/*
 * vimc-capture.c Virtual Media Controller Driver
 *
 * Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/component.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <media/v4l2-ioctl.h>
#include <media/videobuf2-core.h>
#include <media/videobuf2-vmalloc.h>

#include "vimc-common.h"

#define VIMC_CAP_DRV_NAME "vimc-capture"

struct vimc_cap_device {
        struct vimc_ent_device ved;
        struct video_device vdev;
        struct device *dev;
        struct v4l2_pix_format format;
        struct vb2_queue queue;
        struct list_head buf_list;
        /*
         * NOTE: in a real driver, a spin lock must be used to access the
         * queue because the frames are generated from a hardware interruption
         * and the isr is not allowed to sleep.
         * Even if it is not necessary a spinlock in the vimc driver, we
         * use it here as a code reference
         */
        spinlock_t qlock;
        struct mutex lock;
        u32 sequence;
        struct media_pipeline pipe;
};

static const struct v4l2_pix_format fmt_default = {
        .width = 640,
        .height = 480,
        .pixelformat = V4L2_PIX_FMT_RGB24,
        .field = V4L2_FIELD_NONE,
        .colorspace = V4L2_COLORSPACE_DEFAULT,
};

struct vimc_cap_buffer {
        /*
         * struct vb2_v4l2_buffer must be the first element
         * the videobuf2 framework will allocate this struct based on
         * buf_struct_size and use the first sizeof(struct vb2_buffer) bytes of
         * memory as a vb2_buffer
         */
        struct vb2_v4l2_buffer vb2;
        struct list_head list;
};

static int vimc_cap_querycap(struct file *file, void *priv,
                             struct v4l2_capability *cap)
{
        struct vimc_cap_device *vcap = video_drvdata(file);

        strscpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
        strscpy(cap->card, KBUILD_MODNAME, sizeof(cap->card));
        snprintf(cap->bus_info, sizeof(cap->bus_info),
                 "platform:%s", vcap->vdev.v4l2_dev->name);

        return 0;
}

static void vimc_cap_get_format(struct vimc_ent_device *ved,
                                struct v4l2_pix_format *fmt)
{
        struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device,
                                                    ved);

        *fmt = vcap->format;
}

static int vimc_cap_g_fmt_vid_cap(struct file *file, void *priv,
                                  struct v4l2_format *f)
{
        struct vimc_cap_device *vcap = video_drvdata(file);

        f->fmt.pix = vcap->format;

        return 0;
}

static int vimc_cap_try_fmt_vid_cap(struct file *file, void *priv,
                                    struct v4l2_format *f)
{
        struct v4l2_pix_format *format = &f->fmt.pix;
        const struct vimc_pix_map *vpix;

        format->width = clamp_t(u32, format->width, VIMC_FRAME_MIN_WIDTH,
                                VIMC_FRAME_MAX_WIDTH) & ~1;
        format->height = clamp_t(u32, format->height, VIMC_FRAME_MIN_HEIGHT,
                                 VIMC_FRAME_MAX_HEIGHT) & ~1;

        /* Don't accept a pixelformat that is not on the table */
        vpix = vimc_pix_map_by_pixelformat(format->pixelformat);
        if (!vpix) {
                format->pixelformat = fmt_default.pixelformat;
                vpix = vimc_pix_map_by_pixelformat(format->pixelformat);
        }
        /* TODO: Add support for custom bytesperline values */
        format->bytesperline = format->width * vpix->bpp;
        format->sizeimage = format->bytesperline * format->height;

        if (format->field == V4L2_FIELD_ANY)
                format->field = fmt_default.field;

        vimc_colorimetry_clamp(format);

        return 0;
}

static int vimc_cap_s_fmt_vid_cap(struct file *file, void *priv,
                                  struct v4l2_format *f)
{
        struct vimc_cap_device *vcap = video_drvdata(file);

        /* Do not change the format while stream is on */
        if (vb2_is_busy(&vcap->queue))
                return -EBUSY;

        vimc_cap_try_fmt_vid_cap(file, priv, f);

        dev_dbg(vcap->dev, "%s: format update: "
                "old:%dx%d (0x%x, %d, %d, %d, %d) "
                "new:%dx%d (0x%x, %d, %d, %d, %d)\n", vcap->vdev.name,
                /* old */
                vcap->format.width, vcap->format.height,
                vcap->format.pixelformat, vcap->format.colorspace,
                vcap->format.quantization, vcap->format.xfer_func,
                vcap->format.ycbcr_enc,
                /* new */
                f->fmt.pix.width, f->fmt.pix.height,
                f->fmt.pix.pixelformat, f->fmt.pix.colorspace,
                f->fmt.pix.quantization, f->fmt.pix.xfer_func,
                f->fmt.pix.ycbcr_enc);

        vcap->format = f->fmt.pix;

        return 0;
}

static int vimc_cap_enum_fmt_vid_cap(struct file *file, void *priv,
                                     struct v4l2_fmtdesc *f)
{
        const struct vimc_pix_map *vpix = vimc_pix_map_by_index(f->index);

        if (!vpix)
                return -EINVAL;

        f->pixelformat = vpix->pixelformat;

        return 0;
}

static int vimc_cap_enum_framesizes(struct file *file, void *fh,
                                    struct v4l2_frmsizeenum *fsize)
{
        const struct vimc_pix_map *vpix;

        if (fsize->index)
                return -EINVAL;

