l2_subdev sd;
        struct media_pad pad[CSI_NUM_PADS];
        /* the video device at IDMAC output pad */
        struct imx_media_video_dev *vdev;
        struct imx_media_fim *fim;
        int csi_id;
        int smfc_id;

        /* lock to protect all members below */
        struct mutex lock;

        int active_output_pad;

        struct ipuv3_channel *idmac_ch;
        struct ipu_smfc *smfc;
        struct ipu_csi *csi;

        struct v4l2_mbus_framefmt format_mbus[CSI_NUM_PADS];
        const struct imx_media_pixfmt *cc[CSI_NUM_PADS];
        struct v4l2_fract frame_interval[CSI_NUM_PADS];
        struct v4l2_rect crop;
        struct v4l2_rect compose;
        const struct csi_skip_desc *skip;

        /* active vb2 buffers to send to video dev sink */
        struct imx_media_buffer *active_vb2_buf[2];
        struct imx_media_dma_buf underrun_buf;

        int ipu_buf_num;  /* ipu double buffer index: 0-1 */

        /* the sink for the captured frames */
        struct media_entity *sink;
        enum ipu_csi_dest dest;
        /* the source subdev */
        struct v4l2_subdev *src_sd;

        /* the mipi virtual channel number at link validate */
        int vc_num;

        /* the upstream endpoint CSI is receiving from */
        struct v4l2_fwnode_endpoint upstream_ep;

        spinlock_t irqlock; /* protect eof_irq handler */
        struct timer_list eof_timeout_timer;
        int eof_irq;
        int nfb4eof_irq;

        struct v4l2_ctrl_handler ctrl_hdlr;

        int stream_count; /* streaming counter */
        bool last_eof;   /* waiting for last EOF at stream off */
        bool nfb4eof;    /* NFB4EOF encountered during streaming */
        struct completion last_eof_comp;
};

static inline struct csi_priv *sd_to_dev(struct v4l2_subdev *sdev)
{
        return container_of(sdev, struct csi_priv, sd);
}

static inline bool is_parallel_16bit_bus(struct v4l2_fwnode_endpoint *ep)
{
        return ep->bus_type != V4L2_MBUS_CSI2 &&
                ep->bus.parallel.bus_width >= 16;
}

/*
 * Parses the fwnode endpoint from the source pad of the entity
 * connected to this CSI. This will either be the entity directly
 * upstream from the CSI-2 receiver, or directly upstream from the
 * video mux. The endpoint is needed to determine the bus type and
 * bus config coming into the CSI.
 */
static int csi_get_upstream_endpoint(struct csi_priv *priv,
                                     struct v4l2_fwnode_endpoint *ep)
{
        struct device_node *endpoint, *port;
        struct media_entity *src;
        struct v4l2_subdev *sd;
        struct media_pad *pad;

        if (!priv->src_sd)
                return -EPIPE;

        src = &priv->src_sd->entity;

        if (src->function == MEDIA_ENT_F_VID_MUX) {
                /*
                 * CSI is connected directly to video mux, skip up to
                 * CSI-2 receiver if it is in the path, otherwise stay
                 * with video mux.
                 */
                sd = imx_media_find_upstream_subdev(priv->md, src,
                                                    IMX_MEDIA_GRP_ID_CSI2);
                if (!IS_ERR(sd))
                        src = &sd->entity;
        }

        /* get source pad of entity directly upstream from src */
        pad = imx_media_find_upstream_pad(priv->md, src, 0);
        if (IS_ERR(pad))
                return PTR_ERR(pad);

        sd = media_entity_to_v4l2_subdev(pad->entity);

        /*
         * NOTE: this assumes an OF-graph port id is the same as a
         * media pad index.
         */
        port = of_graph_get_port_by_id(sd->dev->of_node, pad->index);
        if (!port)
                return -ENODEV;

        endpoint = of_get_next_child(port, NULL);
        of_node_put(port);
        if (!endpoint)
                return -ENODEV;

        v4l2_fwnode_endpoint_parse(of_fwnode_handle(endpoint), ep);
        of_node_put(endpoint);

        return 0;
}

static void csi_idmac_put_ipu_resources(struct csi_priv *priv)
{
        if (priv->idmac_ch)
                ipu_idmac_put(priv->idmac_ch);
        priv->idmac_ch = NULL;

        if (priv->smfc)
                ipu_smfc_put(priv->smfc);
        priv->smfc = NULL;
}

static int csi_idmac_get_ipu_resources(struct csi_priv *priv)
{
        int ch_num, ret;
        struct ipu_smfc *smfc;
        struct ipuv3_channel *idmac_ch;

        ch_num = IPUV3_CHANNEL_CSI0 + priv->smfc_id;

        smfc = ipu_smfc_get(priv->ipu, ch_num);
        if (IS_ERR(smfc)) {
                v4l2_err(&priv->sd, "failed to get SMFC\n");
                ret = PTR_ERR(smfc);
                goto out;
        }
        priv->smfc = smfc;

        idmac_ch = ipu_idmac_get(priv->ipu, ch_num);
        if (IS_ERR(idmac_ch)) {
                v4l2_err(&priv->sd, "could not get IDMAC channel %u\n",
                         ch_num);
                ret = PTR_ERR(idmac_ch);
                goto out;
        }
        priv->idmac_ch = idmac_ch;

        return 0;
out:
        csi_idmac_put_ipu_resources(priv);
        return ret;
}

static void csi_vb2_buf_done(struct csi_priv *priv)
{
        struct imx_media_video_dev *vdev = priv->vdev;
        struct imx_media_buffer *done, *next;
        struct vb2_buffer *vb;
        dma_addr_t phys;

        done = priv->active_vb2_buf[priv->ipu_buf_num];
        if (done) {
                vb = &done->vbuf.vb2_buf;
                vb->timestamp = ktime_get_ns();
                vb2_buffer_done(vb, priv->nfb4eof ?
                                VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
        }

        priv->nfb4eof = false;

        /* get next queued buffer */
        next = imx_media_capture_device_next_buf(vdev);
        if (next) {
                phys = vb2_dma_contig_plane_dma_addr(&next->vbuf.vb2_buf, 0);
                priv->active_vb2_buf[priv->ipu_buf_num] = next;
        } else {
                phys = priv->underrun_buf.phys;
                priv->active_vb2_buf[priv->ipu_buf_num] = NULL;
        }

        if (ipu_idmac_buffer_is_ready(priv->idmac_ch, priv->ipu_buf_num))
                ipu_idmac_clear_buffer(priv->idmac_ch, priv->ipu_buf_num);

        ipu_cpmem_set_buffer(priv->idmac_ch, priv->ipu_buf_num, phys);
}

static irqreturn_t csi_idmac_eof_interrupt(int irq, void *dev_id)
{
        struct csi_priv *priv = dev_id;

        spin_lock(&priv->irqlock);

        if (priv->last_eof) {
                complete(&priv->last_eof_comp);
                priv->last_eof = false;
                goto unlock;
        }

        if (priv->fim)
                /* call frame interval monitor */
                imx_media_fim_eof_monitor(priv->fim, ktime_get());

        csi_vb2_buf_done(priv);

        /* select new IPU buf */
        ipu_idmac_select_buffer(priv->idmac_ch, priv->ipu_buf_num);
        /* toggle IPU double-buffer index */
        priv->ipu_buf_num ^= 1;

