Merge branch 'for-linus' of master.kernel.org:/pub/scm/linux/kernel/git/dtor/input

[pandora-kernel.git] / drivers / media / video / cafe_ccic.c

/*
 * A driver for the CMOS camera controller in the Marvell 88ALP01 "cafe"
 * multifunction chip.  Currently works with the Omnivision OV7670
 * sensor.
 *
 * Copyright 2006 One Laptop Per Child Association, Inc.
 *
 * Written by Jonathan Corbet, corbet@lwn.net.
 *
 * This file may be distributed under the terms of the GNU General
 * Public License, version 2.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/videodev2.h>
#include <media/v4l2-common.h>
#include <linux/device.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/dma-mapping.h>
#include <linux/delay.h>
#include <linux/debugfs.h>
#include <linux/jiffies.h>
#include <linux/vmalloc.h>

#include <asm/uaccess.h>
#include <asm/io.h>

#include "cafe_ccic-regs.h"

#define CAFE_VERSION 0x000001


/*
 * Parameters.
 */
MODULE_AUTHOR("Jonathan Corbet <corbet@lwn.net>");
MODULE_DESCRIPTION("Marvell 88ALP01 CMOS Camera Controller driver");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("Video");

/*
 * Internal DMA buffer management.  Since the controller cannot do S/G I/O,
 * we must have physically contiguous buffers to bring frames into.
 * These parameters control how many buffers we use, whether we
 * allocate them at load time (better chance of success, but nails down
 * memory) or when somebody tries to use the camera (riskier), and,
 * for load-time allocation, how big they should be.
 *
 * The controller can cycle through three buffers.  We could use
 * more by flipping pointers around, but it probably makes little
 * sense.
 */

#define MAX_DMA_BUFS 3
static int alloc_bufs_at_load = 0;
module_param(alloc_bufs_at_load, bool, 0444);
MODULE_PARM_DESC(alloc_bufs_at_load,
                "Non-zero value causes DMA buffers to be allocated at module "
                "load time.  This increases the chances of successfully getting "
                "those buffers, but at the cost of nailing down the memory from "
                "the outset.");

static int n_dma_bufs = 3;
module_param(n_dma_bufs, uint, 0644);
MODULE_PARM_DESC(n_dma_bufs,
                "The number of DMA buffers to allocate.  Can be either two "
                "(saves memory, makes timing tighter) or three.");

static int dma_buf_size = VGA_WIDTH * VGA_HEIGHT * 2;  /* Worst case */
module_param(dma_buf_size, uint, 0444);
MODULE_PARM_DESC(dma_buf_size,
                "The size of the allocated DMA buffers.  If actual operating "
                "parameters require larger buffers, an attempt to reallocate "
                "will be made.");

static int min_buffers = 1;
module_param(min_buffers, uint, 0644);
MODULE_PARM_DESC(min_buffers,
                "The minimum number of streaming I/O buffers we are willing "
                "to work with.");

static int max_buffers = 10;
module_param(max_buffers, uint, 0644);
MODULE_PARM_DESC(max_buffers,
                "The maximum number of streaming I/O buffers an application "
                "will be allowed to allocate.  These buffers are big and live "
                "in vmalloc space.");

static int flip = 0;
module_param(flip, bool, 0444);
MODULE_PARM_DESC(flip,
                "If set, the sensor will be instructed to flip the image "
                "vertically.");


enum cafe_state {
        S_NOTREADY,     /* Not yet initialized */
        S_IDLE,         /* Just hanging around */
        S_FLAKED,       /* Some sort of problem */
        S_SINGLEREAD,   /* In read() */
        S_SPECREAD,     /* Speculative read (for future read()) */
        S_STREAMING     /* Streaming data */
};

/*
 * Tracking of streaming I/O buffers.
 */
struct cafe_sio_buffer {
        struct list_head list;
        struct v4l2_buffer v4lbuf;
        char *buffer;   /* Where it lives in kernel space */
        int mapcount;
        struct cafe_camera *cam;
};

/*
 * A description of one of our devices.
 * Locking: controlled by s_mutex.  Certain fields, however, require
 *          the dev_lock spinlock; they are marked as such by comments.
 *          dev_lock is also required for access to device registers.
 */
struct cafe_camera
{
        enum cafe_state state;
        unsigned long flags;            /* Buffer status, mainly (dev_lock) */
        int users;                      /* How many open FDs */
        struct file *owner;             /* Who has data access (v4l2) */

        /*
         * Subsystem structures.
         */
        struct pci_dev *pdev;
        struct video_device v4ldev;
        struct i2c_adapter i2c_adapter;
        struct i2c_client *sensor;

        unsigned char __iomem *regs;
        struct list_head dev_list;      /* link to other devices */

        /* DMA buffers */
        unsigned int nbufs;             /* How many are alloc'd */
        int next_buf;                   /* Next to consume (dev_lock) */
        unsigned int dma_buf_size;      /* allocated size */
        void *dma_bufs[MAX_DMA_BUFS];   /* Internal buffer addresses */
        dma_addr_t dma_handles[MAX_DMA_BUFS]; /* Buffer bus addresses */
        unsigned int specframes;        /* Unconsumed spec frames (dev_lock) */
        unsigned int sequence;          /* Frame sequence number */
        unsigned int buf_seq[MAX_DMA_BUFS]; /* Sequence for individual buffers */

        /* Streaming buffers */
        unsigned int n_sbufs;           /* How many we have */
        struct cafe_sio_buffer *sb_bufs; /* The array of housekeeping structs */
        struct list_head sb_avail;      /* Available for data (we own) (dev_lock) */
        struct list_head sb_full;       /* With data (user space owns) (dev_lock) */
        struct tasklet_struct s_tasklet;

        /* Current operating parameters */
        enum v4l2_chip_ident sensor_type;               /* Currently ov7670 only */
        struct v4l2_pix_format pix_format;

        /* Locks */
        struct mutex s_mutex; /* Access to this structure */
        spinlock_t dev_lock;  /* Access to device */

        /* Misc */
        wait_queue_head_t smbus_wait;   /* Waiting on i2c events */
        wait_queue_head_t iowait;       /* Waiting on frame data */
#ifdef CONFIG_VIDEO_ADV_DEBUG
        struct dentry *dfs_regs;
        struct dentry *dfs_cam_regs;
#endif
};