        /* Only accept code in the pix map table */
        vpix = vimc_pix_map_by_code(fsize->pixel_format);
        if (!vpix)
                return -EINVAL;

        fsize->type = V4L2_FRMSIZE_TYPE_CONTINUOUS;
        fsize->stepwise.min_width = VIMC_FRAME_MIN_WIDTH;
        fsize->stepwise.max_width = VIMC_FRAME_MAX_WIDTH;
        fsize->stepwise.min_height = VIMC_FRAME_MIN_HEIGHT;
        fsize->stepwise.max_height = VIMC_FRAME_MAX_HEIGHT;
        fsize->stepwise.step_width = 2;
        fsize->stepwise.step_height = 2;

        return 0;
}

static const struct v4l2_file_operations vimc_cap_fops = {
        .owner          = THIS_MODULE,
        .open           = v4l2_fh_open,
        .release        = vb2_fop_release,
        .read           = vb2_fop_read,
        .poll           = vb2_fop_poll,
        .unlocked_ioctl = video_ioctl2,
        .mmap           = vb2_fop_mmap,
};

static const struct v4l2_ioctl_ops vimc_cap_ioctl_ops = {
        .vidioc_querycap = vimc_cap_querycap,

        .vidioc_g_fmt_vid_cap = vimc_cap_g_fmt_vid_cap,
        .vidioc_s_fmt_vid_cap = vimc_cap_s_fmt_vid_cap,
        .vidioc_try_fmt_vid_cap = vimc_cap_try_fmt_vid_cap,
        .vidioc_enum_fmt_vid_cap = vimc_cap_enum_fmt_vid_cap,
        .vidioc_enum_framesizes = vimc_cap_enum_framesizes,

        .vidioc_reqbufs = vb2_ioctl_reqbufs,
        .vidioc_create_bufs = vb2_ioctl_create_bufs,
        .vidioc_prepare_buf = vb2_ioctl_prepare_buf,
        .vidioc_querybuf = vb2_ioctl_querybuf,
        .vidioc_qbuf = vb2_ioctl_qbuf,
        .vidioc_dqbuf = vb2_ioctl_dqbuf,
        .vidioc_expbuf = vb2_ioctl_expbuf,
        .vidioc_streamon = vb2_ioctl_streamon,
        .vidioc_streamoff = vb2_ioctl_streamoff,
};

static void vimc_cap_return_all_buffers(struct vimc_cap_device *vcap,
                                        enum vb2_buffer_state state)
{
        struct vimc_cap_buffer *vbuf, *node;

        spin_lock(&vcap->qlock);

        list_for_each_entry_safe(vbuf, node, &vcap->buf_list, list) {
                list_del(&vbuf->list);
                vb2_buffer_done(&vbuf->vb2.vb2_buf, state);
        }

        spin_unlock(&vcap->qlock);
}

static int vimc_cap_start_streaming(struct vb2_queue *vq, unsigned int count)
{
        struct vimc_cap_device *vcap = vb2_get_drv_priv(vq);
        struct media_entity *entity = &vcap->vdev.entity;
        int ret;

        vcap->sequence = 0;

        /* Start the media pipeline */
        ret = media_pipeline_start(entity, &vcap->pipe);
        if (ret) {
                vimc_cap_return_all_buffers(vcap, VB2_BUF_STATE_QUEUED);
                return ret;
        }

        /* Enable streaming from the pipe */
        ret = vimc_pipeline_s_stream(&vcap->vdev.entity, 1);
        if (ret) {
                media_pipeline_stop(entity);
                vimc_cap_return_all_buffers(vcap, VB2_BUF_STATE_QUEUED);
                return ret;
        }

        return 0;
}

/*
 * Stop the stream engine. Any remaining buffers in the stream queue are
 * dequeued and passed on to the vb2 framework marked as STATE_ERROR.
 */
static void vimc_cap_stop_streaming(struct vb2_queue *vq)
{
        struct vimc_cap_device *vcap = vb2_get_drv_priv(vq);

        /* Disable streaming from the pipe */
        vimc_pipeline_s_stream(&vcap->vdev.entity, 0);

