V4L/DVB: [v5,2/2] v4l: Add a mem-to-mem videobuf framework test device

This is a virtual device driver for testing the memory-to-memory framework.

This virtual device uses in-memory buffers for both its source and destination.
It is capable of multi-instance, multi-buffer-per-transaction operation
(via the mem2mem framework).

[mchehab@redhat.com: use videobuf_queue_to_vaddr instead of the removed videobuf_queue_to_vmalloc]
Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Vaibhav Hiremath <hvaibhav@ti.com>
Tested-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/Kconfig

@@ -1135,3 +1135,17 @@ menuconfig V4L_MEM2MEM_DRIVERS
 	  use system memory for both source and destination buffers, as opposed
 	  to capture and output drivers, which use memory buffers for just
 	  one of those.
+
+if V4L_MEM2MEM_DRIVERS
+
+config VIDEO_MEM2MEM_TESTDEV
+	tristate "Virtual test device for mem2mem framework"
+	depends on VIDEO_DEV && VIDEO_V4L2
+	select VIDEOBUF_VMALLOC
+	select V4L2_MEM2MEM_DEV
+	default n
+	---help---
+	  This is a virtual test device for the memory-to-memory driver
+	  framework.
+
+endif # V4L_MEM2MEM_DRIVERS

drivers/media/video/Makefile

@@ -151,6 +151,7 @@ obj-$(CONFIG_VIDEO_IVTV) += ivtv/
 obj-$(CONFIG_VIDEO_CX18) += cx18/
 
 obj-$(CONFIG_VIDEO_VIVI) += vivi.o
+obj-$(CONFIG_VIDEO_MEM2MEM_TESTDEV) += mem2mem_testdev.o
 obj-$(CONFIG_VIDEO_CX23885) += cx23885/
 
 obj-$(CONFIG_VIDEO_AK881X)		+= ak881x.o

drivers/media/video/mem2mem_testdev.c

+/*
+ * A virtual v4l2-mem2mem example device.
+ *
+ * This is a virtual device driver for testing mem-to-mem videobuf framework.
+ * It simulates a device that uses memory buffers for both source and
+ * destination, processes the data and issues an "irq" (simulated by a timer).
+ * The device is capable of multi-instance, multi-buffer-per-transaction
+ * operation (via the mem2mem framework).
+ *
+ * Copyright (c) 2009-2010 Samsung Electronics Co., Ltd.
+ * Pawel Osciak, <p.osciak@samsung.com>
+ * Marek Szyprowski, <m.szyprowski@samsung.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
+ */
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/version.h>
+#include <linux/timer.h>
+#include <linux/sched.h>
+
+#include <linux/platform_device.h>
+#include <media/v4l2-mem2mem.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-ioctl.h>
+#include <media/videobuf-vmalloc.h>
+
+#define MEM2MEM_TEST_MODULE_NAME "mem2mem-testdev"
+
+MODULE_DESCRIPTION("Virtual device for mem2mem framework testing");
+MODULE_AUTHOR("Pawel Osciak, <p.osciak@samsung.com>");
+MODULE_LICENSE("GPL");
+
+
+#define MIN_W 32
+#define MIN_H 32
+#define MAX_W 640
+#define MAX_H 480
+#define DIM_ALIGN_MASK 0x08 /* 8-alignment for dimensions */
+
+/* Flags that indicate a format can be used for capture/output */
+#define MEM2MEM_CAPTURE	(1 << 0)
+#define MEM2MEM_OUTPUT	(1 << 1)
+
+#define MEM2MEM_NAME		"m2m-testdev"
+
+/* Per queue */
+#define MEM2MEM_DEF_NUM_BUFS	VIDEO_MAX_FRAME
+/* In bytes, per queue */
+#define MEM2MEM_VID_MEM_LIMIT	(16 * 1024 * 1024)
+
+/* Default transaction time in msec */
+#define MEM2MEM_DEF_TRANSTIME	1000
+/* Default number of buffers per transaction */
+#define MEM2MEM_DEF_TRANSLEN	1
+#define MEM2MEM_COLOR_STEP	(0xff >> 4)
+#define MEM2MEM_NUM_TILES	8
+