/*
 * Status flags.  Always manipulated with bit operations.
 */
#define CF_BUF0_VALID    0      /* Buffers valid - first three */
#define CF_BUF1_VALID    1
#define CF_BUF2_VALID    2
#define CF_DMA_ACTIVE    3      /* A frame is incoming */
#define CF_CONFIG_NEEDED 4      /* Must configure hardware */



/*
 * Start over with DMA buffers - dev_lock needed.
 */
static void cafe_reset_buffers(struct cafe_camera *cam)
{
        int i;

        cam->next_buf = -1;
        for (i = 0; i < cam->nbufs; i++)
                clear_bit(i, &cam->flags);
        cam->specframes = 0;
}

static inline int cafe_needs_config(struct cafe_camera *cam)
{
        return test_bit(CF_CONFIG_NEEDED, &cam->flags);
}

static void cafe_set_config_needed(struct cafe_camera *cam, int needed)
{
        if (needed)
                set_bit(CF_CONFIG_NEEDED, &cam->flags);
        else
                clear_bit(CF_CONFIG_NEEDED, &cam->flags);
}




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


/* ---------------------------------------------------------------------*/
/*
 * We keep a simple list of known devices to search at open time.
 */
static LIST_HEAD(cafe_dev_list);
static DEFINE_MUTEX(cafe_dev_list_lock);

static void cafe_add_dev(struct cafe_camera *cam)
{
        mutex_lock(&cafe_dev_list_lock);
        list_add_tail(&cam->dev_list, &cafe_dev_list);
        mutex_unlock(&cafe_dev_list_lock);
}

static void cafe_remove_dev(struct cafe_camera *cam)
{
        mutex_lock(&cafe_dev_list_lock);
        list_del(&cam->dev_list);
        mutex_unlock(&cafe_dev_list_lock);
}

static struct cafe_camera *cafe_find_dev(int minor)
{
        struct cafe_camera *cam;

        mutex_lock(&cafe_dev_list_lock);
        list_for_each_entry(cam, &cafe_dev_list, dev_list) {
                if (cam->v4ldev.minor == minor)
                        goto done;
        }
        cam = NULL;
  done:
        mutex_unlock(&cafe_dev_list_lock);
        return cam;
}


static struct cafe_camera *cafe_find_by_pdev(struct pci_dev *pdev)
{
        struct cafe_camera *cam;

        mutex_lock(&cafe_dev_list_lock);
        list_for_each_entry(cam, &cafe_dev_list, dev_list) {
                if (cam->pdev == pdev)
                        goto done;
        }
        cam = NULL;
  done:
        mutex_unlock(&cafe_dev_list_lock);
        return cam;
}


/* ------------------------------------------------------------------------ */
/*
 * Device register I/O
 */
static inline void cafe_reg_write(struct cafe_camera *cam, unsigned int reg,
                unsigned int val)
{
        iowrite32(val, cam->regs + reg);
}

static inline unsigned int cafe_reg_read(struct cafe_camera *cam,
                unsigned int reg)
{
        return ioread32(cam->regs + reg);
}


static inline void cafe_reg_write_mask(struct cafe_camera *cam, unsigned int reg,
                unsigned int val, unsigned int mask)
{
        unsigned int v = cafe_reg_read(cam, reg);

        v = (v & ~mask) | (val & mask);
        cafe_reg_write(cam, reg, v);
}

static inline void cafe_reg_clear_bit(struct cafe_camera *cam,
                unsigned int reg, unsigned int val)
{
        cafe_reg_write_mask(cam, reg, 0, val);
}

static inline void cafe_reg_set_bit(struct cafe_camera *cam,
                unsigned int reg, unsigned int val)
{
        cafe_reg_write_mask(cam, reg, val, val);
}



/* -------------------------------------------------------------------- */
/*
 * The I2C/SMBUS interface to the camera itself starts here.  The
 * controller handles SMBUS itself, presenting a relatively simple register
 * interface; all we have to do is to tell it where to route the data.
 */
#define CAFE_SMBUS_TIMEOUT (HZ)  /* generous */

static int cafe_smbus_write_done(struct cafe_camera *cam)
{
        unsigned long flags;
        int c1;

        /*
         * We must delay after the interrupt, or the controller gets confused
         * and never does give us good status.  Fortunately, we don't do this
         * often.
         */
        udelay(20);
        spin_lock_irqsave(&cam->dev_lock, flags);
        c1 = cafe_reg_read(cam, REG_TWSIC1);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
        return (c1 & (TWSIC1_WSTAT|TWSIC1_ERROR)) != TWSIC1_WSTAT;
}

static int cafe_smbus_write_data(struct cafe_camera *cam,
                u16 addr, u8 command, u8 value)
{
        unsigned int rval;
        unsigned long flags;

        spin_lock_irqsave(&cam->dev_lock, flags);
        rval = TWSIC0_EN | ((addr << TWSIC0_SID_SHIFT) & TWSIC0_SID);
        rval |= TWSIC0_OVMAGIC;  /* Make OV sensors work */
        /*
         * Marvell sez set clkdiv to all 1's for now.
         */
        rval |= TWSIC0_CLKDIV;
        cafe_reg_write(cam, REG_TWSIC0, rval);
        (void) cafe_reg_read(cam, REG_TWSIC1); /* force write */
        rval = value | ((command << TWSIC1_ADDR_SHIFT) & TWSIC1_ADDR);
        cafe_reg_write(cam, REG_TWSIC1, rval);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
        msleep(2); /* Required or things flake */

        wait_event_timeout(cam->smbus_wait, cafe_smbus_write_done(cam),
                        CAFE_SMBUS_TIMEOUT);
        spin_lock_irqsave(&cam->dev_lock, flags);
        rval = cafe_reg_read(cam, REG_TWSIC1);
        spin_unlock_irqrestore(&cam->dev_lock, flags);

        if (rval & TWSIC1_WSTAT) {
                cam_err(cam, "SMBUS write (%02x/%02x/%02x) timed out\n", addr,
                                command, value);
                return -EIO;
        }
        if (rval & TWSIC1_ERROR) {
                cam_err(cam, "SMBUS write (%02x/%02x/%02x) error\n", addr,
                                command, value);
                return -EIO;
        }
        return 0;
}



static int cafe_smbus_read_done(struct cafe_camera *cam)
{
        unsigned long flags;
        int c1;