        /* bump the EOF timeout timer */
        mod_timer(&priv->eof_timeout_timer,
                  jiffies + msecs_to_jiffies(IMX_MEDIA_EOF_TIMEOUT));

unlock:
        spin_unlock(&priv->irqlock);
        return IRQ_HANDLED;
}

static irqreturn_t csi_idmac_nfb4eof_interrupt(int irq, void *dev_id)
{
        struct csi_priv *priv = dev_id;

        spin_lock(&priv->irqlock);

        /*
         * this is not an unrecoverable error, just mark
         * the next captured frame with vb2 error flag.
         */
        priv->nfb4eof = true;

        v4l2_err(&priv->sd, "NFB4EOF\n");

        spin_unlock(&priv->irqlock);

        return IRQ_HANDLED;
}

/*
 * EOF timeout timer function. This is an unrecoverable condition
 * without a stream restart.
 */
static void csi_idmac_eof_timeout(struct timer_list *t)
{
        struct csi_priv *priv = from_timer(priv, t, eof_timeout_timer);
        struct imx_media_video_dev *vdev = priv->vdev;

        v4l2_err(&priv->sd, "EOF timeout\n");

        /* signal a fatal error to capture device */
        imx_media_capture_device_error(vdev);
}

static void csi_idmac_setup_vb2_buf(struct csi_priv *priv, dma_addr_t *phys)
{
        struct imx_media_video_dev *vdev = priv->vdev;
        struct imx_media_buffer *buf;
        int i;

        for (i = 0; i < 2; i++) {
                buf = imx_media_capture_device_next_buf(vdev);
                if (buf) {
                        priv->active_vb2_buf[i] = buf;
                        phys[i] = vb2_dma_contig_plane_dma_addr(
                                &buf->vbuf.vb2_buf, 0);
                } else {
                        priv->active_vb2_buf[i] = NULL;
                        phys[i] = priv->underrun_buf.phys;
                }
        }
}

static void csi_idmac_unsetup_vb2_buf(struct csi_priv *priv,
                                      enum vb2_buffer_state return_status)
{
        struct imx_media_buffer *buf;
        int i;

        /* return any remaining active frames with return_status */
        for (i = 0; i < 2; i++) {
                buf = priv->active_vb2_buf[i];
                if (buf) {
                        struct vb2_buffer *vb = &buf->vbuf.vb2_buf;

                        vb->timestamp = ktime_get_ns();
                        vb2_buffer_done(vb, return_status);
                }
        }
}

/* init the SMFC IDMAC channel */
static int csi_idmac_setup_channel(struct csi_priv *priv)
{
        struct imx_media_video_dev *vdev = priv->vdev;
        struct v4l2_mbus_framefmt *infmt;
        struct ipu_image image;
        u32 passthrough_bits;
        dma_addr_t phys[2];
        bool passthrough;
        u32 burst_size;
        int ret;

        infmt = &priv->format_mbus[CSI_SINK_PAD];

        ipu_cpmem_zero(priv->idmac_ch);

        memset(&image, 0, sizeof(image));
        image.pix = vdev->fmt.fmt.pix;
        image.rect.width = image.pix.width;
        image.rect.height = image.pix.height;

        csi_idmac_setup_vb2_buf(priv, phys);

        image.phys0 = phys[0];
        image.phys1 = phys[1];

        /*
         * Check for conditions that require the IPU to handle the
         * data internally as generic data, aka passthrough mode:
         * - raw bayer formats
         * - the CSI is receiving from a 16-bit parallel bus
         */
        switch (image.pix.pixelformat) {
        case V4L2_PIX_FMT_SBGGR8:
        case V4L2_PIX_FMT_SGBRG8:
        case V4L2_PIX_FMT_SGRBG8:
        case V4L2_PIX_FMT_SRGGB8:
        case V4L2_PIX_FMT_GREY:
                burst_size = 16;
                passthrough = true;
                passthrough_bits = 8;
                break;
        case V4L2_PIX_FMT_SBGGR16:
        case V4L2_PIX_FMT_SGBRG16:
        case V4L2_PIX_FMT_SGRBG16:
        case V4L2_PIX_FMT_SRGGB16:
        case V4L2_PIX_FMT_Y16:
                burst_size = 8;
                passthrough = true;
                passthrough_bits = 16;
                break;
        case V4L2_PIX_FMT_YUV420:
        case V4L2_PIX_FMT_NV12:
                burst_size = (image.pix.width & 0x3f) ?
                             ((image.pix.width & 0x1f) ?
                              ((image.pix.width & 0xf) ? 8 : 16) : 32) : 64;
                passthrough = is_parallel_16bit_bus(&priv->upstream_ep);
                passthrough_bits = 16;
                /* Skip writing U and V components to odd rows */
                ipu_cpmem_skip_odd_chroma_rows(priv->idmac_ch);
                break;
        case V4L2_PIX_FMT_YUYV:
        case V4L2_PIX_FMT_UYVY:
                burst_size = (image.pix.width & 0x1f) ?
                             ((image.pix.width & 0xf) ? 8 : 16) : 32;
                passthrough = is_parallel_16bit_bus(&priv->upstream_ep);
                passthrough_bits = 16;
                break;
        default:
                burst_size = (image.pix.width & 0xf) ? 8 : 16;
                passthrough = is_parallel_16bit_bus(&priv->upstream_ep);
                passthrough_bits = 16;
                break;
        }

        if (passthrough) {
                ipu_cpmem_set_resolution(priv->idmac_ch, image.rect.width,
                                         image.rect.height);
                ipu_cpmem_set_stride(priv->idmac_ch, image.pix.bytesperline);
                ipu_cpmem_set_buffer(priv->idmac_ch, 0, image.phys0);
                ipu_cpmem_set_buffer(priv->idmac_ch, 1, image.phys1);
                ipu_cpmem_set_format_passthrough(priv->idmac_ch,
                                                 passthrough_bits);
        } else {
                ret = ipu_cpmem_set_image(priv->idmac_ch, &image);
                if (ret)
                        goto unsetup_vb2;
        }

        ipu_cpmem_set_burstsize(priv->idmac_ch, burst_size);

        /*
         * Set the channel for the direct CSI-->memory via SMFC
         * use-case to very high priority, by enabling the watermark
         * signal in the SMFC, enabling WM in the channel, and setting
         * the channel priority to high.
         *
         * Refer to the i.mx6 rev. D TRM Table 36-8: Calculated priority
         * value.
         *
         * The WM's are set very low by intention here to ensure that
         * the SMFC FIFOs do not overflow.
         */
        ipu_smfc_set_watermark(priv->smfc, 0x02, 0x01);
        ipu_cpmem_set_high_priority(priv->idmac_ch);
        ipu_idmac_enable_watermark(priv->idmac_ch, true);
        ipu_cpmem_set_axi_id(priv->idmac_ch, 0);

        burst_size = passthrough ?
                (burst_size >> 3) - 1 : (burst_size >> 2) - 1;

        ipu_smfc_set_burstsize(priv->smfc, burst_size);

        if (image.pix.field == V4L2_FIELD_NONE &&
            V4L2_FIELD_HAS_BOTH(infmt->field))
                ipu_cpmem_interlaced_scan(priv->idmac_ch,
                                          image.pix.bytesperline);

        ipu_idmac_set_double_buffer(priv->idmac_ch, true);

        return 0;

unsetup_vb2:
        csi_idmac_unsetup_vb2_buf(priv, VB2_BUF_STATE_QUEUED);
        return ret;
}

static void csi_idmac_unsetup(struct csi_priv *priv,
                              enum vb2_buffer_state state)
{
        ipu_idmac_disable_channel(priv->idmac_ch);
        ipu_smfc_disable(priv->smfc);

        csi_idmac_unsetup_vb2_buf(priv, state);
}

static int csi_idmac_setup(struct csi_priv *priv)
{
        int ret;

        ret = csi_idmac_setup_channel(priv);
        if (ret)
                return ret;

        ipu_cpmem_dump(priv->idmac_ch);
        ipu_dump(priv->ipu);

        ipu_smfc_enable(priv->smfc);

