/*
 * STK1160 driver
 *
 * Copyright (C) 2012 Ezequiel Garcia
 * <elezegarcia--a.t--gmail.com>
 *
 * Based on Easycap driver by R.M. Thomas
 *      Copyright (C) 2010 R.M. Thomas
 *      <rmthomas--a.t--sciolus.org>
 *
 * 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/module.h>
#include <linux/usb.h>
#include <linux/mm.h>
#include <linux/slab.h>

#include <linux/videodev2.h>
#include <media/v4l2-device.h>
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>
#include <media/videobuf2-vmalloc.h>

#include <media/i2c/saa7115.h>

#include "stk1160.h"
#include "stk1160-reg.h"

static bool keep_buffers;
module_param(keep_buffers, bool, 0644);
MODULE_PARM_DESC(keep_buffers, "don't release buffers upon stop streaming");

enum stk1160_decimate_mode {
        STK1160_DECIMATE_MORE_THAN_HALF,
        STK1160_DECIMATE_LESS_THAN_HALF,
};

struct stk1160_decimate_ctrl {
        bool col_en, row_en;
        enum stk1160_decimate_mode col_mode, row_mode;
        unsigned int col_n, row_n;
};

/* supported video standards */
static struct stk1160_fmt format[] = {
        {
                .name     = "16 bpp YUY2, 4:2:2, packed",
                .fourcc   = V4L2_PIX_FMT_UYVY,
                .depth    = 16,
        }
};

/*
 * Helper to find the next divisor that results in modulo being zero.
 * This is required to guarantee valid decimation unit counts.
 */
static unsigned int
div_round_integer(unsigned int x, unsigned int y)
{
        for (;; y++) {
                if (x % y == 0)
                        return x / y;
        }
}

static void stk1160_set_std(struct stk1160 *dev)
{
        int i;

        static struct regval std525[] = {

                /* 720x480 */

                /* Frame start */
                {STK116_CFSPO_STX_L, 0x0000},
                {STK116_CFSPO_STX_H, 0x0000},
                {STK116_CFSPO_STY_L, 0x0003},
                {STK116_CFSPO_STY_H, 0x0000},

                /* Frame end */
                {STK116_CFEPO_ENX_L, 0x05a0},
                {STK116_CFEPO_ENX_H, 0x0005},
                {STK116_CFEPO_ENY_L, 0x00f3},
                {STK116_CFEPO_ENY_H, 0x0000},

                {0xffff, 0xffff}
        };

        static struct regval std625[] = {

                /* 720x576 */

                /* TODO: Each line of frame has some junk at the end */
                /* Frame start */
                {STK116_CFSPO,   0x0000},
                {STK116_CFSPO+1, 0x0000},
                {STK116_CFSPO+2, 0x0001},
                {STK116_CFSPO+3, 0x0000},

                /* Frame end */
                {STK116_CFEPO,   0x05a0},
                {STK116_CFEPO+1, 0x0005},
                {STK116_CFEPO+2, 0x0121},
                {STK116_CFEPO+3, 0x0001},

                {0xffff, 0xffff}
        };

        if (dev->norm & V4L2_STD_525_60) {
                stk1160_dbg("registers to NTSC like standard\n");
                for (i = 0; std525[i].reg != 0xffff; i++)
                        stk1160_write_reg(dev, std525[i].reg, std525[i].val);
        } else {
                stk1160_dbg("registers to PAL like standard\n");
                for (i = 0; std625[i].reg != 0xffff; i++)
                        stk1160_write_reg(dev, std625[i].reg, std625[i].val);
        }