        /*
         * We must delay after the interrupt, or the controller gets confused
         * and never does give us good status.  Fortunately, we don't do this
         * often.
         */
        udelay(20);
        spin_lock_irqsave(&cam->dev_lock, flags);
        c1 = cafe_reg_read(cam, REG_TWSIC1);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
        return c1 & (TWSIC1_RVALID|TWSIC1_ERROR);
}



static int cafe_smbus_read_data(struct cafe_camera *cam,
                u16 addr, u8 command, u8 *value)
{
        unsigned int rval;
        unsigned long flags;

        spin_lock_irqsave(&cam->dev_lock, flags);
        rval = TWSIC0_EN | ((addr << TWSIC0_SID_SHIFT) & TWSIC0_SID);
        rval |= TWSIC0_OVMAGIC; /* Make OV sensors work */
        /*
         * Marvel sez set clkdiv to all 1's for now.
         */
        rval |= TWSIC0_CLKDIV;
        cafe_reg_write(cam, REG_TWSIC0, rval);
        (void) cafe_reg_read(cam, REG_TWSIC1); /* force write */
        rval = TWSIC1_READ | ((command << TWSIC1_ADDR_SHIFT) & TWSIC1_ADDR);
        cafe_reg_write(cam, REG_TWSIC1, rval);
        spin_unlock_irqrestore(&cam->dev_lock, flags);

        wait_event_timeout(cam->smbus_wait,
                        cafe_smbus_read_done(cam), CAFE_SMBUS_TIMEOUT);
        spin_lock_irqsave(&cam->dev_lock, flags);
        rval = cafe_reg_read(cam, REG_TWSIC1);
        spin_unlock_irqrestore(&cam->dev_lock, flags);

        if (rval & TWSIC1_ERROR) {
                cam_err(cam, "SMBUS read (%02x/%02x) error\n", addr, command);
                return -EIO;
        }
        if (! (rval & TWSIC1_RVALID)) {
                cam_err(cam, "SMBUS read (%02x/%02x) timed out\n", addr,
                                command);
                return -EIO;
        }
        *value = rval & 0xff;
        return 0;
}

/*
 * Perform a transfer over SMBUS.  This thing is called under
 * the i2c bus lock, so we shouldn't race with ourselves...
 */
static int cafe_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
                unsigned short flags, char rw, u8 command,
                int size, union i2c_smbus_data *data)
{
        struct cafe_camera *cam = i2c_get_adapdata(adapter);
        int ret = -EINVAL;

        /*
         * Refuse to talk to anything but OV cam chips.  We should
         * never even see an attempt to do so, but one never knows.
         */
        if (cam->sensor && addr != cam->sensor->addr) {
                cam_err(cam, "funky smbus addr %d\n", addr);
                return -EINVAL;
        }
        /*
         * This interface would appear to only do byte data ops.  OK
         * it can do word too, but the cam chip has no use for that.
         */
        if (size != I2C_SMBUS_BYTE_DATA) {
                cam_err(cam, "funky xfer size %d\n", size);
                return -EINVAL;
        }

        if (rw == I2C_SMBUS_WRITE)
                ret = cafe_smbus_write_data(cam, addr, command, data->byte);
        else if (rw == I2C_SMBUS_READ)
                ret = cafe_smbus_read_data(cam, addr, command, &data->byte);
        return ret;
}


static void cafe_smbus_enable_irq(struct cafe_camera *cam)
{
        unsigned long flags;

        spin_lock_irqsave(&cam->dev_lock, flags);
        cafe_reg_set_bit(cam, REG_IRQMASK, TWSIIRQS);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
}

static u32 cafe_smbus_func(struct i2c_adapter *adapter)
{
        return I2C_FUNC_SMBUS_READ_BYTE_DATA  |
               I2C_FUNC_SMBUS_WRITE_BYTE_DATA;
}

static struct i2c_algorithm cafe_smbus_algo = {
        .smbus_xfer = cafe_smbus_xfer,
        .functionality = cafe_smbus_func
};

/* Somebody is on the bus */
static int cafe_cam_init(struct cafe_camera *cam);
static void cafe_ctlr_stop_dma(struct cafe_camera *cam);
static void cafe_ctlr_power_down(struct cafe_camera *cam);

static int cafe_smbus_attach(struct i2c_client *client)
{
        struct cafe_camera *cam = i2c_get_adapdata(client->adapter);

        /*
         * Don't talk to chips we don't recognize.
         */
        if (client->driver->id == I2C_DRIVERID_OV7670) {
                cam->sensor = client;
                return cafe_cam_init(cam);
        }
        return -EINVAL;
}

static int cafe_smbus_detach(struct i2c_client *client)
{
        struct cafe_camera *cam = i2c_get_adapdata(client->adapter);

        if (cam->sensor == client) {
                cafe_ctlr_stop_dma(cam);
                cafe_ctlr_power_down(cam);
                cam_err(cam, "lost the sensor!\n");
                cam->sensor = NULL;  /* Bummer, no camera */
                cam->state = S_NOTREADY;
        }
        return 0;
}

static int cafe_smbus_setup(struct cafe_camera *cam)
{
        struct i2c_adapter *adap = &cam->i2c_adapter;
        int ret;

        cafe_smbus_enable_irq(cam);
        adap->id = I2C_HW_SMBUS_CAFE;
        adap->class = I2C_CLASS_CAM_DIGITAL;
        adap->owner = THIS_MODULE;
        adap->client_register = cafe_smbus_attach;
        adap->client_unregister = cafe_smbus_detach;
        adap->algo = &cafe_smbus_algo;
        strcpy(adap->name, "cafe_ccic");
        adap->dev.parent = &cam->pdev->dev;
        i2c_set_adapdata(adap, cam);
        ret = i2c_add_adapter(adap);
        if (ret)
                printk(KERN_ERR "Unable to register cafe i2c adapter\n");
        return ret;
}

static void cafe_smbus_shutdown(struct cafe_camera *cam)
{
        i2c_del_adapter(&cam->i2c_adapter);
}