        /* set buffers ready */
        ipu_idmac_select_buffer(priv->idmac_ch, 0);
        ipu_idmac_select_buffer(priv->idmac_ch, 1);

        /* enable the channels */
        ipu_idmac_enable_channel(priv->idmac_ch);

        return 0;
}

static int csi_idmac_start(struct csi_priv *priv)
{
        struct imx_media_video_dev *vdev = priv->vdev;
        struct v4l2_pix_format *outfmt;
        int ret;

        ret = csi_idmac_get_ipu_resources(priv);
        if (ret)
                return ret;

        ipu_smfc_map_channel(priv->smfc, priv->csi_id, priv->vc_num);

        outfmt = &vdev->fmt.fmt.pix;

        ret = imx_media_alloc_dma_buf(priv->md, &priv->underrun_buf,
                                      outfmt->sizeimage);
        if (ret)
                goto out_put_ipu;

        priv->ipu_buf_num = 0;

        /* init EOF completion waitq */
        init_completion(&priv->last_eof_comp);
        priv->last_eof = false;
        priv->nfb4eof = false;

        ret = csi_idmac_setup(priv);
        if (ret) {
                v4l2_err(&priv->sd, "csi_idmac_setup failed: %d\n", ret);
                goto out_free_dma_buf;
        }

        priv->nfb4eof_irq = ipu_idmac_channel_irq(priv->ipu,
                                                 priv->idmac_ch,
                                                 IPU_IRQ_NFB4EOF);
        ret = devm_request_irq(priv->dev, priv->nfb4eof_irq,
                               csi_idmac_nfb4eof_interrupt, 0,
                               "imx-smfc-nfb4eof", priv);
        if (ret) {
                v4l2_err(&priv->sd,
                         "Error registering NFB4EOF irq: %d\n", ret);
                goto out_unsetup;
        }

        priv->eof_irq = ipu_idmac_channel_irq(priv->ipu, priv->idmac_ch,
                                              IPU_IRQ_EOF);

        ret = devm_request_irq(priv->dev, priv->eof_irq,
                               csi_idmac_eof_interrupt, 0,
                               "imx-smfc-eof", priv);
        if (ret) {
                v4l2_err(&priv->sd,
                         "Error registering eof irq: %d\n", ret);
                goto out_free_nfb4eof_irq;
        }

        /* start the EOF timeout timer */
        mod_timer(&priv->eof_timeout_timer,
                  jiffies + msecs_to_jiffies(IMX_MEDIA_EOF_TIMEOUT));

        return 0;

out_free_nfb4eof_irq:
        devm_free_irq(priv->dev, priv->nfb4eof_irq, priv);
out_unsetup:
        csi_idmac_unsetup(priv, VB2_BUF_STATE_QUEUED);
out_free_dma_buf:
        imx_media_free_dma_buf(priv->md, &priv->underrun_buf);
out_put_ipu:
        csi_idmac_put_ipu_resources(priv);
        return ret;
}

static void csi_idmac_stop(struct csi_priv *priv)
{
        unsigned long flags;
        int ret;

        /* mark next EOF interrupt as the last before stream off */
        spin_lock_irqsave(&priv->irqlock, flags);
        priv->last_eof = true;
        spin_unlock_irqrestore(&priv->irqlock, flags);

        /*
         * and then wait for interrupt handler to mark completion.
         */
        ret = wait_for_completion_timeout(
                &priv->last_eof_comp, msecs_to_jiffies(IMX_MEDIA_EOF_TIMEOUT));
        if (ret == 0)
                v4l2_warn(&priv->sd, "wait last EOF timeout\n");

        devm_free_irq(priv->dev, priv->eof_irq, priv);
        devm_free_irq(priv->dev, priv->nfb4eof_irq, priv);

        csi_idmac_unsetup(priv, VB2_BUF_STATE_ERROR);

        imx_media_free_dma_buf(priv->md, &priv->underrun_buf);

        /* cancel the EOF timeout timer */
        del_timer_sync(&priv->eof_timeout_timer);

        csi_idmac_put_ipu_resources(priv);
}

/* Update the CSI whole sensor and active windows */
static int csi_setup(struct csi_priv *priv)
{
        struct v4l2_mbus_framefmt *infmt, *outfmt;
        struct v4l2_mbus_config mbus_cfg;
        struct v4l2_mbus_framefmt if_fmt;

        infmt = &priv->format_mbus[CSI_SINK_PAD];
        outfmt = &priv->format_mbus[priv->active_output_pad];

        /* compose mbus_config from the upstream endpoint */
        mbus_cfg.type = priv->upstream_ep.bus_type;
        mbus_cfg.flags = (priv->upstream_ep.bus_type == V4L2_MBUS_CSI2) ?
                priv->upstream_ep.bus.mipi_csi2.flags :
                priv->upstream_ep.bus.parallel.flags;

        /*
         * we need to pass input frame to CSI interface, but
         * with translated field type from output format
         */
        if_fmt = *infmt;
        if_fmt.field = outfmt->field;

        ipu_csi_set_window(priv->csi, &priv->crop);

        ipu_csi_set_downsize(priv->csi,
                             priv->crop.width == 2 * priv->compose.width,
                             priv->crop.height == 2 * priv->compose.height);

        ipu_csi_init_interface(priv->csi, &mbus_cfg, &if_fmt);

        ipu_csi_set_dest(priv->csi, priv->dest);

        if (priv->dest == IPU_CSI_DEST_IDMAC)
                ipu_csi_set_skip_smfc(priv->csi, priv->skip->skip_smfc,
                                      priv->skip->max_ratio - 1, 0);

        ipu_csi_dump(priv->csi);

        return 0;
}

static int csi_start(struct csi_priv *priv)
{
        struct v4l2_fract *output_fi;
        int ret;

        output_fi = &priv->frame_interval[priv->active_output_pad];

        if (priv->dest == IPU_CSI_DEST_IDMAC) {
                ret = csi_idmac_start(priv);
                if (ret)
                        return ret;
        }

        ret = csi_setup(priv);
        if (ret)
                goto idmac_stop;

        /* start the frame interval monitor */
        if (priv->fim && priv->dest == IPU_CSI_DEST_IDMAC) {
                ret = imx_media_fim_set_stream(priv->fim, output_fi, true);
                if (ret)
                        goto idmac_stop;
        }

        ret = ipu_csi_enable(priv->csi);
        if (ret) {
                v4l2_err(&priv->sd, "CSI enable error: %d\n", ret);
                goto fim_off;
        }

        return 0;

fim_off:
        if (priv->fim && priv->dest == IPU_CSI_DEST_IDMAC)
                imx_media_fim_set_stream(priv->fim, NULL, false);
idmac_stop:
        if (priv->dest == IPU_CSI_DEST_IDMAC)
                csi_idmac_stop(priv);
        return ret;
}

static void csi_stop(struct csi_priv *priv)
{
        if (priv->dest == IPU_CSI_DEST_IDMAC) {
                csi_idmac_stop(priv);