}

static void stk1160_set_fmt(struct stk1160 *dev,
                            struct stk1160_decimate_ctrl *ctrl)
{
        u32 val = 0;

        if (ctrl) {
                /*
                 * Since the format is UYVY, the device must skip or send
                 * a number of rows/columns multiple of four. This way, the
                 * colour format is preserved. The STK1160_DEC_UNIT_SIZE bit
                 * does exactly this.
                 */
                val |= STK1160_DEC_UNIT_SIZE;
                val |= ctrl->col_en ? STK1160_H_DEC_EN : 0;
                val |= ctrl->row_en ? STK1160_V_DEC_EN : 0;
                val |= ctrl->col_mode ==
                        STK1160_DECIMATE_MORE_THAN_HALF ?
                        STK1160_H_DEC_MODE : 0;
                val |= ctrl->row_mode ==
                        STK1160_DECIMATE_MORE_THAN_HALF ?
                        STK1160_V_DEC_MODE : 0;

                /* Horizontal count units */
                stk1160_write_reg(dev, STK1160_DMCTRL_H_UNITS, ctrl->col_n);
                /* Vertical count units */
                stk1160_write_reg(dev, STK1160_DMCTRL_V_UNITS, ctrl->row_n);

                stk1160_dbg("decimate 0x%x, column units %d, row units %d\n",
                            val, ctrl->col_n, ctrl->row_n);
        }

        /* Decimation control */
        stk1160_write_reg(dev, STK1160_DMCTRL, val);
}

/*
 * Set a new alternate setting.
 * Returns true is dev->max_pkt_size has changed, false otherwise.
 */
static bool stk1160_set_alternate(struct stk1160 *dev)
{
        int i, prev_alt = dev->alt;
        unsigned int min_pkt_size;
        bool new_pkt_size;

        /*
         * If we don't set right alternate,
         * then we will get a green screen with junk.
         */
        min_pkt_size = STK1160_MIN_PKT_SIZE;

        for (i = 0; i < dev->num_alt; i++) {
                /* stop when the selected alt setting offers enough bandwidth */
                if (dev->alt_max_pkt_size[i] >= min_pkt_size) {
                        dev->alt = i;
                        break;
                /*
                 * otherwise make sure that we end up with the maximum bandwidth
                 * because the min_pkt_size equation might be wrong...
                 */
                } else if (dev->alt_max_pkt_size[i] >
                           dev->alt_max_pkt_size[dev->alt])
                        dev->alt = i;
        }

        stk1160_dbg("setting alternate %d\n", dev->alt);

        if (dev->alt != prev_alt) {
                stk1160_dbg("minimum isoc packet size: %u (alt=%d)\n",
                                min_pkt_size, dev->alt);
                stk1160_dbg("setting alt %d with wMaxPacketSize=%u\n",
                               dev->alt, dev->alt_max_pkt_size[dev->alt]);
                usb_set_interface(dev->udev, 0, dev->alt);
        }

        new_pkt_size = dev->max_pkt_size != dev->alt_max_pkt_size[dev->alt];
        dev->max_pkt_size = dev->alt_max_pkt_size[dev->alt];

        return new_pkt_size;
}

static int stk1160_start_streaming(struct stk1160 *dev)
{
        bool new_pkt_size;
        int rc = 0;
        int i;

        /* Check device presence */
        if (!dev->udev)
                return -ENODEV;

        if (mutex_lock_interruptible(&dev->v4l_lock))
                return -ERESTARTSYS;
        /*
         * For some reason it is mandatory to set alternate *first*
         * and only *then* initialize isoc urbs.
         * Someone please explain me why ;)
         */
        new_pkt_size = stk1160_set_alternate(dev);

        /*
         * We (re)allocate isoc urbs if:
         * there is no allocated isoc urbs, OR
         * a new dev->max_pkt_size is detected
         */
        if (!dev->isoc_ctl.num_bufs || new_pkt_size) {
                rc = stk1160_alloc_isoc(dev);
                if (rc < 0)
                        goto out_stop_hw;
        }

        /* submit urbs and enables IRQ */
        for (i = 0; i < dev->isoc_ctl.num_bufs; i++) {
                rc = usb_submit_urb(dev->isoc_ctl.urb[i], GFP_KERNEL);
                if (rc) {
                        stk1160_err("cannot submit urb[%d] (%d)\n", i, rc);
                        goto out_uninit;
                }
        }