/* ------------------------------------------------------------------- */
/*
 * Deal with the controller.
 */

/*
 * Do everything we think we need to have the interface operating
 * according to the desired format.
 */
static void cafe_ctlr_dma(struct cafe_camera *cam)
{
        /*
         * Store the first two Y buffers (we aren't supporting
         * planar formats for now, so no UV bufs).  Then either
         * set the third if it exists, or tell the controller
         * to just use two.
         */
        cafe_reg_write(cam, REG_Y0BAR, cam->dma_handles[0]);
        cafe_reg_write(cam, REG_Y1BAR, cam->dma_handles[1]);
        if (cam->nbufs > 2) {
                cafe_reg_write(cam, REG_Y2BAR, cam->dma_handles[2]);
                cafe_reg_clear_bit(cam, REG_CTRL1, C1_TWOBUFS);
        }
        else
                cafe_reg_set_bit(cam, REG_CTRL1, C1_TWOBUFS);
        cafe_reg_write(cam, REG_UBAR, 0); /* 32 bits only for now */
}

static void cafe_ctlr_image(struct cafe_camera *cam)
{
        int imgsz;
        struct v4l2_pix_format *fmt = &cam->pix_format;

        imgsz = ((fmt->height << IMGSZ_V_SHIFT) & IMGSZ_V_MASK) |
                (fmt->bytesperline & IMGSZ_H_MASK);
        cafe_reg_write(cam, REG_IMGSIZE, imgsz);
        cafe_reg_write(cam, REG_IMGOFFSET, 0);
        /* YPITCH just drops the last two bits */
        cafe_reg_write_mask(cam, REG_IMGPITCH, fmt->bytesperline,
                        IMGP_YP_MASK);
        /*
         * Tell the controller about the image format we are using.
         */
        switch (cam->pix_format.pixelformat) {
        case V4L2_PIX_FMT_YUYV:
            cafe_reg_write_mask(cam, REG_CTRL0,
                            C0_DF_YUV|C0_YUV_PACKED|C0_YUVE_YUYV,
                            C0_DF_MASK);
            break;

        case V4L2_PIX_FMT_RGB444:
            cafe_reg_write_mask(cam, REG_CTRL0,
                            C0_DF_RGB|C0_RGBF_444|C0_RGB4_XRGB,
                            C0_DF_MASK);
                /* Alpha value? */
            break;

        case V4L2_PIX_FMT_RGB565:
            cafe_reg_write_mask(cam, REG_CTRL0,
                            C0_DF_RGB|C0_RGBF_565|C0_RGB5_BGGR,
                            C0_DF_MASK);
            break;

        default:
            cam_err(cam, "Unknown format %x\n", cam->pix_format.pixelformat);
            break;
        }
        /*
         * Make sure it knows we want to use hsync/vsync.
         */
        cafe_reg_write_mask(cam, REG_CTRL0, C0_SIF_HVSYNC,
                        C0_SIFM_MASK);
}


/*
 * Configure the controller for operation; caller holds the
 * device mutex.
 */
static int cafe_ctlr_configure(struct cafe_camera *cam)
{
        unsigned long flags;

        spin_lock_irqsave(&cam->dev_lock, flags);
        cafe_ctlr_dma(cam);
        cafe_ctlr_image(cam);
        cafe_set_config_needed(cam, 0);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
        return 0;
}

static void cafe_ctlr_irq_enable(struct cafe_camera *cam)
{
        /*
         * Clear any pending interrupts, since we do not
         * expect to have I/O active prior to enabling.
         */
        cafe_reg_write(cam, REG_IRQSTAT, FRAMEIRQS);
        cafe_reg_set_bit(cam, REG_IRQMASK, FRAMEIRQS);
}

static void cafe_ctlr_irq_disable(struct cafe_camera *cam)
{
        cafe_reg_clear_bit(cam, REG_IRQMASK, FRAMEIRQS);
}

/*
 * Make the controller start grabbing images.  Everything must
 * be set up before doing this.
 */
static void cafe_ctlr_start(struct cafe_camera *cam)
{
        /* set_bit performs a read, so no other barrier should be
           needed here */
        cafe_reg_set_bit(cam, REG_CTRL0, C0_ENABLE);
}

static void cafe_ctlr_stop(struct cafe_camera *cam)
{
        cafe_reg_clear_bit(cam, REG_CTRL0, C0_ENABLE);
}

static void cafe_ctlr_init(struct cafe_camera *cam)
{
        unsigned long flags;

        spin_lock_irqsave(&cam->dev_lock, flags);
        /*
         * Added magic to bring up the hardware on the B-Test board
         */
        cafe_reg_write(cam, 0x3038, 0x8);
        cafe_reg_write(cam, 0x315c, 0x80008);
        /*
         * Go through the dance needed to wake the device up.
         * Note that these registers are global and shared
         * with the NAND and SD devices.  Interaction between the
         * three still needs to be examined.
         */
        cafe_reg_write(cam, REG_GL_CSR, GCSR_SRS|GCSR_MRS); /* Needed? */
        cafe_reg_write(cam, REG_GL_CSR, GCSR_SRC|GCSR_MRC);
        cafe_reg_write(cam, REG_GL_CSR, GCSR_SRC|GCSR_MRS);
        mdelay(5);      /* FIXME revisit this */
        cafe_reg_write(cam, REG_GL_CSR, GCSR_CCIC_EN|GCSR_SRC|GCSR_MRC);
        cafe_reg_set_bit(cam, REG_GL_IMASK, GIMSK_CCIC_EN);
        /*
         * Make sure it's not powered down.
         */
        cafe_reg_clear_bit(cam, REG_CTRL1, C1_PWRDWN);
        /*
         * Turn off the enable bit.  It sure should be off anyway,
         * but it's good to be sure.
         */
        cafe_reg_clear_bit(cam, REG_CTRL0, C0_ENABLE);
        /*
         * Mask all interrupts.
         */
        cafe_reg_write(cam, REG_IRQMASK, 0);
        /*
         * Clock the sensor appropriately.  Controller clock should
         * be 48MHz, sensor "typical" value is half that.
         */
        cafe_reg_write_mask(cam, REG_CLKCTRL, 2, CLK_DIV_MASK);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
}