+#define dprintk(dev, fmt, arg...) \
+	v4l2_dbg(1, 1, &dev->v4l2_dev, "%s: " fmt, __func__, ## arg)
+
+
+void m2mtest_dev_release(struct device *dev)
+{}
+
+static struct platform_device m2mtest_pdev = {
+	.name		= MEM2MEM_NAME,
+	.dev.release	= m2mtest_dev_release,
+};
+
+struct m2mtest_fmt {
+	char	*name;
+	u32	fourcc;
+	int	depth;
+	/* Types the format can be used for */
+	u32	types;
+};
+
+static struct m2mtest_fmt formats[] = {
+	{
+		.name	= "RGB565 (BE)",
+		.fourcc	= V4L2_PIX_FMT_RGB565X, /* rrrrrggg gggbbbbb */
+		.depth	= 16,
+		/* Both capture and output format */
+		.types	= MEM2MEM_CAPTURE | MEM2MEM_OUTPUT,
+	},
+	{
+		.name	= "4:2:2, packed, YUYV",
+		.fourcc	= V4L2_PIX_FMT_YUYV,
+		.depth	= 16,
+		/* Output-only format */
+		.types	= MEM2MEM_OUTPUT,
+	},
+};
+
+/* Per-queue, driver-specific private data */
+struct m2mtest_q_data {
+	unsigned int		width;
+	unsigned int		height;
+	unsigned int		sizeimage;
+	struct m2mtest_fmt	*fmt;
+};
+
+enum {
+	V4L2_M2M_SRC = 0,
+	V4L2_M2M_DST = 1,
+};
+
+/* Source and destination queue data */
+static struct m2mtest_q_data q_data[2];
+
+static struct m2mtest_q_data *get_q_data(enum v4l2_buf_type type)
+{
+	switch (type) {
+	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
+		return &q_data[V4L2_M2M_SRC];
+	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
+		return &q_data[V4L2_M2M_DST];
+	default:
+		BUG();
+	}
+	return NULL;
+}
+
+#define V4L2_CID_TRANS_TIME_MSEC	V4L2_CID_PRIVATE_BASE
+#define V4L2_CID_TRANS_NUM_BUFS		(V4L2_CID_PRIVATE_BASE + 1)
+
+static struct v4l2_queryctrl m2mtest_ctrls[] = {
+	{
+		.id		= V4L2_CID_TRANS_TIME_MSEC,
+		.type		= V4L2_CTRL_TYPE_INTEGER,
+		.name		= "Transaction time (msec)",
+		.minimum	= 1,
+		.maximum	= 10000,
+		.step		= 100,
+		.default_value	= 1000,
+		.flags		= 0,
+	}, {
+		.id		= V4L2_CID_TRANS_NUM_BUFS,
+		.type		= V4L2_CTRL_TYPE_INTEGER,
+		.name		= "Buffers per transaction",
+		.minimum	= 1,
+		.maximum	= MEM2MEM_DEF_NUM_BUFS,
+		.step		= 1,
+		.default_value	= 1,
+		.flags		= 0,
+	},
+};
+
+#define NUM_FORMATS ARRAY_SIZE(formats)
+
+static struct m2mtest_fmt *find_format(struct v4l2_format *f)
+{
+	struct m2mtest_fmt *fmt;
+	unsigned int k;
+
+	for (k = 0; k < NUM_FORMATS; k++) {
+		fmt = &formats[k];
+		if (fmt->fourcc == f->fmt.pix.pixelformat)
+			break;
+	}
+
+	if (k == NUM_FORMATS)
+		return NULL;
+
+	return &formats[k];
+}
+
+struct m2mtest_dev {
+	struct v4l2_device	v4l2_dev;
+	struct video_device	*vfd;
+
+	atomic_t		num_inst;
+	struct mutex		dev_mutex;
+	spinlock_t		irqlock;
+
+	struct timer_list	timer;
+
+	struct v4l2_m2m_dev	*m2m_dev;
+};
+
+struct m2mtest_ctx {
+	struct m2mtest_dev	*dev;
+
+	/* Processed buffers in this transaction */
+	u8			num_processed;
+
+	/* Transaction length (i.e. how many buffers per transaction) */
+	u32			translen;
+	/* Transaction time (i.e. simulated processing time) in milliseconds */
+	u32			transtime;
+
+	/* Abort requested by m2m */
+	int			aborting;
+
+	struct v4l2_m2m_ctx	*m2m_ctx;
+};
+
+struct m2mtest_buffer {
+	/* vb must be first! */
+	struct videobuf_buffer	vb;
+};
+
+static struct v4l2_queryctrl *get_ctrl(int id)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(m2mtest_ctrls); ++i) {
+		if (id == m2mtest_ctrls[i].id)
+			return &m2mtest_ctrls[i];
+	}
+
+	return NULL;