        /* Start saa711x */
        v4l2_device_call_all(&dev->v4l2_dev, 0, video, s_stream, 1);

        dev->sequence = 0;

        /* Start stk1160 */
        stk1160_write_reg(dev, STK1160_DCTRL, 0xb3);
        stk1160_write_reg(dev, STK1160_DCTRL+3, 0x00);

        stk1160_dbg("streaming started\n");

        mutex_unlock(&dev->v4l_lock);

        return 0;

out_uninit:
        stk1160_uninit_isoc(dev);
out_stop_hw:
        usb_set_interface(dev->udev, 0, 0);
        stk1160_clear_queue(dev);

        mutex_unlock(&dev->v4l_lock);

        return rc;
}

/* Must be called with v4l_lock hold */
static void stk1160_stop_hw(struct stk1160 *dev)
{
        /* If the device is not physically present, there is nothing to do */
        if (!dev->udev)
                return;

        /* set alternate 0 */
        dev->alt = 0;
        stk1160_dbg("setting alternate %d\n", dev->alt);
        usb_set_interface(dev->udev, 0, 0);

        /* Stop stk1160 */
        stk1160_write_reg(dev, STK1160_DCTRL, 0x00);
        stk1160_write_reg(dev, STK1160_DCTRL+3, 0x00);

        /* Stop saa711x */
        v4l2_device_call_all(&dev->v4l2_dev, 0, video, s_stream, 0);
}

static int stk1160_stop_streaming(struct stk1160 *dev)
{
        if (mutex_lock_interruptible(&dev->v4l_lock))
                return -ERESTARTSYS;

        /*
         * Once URBs are cancelled, the URB complete handler
         * won't be running. This is required to safely release the
         * current buffer (dev->isoc_ctl.buf).
         */
        stk1160_cancel_isoc(dev);

        /*
         * It is possible to keep buffers around using a module parameter.
         * This is intended to avoid memory fragmentation.
         */
        if (!keep_buffers)
                stk1160_free_isoc(dev);

        stk1160_stop_hw(dev);

        stk1160_clear_queue(dev);

        stk1160_dbg("streaming stopped\n");

        mutex_unlock(&dev->v4l_lock);

        return 0;
}

static const struct v4l2_file_operations stk1160_fops = {
        .owner = THIS_MODULE,
        .open = v4l2_fh_open,
        .release = vb2_fop_release,
        .read = vb2_fop_read,
        .poll = vb2_fop_poll,
        .mmap = vb2_fop_mmap,
        .unlocked_ioctl = video_ioctl2,
};

/*
 * vidioc ioctls
 */
static int vidioc_querycap(struct file *file,
                void *priv, struct v4l2_capability *cap)
{
        struct stk1160 *dev = video_drvdata(file);

        strcpy(cap->driver, "stk1160");
        strcpy(cap->card, "stk1160");
        usb_make_path(dev->udev, cap->bus_info, sizeof(cap->bus_info));
        cap->device_caps =
                V4L2_CAP_VIDEO_CAPTURE |
                V4L2_CAP_STREAMING |
                V4L2_CAP_READWRITE;
        cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
        return 0;
}

static int vidioc_enum_fmt_vid_cap(struct file *file, void  *priv,
                struct v4l2_fmtdesc *f)
{
        if (f->index != 0)
                return -EINVAL;

        strlcpy(f->description, format[f->index].name, sizeof(f->description));
        f->pixelformat = format[f->index].fourcc;
        return 0;
}

static int vidioc_g_fmt_vid_cap(struct file *file, void *priv,
                                        struct v4l2_format *f)
{
        struct stk1160 *dev = video_drvdata(file);