/*
 * Stop the controller, and don't return until we're really sure that no
 * further DMA is going on.
 */
static void cafe_ctlr_stop_dma(struct cafe_camera *cam)
{
        unsigned long flags;

        /*
         * Theory: stop the camera controller (whether it is operating
         * or not).  Delay briefly just in case we race with the SOF
         * interrupt, then wait until no DMA is active.
         */
        spin_lock_irqsave(&cam->dev_lock, flags);
        cafe_ctlr_stop(cam);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
        mdelay(1);
        wait_event_timeout(cam->iowait,
                        !test_bit(CF_DMA_ACTIVE, &cam->flags), HZ);
        if (test_bit(CF_DMA_ACTIVE, &cam->flags))
                cam_err(cam, "Timeout waiting for DMA to end\n");
                /* This would be bad news - what now? */
        spin_lock_irqsave(&cam->dev_lock, flags);
        cam->state = S_IDLE;
        cafe_ctlr_irq_disable(cam);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
}

/*
 * Power up and down.
 */
static void cafe_ctlr_power_up(struct cafe_camera *cam)
{
        unsigned long flags;

        spin_lock_irqsave(&cam->dev_lock, flags);
        cafe_reg_clear_bit(cam, REG_CTRL1, C1_PWRDWN);
        /*
         * Put the sensor into operational mode (assumes OLPC-style
         * wiring).  Control 0 is reset - set to 1 to operate.
         * Control 1 is power down, set to 0 to operate.
         */
        cafe_reg_write(cam, REG_GPR, GPR_C1EN|GPR_C0EN); /* pwr up, reset */
        mdelay(1); /* Marvell says 1ms will do it */
        cafe_reg_write(cam, REG_GPR, GPR_C1EN|GPR_C0EN|GPR_C0);
        mdelay(1); /* Enough? */
        spin_unlock_irqrestore(&cam->dev_lock, flags);
}

static void cafe_ctlr_power_down(struct cafe_camera *cam)
{
        unsigned long flags;

        spin_lock_irqsave(&cam->dev_lock, flags);
        cafe_reg_write(cam, REG_GPR, GPR_C1EN|GPR_C0EN|GPR_C1);
        cafe_reg_set_bit(cam, REG_CTRL1, C1_PWRDWN);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
}

/* -------------------------------------------------------------------- */
/*
 * Communications with the sensor.
 */

static int __cafe_cam_cmd(struct cafe_camera *cam, int cmd, void *arg)
{
        struct i2c_client *sc = cam->sensor;
        int ret;

        if (sc == NULL || sc->driver == NULL || sc->driver->command == NULL)
                return -EINVAL;
        ret = sc->driver->command(sc, cmd, arg);
        if (ret == -EPERM) /* Unsupported command */
                return 0;
        return ret;
}

static int __cafe_cam_reset(struct cafe_camera *cam)
{
        int zero = 0;
        return __cafe_cam_cmd(cam, VIDIOC_INT_RESET, &zero);
}

/*
 * We have found the sensor on the i2c.  Let's try to have a
 * conversation.
 */
static int cafe_cam_init(struct cafe_camera *cam)
{
        int ret;

        mutex_lock(&cam->s_mutex);
        if (cam->state != S_NOTREADY)
                cam_warn(cam, "Cam init with device in funky state %d",
                                cam->state);
        ret = __cafe_cam_reset(cam);
        if (ret)
                goto out;
        ret = __cafe_cam_cmd(cam, VIDIOC_INT_G_CHIP_IDENT, &cam->sensor_type);
        if (ret)
                goto out;
//      if (cam->sensor->addr != OV7xx0_SID) {
        if (cam->sensor_type != V4L2_IDENT_OV7670) {
                cam_err(cam, "Unsupported sensor type %d", cam->sensor->addr);
                ret = -EINVAL;
                goto out;
        }
/* Get/set parameters? */
        ret = 0;
        cam->state = S_IDLE;
  out:
        mutex_unlock(&cam->s_mutex);
        return ret;
}

/*
 * Configure the sensor to match the parameters we have.  Caller should
 * hold s_mutex
 */
static int cafe_cam_set_flip(struct cafe_camera *cam)
{
        struct v4l2_control ctrl;

        memset(&ctrl, 0, sizeof(ctrl));
        ctrl.id = V4L2_CID_VFLIP;
        ctrl.value = flip;
        return __cafe_cam_cmd(cam, VIDIOC_S_CTRL, &ctrl);
}


static int cafe_cam_configure(struct cafe_camera *cam)
{
        struct v4l2_format fmt;
        int ret, zero = 0;

        if (cam->state != S_IDLE)
                return -EINVAL;
        fmt.fmt.pix = cam->pix_format;
        ret = __cafe_cam_cmd(cam, VIDIOC_INT_INIT, &zero);
        if (ret == 0)
                ret = __cafe_cam_cmd(cam, VIDIOC_S_FMT, &fmt);
        /*
         * OV7670 does weird things if flip is set *before* format...
         */
        ret += cafe_cam_set_flip(cam);
        return ret;
}

/* -------------------------------------------------------------------- */
/*
 * DMA buffer management.  These functions need s_mutex held.
 */

