linux/drivers/media/video/via-camera.c

/*
 * Driver for the VIA Chrome integrated camera controller.
 *
 * Copyright 2009,2010 Jonathan Corbet <corbet@lwn.net>
 * Distributable under the terms of the GNU General Public License, version 2
 *
 * This work was supported by the One Laptop Per Child project
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/videodev2.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-chip-ident.h>
#include <media/videobuf-dma-sg.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/pm_qos_params.h>
#include <linux/via-core.h>
#include <linux/via-gpio.h>
#include <linux/via_i2c.h>
#include <asm/olpc.h>

#include "via-camera.h"

MODULE_ALIAS("platform:viafb-camera");
MODULE_AUTHOR("Jonathan Corbet <corbet@lwn.net>");
MODULE_DESCRIPTION("VIA framebuffer-based camera controller driver");
MODULE_LICENSE("GPL");

static int flip_image;
module_param(flip_image, bool, 0444);
MODULE_PARM_DESC(flip_image,
		"If set, the sensor will be instructed to flip the image "
		"vertically.");

static int override_serial;
module_param(override_serial, bool, 0444);
MODULE_PARM_DESC(override_serial,
		"The camera driver will normally refuse to load if "
		"the XO 1.5 serial port is enabled.  Set this option "
		"to force-enable the camera.");

/*
 * Basic window sizes.
 */
#define VGA_WIDTH	640
#define VGA_HEIGHT	480
#define QCIF_WIDTH	176
#define	QCIF_HEIGHT	144

/*
 * The structure describing our camera.
 */
enum viacam_opstate { S_IDLE = 0, S_RUNNING = 1 };

struct via_camera {
	struct v4l2_device v4l2_dev;
	struct video_device vdev;
	struct v4l2_subdev *sensor;
	struct platform_device *platdev;
	struct viafb_dev *viadev;
	struct mutex lock;
	enum viacam_opstate opstate;
	unsigned long flags;
	struct pm_qos_request_list qos_request;
	/*
	 * GPIO info for power/reset management
	 */
	int power_gpio;
	int reset_gpio;
	/*
	 * I/O memory stuff.
	 */
	void __iomem *mmio;	/* Where the registers live */
	void __iomem *fbmem;	/* Frame buffer memory */
	u32 fb_offset;		/* Reserved memory offset (FB) */
	/*
	 * Capture buffers and related.	 The controller supports
	 * up to three, so that's what we have here.  These buffers
	 * live in frame buffer memory, so we don't call them "DMA".
	 */
	unsigned int cb_offsets[3];	/* offsets into fb mem */
	u8 *cb_addrs[3];		/* Kernel-space addresses */
	int n_cap_bufs;			/* How many are we using? */
	int next_buf;
	struct videobuf_queue vb_queue;
	struct list_head buffer_queue;	/* prot. by reg_lock */
	/*
	 * User tracking.
	 */
	int users;
	struct file *owner;
	/*
	 * Video format information.  sensor_format is kept in a form
	 * that we can use to pass to the sensor.  We always run the
	 * sensor in VGA resolution, though, and let the controller
	 * downscale things if need be.	 So we keep the "real*
	 * dimensions separately.
	 */
	struct v4l2_pix_format sensor_format;
	struct v4l2_pix_format user_format;
	enum v4l2_mbus_pixelcode mbus_code;
};

/*
 * Yes, this is a hack, but there's only going to be one of these
 * on any system we know of.
 */
static struct via_camera *via_cam_info;

/*
 * Flag values, manipulated with bitops
 */
#define CF_DMA_ACTIVE	 0	/* A frame is incoming */
#define CF_CONFIG_NEEDED 1	/* Must configure hardware */


/*
 * Nasty ugly v4l2 boilerplate.
 */
#define sensor_call(cam, optype, func, args...) \
	v4l2_subdev_call(cam->sensor, optype, func, ##args)

/*
 * Debugging and related.
 */
#define cam_err(cam, fmt, arg...) \
	dev_err(&(cam)->platdev->dev, fmt, ##arg);
#define cam_warn(cam, fmt, arg...) \
	dev_warn(&(cam)->platdev->dev, fmt, ##arg);
#define cam_dbg(cam, fmt, arg...) \
	dev_dbg(&(cam)->platdev->dev, fmt, ##arg);

/*
 * Format handling.  This is ripped almost directly from Hans's changes
 * to cafe_ccic.c.  It's a little unfortunate; until this change, we
 * didn't need to know anything about the format except its byte depth;
 * now this information must be managed at this level too.
 */
static struct via_format {
	__u8 *desc;
	__u32 pixelformat;
	int bpp;   /* Bytes per pixel */
	enum v4l2_mbus_pixelcode mbus_code;
} via_formats[] = {
	{
		.desc		= "YUYV 4:2:2",
		.pixelformat	= V4L2_PIX_FMT_YUYV,
		.mbus_code	= V4L2_MBUS_FMT_YUYV8_2X8,
		.bpp		= 2,
	},
	{
		.desc		= "RGB 565",
		.pixelformat	= V4L2_PIX_FMT_RGB565,
		.mbus_code	= V4L2_MBUS_FMT_RGB565_2X8_LE,
		.bpp		= 2,
	},
	/* RGB444 and Bayer should be doable, but have never been
	   tested with this driver. */
};
#define N_VIA_FMTS ARRAY_SIZE(via_formats)

static struct via_format *via_find_format(u32 pixelformat)
{
	unsigned i;

	for (i = 0; i < N_VIA_FMTS; i++)
		if (via_formats[i].pixelformat == pixelformat)
			return via_formats + i;
	/* Not found? Then return the first format. */
	return via_formats;
}