        f->fmt.pix.width = dev->width;
        f->fmt.pix.height = dev->height;
        f->fmt.pix.field = V4L2_FIELD_INTERLACED;
        f->fmt.pix.pixelformat = dev->fmt->fourcc;
        f->fmt.pix.bytesperline = dev->width * 2;
        f->fmt.pix.sizeimage = dev->height * f->fmt.pix.bytesperline;
        f->fmt.pix.colorspace = V4L2_COLORSPACE_SMPTE170M;

        return 0;
}

static int stk1160_try_fmt(struct stk1160 *dev, struct v4l2_format *f,
                            struct stk1160_decimate_ctrl *ctrl)
{
        unsigned int width, height;
        unsigned int base_width, base_height;
        unsigned int col_n, row_n;
        enum stk1160_decimate_mode col_mode, row_mode;
        bool col_en, row_en;

        base_width = 720;
        base_height = (dev->norm & V4L2_STD_525_60) ? 480 : 576;

        /* Minimum width and height is 5% the frame size */
        width = clamp_t(unsigned int, f->fmt.pix.width,
                        base_width / 20, base_width);
        height = clamp_t(unsigned int, f->fmt.pix.height,
                        base_height / 20, base_height);

        /* Let's set default no decimation values */
        col_n = 0;
        row_n = 0;
        col_en = false;
        row_en = false;
        f->fmt.pix.width = base_width;
        f->fmt.pix.height = base_height;
        row_mode = STK1160_DECIMATE_LESS_THAN_HALF;
        col_mode = STK1160_DECIMATE_LESS_THAN_HALF;

        if (width < base_width && width > base_width / 2) {
                /*
                 * The device will send count units for each
                 * unit skipped. This means count unit is:
                 *
                 * n = width / (frame width - width)
                 *
                 * And the width is:
                 *
                 * width = (n / n + 1) * frame width
                 */
                col_n = div_round_integer(width, base_width - width);
                if (col_n > 0 && col_n <= 255) {
                        col_en = true;
                        col_mode = STK1160_DECIMATE_LESS_THAN_HALF;
                        f->fmt.pix.width = (base_width * col_n) / (col_n + 1);
                }

        } else if (width <= base_width / 2) {

                /*
                 * The device will skip count units for each
                 * unit sent. This means count is:
                 *
                 * n = (frame width / width) - 1
                 *
                 * And the width is:
                 *
                 * width = frame width / (n + 1)
                 */
                col_n = div_round_integer(base_width, width) - 1;
                if (col_n > 0 && col_n <= 255) {
                        col_en = true;
                        col_mode = STK1160_DECIMATE_MORE_THAN_HALF;
                        f->fmt.pix.width = base_width / (col_n + 1);
                }
        }

        if (height < base_height && height > base_height / 2) {
                row_n = div_round_integer(height, base_height - height);
                if (row_n > 0 && row_n <= 255) {
                        row_en = true;
                        row_mode = STK1160_DECIMATE_LESS_THAN_HALF;
                        f->fmt.pix.height = (base_height * row_n) / (row_n + 1);
                }

        } else if (height <= base_height / 2) {
                row_n = div_round_integer(base_height, height) - 1;
                if (row_n > 0 && row_n <= 255) {
                        row_en = true;
                        row_mode = STK1160_DECIMATE_MORE_THAN_HALF;
                        f->fmt.pix.height = base_height / (row_n + 1);
                }
        }

        f->fmt.pix.pixelformat = dev->fmt->fourcc;
        f->fmt.pix.field = V4L2_FIELD_INTERLACED;
        f->fmt.pix.bytesperline = f->fmt.pix.width * 2;
        f->fmt.pix.sizeimage = f->fmt.pix.height * f->fmt.pix.bytesperline;
        f->fmt.pix.colorspace = V4L2_COLORSPACE_SMPTE170M;

        if (ctrl) {
                ctrl->col_en = col_en;
                ctrl->col_n = col_n;
                ctrl->col_mode = col_mode;
                ctrl->row_en = row_en;
                ctrl->row_n = row_n;
                ctrl->row_mode = row_mode;
        }