/* FIXME: this is inefficient as hell, since dma_alloc_coherent just
 * does a get_free_pages() call, and we waste a good chunk of an orderN
 * allocation.  Should try to allocate the whole set in one chunk.
 */
static int cafe_alloc_dma_bufs(struct cafe_camera *cam, int loadtime)
{
        int i;

        cafe_set_config_needed(cam, 1);
        if (loadtime)
                cam->dma_buf_size = dma_buf_size;
        else
                cam->dma_buf_size = cam->pix_format.sizeimage;
        if (n_dma_bufs > 3)
                n_dma_bufs = 3;

        cam->nbufs = 0;
        for (i = 0; i < n_dma_bufs; i++) {
                cam->dma_bufs[i] = dma_alloc_coherent(&cam->pdev->dev,
                                cam->dma_buf_size, cam->dma_handles + i,
                                GFP_KERNEL);
                if (cam->dma_bufs[i] == NULL) {
                        cam_warn(cam, "Failed to allocate DMA buffer\n");
                        break;
                }
                /* For debug, remove eventually */
                memset(cam->dma_bufs[i], 0xcc, cam->dma_buf_size);
                (cam->nbufs)++;
        }

        switch (cam->nbufs) {
        case 1:
            dma_free_coherent(&cam->pdev->dev, cam->dma_buf_size,
                            cam->dma_bufs[0], cam->dma_handles[0]);
            cam->nbufs = 0;
        case 0:
            cam_err(cam, "Insufficient DMA buffers, cannot operate\n");
            return -ENOMEM;

        case 2:
            if (n_dma_bufs > 2)
                    cam_warn(cam, "Will limp along with only 2 buffers\n");
            break;
        }
        return 0;
}

static void cafe_free_dma_bufs(struct cafe_camera *cam)
{
        int i;

        for (i = 0; i < cam->nbufs; i++) {
                dma_free_coherent(&cam->pdev->dev, cam->dma_buf_size,
                                cam->dma_bufs[i], cam->dma_handles[i]);
                cam->dma_bufs[i] = NULL;
        }
        cam->nbufs = 0;
}





/* ----------------------------------------------------------------------- */
/*
 * Here starts the V4L2 interface code.
 */

/*
 * Read an image from the device.
 */
static ssize_t cafe_deliver_buffer(struct cafe_camera *cam,
                char __user *buffer, size_t len, loff_t *pos)
{
        int bufno;
        unsigned long flags;

        spin_lock_irqsave(&cam->dev_lock, flags);
        if (cam->next_buf < 0) {
                cam_err(cam, "deliver_buffer: No next buffer\n");
                spin_unlock_irqrestore(&cam->dev_lock, flags);
                return -EIO;
        }
        bufno = cam->next_buf;
        clear_bit(bufno, &cam->flags);
        if (++(cam->next_buf) >= cam->nbufs)
                cam->next_buf = 0;
        if (! test_bit(cam->next_buf, &cam->flags))
                cam->next_buf = -1;
        cam->specframes = 0;
        spin_unlock_irqrestore(&cam->dev_lock, flags);

        if (len > cam->pix_format.sizeimage)
                len = cam->pix_format.sizeimage;
        if (copy_to_user(buffer, cam->dma_bufs[bufno], len))
                return -EFAULT;
        (*pos) += len;
        return len;
}

/*
 * Get everything ready, and start grabbing frames.
 */
static int cafe_read_setup(struct cafe_camera *cam, enum cafe_state state)
{
        int ret;
        unsigned long flags;

        /*
         * Configuration.  If we still don't have DMA buffers,
         * make one last, desperate attempt.
         */
        if (cam->nbufs == 0)
                if (cafe_alloc_dma_bufs(cam, 0))
                        return -ENOMEM;

        if (cafe_needs_config(cam)) {
                cafe_cam_configure(cam);
                ret = cafe_ctlr_configure(cam);
                if (ret)
                        return ret;
        }

        /*
         * Turn it loose.
         */
        spin_lock_irqsave(&cam->dev_lock, flags);
        cafe_reset_buffers(cam);
        cafe_ctlr_irq_enable(cam);
        cam->state = state;
        cafe_ctlr_start(cam);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
        return 0;
}


static ssize_t cafe_v4l_read(struct file *filp,
                char __user *buffer, size_t len, loff_t *pos)
{
        struct cafe_camera *cam = filp->private_data;
        int ret = 0;

        /*
         * Perhaps we're in speculative read mode and already
         * have data?
         */
        mutex_lock(&cam->s_mutex);
        if (cam->state == S_SPECREAD) {
                if (cam->next_buf >= 0) {
                        ret = cafe_deliver_buffer(cam, buffer, len, pos);
                        if (ret != 0)
                                goto out_unlock;
                }
        } else if (cam->state == S_FLAKED || cam->state == S_NOTREADY) {
                ret = -EIO;
                goto out_unlock;
        } else if (cam->state != S_IDLE) {
                ret = -EBUSY;
                goto out_unlock;
        }

        /*
         * v4l2: multiple processes can open the device, but only
         * one gets to grab data from it.
         */
        if (cam->owner && cam->owner != filp) {
                ret = -EBUSY;
                goto out_unlock;
        }
        cam->owner = filp;

        /*
         * Do setup if need be.
         */
        if (cam->state != S_SPECREAD) {
                ret = cafe_read_setup(cam, S_SINGLEREAD);
                if (ret)
                        goto out_unlock;
        }
        /*
         * Wait for something to happen.  This should probably
         * be interruptible (FIXME).
         */
        wait_event_timeout(cam->iowait, cam->next_buf >= 0, HZ);
        if (cam->next_buf < 0) {
                cam_err(cam, "read() operation timed out\n");
                cafe_ctlr_stop_dma(cam);
                ret = -EIO;
                goto out_unlock;
        }
        /*
         * Give them their data and we should be done.
         */
        ret = cafe_deliver_buffer(cam, buffer, len, pos);

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








/*
 * Streaming I/O support.
 */



static int cafe_vidioc_streamon(struct file *filp, void *priv,
                enum v4l2_buf_type type)
{
        struct cafe_camera *cam = filp->private_data;
        int ret = -EINVAL;

        if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                goto out;
        mutex_lock(&cam->s_mutex);
        if (cam->state != S_IDLE || cam->n_sbufs == 0)
                goto out_unlock;

        cam->sequence = 0;
        ret = cafe_read_setup(cam, S_STREAMING);

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


static int cafe_vidioc_streamoff(struct file *filp, void *priv,
                enum v4l2_buf_type type)
{
        struct cafe_camera *cam = filp->private_data;
        int ret = -EINVAL;

        if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                goto out;
        mutex_lock(&cam->s_mutex);
        if (cam->state != S_STREAMING)
                goto out_unlock;

        cafe_ctlr_stop_dma(cam);
        ret = 0;

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



static int cafe_setup_siobuf(struct cafe_camera *cam, int index)
{
        struct cafe_sio_buffer *buf = cam->sb_bufs + index;