/*--------------------------------------------------------------------------*/
/*
 * Sensor power/reset management.  This piece is OLPC-specific for
 * sure; other configurations will have things connected differently.
 */
static int via_sensor_power_setup(struct via_camera *cam)
{
	int ret;

	cam->power_gpio = viafb_gpio_lookup("VGPIO3");
	cam->reset_gpio = viafb_gpio_lookup("VGPIO2");
	if (cam->power_gpio < 0 || cam->reset_gpio < 0) {
		dev_err(&cam->platdev->dev, "Unable to find GPIO lines\n");
		return -EINVAL;
	}
	ret = gpio_request(cam->power_gpio, "viafb-camera");
	if (ret) {
		dev_err(&cam->platdev->dev, "Unable to request power GPIO\n");
		return ret;
	}
	ret = gpio_request(cam->reset_gpio, "viafb-camera");
	if (ret) {
		dev_err(&cam->platdev->dev, "Unable to request reset GPIO\n");
		gpio_free(cam->power_gpio);
		return ret;
	}
	gpio_direction_output(cam->power_gpio, 0);
	gpio_direction_output(cam->reset_gpio, 0);
	return 0;
}

/*
 * Power up the sensor and perform the reset dance.
 */
static void via_sensor_power_up(struct via_camera *cam)
{
	gpio_set_value(cam->power_gpio, 1);
	gpio_set_value(cam->reset_gpio, 0);
	msleep(20);  /* Probably excessive */
	gpio_set_value(cam->reset_gpio, 1);
	msleep(20);
}

static void via_sensor_power_down(struct via_camera *cam)
{
	gpio_set_value(cam->power_gpio, 0);
	gpio_set_value(cam->reset_gpio, 0);
}


static void via_sensor_power_release(struct via_camera *cam)
{
	via_sensor_power_down(cam);
	gpio_free(cam->power_gpio);
	gpio_free(cam->reset_gpio);
}

/* --------------------------------------------------------------------------*/
/* Sensor ops */

/*
 * Manage the ov7670 "flip" bit, which needs special help.
 */
static int viacam_set_flip(struct via_camera *cam)
{
	struct v4l2_control ctrl;

	memset(&ctrl, 0, sizeof(ctrl));
	ctrl.id = V4L2_CID_VFLIP;
	ctrl.value = flip_image;
	return sensor_call(cam, core, s_ctrl, &ctrl);
}

/*
 * Configure the sensor.  It's up to the caller to ensure
 * that the camera is in the correct operating state.
 */
static int viacam_configure_sensor(struct via_camera *cam)
{
	struct v4l2_mbus_framefmt mbus_fmt;
	int ret;

	v4l2_fill_mbus_format(&mbus_fmt, &cam->sensor_format, cam->mbus_code);
	ret = sensor_call(cam, core, init, 0);
	if (ret == 0)
		ret = sensor_call(cam, video, s_mbus_fmt, &mbus_fmt);
	/*
	 * OV7670 does weird things if flip is set *before* format...
	 */
	if (ret == 0)
		ret = viacam_set_flip(cam);
	return ret;
}



/* --------------------------------------------------------------------------*/
/*
 * Some simple register accessors; they assume that the lock is held.
 *
 * Should we want to support the second capture engine, we could
 * hide the register difference by adding 0x1000 to registers in the
 * 0x300-350 range.
 */
static inline void viacam_write_reg(struct via_camera *cam,
		int reg, int value)
{
	iowrite32(value, cam->mmio + reg);
}

static inline int viacam_read_reg(struct via_camera *cam, int reg)
{
	return ioread32(cam->mmio + reg);
}

static inline void viacam_write_reg_mask(struct via_camera *cam,
		int reg, int value, int mask)
{
	int tmp = viacam_read_reg(cam, reg);

	tmp = (tmp & ~mask) | (value & mask);
	viacam_write_reg(cam, reg, tmp);
}


/* --------------------------------------------------------------------------*/
/* Interrupt management and handling */

static irqreturn_t viacam_quick_irq(int irq, void *data)
{
	struct via_camera *cam = data;
	irqreturn_t ret = IRQ_NONE;
	int icv;

	/*
	 * All we do here is to clear the interrupts and tell
	 * the handler thread to wake up.
	 */
	spin_lock(&cam->viadev->reg_lock);
	icv = viacam_read_reg(cam, VCR_INTCTRL);
	if (icv & VCR_IC_EAV) {
		icv |= VCR_IC_EAV|VCR_IC_EVBI|VCR_IC_FFULL;
		viacam_write_reg(cam, VCR_INTCTRL, icv);
		ret = IRQ_WAKE_THREAD;
	}
	spin_unlock(&cam->viadev->reg_lock);
	return ret;
}

/*
 * Find the next videobuf buffer which has somebody waiting on it.
 */
static struct videobuf_buffer *viacam_next_buffer(struct via_camera *cam)
{
	unsigned long flags;
	struct videobuf_buffer *buf = NULL;

	spin_lock_irqsave(&cam->viadev->reg_lock, flags);
	if (cam->opstate != S_RUNNING)
		goto out;
	if (list_empty(&cam->buffer_queue))
		goto out;
	buf = list_entry(cam->buffer_queue.next, struct videobuf_buffer, queue);
	if (!waitqueue_active(&buf->done)) {/* Nobody waiting */
		buf = NULL;
		goto out;
	}
	list_del(&buf->queue);
	buf->state = VIDEOBUF_ACTIVE;
out:
	spin_unlock_irqrestore(&cam->viadev->reg_lock, flags);
	return buf;
}

/*
 * The threaded IRQ handler.
 */
static irqreturn_t viacam_irq(int irq, void *data)
{
	int bufn;
	struct videobuf_buffer *vb;
	struct via_camera *cam = data;
	struct videobuf_dmabuf *vdma;

	/*
	 * If there is no place to put the data frame, don't bother
	 * with anything else.
	 */
	vb = viacam_next_buffer(cam);
	if (vb == NULL)
		goto done;
	/*
	 * Figure out which buffer we just completed.
	 */
	bufn = (viacam_read_reg(cam, VCR_INTCTRL) & VCR_IC_ACTBUF) >> 3;
	bufn -= 1;
	if (bufn < 0)
		bufn = cam->n_cap_bufs - 1;
	/*
	 * Copy over the data and let any waiters know.
	 */
	vdma = videobuf_to_dma(vb);
	viafb_dma_copy_out_sg(cam->cb_offsets[bufn], vdma->sglist, vdma->sglen);
	vb->state = VIDEOBUF_DONE;
	vb->size = cam->user_format.sizeimage;
	wake_up(&vb->done);
done:
	return IRQ_HANDLED;
}