        stk1160_dbg("width %d, height %d\n",
                    f->fmt.pix.width, f->fmt.pix.height);
        return 0;
}

static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
                                  struct v4l2_format *f)
{
        struct stk1160 *dev = video_drvdata(file);

        return stk1160_try_fmt(dev, f, NULL);
}

static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
                                        struct v4l2_format *f)
{
        struct stk1160 *dev = video_drvdata(file);
        struct vb2_queue *q = &dev->vb_vidq;
        struct stk1160_decimate_ctrl ctrl;
        int rc;

        if (vb2_is_busy(q))
                return -EBUSY;

        rc = stk1160_try_fmt(dev, f, &ctrl);
        if (rc < 0)
                return rc;
        dev->width = f->fmt.pix.width;
        dev->height = f->fmt.pix.height;
        stk1160_set_fmt(dev, &ctrl);

        return 0;
}

static int vidioc_querystd(struct file *file, void *priv, v4l2_std_id *norm)
{
        struct stk1160 *dev = video_drvdata(file);
        v4l2_device_call_all(&dev->v4l2_dev, 0, video, querystd, norm);
        return 0;
}

static int vidioc_g_std(struct file *file, void *priv, v4l2_std_id *norm)
{
        struct stk1160 *dev = video_drvdata(file);

        *norm = dev->norm;
        return 0;
}

static int vidioc_s_std(struct file *file, void *priv, v4l2_std_id norm)
{
        struct stk1160 *dev = video_drvdata(file);
        struct vb2_queue *q = &dev->vb_vidq;

        if (dev->norm == norm)
                return 0;

        if (vb2_is_busy(q))
                return -EBUSY;

        /* Check device presence */
        if (!dev->udev)
                return -ENODEV;

        /* We need to set this now, before we call stk1160_set_std */
        dev->width = 720;
        dev->height = (norm & V4L2_STD_525_60) ? 480 : 576;
        dev->norm = norm;

        stk1160_set_std(dev);

        /* Calling with NULL disables frame decimation */
        stk1160_set_fmt(dev, NULL);

        v4l2_device_call_all(&dev->v4l2_dev, 0, video, s_std,
                        dev->norm);

        return 0;
}


static int vidioc_enum_input(struct file *file, void *priv,
                                struct v4l2_input *i)
{
        struct stk1160 *dev = video_drvdata(file);

        if (i->index > STK1160_MAX_INPUT)
                return -EINVAL;

        /* S-Video special handling */
        if (i->index == STK1160_SVIDEO_INPUT)
                sprintf(i->name, "S-Video");
        else
                sprintf(i->name, "Composite%d", i->index);

        i->type = V4L2_INPUT_TYPE_CAMERA;
        i->std = dev->vdev.tvnorms;
        return 0;
}

static int vidioc_g_input(struct file *file, void *priv, unsigned int *i)
{
        struct stk1160 *dev = video_drvdata(file);
        *i = dev->ctl_input;
        return 0;
}

static int vidioc_s_input(struct file *file, void *priv, unsigned int i)
{
        struct stk1160 *dev = video_drvdata(file);

        if (i > STK1160_MAX_INPUT)
                return -EINVAL;

        dev->ctl_input = i;

        stk1160_select_input(dev);

        return 0;
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int vidioc_g_register(struct file *file, void *priv,
                             struct v4l2_dbg_register *reg)
{
        struct stk1160 *dev = video_drvdata(file);
        int rc;
        u8 val;

        /* Match host */
        rc = stk1160_read_reg(dev, reg->reg, &val);
        reg->val = val;
        reg->size = 1;

        return rc;
}

static int vidioc_s_register(struct file *file, void *priv,
                             const struct v4l2_dbg_register *reg)
{
        struct stk1160 *dev = video_drvdata(file);