        /* Stop the media pipeline */
        media_pipeline_stop(&vcap->vdev.entity);

        /* Release all active buffers */
        vimc_cap_return_all_buffers(vcap, VB2_BUF_STATE_ERROR);
}

static void vimc_cap_buf_queue(struct vb2_buffer *vb2_buf)
{
        struct vimc_cap_device *vcap = vb2_get_drv_priv(vb2_buf->vb2_queue);
        struct vimc_cap_buffer *buf = container_of(vb2_buf,
                                                   struct vimc_cap_buffer,
                                                   vb2.vb2_buf);

        spin_lock(&vcap->qlock);
        list_add_tail(&buf->list, &vcap->buf_list);
        spin_unlock(&vcap->qlock);
}

static int vimc_cap_queue_setup(struct vb2_queue *vq, unsigned int *nbuffers,
                                unsigned int *nplanes, unsigned int sizes[],
                                struct device *alloc_devs[])
{
        struct vimc_cap_device *vcap = vb2_get_drv_priv(vq);

        if (*nplanes)
                return sizes[0] < vcap->format.sizeimage ? -EINVAL : 0;
        /* We don't support multiplanes for now */
        *nplanes = 1;
        sizes[0] = vcap->format.sizeimage;

        return 0;
}

static int vimc_cap_buffer_prepare(struct vb2_buffer *vb)
{
        struct vimc_cap_device *vcap = vb2_get_drv_priv(vb->vb2_queue);
        unsigned long size = vcap->format.sizeimage;

        if (vb2_plane_size(vb, 0) < size) {
                dev_err(vcap->dev, "%s: buffer too small (%lu < %lu)\n",
                        vcap->vdev.name, vb2_plane_size(vb, 0), size);
                return -EINVAL;
        }
        return 0;
}

static const struct vb2_ops vimc_cap_qops = {
        .start_streaming        = vimc_cap_start_streaming,
        .stop_streaming         = vimc_cap_stop_streaming,
        .buf_queue              = vimc_cap_buf_queue,
        .queue_setup            = vimc_cap_queue_setup,
        .buf_prepare            = vimc_cap_buffer_prepare,
        /*
         * Since q->lock is set we can use the standard
         * vb2_ops_wait_prepare/finish helper functions.
         */
        .wait_prepare           = vb2_ops_wait_prepare,
        .wait_finish            = vb2_ops_wait_finish,
};

static const struct media_entity_operations vimc_cap_mops = {
        .link_validate          = vimc_link_validate,
};

static void vimc_cap_comp_unbind(struct device *comp, struct device *master,
                                 void *master_data)
{
        struct vimc_ent_device *ved = dev_get_drvdata(comp);
        struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device,
                                                    ved);

        vb2_queue_release(&vcap->queue);
        media_entity_cleanup(ved->ent);
        video_unregister_device(&vcap->vdev);
        vimc_pads_cleanup(vcap->ved.pads);
        kfree(vcap);
}

static void vimc_cap_process_frame(struct vimc_ent_device *ved,
                                   struct media_pad *sink, const void *frame)
{
        struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device,
                                                    ved);
        struct vimc_cap_buffer *vimc_buf;
        void *vbuf;

        spin_lock(&vcap->qlock);

        /* Get the first entry of the list */
        vimc_buf = list_first_entry_or_null(&vcap->buf_list,
                                            typeof(*vimc_buf), list);
        if (!vimc_buf) {
                spin_unlock(&vcap->qlock);
                return;
        }

        /* Remove this entry from the list */
        list_del(&vimc_buf->list);

        spin_unlock(&vcap->qlock);

        /* Fill the buffer */
        vimc_buf->vb2.vb2_buf.timestamp = ktime_get_ns();
        vimc_buf->vb2.sequence = vcap->sequence++;
        vimc_buf->vb2.field = vcap->format.field;

        vbuf = vb2_plane_vaddr(&vimc_buf->vb2.vb2_buf, 0);

        memcpy(vbuf, frame, vcap->format.sizeimage);

        /* Set it as ready */
        vb2_set_plane_payload(&vimc_buf->vb2.vb2_buf, 0,
                              vcap->format.sizeimage);
        vb2_buffer_done(&vimc_buf->vb2.vb2_buf, VB2_BUF_STATE_DONE);
}

static int vimc_cap_comp_bind(struct device *comp, struct device *master,
                              void *master_data)
{
        struct v4l2_device *v4l2_dev = master_data;
        struct vimc_platform_data *pdata = comp->platform_data;
        const struct vimc_pix_map *vpix;
        struct vimc_cap_device *vcap;
        struct video_device *vdev;
        struct vb2_queue *q;
        int ret;