                /* stop the frame interval monitor */
                if (priv->fim)
                        imx_media_fim_set_stream(priv->fim, NULL, false);
        }

        ipu_csi_disable(priv->csi);
}

static const struct csi_skip_desc csi_skip[12] = {
        { 1, 1, 0x00 }, /* Keep all frames */
        { 5, 6, 0x10 }, /* Skip every sixth frame */
        { 4, 5, 0x08 }, /* Skip every fifth frame */
        { 3, 4, 0x04 }, /* Skip every fourth frame */
        { 2, 3, 0x02 }, /* Skip every third frame */
        { 3, 5, 0x0a }, /* Skip frames 1 and 3 of every 5 */
        { 1, 2, 0x01 }, /* Skip every second frame */
        { 2, 5, 0x0b }, /* Keep frames 1 and 4 of every 5 */
        { 1, 3, 0x03 }, /* Keep one in three frames */
        { 1, 4, 0x07 }, /* Keep one in four frames */
        { 1, 5, 0x0f }, /* Keep one in five frames */
        { 1, 6, 0x1f }, /* Keep one in six frames */
};

static void csi_apply_skip_interval(const struct csi_skip_desc *skip,
                                    struct v4l2_fract *interval)
{
        unsigned int div;

        interval->numerator *= skip->max_ratio;
        interval->denominator *= skip->keep;

        /* Reduce fraction to lowest terms */
        div = gcd(interval->numerator, interval->denominator);
        if (div > 1) {
                interval->numerator /= div;
                interval->denominator /= div;
        }
}

/*
 * Find the skip pattern to produce the output frame interval closest to the
 * requested one, for the given input frame interval. Updates the output frame
 * interval to the exact value.
 */
static const struct csi_skip_desc *csi_find_best_skip(struct v4l2_fract *in,
                                                      struct v4l2_fract *out)
{
        const struct csi_skip_desc *skip = &csi_skip[0], *best_skip = skip;
        u32 min_err = UINT_MAX;
        u64 want_us;
        int i;

        /* Default to 1:1 ratio */
        if (out->numerator == 0 || out->denominator == 0 ||
            in->numerator == 0 || in->denominator == 0) {
                *out = *in;
                return best_skip;
        }

        want_us = div_u64((u64)USEC_PER_SEC * out->numerator, out->denominator);

        /* Find the reduction closest to the requested time per frame */
        for (i = 0; i < ARRAY_SIZE(csi_skip); i++, skip++) {
                u64 tmp, err;

                tmp = div_u64((u64)USEC_PER_SEC * in->numerator *
                              skip->max_ratio, in->denominator * skip->keep);

                err = abs((s64)tmp - want_us);
                if (err < min_err) {
                        min_err = err;
                        best_skip = skip;
                }
        }

        *out = *in;
        csi_apply_skip_interval(best_skip, out);

        return best_skip;
}

/*
 * V4L2 subdev operations.
 */

static int csi_g_frame_interval(struct v4l2_subdev *sd,
                                struct v4l2_subdev_frame_interval *fi)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);

        if (fi->pad >= CSI_NUM_PADS)
                return -EINVAL;

        mutex_lock(&priv->lock);

        fi->interval = priv->frame_interval[fi->pad];

        mutex_unlock(&priv->lock);

        return 0;
}

static int csi_s_frame_interval(struct v4l2_subdev *sd,
                                struct v4l2_subdev_frame_interval *fi)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        struct v4l2_fract *input_fi;
        int ret = 0;

        mutex_lock(&priv->lock);

        input_fi = &priv->frame_interval[CSI_SINK_PAD];

        switch (fi->pad) {
        case CSI_SINK_PAD:
                /* No limits on input frame interval */
                /* Reset output intervals and frame skipping ratio to 1:1 */
                priv->frame_interval[CSI_SRC_PAD_IDMAC] = fi->interval;
                priv->frame_interval[CSI_SRC_PAD_DIRECT] = fi->interval;
                priv->skip = &csi_skip[0];
                break;
        case CSI_SRC_PAD_IDMAC:
                /*
                 * frame interval at IDMAC output pad depends on input
                 * interval, modified by frame skipping.
                 */
                priv->skip = csi_find_best_skip(input_fi, &fi->interval);
                break;
        case CSI_SRC_PAD_DIRECT:
                /*
                 * frame interval at DIRECT output pad is same as input
                 * interval.
                 */
                fi->interval = *input_fi;
                break;
        default:
                ret = -EINVAL;
                goto out;
        }

        priv->frame_interval[fi->pad] = fi->interval;
out:
        mutex_unlock(&priv->lock);
        return ret;
}

static int csi_s_stream(struct v4l2_subdev *sd, int enable)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        int ret = 0;

        mutex_lock(&priv->lock);

        if (!priv->src_sd || !priv->sink) {
                ret = -EPIPE;
                goto out;
        }

        /*
         * enable/disable streaming only if stream_count is
         * going from 0 to 1 / 1 to 0.
         */
        if (priv->stream_count != !enable)
                goto update_count;

        if (enable) {
                /* upstream must be started first, before starting CSI */
                ret = v4l2_subdev_call(priv->src_sd, video, s_stream, 1);
                ret = (ret && ret != -ENOIOCTLCMD) ? ret : 0;
                if (ret)
                        goto out;

                dev_dbg(priv->dev, "stream ON\n");
                ret = csi_start(priv);
                if (ret) {
                        v4l2_subdev_call(priv->src_sd, video, s_stream, 0);
                        goto out;
                }
        } else {
                dev_dbg(priv->dev, "stream OFF\n");
                /* CSI must be stopped first, then stop upstream */
                csi_stop(priv);
                v4l2_subdev_call(priv->src_sd, video, s_stream, 0);
        }

update_count:
        priv->stream_count += enable ? 1 : -1;
        if (priv->stream_count < 0)
                priv->stream_count = 0;
out:
        mutex_unlock(&priv->lock);
        return ret;
}

static int csi_link_setup(struct media_entity *entity,
                          const struct media_pad *local,
                          const struct media_pad *remote, u32 flags)
{
        struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        struct v4l2_subdev *remote_sd;
        int ret = 0;

        dev_dbg(priv->dev, "link setup %s -> %s\n", remote->entity->name,
                local->entity->name);

        mutex_lock(&priv->lock);

        if (local->flags & MEDIA_PAD_FL_SINK) {
                if (!is_media_entity_v4l2_subdev(remote->entity)) {
                        ret = -EINVAL;
                        goto out;
                }

                remote_sd = media_entity_to_v4l2_subdev(remote->entity);

                if (flags & MEDIA_LNK_FL_ENABLED) {
                        if (priv->src_sd) {
                                ret = -EBUSY;
                                goto out;
                        }
                        priv->src_sd = remote_sd;
                } else {
                        priv->src_sd = NULL;
                }

                goto out;
        }

        /* this is a source pad */

        if (flags & MEDIA_LNK_FL_ENABLED) {
                if (priv->sink) {
                        ret = -EBUSY;
                        goto out;
                }
        } else {
                v4l2_ctrl_handler_free(&priv->ctrl_hdlr);
                v4l2_ctrl_handler_init(&priv->ctrl_hdlr, 0);
                priv->sink = NULL;
                goto out;
        }

        /* record which output pad is now active */
        priv->active_output_pad = local->index;