/*
 * These functions must mess around with the general interrupt
 * control register, which is relevant to much more than just the
 * camera.  Nothing else uses interrupts, though, as of this writing.
 * Should that situation change, we'll have to improve support at
 * the via-core level.
 */
static void viacam_int_enable(struct via_camera *cam)
{
	viacam_write_reg(cam, VCR_INTCTRL,
			VCR_IC_INTEN|VCR_IC_EAV|VCR_IC_EVBI|VCR_IC_FFULL);
	viafb_irq_enable(VDE_I_C0AVEN);
}

static void viacam_int_disable(struct via_camera *cam)
{
	viafb_irq_disable(VDE_I_C0AVEN);
	viacam_write_reg(cam, VCR_INTCTRL, 0);
}



/* --------------------------------------------------------------------------*/
/* Controller operations */

/*
 * Set up our capture buffers in framebuffer memory.
 */
static int viacam_ctlr_cbufs(struct via_camera *cam)
{
	int nbuf = cam->viadev->camera_fbmem_size/cam->sensor_format.sizeimage;
	int i;
	unsigned int offset;

	/*
	 * See how many buffers we can work with.
	 */
	if (nbuf >= 3) {
		cam->n_cap_bufs = 3;
		viacam_write_reg_mask(cam, VCR_CAPINTC, VCR_CI_3BUFS,
				VCR_CI_3BUFS);
	} else if (nbuf == 2) {
		cam->n_cap_bufs = 2;
		viacam_write_reg_mask(cam, VCR_CAPINTC, 0, VCR_CI_3BUFS);
	} else {
		cam_warn(cam, "Insufficient frame buffer memory\n");
		return -ENOMEM;
	}
	/*
	 * Set them up.
	 */
	offset = cam->fb_offset;
	for (i = 0; i < cam->n_cap_bufs; i++) {
		cam->cb_offsets[i] = offset;
		cam->cb_addrs[i] = cam->fbmem + offset;
		viacam_write_reg(cam, VCR_VBUF1 + i*4, offset & VCR_VBUF_MASK);
		offset += cam->sensor_format.sizeimage;
	}
	return 0;
}

/*
 * Set the scaling register for downscaling the image.
 *
 * This register works like this...  Vertical scaling is enabled
 * by bit 26; if that bit is set, downscaling is controlled by the
 * value in bits 16:25.	 Those bits are divided by 1024 to get
 * the scaling factor; setting just bit 25 thus cuts the height
 * in half.
 *
 * Horizontal scaling works about the same, but it's enabled by
 * bit 11, with bits 0:10 giving the numerator of a fraction
 * (over 2048) for the scaling value.
 *
 * This function is naive in that, if the user departs from
 * the 3x4 VGA scaling factor, the image will distort.	We
 * could work around that if it really seemed important.
 */
static void viacam_set_scale(struct via_camera *cam)
{
	unsigned int avscale;
	int sf;

	if (cam->user_format.width == VGA_WIDTH)
		avscale = 0;
	else {
		sf = (cam->user_format.width*2048)/VGA_WIDTH;
		avscale = VCR_AVS_HEN | sf;
	}
	if (cam->user_format.height < VGA_HEIGHT) {
		sf = (1024*cam->user_format.height)/VGA_HEIGHT;
		avscale |= VCR_AVS_VEN | (sf << 16);
	}
	viacam_write_reg(cam, VCR_AVSCALE, avscale);
}


/*
 * Configure image-related information into the capture engine.
 */
static void viacam_ctlr_image(struct via_camera *cam)
{
	int cicreg;

	/*
	 * Disable clock before messing with stuff - from the via
	 * sample driver.
	 */
	viacam_write_reg(cam, VCR_CAPINTC, ~(VCR_CI_ENABLE|VCR_CI_CLKEN));
	/*
	 * Set up the controller for VGA resolution, modulo magic
	 * offsets from the via sample driver.
	 */
	viacam_write_reg(cam, VCR_HORRANGE, 0x06200120);
	viacam_write_reg(cam, VCR_VERTRANGE, 0x01de0000);
	viacam_set_scale(cam);
	/*
	 * Image size info.
	 */
	viacam_write_reg(cam, VCR_MAXDATA,
			(cam->sensor_format.height << 16) |
			(cam->sensor_format.bytesperline >> 3));
	viacam_write_reg(cam, VCR_MAXVBI, 0);
	viacam_write_reg(cam, VCR_VSTRIDE,
			cam->user_format.bytesperline & VCR_VS_STRIDE);
	/*
	 * Set up the capture interface control register,
	 * everything but the "go" bit.
	 *
	 * The FIFO threshold is a bit of a magic number; 8 is what
	 * VIA's sample code uses.
	 */
	cicreg = VCR_CI_CLKEN |
		0x08000000 |		/* FIFO threshold */
		VCR_CI_FLDINV |		/* OLPC-specific? */
		VCR_CI_VREFINV |	/* OLPC-specific? */
		VCR_CI_DIBOTH |		/* Capture both fields */
		VCR_CI_CCIR601_8;
	if (cam->n_cap_bufs == 3)
		cicreg |= VCR_CI_3BUFS;
	/*
	 * YUV formats need different byte swapping than RGB.
	 */
	if (cam->user_format.pixelformat == V4L2_PIX_FMT_YUYV)
		cicreg |= VCR_CI_YUYV;
	else
		cicreg |= VCR_CI_UYVY;
	viacam_write_reg(cam, VCR_CAPINTC, cicreg);
}


static int viacam_config_controller(struct via_camera *cam)
{
	int ret;
	unsigned long flags;

	spin_lock_irqsave(&cam->viadev->reg_lock, flags);
	ret = viacam_ctlr_cbufs(cam);
	if (!ret)
		viacam_ctlr_image(cam);
	spin_unlock_irqrestore(&cam->viadev->reg_lock, flags);
	clear_bit(CF_CONFIG_NEEDED, &cam->flags);
	return ret;
}