        INIT_LIST_HEAD(&buf->list);
        buf->v4lbuf.length = PAGE_ALIGN(cam->pix_format.sizeimage);
        buf->buffer = vmalloc_user(buf->v4lbuf.length);
        if (buf->buffer == NULL)
                return -ENOMEM;
        buf->mapcount = 0;
        buf->cam = cam;

        buf->v4lbuf.index = index;
        buf->v4lbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf->v4lbuf.field = V4L2_FIELD_NONE;
        buf->v4lbuf.memory = V4L2_MEMORY_MMAP;
        /*
         * Offset: must be 32-bit even on a 64-bit system.  video-buf
         * just uses the length times the index, but the spec warns
         * against doing just that - vma merging problems.  So we
         * leave a gap between each pair of buffers.
         */
        buf->v4lbuf.m.offset = 2*index*buf->v4lbuf.length;
        return 0;
}

static int cafe_free_sio_buffers(struct cafe_camera *cam)
{
        int i;

        /*
         * If any buffers are mapped, we cannot free them at all.
         */
        for (i = 0; i < cam->n_sbufs; i++)
                if (cam->sb_bufs[i].mapcount > 0)
                        return -EBUSY;
        /*
         * OK, let's do it.
         */
        for (i = 0; i < cam->n_sbufs; i++)
                vfree(cam->sb_bufs[i].buffer);
        cam->n_sbufs = 0;
        kfree(cam->sb_bufs);
        cam->sb_bufs = NULL;
        INIT_LIST_HEAD(&cam->sb_avail);
        INIT_LIST_HEAD(&cam->sb_full);
        return 0;
}



static int cafe_vidioc_reqbufs(struct file *filp, void *priv,
                struct v4l2_requestbuffers *req)
{
        struct cafe_camera *cam = filp->private_data;
        int ret = 0;  /* Silence warning */

        /*
         * Make sure it's something we can do.  User pointers could be
         * implemented without great pain, but that's not been done yet.
         */
        if (req->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;
        if (req->memory != V4L2_MEMORY_MMAP)
                return -EINVAL;
        /*
         * If they ask for zero buffers, they really want us to stop streaming
         * (if it's happening) and free everything.  Should we check owner?
         */
        mutex_lock(&cam->s_mutex);
        if (req->count == 0) {
                if (cam->state == S_STREAMING)
                        cafe_ctlr_stop_dma(cam);
                ret = cafe_free_sio_buffers (cam);
                goto out;
        }
        /*
         * Device needs to be idle and working.  We *could* try to do the
         * right thing in S_SPECREAD by shutting things down, but it
         * probably doesn't matter.
         */
        if (cam->state != S_IDLE || (cam->owner && cam->owner != filp)) {
                ret = -EBUSY;
                goto out;
        }
        cam->owner = filp;

        if (req->count < min_buffers)
                req->count = min_buffers;
        else if (req->count > max_buffers)
                req->count = max_buffers;
        if (cam->n_sbufs > 0) {
                ret = cafe_free_sio_buffers(cam);
                if (ret)
                        goto out;
        }

        cam->sb_bufs = kzalloc(req->count*sizeof(struct cafe_sio_buffer),
                        GFP_KERNEL);
        if (cam->sb_bufs == NULL) {
                ret = -ENOMEM;
                goto out;
        }
        for (cam->n_sbufs = 0; cam->n_sbufs < req->count; (cam->n_sbufs++)) {
                ret = cafe_setup_siobuf(cam, cam->n_sbufs);
                if (ret)
                        break;
        }

        if (cam->n_sbufs == 0)  /* no luck at all - ret already set */
                kfree(cam->sb_bufs);
        req->count = cam->n_sbufs;  /* In case of partial success */

  out:
        mutex_unlock(&cam->s_mutex);
        return ret;
}


static int cafe_vidioc_querybuf(struct file *filp, void *priv,
                struct v4l2_buffer *buf)
{
        struct cafe_camera *cam = filp->private_data;
        int ret = -EINVAL;

        mutex_lock(&cam->s_mutex);
        if (buf->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                goto out;
        if (buf->index < 0 || buf->index >= cam->n_sbufs)
                goto out;
        *buf = cam->sb_bufs[buf->index].v4lbuf;
        ret = 0;
  out:
        mutex_unlock(&cam->s_mutex);
        return ret;
}

static int cafe_vidioc_qbuf(struct file *filp, void *priv,
                struct v4l2_buffer *buf)
{
        struct cafe_camera *cam = filp->private_data;
        struct cafe_sio_buffer *sbuf;
        int ret = -EINVAL;
        unsigned long flags;

        mutex_lock(&cam->s_mutex);
        if (buf->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                goto out;
        if (buf->index < 0 || buf->index >= cam->n_sbufs)
                goto out;
        sbuf = cam->sb_bufs + buf->index;
        if (sbuf->v4lbuf.flags & V4L2_BUF_FLAG_QUEUED) {
                ret = 0; /* Already queued?? */
                goto out;
        }
        if (sbuf->v4lbuf.flags & V4L2_BUF_FLAG_DONE) {
                /* Spec doesn't say anything, seems appropriate tho */
                ret = -EBUSY;
                goto out;
        }
        sbuf->v4lbuf.flags |= V4L2_BUF_FLAG_QUEUED;
        spin_lock_irqsave(&cam->dev_lock, flags);
        list_add(&sbuf->list, &cam->sb_avail);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
        ret = 0;
  out:
        mutex_unlock(&cam->s_mutex);
        return ret;
}

static int cafe_vidioc_dqbuf(struct file *filp, void *priv,
                struct v4l2_buffer *buf)
{
        struct cafe_camera *cam = filp->private_data;
        struct cafe_sio_buffer *sbuf;
        int ret = -EINVAL;
        unsigned long flags;

        mutex_lock(&cam->s_mutex);
        if (buf->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                goto out_unlock;
        if (cam->state != S_STREAMING)
                goto out_unlock;
        if (list_empty(&cam->sb_full) && filp->f_flags & O_NONBLOCK) {
                ret = -EAGAIN;
                goto out_unlock;
        }

        while (list_empty(&cam->sb_full) && cam->state == S_STREAMING) {
                mutex_unlock(&cam->s_mutex);
                if (wait_event_interruptible(cam->iowait,
                                                !list_empty(&cam->sb_full))) {
                        ret = -ERESTARTSYS;
                        goto out;
                }
                mutex_lock(&cam->s_mutex);
        }

        if (cam->state != S_STREAMING)
                ret = -EINTR;
        else {
                spin_lock_irqsave(&cam->dev_lock, flags);
                /* Should probably recheck !list_empty() here */
                sbuf = list_entry(cam->sb_full.next,
                                struct cafe_sio_buffer, list);
                list_del_init(&sbuf->list);
                spin_unlock_irqrestore(&cam->dev_lock, flags);
                sbuf->v4lbuf.flags &= ~V4L2_BUF_FLAG_DONE;
                *buf = sbuf->v4lbuf;
                ret = 0;
        }