        /* set CSI destination */
        if (local->index == CSI_SRC_PAD_IDMAC) {
                if (!is_media_entity_v4l2_video_device(remote->entity)) {
                        ret = -EINVAL;
                        goto out;
                }

                if (priv->fim) {
                        ret = imx_media_fim_add_controls(priv->fim);
                        if (ret)
                                goto out;
                }

                priv->dest = IPU_CSI_DEST_IDMAC;
        } else {
                if (!is_media_entity_v4l2_subdev(remote->entity)) {
                        ret = -EINVAL;
                        goto out;
                }

                remote_sd = media_entity_to_v4l2_subdev(remote->entity);
                switch (remote_sd->grp_id) {
                case IMX_MEDIA_GRP_ID_VDIC:
                        priv->dest = IPU_CSI_DEST_VDIC;
                        break;
                case IMX_MEDIA_GRP_ID_IC_PRP:
                        priv->dest = IPU_CSI_DEST_IC;
                        break;
                default:
                        ret = -EINVAL;
                        goto out;
                }
        }

        priv->sink = remote->entity;
out:
        mutex_unlock(&priv->lock);
        return ret;

}

static int csi_link_validate(struct v4l2_subdev *sd,
                             struct media_link *link,
                             struct v4l2_subdev_format *source_fmt,
                             struct v4l2_subdev_format *sink_fmt)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        struct v4l2_fwnode_endpoint upstream_ep = {};
        const struct imx_media_pixfmt *incc;
        bool is_csi2;
        int ret;

        ret = v4l2_subdev_link_validate_default(sd, link,
                                                source_fmt, sink_fmt);
        if (ret)
                return ret;

        ret = csi_get_upstream_endpoint(priv, &upstream_ep);
        if (ret) {
                v4l2_err(&priv->sd, "failed to find upstream endpoint\n");
                return ret;
        }

        mutex_lock(&priv->lock);

        priv->upstream_ep = upstream_ep;
        is_csi2 = (upstream_ep.bus_type == V4L2_MBUS_CSI2);
        incc = priv->cc[CSI_SINK_PAD];

        if (priv->dest != IPU_CSI_DEST_IDMAC &&
            (incc->bayer || is_parallel_16bit_bus(&upstream_ep))) {
                v4l2_err(&priv->sd,
                         "bayer/16-bit parallel buses must go to IDMAC pad\n");
                ret = -EINVAL;
                goto out;
        }

        if (is_csi2) {
                int vc_num = 0;
                /*
                 * NOTE! It seems the virtual channels from the mipi csi-2
                 * receiver are used only for routing by the video mux's,
                 * or for hard-wired routing to the CSI's. Once the stream
                 * enters the CSI's however, they are treated internally
                 * in the IPU as virtual channel 0.
                 */
#if 0
                mutex_unlock(&priv->lock);
                vc_num = imx_media_find_mipi_csi2_channel(priv->md,
                                                          &priv->sd.entity);
                if (vc_num < 0)
                        return vc_num;
                mutex_lock(&priv->lock);
#endif
                ipu_csi_set_mipi_datatype(priv->csi, vc_num,
                                          &priv->format_mbus[CSI_SINK_PAD]);
        }

        /* select either parallel or MIPI-CSI2 as input to CSI */
        ipu_set_csi_src_mux(priv->ipu, priv->csi_id, is_csi2);
out:
        mutex_unlock(&priv->lock);
        return ret;
}

static struct v4l2_mbus_framefmt *
__csi_get_fmt(struct csi_priv *priv, struct v4l2_subdev_pad_config *cfg,
              unsigned int pad, enum v4l2_subdev_format_whence which)
{
        if (which == V4L2_SUBDEV_FORMAT_TRY)
                return v4l2_subdev_get_try_format(&priv->sd, cfg, pad);
        else
                return &priv->format_mbus[pad];
}

static struct v4l2_rect *
__csi_get_crop(struct csi_priv *priv, struct v4l2_subdev_pad_config *cfg,
               enum v4l2_subdev_format_whence which)
{
        if (which == V4L2_SUBDEV_FORMAT_TRY)
                return v4l2_subdev_get_try_crop(&priv->sd, cfg, CSI_SINK_PAD);
        else
                return &priv->crop;
}

static struct v4l2_rect *
__csi_get_compose(struct csi_priv *priv, struct v4l2_subdev_pad_config *cfg,
                  enum v4l2_subdev_format_whence which)
{
        if (which == V4L2_SUBDEV_FORMAT_TRY)
                return v4l2_subdev_get_try_compose(&priv->sd, cfg,
                                                   CSI_SINK_PAD);
        else
                return &priv->compose;
}

static void csi_try_crop(struct csi_priv *priv,
                         struct v4l2_rect *crop,
                         struct v4l2_subdev_pad_config *cfg,
                         struct v4l2_mbus_framefmt *infmt,
                         struct v4l2_fwnode_endpoint *upstream_ep)
{
        crop->width = min_t(__u32, infmt->width, crop->width);
        if (crop->left + crop->width > infmt->width)
                crop->left = infmt->width - crop->width;
        /* adjust crop left/width to h/w alignment restrictions */
        crop->left &= ~0x3;
        crop->width &= ~0x7;

        /*
         * FIXME: not sure why yet, but on interlaced bt.656,
         * changing the vertical cropping causes loss of vertical
         * sync, so fix it to NTSC/PAL active lines. NTSC contains
         * 2 extra lines of active video that need to be cropped.
         */
        if (upstream_ep->bus_type == V4L2_MBUS_BT656 &&
            (V4L2_FIELD_HAS_BOTH(infmt->field) ||
             infmt->field == V4L2_FIELD_ALTERNATE)) {
                crop->height = infmt->height;
                crop->top = (infmt->height == 480) ? 2 : 0;
        } else {
                crop->height = min_t(__u32, infmt->height, crop->height);
                if (crop->top + crop->height > infmt->height)
                        crop->top = infmt->height - crop->height;
        }
}

static int csi_enum_mbus_code(struct v4l2_subdev *sd,
                              struct v4l2_subdev_pad_config *cfg,
                              struct v4l2_subdev_mbus_code_enum *code)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        const struct imx_media_pixfmt *incc;
        struct v4l2_mbus_framefmt *infmt;
        int ret = 0;

        mutex_lock(&priv->lock);

        infmt = __csi_get_fmt(priv, cfg, CSI_SINK_PAD, code->which);
        incc = imx_media_find_mbus_format(infmt->code, CS_SEL_ANY, true);

        switch (code->pad) {
        case CSI_SINK_PAD:
                ret = imx_media_enum_mbus_format(&code->code, code->index,
                                                 CS_SEL_ANY, true);
                break;
        case CSI_SRC_PAD_DIRECT:
        case CSI_SRC_PAD_IDMAC:
                if (incc->bayer) {
                        if (code->index != 0) {
                                ret = -EINVAL;
                                goto out;
                        }
                        code->code = infmt->code;
                } else {
                        u32 cs_sel = (incc->cs == IPUV3_COLORSPACE_YUV) ?
                                CS_SEL_YUV : CS_SEL_RGB;
                        ret = imx_media_enum_ipu_format(&code->code,
                                                        code->index,
                                                        cs_sel);
                }
                break;
        default:
                ret = -EINVAL;
        }

out:
        mutex_unlock(&priv->lock);
        return ret;
}

static int csi_enum_frame_size(struct v4l2_subdev *sd,
                               struct v4l2_subdev_pad_config *cfg,
                               struct v4l2_subdev_frame_size_enum *fse)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        struct v4l2_rect *crop;
        int ret = 0;

        if (fse->pad >= CSI_NUM_PADS ||
            fse->index > (fse->pad == CSI_SINK_PAD ? 0 : 3))
                return -EINVAL;

        mutex_lock(&priv->lock);

        if (fse->pad == CSI_SINK_PAD) {
                fse->min_width = MIN_W;
                fse->max_width = MAX_W;
                fse->min_height = MIN_H;
                fse->max_height = MAX_H;
        } else {
                crop = __csi_get_crop(priv, cfg, fse->which);