+}
+
+static int device_process(struct m2mtest_ctx *ctx,
+			  struct m2mtest_buffer *in_buf,
+			  struct m2mtest_buffer *out_buf)
+{
+	struct m2mtest_dev *dev = ctx->dev;
+	u8 *p_in, *p_out;
+	int x, y, t, w;
+	int tile_w, bytes_left;
+	struct videobuf_queue *src_q;
+	struct videobuf_queue *dst_q;
+
+	src_q = v4l2_m2m_get_src_vq(ctx->m2m_ctx);
+	dst_q = v4l2_m2m_get_dst_vq(ctx->m2m_ctx);
+	p_in = videobuf_queue_to_vaddr(src_q, &in_buf->vb);
+	p_out = videobuf_queue_to_vaddr(dst_q, &out_buf->vb);
+	if (!p_in || !p_out) {
+		v4l2_err(&dev->v4l2_dev,
+			 "Acquiring kernel pointers to buffers failed\n");
+		return -EFAULT;
+	}
+
+	if (in_buf->vb.size < out_buf->vb.size) {
+		v4l2_err(&dev->v4l2_dev, "Output buffer is too small\n");
+		return -EINVAL;
+	}
+
+	tile_w = (in_buf->vb.width * (q_data[V4L2_M2M_DST].fmt->depth >> 3))
+		/ MEM2MEM_NUM_TILES;
+	bytes_left = in_buf->vb.bytesperline - tile_w * MEM2MEM_NUM_TILES;
+	w = 0;
+
+	for (y = 0; y < in_buf->vb.height; ++y) {
+		for (t = 0; t < MEM2MEM_NUM_TILES; ++t) {
+			if (w & 0x1) {
+				for (x = 0; x < tile_w; ++x)
+					*p_out++ = *p_in++ + MEM2MEM_COLOR_STEP;
+			} else {
+				for (x = 0; x < tile_w; ++x)
+					*p_out++ = *p_in++ - MEM2MEM_COLOR_STEP;
+			}
+			++w;
+		}
+		p_in += bytes_left;
+		p_out += bytes_left;
+	}
+
+	return 0;
+}
+
+static void schedule_irq(struct m2mtest_dev *dev, int msec_timeout)
+{
+	dprintk(dev, "Scheduling a simulated irq\n");
+	mod_timer(&dev->timer, jiffies + msecs_to_jiffies(msec_timeout));
+}
+
+/*
+ * mem2mem callbacks
+ */
+
+/**
+ * job_ready() - check whether an instance is ready to be scheduled to run
+ */
+static int job_ready(void *priv)
+{
+	struct m2mtest_ctx *ctx = priv;
+
+	if (v4l2_m2m_num_src_bufs_ready(ctx->m2m_ctx) < ctx->translen
+	    || v4l2_m2m_num_dst_bufs_ready(ctx->m2m_ctx) < ctx->translen) {
+		dprintk(ctx->dev, "Not enough buffers available\n");
+		return 0;
+	}
+
+	return 1;
+}
+
+static void job_abort(void *priv)
+{
+	struct m2mtest_ctx *ctx = priv;
+
+	/* Will cancel the transaction in the next interrupt handler */
+	ctx->aborting = 1;
+}
+
+/* device_run() - prepares and starts the device
+ *
+ * This simulates all the immediate preparations required before starting
+ * a device. This will be called by the framework when it decides to schedule
+ * a particular instance.
+ */
+static void device_run(void *priv)
+{
+	struct m2mtest_ctx *ctx = priv;
+	struct m2mtest_dev *dev = ctx->dev;
+	struct m2mtest_buffer *src_buf, *dst_buf;
+
+	src_buf = v4l2_m2m_next_src_buf(ctx->m2m_ctx);
+	dst_buf = v4l2_m2m_next_dst_buf(ctx->m2m_ctx);
+
+	device_process(ctx, src_buf, dst_buf);
+
+	/* Run a timer, which simulates a hardware irq  */
+	schedule_irq(dev, ctx->transtime);
+}
+
+
+static void device_isr(unsigned long priv)
+{
+	struct m2mtest_dev *m2mtest_dev = (struct m2mtest_dev *)priv;
+	struct m2mtest_ctx *curr_ctx;
+	struct m2mtest_buffer *src_buf, *dst_buf;
+	unsigned long flags;
+
+	curr_ctx = v4l2_m2m_get_curr_priv(m2mtest_dev->m2m_dev);
+
+	if (NULL == curr_ctx) {
+		printk(KERN_ERR
+			"Instance released before the end of transaction\n");
+		return;
+	}
+
+	src_buf = v4l2_m2m_src_buf_remove(curr_ctx->m2m_ctx);
+	dst_buf = v4l2_m2m_dst_buf_remove(curr_ctx->m2m_ctx);
+	curr_ctx->num_processed++;
+