/*
 * Make it start grabbing data.
 */
static void viacam_start_engine(struct via_camera *cam)
{
	spin_lock_irq(&cam->viadev->reg_lock);
	cam->next_buf = 0;
	viacam_write_reg_mask(cam, VCR_CAPINTC, VCR_CI_ENABLE, VCR_CI_ENABLE);
	viacam_int_enable(cam);
	(void) viacam_read_reg(cam, VCR_CAPINTC); /* Force post */
	cam->opstate = S_RUNNING;
	spin_unlock_irq(&cam->viadev->reg_lock);
}


static void viacam_stop_engine(struct via_camera *cam)
{
	spin_lock_irq(&cam->viadev->reg_lock);
	viacam_int_disable(cam);
	viacam_write_reg_mask(cam, VCR_CAPINTC, 0, VCR_CI_ENABLE);
	(void) viacam_read_reg(cam, VCR_CAPINTC); /* Force post */
	cam->opstate = S_IDLE;
	spin_unlock_irq(&cam->viadev->reg_lock);
}


/* --------------------------------------------------------------------------*/
/* Videobuf callback ops */

/*
 * buffer_setup.  The purpose of this one would appear to be to tell
 * videobuf how big a single image is.	It's also evidently up to us
 * to put some sort of limit on the maximum number of buffers allowed.
 */
static int viacam_vb_buf_setup(struct videobuf_queue *q,
		unsigned int *count, unsigned int *size)
{
	struct via_camera *cam = q->priv_data;

	*size = cam->user_format.sizeimage;
	if (*count == 0 || *count > 6)	/* Arbitrary number */
		*count = 6;
	return 0;
}

/*
 * Prepare a buffer.
 */
static int viacam_vb_buf_prepare(struct videobuf_queue *q,
		struct videobuf_buffer *vb, enum v4l2_field field)
{
	struct via_camera *cam = q->priv_data;

	vb->size = cam->user_format.sizeimage;
	vb->width = cam->user_format.width; /* bytesperline???? */
	vb->height = cam->user_format.height;
	vb->field = field;
	if (vb->state == VIDEOBUF_NEEDS_INIT) {
		int ret = videobuf_iolock(q, vb, NULL);
		if (ret)
			return ret;
	}
	vb->state = VIDEOBUF_PREPARED;
	return 0;
}

/*
 * We've got a buffer to put data into.
 *
 * FIXME: check for a running engine and valid buffers?
 */
static void viacam_vb_buf_queue(struct videobuf_queue *q,
		struct videobuf_buffer *vb)
{
	struct via_camera *cam = q->priv_data;

	/*
	 * Note that videobuf holds the lock when it calls
	 * us, so we need not (indeed, cannot) take it here.
	 */
	vb->state = VIDEOBUF_QUEUED;
	list_add_tail(&vb->queue, &cam->buffer_queue);
}

/*
 * Free a buffer.
 */
static void viacam_vb_buf_release(struct videobuf_queue *q,
		struct videobuf_buffer *vb)
{
	struct via_camera *cam = q->priv_data;

	videobuf_dma_unmap(&cam->platdev->dev, videobuf_to_dma(vb));
	videobuf_dma_free(videobuf_to_dma(vb));
	vb->state = VIDEOBUF_NEEDS_INIT;
}

static const struct videobuf_queue_ops viacam_vb_ops = {
	.buf_setup	= viacam_vb_buf_setup,
	.buf_prepare	= viacam_vb_buf_prepare,
	.buf_queue	= viacam_vb_buf_queue,
	.buf_release	= viacam_vb_buf_release,
};

/* --------------------------------------------------------------------------*/
/* File operations */

static int viacam_open(struct file *filp)
{
	struct via_camera *cam = video_drvdata(filp);

	filp->private_data = cam;
	/*
	 * Note the new user.  If this is the first one, we'll also
	 * need to power up the sensor.
	 */
	mutex_lock(&cam->lock);
	if (cam->users == 0) {
		int ret = viafb_request_dma();

		if (ret) {
			mutex_unlock(&cam->lock);
			return ret;
		}
		via_sensor_power_up(cam);
		set_bit(CF_CONFIG_NEEDED, &cam->flags);
		/*
		 * Hook into videobuf.	Evidently this cannot fail.
		 */
		videobuf_queue_sg_init(&cam->vb_queue, &viacam_vb_ops,
				&cam->platdev->dev, &cam->viadev->reg_lock,
				V4L2_BUF_TYPE_VIDEO_CAPTURE, V4L2_FIELD_NONE,
				sizeof(struct videobuf_buffer), cam, NULL);
	}
	(cam->users)++;
	mutex_unlock(&cam->lock);
	return 0;
}

static int viacam_release(struct file *filp)
{
	struct via_camera *cam = video_drvdata(filp);

	mutex_lock(&cam->lock);
	(cam->users)--;
	/*
	 * If the "owner" is closing, shut down any ongoing
	 * operations.
	 */
	if (filp == cam->owner) {
		videobuf_stop(&cam->vb_queue);
		/*
		 * We don't hold the spinlock here, but, if release()
		 * is being called by the owner, nobody else will
		 * be changing the state.  And an extra stop would
		 * not hurt anyway.
		 */
		if (cam->opstate != S_IDLE)
			viacam_stop_engine(cam);
		cam->owner = NULL;
	}
	/*
	 * Last one out needs to turn out the lights.
	 */
	if (cam->users == 0) {
		videobuf_mmap_free(&cam->vb_queue);
		via_sensor_power_down(cam);
		viafb_release_dma();
	}
	mutex_unlock(&cam->lock);
	return 0;
}