        /* Match host */
        return stk1160_write_reg(dev, reg->reg, reg->val);
}
#endif

static const struct v4l2_ioctl_ops stk1160_ioctl_ops = {
        .vidioc_querycap      = vidioc_querycap,
        .vidioc_enum_fmt_vid_cap  = vidioc_enum_fmt_vid_cap,
        .vidioc_g_fmt_vid_cap     = vidioc_g_fmt_vid_cap,
        .vidioc_try_fmt_vid_cap   = vidioc_try_fmt_vid_cap,
        .vidioc_s_fmt_vid_cap     = vidioc_s_fmt_vid_cap,
        .vidioc_querystd      = vidioc_querystd,
        .vidioc_g_std         = vidioc_g_std,
        .vidioc_s_std         = vidioc_s_std,
        .vidioc_enum_input    = vidioc_enum_input,
        .vidioc_g_input       = vidioc_g_input,
        .vidioc_s_input       = vidioc_s_input,

        /* vb2 takes care of these */
        .vidioc_reqbufs       = vb2_ioctl_reqbufs,
        .vidioc_querybuf      = vb2_ioctl_querybuf,
        .vidioc_qbuf          = vb2_ioctl_qbuf,
        .vidioc_dqbuf         = vb2_ioctl_dqbuf,
        .vidioc_streamon      = vb2_ioctl_streamon,
        .vidioc_streamoff     = vb2_ioctl_streamoff,
        .vidioc_expbuf        = vb2_ioctl_expbuf,

        .vidioc_log_status  = v4l2_ctrl_log_status,
        .vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
        .vidioc_unsubscribe_event = v4l2_event_unsubscribe,

#ifdef CONFIG_VIDEO_ADV_DEBUG
        .vidioc_g_register = vidioc_g_register,
        .vidioc_s_register = vidioc_s_register,
#endif
};

/********************************************************************/

/*
 * Videobuf2 operations
 */
static int queue_setup(struct vb2_queue *vq,
                                unsigned int *nbuffers, unsigned int *nplanes,
                                unsigned int sizes[], struct device *alloc_devs[])
{
        struct stk1160 *dev = vb2_get_drv_priv(vq);
        unsigned long size;

        size = dev->width * dev->height * 2;

        /*
         * Here we can change the number of buffers being requested.
         * So, we set a minimum and a maximum like this:
         */
        *nbuffers = clamp_t(unsigned int, *nbuffers,
                        STK1160_MIN_VIDEO_BUFFERS, STK1160_MAX_VIDEO_BUFFERS);

        if (*nplanes)
                return sizes[0] < size ? -EINVAL : 0;

        /* This means a packed colorformat */
        *nplanes = 1;

        sizes[0] = size;

        stk1160_dbg("%s: buffer count %d, each %ld bytes\n",
                    __func__, *nbuffers, size);

        return 0;
}

static void buffer_queue(struct vb2_buffer *vb)
{
        unsigned long flags;
        struct stk1160 *dev = vb2_get_drv_priv(vb->vb2_queue);
        struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
        struct stk1160_buffer *buf =
                container_of(vbuf, struct stk1160_buffer, vb);

        spin_lock_irqsave(&dev->buf_lock, flags);
        if (!dev->udev) {
                /*
                 * If the device is disconnected return the buffer to userspace
                 * directly. The next QBUF call will fail with -ENODEV.
                 */
                vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
        } else {

                buf->mem = vb2_plane_vaddr(vb, 0);
                buf->length = vb2_plane_size(vb, 0);
                buf->bytesused = 0;
                buf->pos = 0;

                /*
                 * If buffer length is less from expected then we return
                 * the buffer to userspace directly.
                 */
                if (buf->length < dev->width * dev->height * 2)
                        vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
                else
                        list_add_tail(&buf->list, &dev->avail_bufs);

        }
        spin_unlock_irqrestore(&dev->buf_lock, flags);
}

static int start_streaming(struct vb2_queue *vq, unsigned int count)
{
        struct stk1160 *dev = vb2_get_drv_priv(vq);
        return stk1160_start_streaming(dev);
}