+	if (curr_ctx->num_processed == curr_ctx->translen
+	    || curr_ctx->aborting) {
+		dprintk(curr_ctx->dev, "Finishing transaction\n");
+		curr_ctx->num_processed = 0;
+		spin_lock_irqsave(&m2mtest_dev->irqlock, flags);
+		src_buf->vb.state = dst_buf->vb.state = VIDEOBUF_DONE;
+		wake_up(&src_buf->vb.done);
+		wake_up(&dst_buf->vb.done);
+		spin_unlock_irqrestore(&m2mtest_dev->irqlock, flags);
+		v4l2_m2m_job_finish(m2mtest_dev->m2m_dev, curr_ctx->m2m_ctx);
+	} else {
+		spin_lock_irqsave(&m2mtest_dev->irqlock, flags);
+		src_buf->vb.state = dst_buf->vb.state = VIDEOBUF_DONE;
+		wake_up(&src_buf->vb.done);
+		wake_up(&dst_buf->vb.done);
+		spin_unlock_irqrestore(&m2mtest_dev->irqlock, flags);
+		device_run(curr_ctx);
+	}
+}
+
+
+/*
+ * video ioctls
+ */
+static int vidioc_querycap(struct file *file, void *priv,
+			   struct v4l2_capability *cap)
+{
+	strncpy(cap->driver, MEM2MEM_NAME, sizeof(cap->driver) - 1);
+	strncpy(cap->card, MEM2MEM_NAME, sizeof(cap->card) - 1);
+	cap->bus_info[0] = 0;
+	cap->version = KERNEL_VERSION(0, 1, 0);
+	cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_VIDEO_OUTPUT
+			  | V4L2_CAP_STREAMING;
+
+	return 0;
+}
+
+static int enum_fmt(struct v4l2_fmtdesc *f, u32 type)
+{
+	int i, num;
+	struct m2mtest_fmt *fmt;
+
+	num = 0;
+
+	for (i = 0; i < NUM_FORMATS; ++i) {
+		if (formats[i].types & type) {
+			/* index-th format of type type found ? */
+			if (num == f->index)
+				break;
+			/* Correct type but haven't reached our index yet,
+			 * just increment per-type index */
+			++num;
+		}
+	}
+
+	if (i < NUM_FORMATS) {
+		/* Format found */
+		fmt = &formats[i];
+		strncpy(f->description, fmt->name, sizeof(f->description) - 1);
+		f->pixelformat = fmt->fourcc;
+		return 0;
+	}
+
+	/* Format not found */
+	return -EINVAL;
+}
+
+static int vidioc_enum_fmt_vid_cap(struct file *file, void *priv,
+				   struct v4l2_fmtdesc *f)
+{
+	return enum_fmt(f, MEM2MEM_CAPTURE);
+}
+
+static int vidioc_enum_fmt_vid_out(struct file *file, void *priv,
+				   struct v4l2_fmtdesc *f)
+{
+	return enum_fmt(f, MEM2MEM_OUTPUT);
+}
+
+static int vidioc_g_fmt(struct m2mtest_ctx *ctx, struct v4l2_format *f)
+{
+	struct videobuf_queue *vq;
+	struct m2mtest_q_data *q_data;
+
+	vq = v4l2_m2m_get_vq(ctx->m2m_ctx, f->type);
+	if (!vq)
+		return -EINVAL;
+
+	q_data = get_q_data(f->type);
+
+	f->fmt.pix.width	= q_data->width;
+	f->fmt.pix.height	= q_data->height;
+	f->fmt.pix.field	= vq->field;
+	f->fmt.pix.pixelformat	= q_data->fmt->fourcc;
+	f->fmt.pix.bytesperline	= (q_data->width * q_data->fmt->depth) >> 3;
+	f->fmt.pix.sizeimage	= q_data->sizeimage;
+
+	return 0;
+}
+
+static int vidioc_g_fmt_vid_out(struct file *file, void *priv,
+				struct v4l2_format *f)
+{
+	return vidioc_g_fmt(priv, f);
+}
+
+static int vidioc_g_fmt_vid_cap(struct file *file, void *priv,
+				struct v4l2_format *f)
+{
+	return vidioc_g_fmt(priv, f);
+}
+
+static int vidioc_try_fmt(struct v4l2_format *f, struct m2mtest_fmt *fmt)
+{
+	enum v4l2_field field;
+
+	field = f->fmt.pix.field;
+
+	if (field == V4L2_FIELD_ANY)
+		field = V4L2_FIELD_NONE;
+	else if (V4L2_FIELD_NONE != field)
+		return -EINVAL;
+
+	/* V4L2 specification suggests the driver corrects the format struct
+	 * if any of the dimensions is unsupported */
+	f->fmt.pix.field = field;
+