                fse->min_width = fse->max_width = fse->index & 1 ?
                        crop->width / 2 : crop->width;
                fse->min_height = fse->max_height = fse->index & 2 ?
                        crop->height / 2 : crop->height;
        }

        mutex_unlock(&priv->lock);
        return ret;
}

static int csi_enum_frame_interval(struct v4l2_subdev *sd,
                                   struct v4l2_subdev_pad_config *cfg,
                                   struct v4l2_subdev_frame_interval_enum *fie)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        struct v4l2_fract *input_fi;
        struct v4l2_rect *crop;
        int ret = 0;

        if (fie->pad >= CSI_NUM_PADS ||
            fie->index >= (fie->pad != CSI_SRC_PAD_IDMAC ?
                           1 : ARRAY_SIZE(csi_skip)))
                return -EINVAL;

        mutex_lock(&priv->lock);

        input_fi = &priv->frame_interval[CSI_SINK_PAD];
        crop = __csi_get_crop(priv, cfg, fie->which);

        if ((fie->width != crop->width && fie->width != crop->width / 2) ||
            (fie->height != crop->height && fie->height != crop->height / 2)) {
                ret = -EINVAL;
                goto out;
        }

        fie->interval = *input_fi;

        if (fie->pad == CSI_SRC_PAD_IDMAC)
                csi_apply_skip_interval(&csi_skip[fie->index],
                                        &fie->interval);

out:
        mutex_unlock(&priv->lock);
        return ret;
}

static int csi_get_fmt(struct v4l2_subdev *sd,
                       struct v4l2_subdev_pad_config *cfg,
                       struct v4l2_subdev_format *sdformat)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        struct v4l2_mbus_framefmt *fmt;
        int ret = 0;

        if (sdformat->pad >= CSI_NUM_PADS)
                return -EINVAL;

        mutex_lock(&priv->lock);

        fmt = __csi_get_fmt(priv, cfg, sdformat->pad, sdformat->which);
        if (!fmt) {
                ret = -EINVAL;
                goto out;
        }

        sdformat->format = *fmt;
out:
        mutex_unlock(&priv->lock);
        return ret;
}

static void csi_try_fmt(struct csi_priv *priv,
                        struct v4l2_fwnode_endpoint *upstream_ep,
                        struct v4l2_subdev_pad_config *cfg,
                        struct v4l2_subdev_format *sdformat,
                        struct v4l2_rect *crop,
                        struct v4l2_rect *compose,
                        const struct imx_media_pixfmt **cc)
{
        const struct imx_media_pixfmt *incc;
        struct v4l2_mbus_framefmt *infmt;
        u32 code;

        infmt = __csi_get_fmt(priv, cfg, CSI_SINK_PAD, sdformat->which);

        switch (sdformat->pad) {
        case CSI_SRC_PAD_DIRECT:
        case CSI_SRC_PAD_IDMAC:
                incc = imx_media_find_mbus_format(infmt->code,
                                                  CS_SEL_ANY, true);

                sdformat->format.width = compose->width;
                sdformat->format.height = compose->height;

                if (incc->bayer) {
                        sdformat->format.code = infmt->code;
                        *cc = incc;
                } else {
                        u32 cs_sel = (incc->cs == IPUV3_COLORSPACE_YUV) ?
                                CS_SEL_YUV : CS_SEL_RGB;

                        *cc = imx_media_find_ipu_format(sdformat->format.code,
                                                        cs_sel);
                        if (!*cc) {
                                imx_media_enum_ipu_format(&code, 0, cs_sel);
                                *cc = imx_media_find_ipu_format(code, cs_sel);
                                sdformat->format.code = (*cc)->codes[0];
                        }
                }

                if (sdformat->pad == CSI_SRC_PAD_DIRECT ||
                    sdformat->format.field != V4L2_FIELD_NONE)
                        sdformat->format.field = infmt->field;

                /*
                 * translate V4L2_FIELD_ALTERNATE to SEQ_TB or SEQ_BT
                 * depending on input height (assume NTSC top-bottom
                 * order if 480 lines, otherwise PAL bottom-top order).
                 */
                if (sdformat->format.field == V4L2_FIELD_ALTERNATE) {
                        sdformat->format.field =  (infmt->height == 480) ?
                                V4L2_FIELD_SEQ_TB : V4L2_FIELD_SEQ_BT;
                }

                /* propagate colorimetry from sink */
                sdformat->format.colorspace = infmt->colorspace;
                sdformat->format.xfer_func = infmt->xfer_func;
                sdformat->format.quantization = infmt->quantization;
                sdformat->format.ycbcr_enc = infmt->ycbcr_enc;
                break;
        case CSI_SINK_PAD:
                v4l_bound_align_image(&sdformat->format.width, MIN_W, MAX_W,
                                      W_ALIGN, &sdformat->format.height,
                                      MIN_H, MAX_H, H_ALIGN, S_ALIGN);

                /* Reset crop and compose rectangles */
                crop->left = 0;
                crop->top = 0;
                crop->width = sdformat->format.width;
                crop->height = sdformat->format.height;
                csi_try_crop(priv, crop, cfg, &sdformat->format, upstream_ep);
                compose->left = 0;
                compose->top = 0;
                compose->width = crop->width;
                compose->height = crop->height;

                *cc = imx_media_find_mbus_format(sdformat->format.code,
                                                 CS_SEL_ANY, true);
                if (!*cc) {
                        imx_media_enum_mbus_format(&code, 0,
                                                   CS_SEL_ANY, false);
                        *cc = imx_media_find_mbus_format(code,
                                                        CS_SEL_ANY, false);
                        sdformat->format.code = (*cc)->codes[0];
                }

                imx_media_fill_default_mbus_fields(
                        &sdformat->format, infmt,
                        priv->active_output_pad == CSI_SRC_PAD_DIRECT);
                break;
        }
}

static int csi_set_fmt(struct v4l2_subdev *sd,
                       struct v4l2_subdev_pad_config *cfg,
                       struct v4l2_subdev_format *sdformat)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        struct imx_media_video_dev *vdev = priv->vdev;
        struct v4l2_fwnode_endpoint upstream_ep;
        const struct imx_media_pixfmt *cc;
        struct v4l2_pix_format vdev_fmt;
        struct v4l2_mbus_framefmt *fmt;
        struct v4l2_rect *crop, *compose;
        int ret;

        if (sdformat->pad >= CSI_NUM_PADS)
                return -EINVAL;

        ret = csi_get_upstream_endpoint(priv, &upstream_ep);
        if (ret) {
                v4l2_err(&priv->sd, "failed to find upstream endpoint\n");
                return ret;
        }

        mutex_lock(&priv->lock);

        if (priv->stream_count > 0) {
                ret = -EBUSY;
                goto out;
        }

        crop = __csi_get_crop(priv, cfg, sdformat->which);
        compose = __csi_get_compose(priv, cfg, sdformat->which);

        csi_try_fmt(priv, &upstream_ep, cfg, sdformat, crop, compose, &cc);

        fmt = __csi_get_fmt(priv, cfg, sdformat->pad, sdformat->which);
        *fmt = sdformat->format;

        if (sdformat->pad == CSI_SINK_PAD) {
                int pad;

                /* propagate format to source pads */
                for (pad = CSI_SINK_PAD + 1; pad < CSI_NUM_PADS; pad++) {
                        const struct imx_media_pixfmt *outcc;
                        struct v4l2_mbus_framefmt *outfmt;
                        struct v4l2_subdev_format format;