/* abort streaming and wait for last buffer */
static void stop_streaming(struct vb2_queue *vq)
{
        struct stk1160 *dev = vb2_get_drv_priv(vq);
        stk1160_stop_streaming(dev);
}

static const struct vb2_ops stk1160_video_qops = {
        .queue_setup            = queue_setup,
        .buf_queue              = buffer_queue,
        .start_streaming        = start_streaming,
        .stop_streaming         = stop_streaming,
        .wait_prepare           = vb2_ops_wait_prepare,
        .wait_finish            = vb2_ops_wait_finish,
};

static const struct video_device v4l_template = {
        .name = "stk1160",
        .tvnorms = V4L2_STD_525_60 | V4L2_STD_625_50,
        .fops = &stk1160_fops,
        .ioctl_ops = &stk1160_ioctl_ops,
        .release = video_device_release_empty,
};

/********************************************************************/

/* Must be called with both v4l_lock and vb_queue_lock hold */
void stk1160_clear_queue(struct stk1160 *dev)
{
        struct stk1160_buffer *buf;
        unsigned long flags;

        /* Release all active buffers */
        spin_lock_irqsave(&dev->buf_lock, flags);
        while (!list_empty(&dev->avail_bufs)) {
                buf = list_first_entry(&dev->avail_bufs,
                        struct stk1160_buffer, list);
                list_del(&buf->list);
                vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
                stk1160_dbg("buffer [%p/%d] aborted\n",
                            buf, buf->vb.vb2_buf.index);
        }

        /* It's important to release the current buffer */
        if (dev->isoc_ctl.buf) {
                buf = dev->isoc_ctl.buf;
                dev->isoc_ctl.buf = NULL;

                vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
                stk1160_dbg("buffer [%p/%d] aborted\n",
                            buf, buf->vb.vb2_buf.index);
        }
        spin_unlock_irqrestore(&dev->buf_lock, flags);
}

int stk1160_vb2_setup(struct stk1160 *dev)
{
        int rc;
        struct vb2_queue *q;

        q = &dev->vb_vidq;
        q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        q->io_modes = VB2_READ | VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
        q->drv_priv = dev;
        q->buf_struct_size = sizeof(struct stk1160_buffer);
        q->ops = &stk1160_video_qops;
        q->mem_ops = &vb2_vmalloc_memops;
        q->lock = &dev->vb_queue_lock;
        q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;

        rc = vb2_queue_init(q);
        if (rc < 0)
                return rc;

        /* initialize video dma queue */
        INIT_LIST_HEAD(&dev->avail_bufs);

        return 0;
}

int stk1160_video_register(struct stk1160 *dev)
{
        int rc;

        /* Initialize video_device with a template structure */
        dev->vdev = v4l_template;
        dev->vdev.queue = &dev->vb_vidq;

        /*
         * Provide mutexes for v4l2 core and for videobuf2 queue.
         * It will be used to protect *only* v4l2 ioctls.
         */
        dev->vdev.lock = &dev->v4l_lock;

        /* This will be used to set video_device parent */
        dev->vdev.v4l2_dev = &dev->v4l2_dev;

        /* NTSC is default */
        dev->norm = V4L2_STD_NTSC_M;
        dev->width = 720;
        dev->height = 480;

        /* set default format */
        dev->fmt = &format[0];
        stk1160_set_std(dev);

        v4l2_device_call_all(&dev->v4l2_dev, 0, video, s_std,
                        dev->norm);

        video_set_drvdata(&dev->vdev, dev);
        rc = video_register_device(&dev->vdev, VFL_TYPE_GRABBER, -1);
        if (rc < 0) {
                stk1160_err("video_register_device failed (%d)\n", rc);
                return rc;
        }

        v4l2_info(&dev->v4l2_dev, "V4L2 device registered as %s\n",
                  video_device_node_name(&dev->vdev));

        return 0;
}