+	if (f->fmt.pix.height < MIN_H)
+		f->fmt.pix.height = MIN_H;
+	else if (f->fmt.pix.height > MAX_H)
+		f->fmt.pix.height = MAX_H;
+
+	if (f->fmt.pix.width < MIN_W)
+		f->fmt.pix.width = MIN_W;
+	else if (f->fmt.pix.width > MAX_W)
+		f->fmt.pix.width = MAX_W;
+
+	f->fmt.pix.width &= ~DIM_ALIGN_MASK;
+	f->fmt.pix.bytesperline = (f->fmt.pix.width * fmt->depth) >> 3;
+	f->fmt.pix.sizeimage = f->fmt.pix.height * f->fmt.pix.bytesperline;
+
+	return 0;
+}
+
+static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
+				  struct v4l2_format *f)
+{
+	struct m2mtest_fmt *fmt;
+	struct m2mtest_ctx *ctx = priv;
+
+	fmt = find_format(f);
+	if (!fmt || !(fmt->types & MEM2MEM_CAPTURE)) {
+		v4l2_err(&ctx->dev->v4l2_dev,
+			 "Fourcc format (0x%08x) invalid.\n",
+			 f->fmt.pix.pixelformat);
+		return -EINVAL;
+	}
+
+	return vidioc_try_fmt(f, fmt);
+}
+
+static int vidioc_try_fmt_vid_out(struct file *file, void *priv,
+				  struct v4l2_format *f)
+{
+	struct m2mtest_fmt *fmt;
+	struct m2mtest_ctx *ctx = priv;
+
+	fmt = find_format(f);
+	if (!fmt || !(fmt->types & MEM2MEM_OUTPUT)) {
+		v4l2_err(&ctx->dev->v4l2_dev,
+			 "Fourcc format (0x%08x) invalid.\n",
+			 f->fmt.pix.pixelformat);
+		return -EINVAL;
+	}
+
+	return vidioc_try_fmt(f, fmt);
+}
+
+static int vidioc_s_fmt(struct m2mtest_ctx *ctx, struct v4l2_format *f)
+{
+	struct m2mtest_q_data *q_data;
+	struct videobuf_queue *vq;
+	int ret = 0;
+
+	vq = v4l2_m2m_get_vq(ctx->m2m_ctx, f->type);
+	if (!vq)
+		return -EINVAL;
+
+	q_data = get_q_data(f->type);
+	if (!q_data)
+		return -EINVAL;
+
+	mutex_lock(&vq->vb_lock);
+
+	if (videobuf_queue_is_busy(vq)) {
+		v4l2_err(&ctx->dev->v4l2_dev, "%s queue busy\n", __func__);
+		ret = -EBUSY;
+		goto out;
+	}
+
+	q_data->fmt		= find_format(f);
+	q_data->width		= f->fmt.pix.width;
+	q_data->height		= f->fmt.pix.height;
+	q_data->sizeimage	= q_data->width * q_data->height
+				* q_data->fmt->depth >> 3;
+	vq->field		= f->fmt.pix.field;
+
+	dprintk(ctx->dev,
+		"Setting format for type %d, wxh: %dx%d, fmt: %d\n",
+		f->type, q_data->width, q_data->height, q_data->fmt->fourcc);
+
+out:
+	mutex_unlock(&vq->vb_lock);
+	return ret;
+}
+
+static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
+				struct v4l2_format *f)
+{
+	int ret;
+
+	ret = vidioc_try_fmt_vid_cap(file, priv, f);
+	if (ret)
+		return ret;
+
+	return vidioc_s_fmt(priv, f);
+}
+
+static int vidioc_s_fmt_vid_out(struct file *file, void *priv,
+				struct v4l2_format *f)
+{
+	int ret;
+
+	ret = vidioc_try_fmt_vid_out(file, priv, f);
+	if (ret)
+		return ret;
+
+	return vidioc_s_fmt(priv, f);
+}
+
+static int vidioc_reqbufs(struct file *file, void *priv,
+			  struct v4l2_requestbuffers *reqbufs)
+{
+	struct m2mtest_ctx *ctx = priv;
+
+	return v4l2_m2m_reqbufs(file, ctx->m2m_ctx, reqbufs);
+}
+
+static int vidioc_querybuf(struct file *file, void *priv,
+			   struct v4l2_buffer *buf)
+{
+	struct m2mtest_ctx *ctx = priv;
+
+	return v4l2_m2m_querybuf(file, ctx->m2m_ctx, buf);
+}
+
+static int vidioc_qbuf(struct file *file, void *priv, struct v4l2_buffer *buf)
+{
+	struct m2mtest_ctx *ctx = priv;
+
+	return v4l2_m2m_qbuf(file, ctx->m2m_ctx, buf);
+}
+
+static int vidioc_dqbuf(struct file *file, void *priv, struct v4l2_buffer *buf)
+{
+	struct m2mtest_ctx *ctx = priv;
+