/*
 * Read a frame from the device.
 */
static ssize_t viacam_read(struct file *filp, char __user *buffer,
		size_t len, loff_t *pos)
{
	struct via_camera *cam = video_drvdata(filp);
	int ret;

	mutex_lock(&cam->lock);
	/*
	 * Enforce the V4l2 "only one owner gets to read data" rule.
	 */
	if (cam->owner && cam->owner != filp) {
		ret = -EBUSY;
		goto out_unlock;
	}
	cam->owner = filp;
	/*
	 * Do we need to configure the hardware?
	 */
	if (test_bit(CF_CONFIG_NEEDED, &cam->flags)) {
		ret = viacam_configure_sensor(cam);
		if (!ret)
			ret = viacam_config_controller(cam);
		if (ret)
			goto out_unlock;
	}
	/*
	 * Fire up the capture engine, then have videobuf do
	 * the heavy lifting.  Someday it would be good to avoid
	 * stopping and restarting the engine each time.
	 */
	INIT_LIST_HEAD(&cam->buffer_queue);
	viacam_start_engine(cam);
	ret = videobuf_read_stream(&cam->vb_queue, buffer, len, pos, 0,
			filp->f_flags & O_NONBLOCK);
	viacam_stop_engine(cam);
	/* videobuf_stop() ?? */

out_unlock:
	mutex_unlock(&cam->lock);
	return ret;
}


static unsigned int viacam_poll(struct file *filp, struct poll_table_struct *pt)
{
	struct via_camera *cam = video_drvdata(filp);

	return videobuf_poll_stream(filp, &cam->vb_queue, pt);
}


static int viacam_mmap(struct file *filp, struct vm_area_struct *vma)
{
	struct via_camera *cam = video_drvdata(filp);

	return videobuf_mmap_mapper(&cam->vb_queue, vma);
}



static const struct v4l2_file_operations viacam_fops = {
	.owner		= THIS_MODULE,
	.open		= viacam_open,
	.release	= viacam_release,
	.read		= viacam_read,
	.poll		= viacam_poll,
	.mmap		= viacam_mmap,
	.unlocked_ioctl	= video_ioctl2,
};

/*----------------------------------------------------------------------------*/
/*
 * The long list of v4l2 ioctl ops
 */

static int viacam_g_chip_ident(struct file *file, void *priv,
		struct v4l2_dbg_chip_ident *ident)
{
	struct via_camera *cam = priv;

	ident->ident = V4L2_IDENT_NONE;
	ident->revision = 0;
	if (v4l2_chip_match_host(&ident->match)) {
		ident->ident = V4L2_IDENT_VIA_VX855;
		return 0;
	}
	return sensor_call(cam, core, g_chip_ident, ident);
}

/*
 * Control ops are passed through to the sensor.
 */
static int viacam_queryctrl(struct file *filp, void *priv,
		struct v4l2_queryctrl *qc)
{
	struct via_camera *cam = priv;
	int ret;

	mutex_lock(&cam->lock);
	ret = sensor_call(cam, core, queryctrl, qc);
	mutex_unlock(&cam->lock);
	return ret;
}


static int viacam_g_ctrl(struct file *filp, void *priv,
		struct v4l2_control *ctrl)
{
	struct via_camera *cam = priv;
	int ret;

	mutex_lock(&cam->lock);
	ret = sensor_call(cam, core, g_ctrl, ctrl);
	mutex_unlock(&cam->lock);
	return ret;
}


static int viacam_s_ctrl(struct file *filp, void *priv,
		struct v4l2_control *ctrl)
{
	struct via_camera *cam = priv;
	int ret;

	mutex_lock(&cam->lock);
	ret = sensor_call(cam, core, s_ctrl, ctrl);
	mutex_unlock(&cam->lock);
	return ret;
}

/*
 * Only one input.
 */
static int viacam_enum_input(struct file *filp, void *priv,
		struct v4l2_input *input)
{
	if (input->index != 0)
		return -EINVAL;

	input->type = V4L2_INPUT_TYPE_CAMERA;
	input->std = V4L2_STD_ALL; /* Not sure what should go here */
	strcpy(input->name, "Camera");
	return 0;
}

static int viacam_g_input(struct file *filp, void *priv, unsigned int *i)
{
	*i = 0;
	return 0;
}

static int viacam_s_input(struct file *filp, void *priv, unsigned int i)
{
	if (i != 0)
		return -EINVAL;
	return 0;
}

static int viacam_s_std(struct file *filp, void *priv, v4l2_std_id *std)
{
	return 0;
}

/*
 * Video format stuff.	Here is our default format until
 * user space messes with things.
 */
static const struct v4l2_pix_format viacam_def_pix_format = {
	.width		= VGA_WIDTH,
	.height		= VGA_HEIGHT,
	.pixelformat	= V4L2_PIX_FMT_YUYV,
	.field		= V4L2_FIELD_NONE,
	.bytesperline	= VGA_WIDTH * 2,
	.sizeimage	= VGA_WIDTH * VGA_HEIGHT * 2,
};

static const enum v4l2_mbus_pixelcode via_def_mbus_code = V4L2_MBUS_FMT_YUYV8_2X8;

static int viacam_enum_fmt_vid_cap(struct file *filp, void *priv,
		struct v4l2_fmtdesc *fmt)
{
	if (fmt->index >= N_VIA_FMTS)
		return -EINVAL;
	strlcpy(fmt->description, via_formats[fmt->index].desc,
			sizeof(fmt->description));
	fmt->pixelformat = via_formats[fmt->index].pixelformat;
	return 0;
}

/*
 * Figure out proper image dimensions, but always force the
 * sensor to VGA.
 */
static void viacam_fmt_pre(struct v4l2_pix_format *userfmt,
		struct v4l2_pix_format *sensorfmt)
{
	*sensorfmt = *userfmt;
	if (userfmt->width < QCIF_WIDTH || userfmt->height < QCIF_HEIGHT) {
		userfmt->width = QCIF_WIDTH;
		userfmt->height = QCIF_HEIGHT;
	}
	if (userfmt->width > VGA_WIDTH || userfmt->height > VGA_HEIGHT) {
		userfmt->width = VGA_WIDTH;
		userfmt->height = VGA_HEIGHT;
	}
	sensorfmt->width = VGA_WIDTH;
	sensorfmt->height = VGA_HEIGHT;
}

static void viacam_fmt_post(struct v4l2_pix_format *userfmt,
		struct v4l2_pix_format *sensorfmt)
{
	struct via_format *f = via_find_format(userfmt->pixelformat);

	sensorfmt->bytesperline = sensorfmt->width * f->bpp;
	sensorfmt->sizeimage = sensorfmt->height * sensorfmt->bytesperline;
	userfmt->pixelformat = sensorfmt->pixelformat;
	userfmt->field = sensorfmt->field;
	userfmt->bytesperline = 2 * userfmt->width;
	userfmt->sizeimage = userfmt->bytesperline * userfmt->height;
}