                        format.pad = pad;
                        format.which = sdformat->which;
                        format.format = sdformat->format;
                        csi_try_fmt(priv, &upstream_ep, cfg, &format,
                                    NULL, compose, &outcc);

                        outfmt = __csi_get_fmt(priv, cfg, pad, sdformat->which);
                        *outfmt = format.format;

                        if (sdformat->which == V4L2_SUBDEV_FORMAT_ACTIVE)
                                priv->cc[pad] = outcc;
                }
        }

        if (sdformat->which == V4L2_SUBDEV_FORMAT_TRY)
                goto out;

        priv->cc[sdformat->pad] = cc;

        /* propagate IDMAC output pad format to capture device */
        imx_media_mbus_fmt_to_pix_fmt(&vdev_fmt,
                                      &priv->format_mbus[CSI_SRC_PAD_IDMAC],
                                      priv->cc[CSI_SRC_PAD_IDMAC]);
        mutex_unlock(&priv->lock);
        imx_media_capture_device_set_format(vdev, &vdev_fmt);

        return 0;
out:
        mutex_unlock(&priv->lock);
        return ret;
}

static int csi_get_selection(struct v4l2_subdev *sd,
                             struct v4l2_subdev_pad_config *cfg,
                             struct v4l2_subdev_selection *sel)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        struct v4l2_mbus_framefmt *infmt;
        struct v4l2_rect *crop, *compose;
        int ret = 0;

        if (sel->pad != CSI_SINK_PAD)
                return -EINVAL;

        mutex_lock(&priv->lock);

        infmt = __csi_get_fmt(priv, cfg, CSI_SINK_PAD, sel->which);
        crop = __csi_get_crop(priv, cfg, sel->which);
        compose = __csi_get_compose(priv, cfg, sel->which);

        switch (sel->target) {
        case V4L2_SEL_TGT_CROP_BOUNDS:
                sel->r.left = 0;
                sel->r.top = 0;
                sel->r.width = infmt->width;
                sel->r.height = infmt->height;
                break;
        case V4L2_SEL_TGT_CROP:
                sel->r = *crop;
                break;
        case V4L2_SEL_TGT_COMPOSE_BOUNDS:
                sel->r.left = 0;
                sel->r.top = 0;
                sel->r.width = crop->width;
                sel->r.height = crop->height;
                break;
        case V4L2_SEL_TGT_COMPOSE:
                sel->r = *compose;
                break;
        default:
                ret = -EINVAL;
        }

        mutex_unlock(&priv->lock);
        return ret;
}

static int csi_set_scale(u32 *compose, u32 crop, u32 flags)
{
        if ((flags & (V4L2_SEL_FLAG_LE | V4L2_SEL_FLAG_GE)) ==
                     (V4L2_SEL_FLAG_LE | V4L2_SEL_FLAG_GE) &&
            *compose != crop && *compose != crop / 2)
                return -ERANGE;

        if (*compose <= crop / 2 ||
            (*compose < crop * 3 / 4 && !(flags & V4L2_SEL_FLAG_GE)) ||
            (*compose < crop && (flags & V4L2_SEL_FLAG_LE)))
                *compose = crop / 2;
        else
                *compose = crop;

        return 0;
}

static int csi_set_selection(struct v4l2_subdev *sd,
                             struct v4l2_subdev_pad_config *cfg,
                             struct v4l2_subdev_selection *sel)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        struct v4l2_fwnode_endpoint upstream_ep;
        struct v4l2_mbus_framefmt *infmt;
        struct v4l2_rect *crop, *compose;
        int pad, ret;

        if (sel->pad != CSI_SINK_PAD)
                return -EINVAL;

        ret = csi_get_upstream_endpoint(priv, &upstream_ep);
        if (ret) {
                v4l2_err(&priv->sd, "failed to find upstream endpoint\n");
                return ret;
        }

        mutex_lock(&priv->lock);

        if (priv->stream_count > 0) {
                ret = -EBUSY;
                goto out;
        }

        infmt = __csi_get_fmt(priv, cfg, CSI_SINK_PAD, sel->which);
        crop = __csi_get_crop(priv, cfg, sel->which);
        compose = __csi_get_compose(priv, cfg, sel->which);

        switch (sel->target) {
        case V4L2_SEL_TGT_CROP:
                /*
                 * Modifying the crop rectangle always changes the format on
                 * the source pads. If the KEEP_CONFIG flag is set, just return
                 * the current crop rectangle.
                 */
                if (sel->flags & V4L2_SEL_FLAG_KEEP_CONFIG) {
                        sel->r = priv->crop;
                        if (sel->which == V4L2_SUBDEV_FORMAT_TRY)
                                *crop = sel->r;
                        goto out;
                }

                csi_try_crop(priv, &sel->r, cfg, infmt, &upstream_ep);

                *crop = sel->r;

                /* Reset scaling to 1:1 */
                compose->width = crop->width;
                compose->height = crop->height;
                break;
        case V4L2_SEL_TGT_COMPOSE:
                /*
                 * Modifying the compose rectangle always changes the format on
                 * the source pads. If the KEEP_CONFIG flag is set, just return
                 * the current compose rectangle.
                 */
                if (sel->flags & V4L2_SEL_FLAG_KEEP_CONFIG) {
                        sel->r = priv->compose;
                        if (sel->which == V4L2_SUBDEV_FORMAT_TRY)
                                *compose = sel->r;
                        goto out;
                }

                sel->r.left = 0;
                sel->r.top = 0;
                ret = csi_set_scale(&sel->r.width, crop->width, sel->flags);
                if (ret)
                        goto out;
                ret = csi_set_scale(&sel->r.height, crop->height, sel->flags);
                if (ret)
                        goto out;

                *compose = sel->r;
                break;
        default:
                ret = -EINVAL;
                goto out;
        }

        /* Reset source pads to sink compose rectangle */
        for (pad = CSI_SINK_PAD + 1; pad < CSI_NUM_PADS; pad++) {
                struct v4l2_mbus_framefmt *outfmt;

                outfmt = __csi_get_fmt(priv, cfg, pad, sel->which);
                outfmt->width = compose->width;
                outfmt->height = compose->height;
        }

out:
        mutex_unlock(&priv->lock);
        return ret;
}

static int csi_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
                               struct v4l2_event_subscription *sub)
{
        if (sub->type != V4L2_EVENT_IMX_FRAME_INTERVAL_ERROR)
                return -EINVAL;
        if (sub->id != 0)
                return -EINVAL;

        return v4l2_event_subscribe(fh, sub, 0, NULL);
}

static int csi_unsubscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
                                 struct v4l2_event_subscription *sub)
{
        return v4l2_event_unsubscribe(fh, sub);
}

/*
 * retrieve our pads parsed from the OF graph by the media device
 */
static int csi_registered(struct v4l2_subdev *sd)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);
        struct ipu_csi *csi;
        int i, ret;
        u32 code;

        /* get media device */
        priv->md = dev_get_drvdata(sd->v4l2_dev->dev);

        /* get handle to IPU CSI */
        csi = ipu_csi_get(priv->ipu, priv->csi_id);
        if (IS_ERR(csi)) {
                v4l2_err(&priv->sd, "failed to get CSI%d\n", priv->csi_id);
                return PTR_ERR(csi);
        }
        priv->csi = csi;

        for (i = 0; i < CSI_NUM_PADS; i++) {
                priv->pad[i].flags = (i == CSI_SINK_PAD) ?
                        MEDIA_PAD_FL_SINK : MEDIA_PAD_FL_SOURCE;

                code = 0;
                if (i != CSI_SINK_PAD)
                        imx_media_enum_ipu_format(&code, 0, CS_SEL_YUV);