+	return v4l2_m2m_dqbuf(file, ctx->m2m_ctx, buf);
+}
+
+static int vidioc_streamon(struct file *file, void *priv,
+			   enum v4l2_buf_type type)
+{
+	struct m2mtest_ctx *ctx = priv;
+
+	return v4l2_m2m_streamon(file, ctx->m2m_ctx, type);
+}
+
+static int vidioc_streamoff(struct file *file, void *priv,
+			    enum v4l2_buf_type type)
+{
+	struct m2mtest_ctx *ctx = priv;
+
+	return v4l2_m2m_streamoff(file, ctx->m2m_ctx, type);
+}
+
+static int vidioc_queryctrl(struct file *file, void *priv,
+			    struct v4l2_queryctrl *qc)
+{
+	struct v4l2_queryctrl *c;
+
+	c = get_ctrl(qc->id);
+	if (!c)
+		return -EINVAL;
+
+	*qc = *c;
+	return 0;
+}
+
+static int vidioc_g_ctrl(struct file *file, void *priv,
+			 struct v4l2_control *ctrl)
+{
+	struct m2mtest_ctx *ctx = priv;
+
+	switch (ctrl->id) {
+	case V4L2_CID_TRANS_TIME_MSEC:
+		ctrl->value = ctx->transtime;
+		break;
+
+	case V4L2_CID_TRANS_NUM_BUFS:
+		ctrl->value = ctx->translen;
+		break;
+
+	default:
+		v4l2_err(&ctx->dev->v4l2_dev, "Invalid control\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int check_ctrl_val(struct m2mtest_ctx *ctx, struct v4l2_control *ctrl)
+{
+	struct v4l2_queryctrl *c;
+
+	c = get_ctrl(ctrl->id);
+	if (!c)
+		return -EINVAL;
+
+	if (ctrl->value < c->minimum || ctrl->value > c->maximum) {
+		v4l2_err(&ctx->dev->v4l2_dev, "Value out of range\n");
+		return -ERANGE;
+	}
+
+	return 0;
+}
+
+static int vidioc_s_ctrl(struct file *file, void *priv,
+			 struct v4l2_control *ctrl)
+{
+	struct m2mtest_ctx *ctx = priv;
+	int ret = 0;
+
+	ret = check_ctrl_val(ctx, ctrl);
+	if (ret != 0)
+		return ret;
+
+	switch (ctrl->id) {
+	case V4L2_CID_TRANS_TIME_MSEC:
+		ctx->transtime = ctrl->value;
+		break;
+
+	case V4L2_CID_TRANS_NUM_BUFS:
+		ctx->translen = ctrl->value;
+		break;
+
+	default:
+		v4l2_err(&ctx->dev->v4l2_dev, "Invalid control\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+
+static const struct v4l2_ioctl_ops m2mtest_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_enum_fmt_vid_out = vidioc_enum_fmt_vid_out,
+	.vidioc_g_fmt_vid_out	= vidioc_g_fmt_vid_out,
+	.vidioc_try_fmt_vid_out	= vidioc_try_fmt_vid_out,
+	.vidioc_s_fmt_vid_out	= vidioc_s_fmt_vid_out,
+
+	.vidioc_reqbufs		= vidioc_reqbufs,
+	.vidioc_querybuf	= vidioc_querybuf,
+
+	.vidioc_qbuf		= vidioc_qbuf,
+	.vidioc_dqbuf		= vidioc_dqbuf,
+
+	.vidioc_streamon	= vidioc_streamon,
+	.vidioc_streamoff	= vidioc_streamoff,
+
+	.vidioc_queryctrl	= vidioc_queryctrl,
+	.vidioc_g_ctrl		= vidioc_g_ctrl,
+	.vidioc_s_ctrl		= vidioc_s_ctrl,
+};
+
+
+/*
+ * Queue operations
+ */
+
+static void m2mtest_buf_release(struct videobuf_queue *vq,
+				struct videobuf_buffer *vb)
+{
+	struct m2mtest_ctx *ctx = vq->priv_data;
+
+	dprintk(ctx->dev, "type: %d, index: %d, state: %d\n",
+		vq->type, vb->i, vb->state);
+
+	videobuf_vmalloc_free(vb);
+	vb->state = VIDEOBUF_NEEDS_INIT;
+}
+
+static int m2mtest_buf_setup(struct videobuf_queue *vq, unsigned int *count,
+			  unsigned int *size)
+{
+	struct m2mtest_ctx *ctx = vq->priv_data;
+	struct m2mtest_q_data *q_data;
+
+	q_data = get_q_data(vq->type);
+
+	*size = q_data->width * q_data->height * q_data->fmt->depth >> 3;
+	dprintk(ctx->dev, "size:%d, w/h %d/%d, depth: %d\n",
+		*size, q_data->width, q_data->height, q_data->fmt->depth);
+
+	if (0 == *count)