/*
 * The real work of figuring out a workable format.
 */
static int viacam_do_try_fmt(struct via_camera *cam,
		struct v4l2_pix_format *upix, struct v4l2_pix_format *spix)
{
	int ret;
	struct v4l2_mbus_framefmt mbus_fmt;
	struct via_format *f = via_find_format(upix->pixelformat);

	upix->pixelformat = f->pixelformat;
	viacam_fmt_pre(upix, spix);
	v4l2_fill_mbus_format(&mbus_fmt, upix, f->mbus_code);
	ret = sensor_call(cam, video, try_mbus_fmt, &mbus_fmt);
	v4l2_fill_pix_format(spix, &mbus_fmt);
	viacam_fmt_post(upix, spix);
	return ret;
}



static int viacam_try_fmt_vid_cap(struct file *filp, void *priv,
		struct v4l2_format *fmt)
{
	struct via_camera *cam = priv;
	struct v4l2_format sfmt;
	int ret;

	mutex_lock(&cam->lock);
	ret = viacam_do_try_fmt(cam, &fmt->fmt.pix, &sfmt.fmt.pix);
	mutex_unlock(&cam->lock);
	return ret;
}


static int viacam_g_fmt_vid_cap(struct file *filp, void *priv,
		struct v4l2_format *fmt)
{
	struct via_camera *cam = priv;

	mutex_lock(&cam->lock);
	fmt->fmt.pix = cam->user_format;
	mutex_unlock(&cam->lock);
	return 0;
}

static int viacam_s_fmt_vid_cap(struct file *filp, void *priv,
		struct v4l2_format *fmt)
{
	struct via_camera *cam = priv;
	int ret;
	struct v4l2_format sfmt;
	struct via_format *f = via_find_format(fmt->fmt.pix.pixelformat);

	/*
	 * Camera must be idle or we can't mess with the
	 * video setup.
	 */
	mutex_lock(&cam->lock);
	if (cam->opstate != S_IDLE) {
		ret = -EBUSY;
		goto out;
	}
	/*
	 * Let the sensor code look over and tweak the
	 * requested formatting.
	 */
	ret = viacam_do_try_fmt(cam, &fmt->fmt.pix, &sfmt.fmt.pix);
	if (ret)
		goto out;
	/*
	 * OK, let's commit to the new format.
	 */
	cam->user_format = fmt->fmt.pix;
	cam->sensor_format = sfmt.fmt.pix;
	cam->mbus_code = f->mbus_code;
	ret = viacam_configure_sensor(cam);
	if (!ret)
		ret = viacam_config_controller(cam);
out:
	mutex_unlock(&cam->lock);
	return ret;
}

static int viacam_querycap(struct file *filp, void *priv,
		struct v4l2_capability *cap)
{
	strcpy(cap->driver, "via-camera");
	strcpy(cap->card, "via-camera");
	cap->version = 1;
	cap->capabilities = V4L2_CAP_VIDEO_CAPTURE |
		V4L2_CAP_READWRITE | V4L2_CAP_STREAMING;
	return 0;
}

/*
 * Streaming operations - pure videobuf stuff.
 */
static int viacam_reqbufs(struct file *filp, void *priv,
		struct v4l2_requestbuffers *rb)
{
	struct via_camera *cam = priv;

	return videobuf_reqbufs(&cam->vb_queue, rb);
}

static int viacam_querybuf(struct file *filp, void *priv,
		struct v4l2_buffer *buf)
{
	struct via_camera *cam = priv;

	return videobuf_querybuf(&cam->vb_queue, buf);
}

static int viacam_qbuf(struct file *filp, void *priv, struct v4l2_buffer *buf)
{
	struct via_camera *cam = priv;

	return videobuf_qbuf(&cam->vb_queue, buf);
}

static int viacam_dqbuf(struct file *filp, void *priv, struct v4l2_buffer *buf)
{
	struct via_camera *cam = priv;

	return videobuf_dqbuf(&cam->vb_queue, buf, filp->f_flags & O_NONBLOCK);
}

static int viacam_streamon(struct file *filp, void *priv, enum v4l2_buf_type t)
{
	struct via_camera *cam = priv;
	int ret = 0;

	if (t != V4L2_BUF_TYPE_VIDEO_CAPTURE)
		return -EINVAL;

	mutex_lock(&cam->lock);
	if (cam->opstate != S_IDLE) {
		ret = -EBUSY;
		goto out;
	}
	/*
	 * Enforce the V4l2 "only one owner gets to read data" rule.
	 */
	if (cam->owner && cam->owner != filp) {
		ret = -EBUSY;
		goto out;
	}
	cam->owner = filp;
	/*
	 * Configure things if need be.
	 */
	if (test_bit(CF_CONFIG_NEEDED, &cam->flags)) {
		ret = viacam_configure_sensor(cam);
		if (ret)
			goto out;
		ret = viacam_config_controller(cam);
		if (ret)
			goto out;
	}
	/*
	 * If the CPU goes into C3, the DMA transfer gets corrupted and
	 * users start filing unsightly bug reports.  Put in a "latency"
	 * requirement which will keep the CPU out of the deeper sleep
	 * states.
	 */
	pm_qos_add_request(&cam->qos_request, PM_QOS_CPU_DMA_LATENCY, 50);
	/*
	 * Fire things up.
	 */
	INIT_LIST_HEAD(&cam->buffer_queue);
	ret = videobuf_streamon(&cam->vb_queue);
	if (!ret)
		viacam_start_engine(cam);
out:
	mutex_unlock(&cam->lock);
	return ret;
}

static int viacam_streamoff(struct file *filp, void *priv, enum v4l2_buf_type t)
{
	struct via_camera *cam = priv;
	int ret;

	if (t != V4L2_BUF_TYPE_VIDEO_CAPTURE)
		return -EINVAL;
	mutex_lock(&cam->lock);
	if (cam->opstate != S_RUNNING) {
		ret = -EINVAL;
		goto out;
	}
	pm_qos_remove_request(&cam->qos_request);
	viacam_stop_engine(cam);
	/*
	 * Videobuf will recycle all of the outstanding buffers, but
	 * we should be sure we don't retain any references to
	 * any of them.
	 */
	ret = videobuf_streamoff(&cam->vb_queue);
	INIT_LIST_HEAD(&cam->buffer_queue);
out:
	mutex_unlock(&cam->lock);
	return ret;
}