        /* Allocate the vimc_cap_device struct */
        vcap = kzalloc(sizeof(*vcap), GFP_KERNEL);
        if (!vcap)
                return -ENOMEM;

        /* Allocate the pads */
        vcap->ved.pads =
                vimc_pads_init(1, (const unsigned long[1]) {MEDIA_PAD_FL_SINK});
        if (IS_ERR(vcap->ved.pads)) {
                ret = PTR_ERR(vcap->ved.pads);
                goto err_free_vcap;
        }

        /* Initialize the media entity */
        vcap->vdev.entity.name = pdata->entity_name;
        vcap->vdev.entity.function = MEDIA_ENT_F_IO_V4L;
        ret = media_entity_pads_init(&vcap->vdev.entity,
                                     1, vcap->ved.pads);
        if (ret)
                goto err_clean_pads;

        /* Initialize the lock */
        mutex_init(&vcap->lock);

        /* Initialize the vb2 queue */
        q = &vcap->queue;
        q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        q->io_modes = VB2_MMAP | VB2_DMABUF;
        q->drv_priv = vcap;
        q->buf_struct_size = sizeof(struct vimc_cap_buffer);
        q->ops = &vimc_cap_qops;
        q->mem_ops = &vb2_vmalloc_memops;
        q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
        q->min_buffers_needed = 2;
        q->lock = &vcap->lock;

        ret = vb2_queue_init(q);
        if (ret) {
                dev_err(comp, "%s: vb2 queue init failed (err=%d)\n",
                        pdata->entity_name, ret);
                goto err_clean_m_ent;
        }

        /* Initialize buffer list and its lock */
        INIT_LIST_HEAD(&vcap->buf_list);
        spin_lock_init(&vcap->qlock);

        /* Set default frame format */
        vcap->format = fmt_default;
        vpix = vimc_pix_map_by_pixelformat(vcap->format.pixelformat);
        vcap->format.bytesperline = vcap->format.width * vpix->bpp;
        vcap->format.sizeimage = vcap->format.bytesperline *
                                 vcap->format.height;

        /* Fill the vimc_ent_device struct */
        vcap->ved.ent = &vcap->vdev.entity;
        vcap->ved.process_frame = vimc_cap_process_frame;
        vcap->ved.vdev_get_format = vimc_cap_get_format;
        dev_set_drvdata(comp, &vcap->ved);
        vcap->dev = comp;

        /* Initialize the video_device struct */
        vdev = &vcap->vdev;
        vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
        vdev->entity.ops = &vimc_cap_mops;
        vdev->release = video_device_release_empty;
        vdev->fops = &vimc_cap_fops;
        vdev->ioctl_ops = &vimc_cap_ioctl_ops;
        vdev->lock = &vcap->lock;
        vdev->queue = q;
        vdev->v4l2_dev = v4l2_dev;
        vdev->vfl_dir = VFL_DIR_RX;
        strscpy(vdev->name, pdata->entity_name, sizeof(vdev->name));
        video_set_drvdata(vdev, &vcap->ved);

        /* Register the video_device with the v4l2 and the media framework */
        ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
        if (ret) {
                dev_err(comp, "%s: video register failed (err=%d)\n",
                        vcap->vdev.name, ret);
                goto err_release_queue;
        }

        return 0;

err_release_queue:
        vb2_queue_release(q);
err_clean_m_ent:
        media_entity_cleanup(&vcap->vdev.entity);
err_clean_pads:
        vimc_pads_cleanup(vcap->ved.pads);
err_free_vcap:
        kfree(vcap);

        return ret;
}

static const struct component_ops vimc_cap_comp_ops = {
        .bind = vimc_cap_comp_bind,
        .unbind = vimc_cap_comp_unbind,
};

static int vimc_cap_probe(struct platform_device *pdev)
{
        return component_add(&pdev->dev, &vimc_cap_comp_ops);
}

static int vimc_cap_remove(struct platform_device *pdev)
{
        component_del(&pdev->dev, &vimc_cap_comp_ops);

        return 0;
}

static const struct platform_device_id vimc_cap_driver_ids[] = {
        {
                .name           = VIMC_CAP_DRV_NAME,
        },
        { }
};

static struct platform_driver vimc_cap_pdrv = {
        .probe          = vimc_cap_probe,
        .remove         = vimc_cap_remove,
        .id_table       = vimc_cap_driver_ids,
        .driver         = {
                .name   = VIMC_CAP_DRV_NAME,
        },
};

module_platform_driver(vimc_cap_pdrv);

MODULE_DEVICE_TABLE(platform, vimc_cap_driver_ids);

MODULE_DESCRIPTION("Virtual Media Controller Driver (VIMC) Capture");
MODULE_AUTHOR("Helen Mae Koike Fornazier <helen.fornazier@gmail.com>");
MODULE_LICENSE("GPL");