+		*count = MEM2MEM_DEF_NUM_BUFS;
+
+	while (*size * *count > MEM2MEM_VID_MEM_LIMIT)
+		(*count)--;
+
+	v4l2_info(&ctx->dev->v4l2_dev,
+		  "%d buffers of size %d set up.\n", *count, *size);
+
+	return 0;
+}
+
+static int m2mtest_buf_prepare(struct videobuf_queue *vq,
+			       struct videobuf_buffer *vb,
+			       enum v4l2_field field)
+{
+	struct m2mtest_ctx *ctx = vq->priv_data;
+	struct m2mtest_q_data *q_data;
+	int ret;
+
+	dprintk(ctx->dev, "type: %d, index: %d, state: %d\n",
+		vq->type, vb->i, vb->state);
+
+	q_data = get_q_data(vq->type);
+
+	if (vb->baddr) {
+		/* User-provided buffer */
+		if (vb->bsize < q_data->sizeimage) {
+			/* Buffer too small to fit a frame */
+			v4l2_err(&ctx->dev->v4l2_dev,
+				 "User-provided buffer too small\n");
+			return -EINVAL;
+		}
+	} else if (vb->state != VIDEOBUF_NEEDS_INIT
+			&& vb->bsize < q_data->sizeimage) {
+		/* We provide the buffer, but it's already been initialized
+		 * and is too small */
+		return -EINVAL;
+	}
+
+	vb->width	= q_data->width;
+	vb->height	= q_data->height;
+	vb->bytesperline = (q_data->width * q_data->fmt->depth) >> 3;
+	vb->size	= q_data->sizeimage;
+	vb->field	= field;
+
+	if (VIDEOBUF_NEEDS_INIT == vb->state) {
+		ret = videobuf_iolock(vq, vb, NULL);
+		if (ret) {
+			v4l2_err(&ctx->dev->v4l2_dev,
+				 "Iolock failed\n");
+			goto fail;
+		}
+	}
+
+	vb->state = VIDEOBUF_PREPARED;
+
+	return 0;
+fail:
+	m2mtest_buf_release(vq, vb);
+	return ret;
+}
+
+static void m2mtest_buf_queue(struct videobuf_queue *vq,
+			   struct videobuf_buffer *vb)
+{
+	struct m2mtest_ctx *ctx = vq->priv_data;
+
+	v4l2_m2m_buf_queue(ctx->m2m_ctx, vq, vb);
+}
+
+static struct videobuf_queue_ops m2mtest_qops = {
+	.buf_setup	= m2mtest_buf_setup,
+	.buf_prepare	= m2mtest_buf_prepare,
+	.buf_queue	= m2mtest_buf_queue,
+	.buf_release	= m2mtest_buf_release,
+};
+
+static void queue_init(void *priv, struct videobuf_queue *vq,
+		       enum v4l2_buf_type type)
+{
+	struct m2mtest_ctx *ctx = priv;
+
+	videobuf_queue_vmalloc_init(vq, &m2mtest_qops, ctx->dev->v4l2_dev.dev,
+				    &ctx->dev->irqlock, type, V4L2_FIELD_NONE,
+				    sizeof(struct m2mtest_buffer), priv);
+}
+
+
+/*
+ * File operations
+ */
+static int m2mtest_open(struct file *file)
+{
+	struct m2mtest_dev *dev = video_drvdata(file);
+	struct m2mtest_ctx *ctx = NULL;
+
+	ctx = kzalloc(sizeof *ctx, GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	file->private_data = ctx;
+	ctx->dev = dev;
+	ctx->translen = MEM2MEM_DEF_TRANSLEN;
+	ctx->transtime = MEM2MEM_DEF_TRANSTIME;
+	ctx->num_processed = 0;
+
+	ctx->m2m_ctx = v4l2_m2m_ctx_init(ctx, dev->m2m_dev, queue_init);
+	if (IS_ERR(ctx->m2m_ctx)) {
+		kfree(ctx);
+		return PTR_ERR(ctx->m2m_ctx);
+	}
+
+	atomic_inc(&dev->num_inst);
+
+	dprintk(dev, "Created instance %p, m2m_ctx: %p\n", ctx, ctx->m2m_ctx);
+
+	return 0;
+}
+
+static int m2mtest_release(struct file *file)
+{
+	struct m2mtest_dev *dev = video_drvdata(file);
+	struct m2mtest_ctx *ctx = file->private_data;
+
+	dprintk(dev, "Releasing instance %p\n", ctx);
+
+	v4l2_m2m_ctx_release(ctx->m2m_ctx);
+	kfree(ctx);
+
+	atomic_dec(&dev->num_inst);
+
+	return 0;
+}
+
+static unsigned int m2mtest_poll(struct file *file,
+				 struct poll_table_struct *wait)
+{
+	struct m2mtest_ctx *ctx = (struct m2mtest_ctx *)file->private_data;