/* G/S_PARM */

static int viacam_g_parm(struct file *filp, void *priv,
		struct v4l2_streamparm *parm)
{
	struct via_camera *cam = priv;
	int ret;

	mutex_lock(&cam->lock);
	ret = sensor_call(cam, video, g_parm, parm);
	mutex_unlock(&cam->lock);
	parm->parm.capture.readbuffers = cam->n_cap_bufs;
	return ret;
}

static int viacam_s_parm(struct file *filp, void *priv,
		struct v4l2_streamparm *parm)
{
	struct via_camera *cam = priv;
	int ret;

	mutex_lock(&cam->lock);
	ret = sensor_call(cam, video, s_parm, parm);
	mutex_unlock(&cam->lock);
	parm->parm.capture.readbuffers = cam->n_cap_bufs;
	return ret;
}

static int viacam_enum_framesizes(struct file *filp, void *priv,
		struct v4l2_frmsizeenum *sizes)
{
	if (sizes->index != 0)
		return -EINVAL;
	sizes->type = V4L2_FRMSIZE_TYPE_CONTINUOUS;
	sizes->stepwise.min_width = QCIF_WIDTH;
	sizes->stepwise.min_height = QCIF_HEIGHT;
	sizes->stepwise.max_width = VGA_WIDTH;
	sizes->stepwise.max_height = VGA_HEIGHT;
	sizes->stepwise.step_width = sizes->stepwise.step_height = 1;
	return 0;
}

static int viacam_enum_frameintervals(struct file *filp, void *priv,
		struct v4l2_frmivalenum *interval)
{
	struct via_camera *cam = priv;
	int ret;

	mutex_lock(&cam->lock);
	ret = sensor_call(cam, video, enum_frameintervals, interval);
	mutex_unlock(&cam->lock);
	return ret;
}



static const struct v4l2_ioctl_ops viacam_ioctl_ops = {
	.vidioc_g_chip_ident	= viacam_g_chip_ident,
	.vidioc_queryctrl	= viacam_queryctrl,
	.vidioc_g_ctrl		= viacam_g_ctrl,
	.vidioc_s_ctrl		= viacam_s_ctrl,
	.vidioc_enum_input	= viacam_enum_input,
	.vidioc_g_input		= viacam_g_input,
	.vidioc_s_input		= viacam_s_input,
	.vidioc_s_std		= viacam_s_std,
	.vidioc_enum_fmt_vid_cap = viacam_enum_fmt_vid_cap,
	.vidioc_try_fmt_vid_cap = viacam_try_fmt_vid_cap,
	.vidioc_g_fmt_vid_cap	= viacam_g_fmt_vid_cap,
	.vidioc_s_fmt_vid_cap	= viacam_s_fmt_vid_cap,
	.vidioc_querycap	= viacam_querycap,
	.vidioc_reqbufs		= viacam_reqbufs,
	.vidioc_querybuf	= viacam_querybuf,
	.vidioc_qbuf		= viacam_qbuf,
	.vidioc_dqbuf		= viacam_dqbuf,
	.vidioc_streamon	= viacam_streamon,
	.vidioc_streamoff	= viacam_streamoff,
	.vidioc_g_parm		= viacam_g_parm,
	.vidioc_s_parm		= viacam_s_parm,
	.vidioc_enum_framesizes = viacam_enum_framesizes,
	.vidioc_enum_frameintervals = viacam_enum_frameintervals,
};

/*----------------------------------------------------------------------------*/

/*
 * Power management.
 */
#ifdef CONFIG_PM

static int viacam_suspend(void *priv)
{
	struct via_camera *cam = priv;
	enum viacam_opstate state = cam->opstate;

	if (cam->opstate != S_IDLE) {
		viacam_stop_engine(cam);
		cam->opstate = state; /* So resume restarts */
	}

	return 0;
}

static int viacam_resume(void *priv)
{
	struct via_camera *cam = priv;
	int ret = 0;

	/*
	 * Get back to a reasonable operating state.
	 */
	via_write_reg_mask(VIASR, 0x78, 0, 0x80);
	via_write_reg_mask(VIASR, 0x1e, 0xc0, 0xc0);
	viacam_int_disable(cam);
	set_bit(CF_CONFIG_NEEDED, &cam->flags);
	/*
	 * Make sure the sensor's power state is correct
	 */
	if (cam->users > 0)
		via_sensor_power_up(cam);
	else
		via_sensor_power_down(cam);
	/*
	 * If it was operating, try to restart it.
	 */
	if (cam->opstate != S_IDLE) {
		mutex_lock(&cam->lock);
		ret = viacam_configure_sensor(cam);
		if (!ret)
			ret = viacam_config_controller(cam);
		mutex_unlock(&cam->lock);
		if (!ret)
			viacam_start_engine(cam);
	}

	return ret;
}

static struct viafb_pm_hooks viacam_pm_hooks = {
	.suspend = viacam_suspend,
	.resume = viacam_resume
};

#endif /* CONFIG_PM */

/*
 * Setup stuff.
 */

static struct video_device viacam_v4l_template = {
	.name		= "via-camera",
	.minor		= -1,
	.tvnorms	= V4L2_STD_NTSC_M,
	.current_norm	= V4L2_STD_NTSC_M,
	.fops		= &viacam_fops,
	.ioctl_ops	= &viacam_ioctl_ops,
	.release	= video_device_release_empty, /* Check this */
};