                /* set a default mbus format  */
                ret = imx_media_init_mbus_fmt(&priv->format_mbus[i],
                                              640, 480, code, V4L2_FIELD_NONE,
                                              &priv->cc[i]);
                if (ret)
                        goto put_csi;

                /* init default frame interval */
                priv->frame_interval[i].numerator = 1;
                priv->frame_interval[i].denominator = 30;
        }

        /* disable frame skipping */
        priv->skip = &csi_skip[0];

        /* init default crop and compose rectangle sizes */
        priv->crop.width = 640;
        priv->crop.height = 480;
        priv->compose.width = 640;
        priv->compose.height = 480;

        priv->fim = imx_media_fim_init(&priv->sd);
        if (IS_ERR(priv->fim)) {
                ret = PTR_ERR(priv->fim);
                goto put_csi;
        }

        ret = media_entity_pads_init(&sd->entity, CSI_NUM_PADS, priv->pad);
        if (ret)
                goto free_fim;

        ret = imx_media_capture_device_register(priv->vdev);
        if (ret)
                goto free_fim;

        ret = imx_media_add_video_device(priv->md, priv->vdev);
        if (ret)
                goto unreg;

        return 0;
unreg:
        imx_media_capture_device_unregister(priv->vdev);
free_fim:
        if (priv->fim)
                imx_media_fim_free(priv->fim);
put_csi:
        ipu_csi_put(priv->csi);
        return ret;
}

static void csi_unregistered(struct v4l2_subdev *sd)
{
        struct csi_priv *priv = v4l2_get_subdevdata(sd);

        imx_media_capture_device_unregister(priv->vdev);

        if (priv->fim)
                imx_media_fim_free(priv->fim);

        if (priv->csi)
                ipu_csi_put(priv->csi);
}

static const struct media_entity_operations csi_entity_ops = {
        .link_setup = csi_link_setup,
        .link_validate = v4l2_subdev_link_validate,
};

static const struct v4l2_subdev_core_ops csi_core_ops = {
        .subscribe_event = csi_subscribe_event,
        .unsubscribe_event = csi_unsubscribe_event,
};

static const struct v4l2_subdev_video_ops csi_video_ops = {
        .g_frame_interval = csi_g_frame_interval,
        .s_frame_interval = csi_s_frame_interval,
        .s_stream = csi_s_stream,
};

static const struct v4l2_subdev_pad_ops csi_pad_ops = {
        .init_cfg = imx_media_init_cfg,
        .enum_mbus_code = csi_enum_mbus_code,
        .enum_frame_size = csi_enum_frame_size,
        .enum_frame_interval = csi_enum_frame_interval,
        .get_fmt = csi_get_fmt,
        .set_fmt = csi_set_fmt,
        .get_selection = csi_get_selection,
        .set_selection = csi_set_selection,
        .link_validate = csi_link_validate,
};

static const struct v4l2_subdev_ops csi_subdev_ops = {
        .core = &csi_core_ops,
        .video = &csi_video_ops,
        .pad = &csi_pad_ops,
};

static const struct v4l2_subdev_internal_ops csi_internal_ops = {
        .registered = csi_registered,
        .unregistered = csi_unregistered,
};

static int imx_csi_probe(struct platform_device *pdev)
{
        struct ipu_client_platformdata *pdata;
        struct pinctrl *pinctrl;
        struct csi_priv *priv;
        int ret;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        platform_set_drvdata(pdev, &priv->sd);
        priv->dev = &pdev->dev;

        ret = dma_set_coherent_mask(priv->dev, DMA_BIT_MASK(32));
        if (ret)
                return ret;

        /* get parent IPU */
        priv->ipu = dev_get_drvdata(priv->dev->parent);

        /* get our CSI id */
        pdata = priv->dev->platform_data;
        priv->csi_id = pdata->csi;
        priv->smfc_id = (priv->csi_id == 0) ? 0 : 2;

        timer_setup(&priv->eof_timeout_timer, csi_idmac_eof_timeout, 0);
        spin_lock_init(&priv->irqlock);

        v4l2_subdev_init(&priv->sd, &csi_subdev_ops);
        v4l2_set_subdevdata(&priv->sd, priv);
        priv->sd.internal_ops = &csi_internal_ops;
        priv->sd.entity.ops = &csi_entity_ops;
        priv->sd.entity.function = MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER;
        priv->sd.dev = &pdev->dev;
        priv->sd.fwnode = of_fwnode_handle(pdata->of_node);
        priv->sd.owner = THIS_MODULE;
        priv->sd.flags = V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;
        priv->sd.grp_id = priv->csi_id ?
                IMX_MEDIA_GRP_ID_CSI1 : IMX_MEDIA_GRP_ID_CSI0;
        imx_media_grp_id_to_sd_name(priv->sd.name, sizeof(priv->sd.name),
                                    priv->sd.grp_id, ipu_get_num(priv->ipu));

        priv->vdev = imx_media_capture_device_init(&priv->sd,
                                                   CSI_SRC_PAD_IDMAC);
        if (IS_ERR(priv->vdev))
                return PTR_ERR(priv->vdev);

        mutex_init(&priv->lock);

        v4l2_ctrl_handler_init(&priv->ctrl_hdlr, 0);
        priv->sd.ctrl_handler = &priv->ctrl_hdlr;

        /*
         * The IPUv3 driver did not assign an of_node to this
         * device. As a result, pinctrl does not automatically
         * configure our pin groups, so we need to do that manually
         * here, after setting this device's of_node.
         */
        priv->dev->of_node = pdata->of_node;
        pinctrl = devm_pinctrl_get_select_default(priv->dev);
        if (IS_ERR(pinctrl)) {
                ret = PTR_ERR(pinctrl);
                dev_dbg(priv->dev,
                        "devm_pinctrl_get_select_default() failed: %d\n", ret);
                if (ret != -ENODEV)
                        goto free;
        }

        ret = v4l2_async_register_subdev(&priv->sd);
        if (ret)
                goto free;

        return 0;
free:
        v4l2_ctrl_handler_free(&priv->ctrl_hdlr);
        mutex_destroy(&priv->lock);
        imx_media_capture_device_remove(priv->vdev);
        return ret;
}

static int imx_csi_remove(struct platform_device *pdev)
{
        struct v4l2_subdev *sd = platform_get_drvdata(pdev);
        struct csi_priv *priv = sd_to_dev(sd);

        v4l2_ctrl_handler_free(&priv->ctrl_hdlr);
        mutex_destroy(&priv->lock);
        imx_media_capture_device_remove(priv->vdev);
        v4l2_async_unregister_subdev(sd);
        media_entity_cleanup(&sd->entity);

        return 0;
}

static const struct platform_device_id imx_csi_ids[] = {
        { .name = "imx-ipuv3-csi" },
        { },
};
MODULE_DEVICE_TABLE(platform, imx_csi_ids);

static struct platform_driver imx_csi_driver = {
        .probe = imx_csi_probe,
        .remove = imx_csi_remove,
        .id_table = imx_csi_ids,
        .driver = {
                .name = "imx-ipuv3-csi",
        },
};
module_platform_driver(imx_csi_driver);

MODULE_DESCRIPTION("i.MX CSI subdev driver");
MODULE_AUTHOR("Steve Longerbeam <steve_longerbeam@mentor.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:imx-ipuv3-csi");