+
+	return v4l2_m2m_poll(file, ctx->m2m_ctx, wait);
+}
+
+static int m2mtest_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct m2mtest_ctx *ctx = (struct m2mtest_ctx *)file->private_data;
+
+	return v4l2_m2m_mmap(file, ctx->m2m_ctx, vma);
+}
+
+static const struct v4l2_file_operations m2mtest_fops = {
+	.owner		= THIS_MODULE,
+	.open		= m2mtest_open,
+	.release	= m2mtest_release,
+	.poll		= m2mtest_poll,
+	.ioctl		= video_ioctl2,
+	.mmap		= m2mtest_mmap,
+};
+
+static struct video_device m2mtest_videodev = {
+	.name		= MEM2MEM_NAME,
+	.fops		= &m2mtest_fops,
+	.ioctl_ops	= &m2mtest_ioctl_ops,
+	.minor		= -1,
+	.release	= video_device_release,
+};
+
+static struct v4l2_m2m_ops m2m_ops = {
+	.device_run	= device_run,
+	.job_ready	= job_ready,
+	.job_abort	= job_abort,
+};
+
+static int m2mtest_probe(struct platform_device *pdev)
+{
+	struct m2mtest_dev *dev;
+	struct video_device *vfd;
+	int ret;
+
+	dev = kzalloc(sizeof *dev, GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	spin_lock_init(&dev->irqlock);
+
+	ret = v4l2_device_register(&pdev->dev, &dev->v4l2_dev);
+	if (ret)
+		goto free_dev;
+
+	atomic_set(&dev->num_inst, 0);
+	mutex_init(&dev->dev_mutex);
+
+	vfd = video_device_alloc();
+	if (!vfd) {
+		v4l2_err(&dev->v4l2_dev, "Failed to allocate video device\n");
+		ret = -ENOMEM;
+		goto unreg_dev;
+	}
+
+	*vfd = m2mtest_videodev;
+
+	ret = video_register_device(vfd, VFL_TYPE_GRABBER, 0);
+	if (ret) {
+		v4l2_err(&dev->v4l2_dev, "Failed to register video device\n");
+		goto rel_vdev;
+	}
+
+	video_set_drvdata(vfd, dev);
+	snprintf(vfd->name, sizeof(vfd->name), "%s", m2mtest_videodev.name);
+	dev->vfd = vfd;
+	v4l2_info(&dev->v4l2_dev, MEM2MEM_TEST_MODULE_NAME
+			"Device registered as /dev/video%d\n", vfd->num);
+
+	setup_timer(&dev->timer, device_isr, (long)dev);
+	platform_set_drvdata(pdev, dev);
+
+	dev->m2m_dev = v4l2_m2m_init(&m2m_ops);
+	if (IS_ERR(dev->m2m_dev)) {
+		v4l2_err(&dev->v4l2_dev, "Failed to init mem2mem device\n");
+		ret = PTR_ERR(dev->m2m_dev);
+		goto err_m2m;
+	}
+
+	return 0;
+
+err_m2m:
+	video_unregister_device(dev->vfd);
+rel_vdev:
+	video_device_release(vfd);
+unreg_dev:
+	v4l2_device_unregister(&dev->v4l2_dev);
+free_dev:
+	kfree(dev);
+
+	return ret;
+}
+
+static int m2mtest_remove(struct platform_device *pdev)
+{
+	struct m2mtest_dev *dev =
+		(struct m2mtest_dev *)platform_get_drvdata(pdev);
+
+	v4l2_info(&dev->v4l2_dev, "Removing " MEM2MEM_TEST_MODULE_NAME);
+	v4l2_m2m_release(dev->m2m_dev);
+	del_timer_sync(&dev->timer);
+	video_unregister_device(dev->vfd);
+	v4l2_device_unregister(&dev->v4l2_dev);
+	kfree(dev);
+
+	return 0;
+}
+
+static struct platform_driver m2mtest_pdrv = {
+	.probe		= m2mtest_probe,
+	.remove		= m2mtest_remove,
+	.driver		= {
+		.name	= MEM2MEM_NAME,
+		.owner	= THIS_MODULE,
+	},
+};
+
+static void __exit m2mtest_exit(void)
+{
+	platform_driver_unregister(&m2mtest_pdrv);
+	platform_device_unregister(&m2mtest_pdev);
+}
+
+static int __init m2mtest_init(void)
+{
+	int ret;
+
+	ret = platform_device_register(&m2mtest_pdev);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&m2mtest_pdrv);
+	if (ret)
+		platform_device_unregister(&m2mtest_pdev);
+
+	return 0;
+}
+
+module_init(m2mtest_init);
+module_exit(m2mtest_exit);
+