/*
 * The OLPC folks put the serial port on the same pin as
 * the camera.	They also get grumpy if we break the
 * serial port and keep them from using it.  So we have
 * to check the serial enable bit and not step on it.
 */
#define VIACAM_SERIAL_DEVFN 0x88
#define VIACAM_SERIAL_CREG 0x46
#define VIACAM_SERIAL_BIT 0x40

static __devinit bool viacam_serial_is_enabled(void)
{
	struct pci_bus *pbus = pci_find_bus(0, 0);
	u8 cbyte;

	if (!pbus)
		return false;
	pci_bus_read_config_byte(pbus, VIACAM_SERIAL_DEVFN,
			VIACAM_SERIAL_CREG, &cbyte);
	if ((cbyte & VIACAM_SERIAL_BIT) == 0)
		return false; /* Not enabled */
	if (override_serial == 0) {
		printk(KERN_NOTICE "Via camera: serial port is enabled, " \
				"refusing to load.\n");
		printk(KERN_NOTICE "Specify override_serial=1 to force " \
				"module loading.\n");
		return true;
	}
	printk(KERN_NOTICE "Via camera: overriding serial port\n");
	pci_bus_write_config_byte(pbus, VIACAM_SERIAL_DEVFN,
			VIACAM_SERIAL_CREG, cbyte & ~VIACAM_SERIAL_BIT);
	return false;
}

static __devinit int viacam_probe(struct platform_device *pdev)
{
	int ret;
	struct i2c_adapter *sensor_adapter;
	struct viafb_dev *viadev = pdev->dev.platform_data;

	/*
	 * Note that there are actually two capture channels on
	 * the device.	We only deal with one for now.	That
	 * is encoded here; nothing else assumes it's dealing with
	 * a unique capture device.
	 */
	struct via_camera *cam;

	/*
	 * Ensure that frame buffer memory has been set aside for
	 * this purpose.  As an arbitrary limit, refuse to work
	 * with less than two frames of VGA 16-bit data.
	 *
	 * If we ever support the second port, we'll need to set
	 * aside more memory.
	 */
	if (viadev->camera_fbmem_size < (VGA_HEIGHT*VGA_WIDTH*4)) {
		printk(KERN_ERR "viacam: insufficient FB memory reserved\n");
		return -ENOMEM;
	}
	if (viadev->engine_mmio == NULL) {
		printk(KERN_ERR "viacam: No I/O memory, so no pictures\n");
		return -ENOMEM;
	}

	if (machine_is_olpc() && viacam_serial_is_enabled())
		return -EBUSY;

	/*
	 * Basic structure initialization.
	 */
	cam = kzalloc (sizeof(struct via_camera), GFP_KERNEL);
	if (cam == NULL)
		return -ENOMEM;
	via_cam_info = cam;
	cam->platdev = pdev;
	cam->viadev = viadev;
	cam->users = 0;
	cam->owner = NULL;
	cam->opstate = S_IDLE;
	cam->user_format = cam->sensor_format = viacam_def_pix_format;
	mutex_init(&cam->lock);
	INIT_LIST_HEAD(&cam->buffer_queue);
	cam->mmio = viadev->engine_mmio;
	cam->fbmem = viadev->fbmem;
	cam->fb_offset = viadev->camera_fbmem_offset;
	cam->flags = 1 << CF_CONFIG_NEEDED;
	cam->mbus_code = via_def_mbus_code;
	/*
	 * Tell V4L that we exist.
	 */
	ret = v4l2_device_register(&pdev->dev, &cam->v4l2_dev);
	if (ret) {
		dev_err(&pdev->dev, "Unable to register v4l2 device\n");
		return ret;
	}
	/*
	 * Convince the system that we can do DMA.
	 */
	pdev->dev.dma_mask = &viadev->pdev->dma_mask;
	dma_set_mask(&pdev->dev, 0xffffffff);
	/*
	 * Fire up the capture port.  The write to 0x78 looks purely
	 * OLPCish; any system will need to tweak 0x1e.
	 */
	via_write_reg_mask(VIASR, 0x78, 0, 0x80);
	via_write_reg_mask(VIASR, 0x1e, 0xc0, 0xc0);
	/*
	 * Get the sensor powered up.
	 */
	ret = via_sensor_power_setup(cam);
	if (ret)
		goto out_unregister;
	via_sensor_power_up(cam);

	/*
	 * See if we can't find it on the bus.	The VIA_PORT_31 assumption
	 * is OLPC-specific.  0x42 assumption is ov7670-specific.
	 */
	sensor_adapter = viafb_find_i2c_adapter(VIA_PORT_31);
	cam->sensor = v4l2_i2c_new_subdev(&cam->v4l2_dev, sensor_adapter,
			"ov7670", 0x42 >> 1, NULL);
	if (cam->sensor == NULL) {
		dev_err(&pdev->dev, "Unable to find the sensor!\n");
		ret = -ENODEV;
		goto out_power_down;
	}
	/*
	 * Get the IRQ.
	 */
	viacam_int_disable(cam);
	ret = request_threaded_irq(viadev->pdev->irq, viacam_quick_irq,
			viacam_irq, IRQF_SHARED, "via-camera", cam);
	if (ret)
		goto out_power_down;
	/*
	 * Tell V4l2 that we exist.
	 */
	cam->vdev = viacam_v4l_template;
	cam->vdev.v4l2_dev = &cam->v4l2_dev;
	ret = video_register_device(&cam->vdev, VFL_TYPE_GRABBER, -1);
	if (ret)
		goto out_irq;
	video_set_drvdata(&cam->vdev, cam);

#ifdef CONFIG_PM
	/*
	 * Hook into PM events
	 */
	viacam_pm_hooks.private = cam;
	viafb_pm_register(&viacam_pm_hooks);
#endif

	/* Power the sensor down until somebody opens the device */
	via_sensor_power_down(cam);
	return 0;

out_irq:
	free_irq(viadev->pdev->irq, cam);
out_power_down:
	via_sensor_power_release(cam);
out_unregister:
	v4l2_device_unregister(&cam->v4l2_dev);
	return ret;
}

static __devexit int viacam_remove(struct platform_device *pdev)
{
	struct via_camera *cam = via_cam_info;
	struct viafb_dev *viadev = pdev->dev.platform_data;

	video_unregister_device(&cam->vdev);
	v4l2_device_unregister(&cam->v4l2_dev);
	free_irq(viadev->pdev->irq, cam);
	via_sensor_power_release(cam);
	via_cam_info = NULL;
	return 0;
}

static struct platform_driver viacam_driver = {
	.driver = {
		.name = "viafb-camera",
	},
	.probe = viacam_probe,
	.remove = viacam_remove,
};

static int viacam_init(void)
{
	return platform_driver_register(&viacam_driver);
}
module_init(viacam_init);

static void viacam_exit(void)
{
	platform_driver_unregister(&viacam_driver);
}
module_exit(viacam_exit);