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



static void cafe_v4l_vm_open(struct vm_area_struct *vma)
{
        struct cafe_sio_buffer *sbuf = vma->vm_private_data;
        /*
         * Locking: done under mmap_sem, so we don't need to
         * go back to the camera lock here.
         */
        sbuf->mapcount++;
}


static void cafe_v4l_vm_close(struct vm_area_struct *vma)
{
        struct cafe_sio_buffer *sbuf = vma->vm_private_data;

        mutex_lock(&sbuf->cam->s_mutex);
        sbuf->mapcount--;
        /* Docs say we should stop I/O too... */
        if (sbuf->mapcount == 0)
                sbuf->v4lbuf.flags &= ~V4L2_BUF_FLAG_MAPPED;
        mutex_unlock(&sbuf->cam->s_mutex);
}

static struct vm_operations_struct cafe_v4l_vm_ops = {
        .open = cafe_v4l_vm_open,
        .close = cafe_v4l_vm_close
};


static int cafe_v4l_mmap(struct file *filp, struct vm_area_struct *vma)
{
        struct cafe_camera *cam = filp->private_data;
        unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
        int ret = -EINVAL;
        int i;
        struct cafe_sio_buffer *sbuf = NULL;

        if (! (vma->vm_flags & VM_WRITE) || ! (vma->vm_flags & VM_SHARED))
                return -EINVAL;
        /*
         * Find the buffer they are looking for.
         */
        mutex_lock(&cam->s_mutex);
        for (i = 0; i < cam->n_sbufs; i++)
                if (cam->sb_bufs[i].v4lbuf.m.offset == offset) {
                        sbuf = cam->sb_bufs + i;
                        break;
                }
        if (sbuf == NULL)
                goto out;

        ret = remap_vmalloc_range(vma, sbuf->buffer, 0);
        if (ret)
                goto out;
        vma->vm_flags |= VM_DONTEXPAND;
        vma->vm_private_data = sbuf;
        vma->vm_ops = &cafe_v4l_vm_ops;
        sbuf->v4lbuf.flags |= V4L2_BUF_FLAG_MAPPED;
        cafe_v4l_vm_open(vma);
        ret = 0;
  out:
        mutex_unlock(&cam->s_mutex);
        return ret;
}



static int cafe_v4l_open(struct inode *inode, struct file *filp)
{
        struct cafe_camera *cam;

        cam = cafe_find_dev(iminor(inode));
        if (cam == NULL)
                return -ENODEV;
        filp->private_data = cam;

        mutex_lock(&cam->s_mutex);
        if (cam->users == 0) {
                cafe_ctlr_power_up(cam);
                __cafe_cam_reset(cam);
                cafe_set_config_needed(cam, 1);
        /* FIXME make sure this is complete */
        }
        (cam->users)++;
        mutex_unlock(&cam->s_mutex);
        return 0;
}


static int cafe_v4l_release(struct inode *inode, struct file *filp)
{
        struct cafe_camera *cam = filp->private_data;

        mutex_lock(&cam->s_mutex);
        (cam->users)--;
        if (filp == cam->owner) {
                cafe_ctlr_stop_dma(cam);
                cafe_free_sio_buffers(cam);
                cam->owner = NULL;
        }
        if (cam->users == 0) {
                cafe_ctlr_power_down(cam);
                if (! alloc_bufs_at_load)
                        cafe_free_dma_bufs(cam);
        }
        mutex_unlock(&cam->s_mutex);
        return 0;
}



static unsigned int cafe_v4l_poll(struct file *filp,
                struct poll_table_struct *pt)
{
        struct cafe_camera *cam = filp->private_data;

        poll_wait(filp, &cam->iowait, pt);
        if (cam->next_buf >= 0)
                return POLLIN | POLLRDNORM;
        return 0;
}



static int cafe_vidioc_queryctrl(struct file *filp, void *priv,
                struct v4l2_queryctrl *qc)
{
        struct cafe_camera *cam = filp->private_data;
        int ret;

        mutex_lock(&cam->s_mutex);
        ret = __cafe_cam_cmd(cam, VIDIOC_QUERYCTRL, qc);
        mutex_unlock(&cam->s_mutex);
        return ret;
}


static int cafe_vidioc_g_ctrl(struct file *filp, void *priv,
                struct v4l2_control *ctrl)
{
        struct cafe_camera *cam = filp->private_data;
        int ret;

        mutex_lock(&cam->s_mutex);
        ret = __cafe_cam_cmd(cam, VIDIOC_G_CTRL, ctrl);
        mutex_unlock(&cam->s_mutex);
        return ret;
}


static int cafe_vidioc_s_ctrl(struct file *filp, void *priv,
                struct v4l2_control *ctrl)
{
        struct cafe_camera *cam = filp->private_data;
        int ret;

        mutex_lock(&cam->s_mutex);
        ret = __cafe_cam_cmd(cam, VIDIOC_S_CTRL, ctrl);
        mutex_unlock(&cam->s_mutex);
        return ret;
}





static int cafe_vidioc_querycap(struct file *file, void *priv,
                struct v4l2_capability *cap)
{
        strcpy(cap->driver, "cafe_ccic");
        strcpy(cap->card, "cafe_ccic");
        cap->version = CAFE_VERSION;
        cap->capabilities = V4L2_CAP_VIDEO_CAPTURE |
                V4L2_CAP_READWRITE | V4L2_CAP_STREAMING;
        return 0;
}


/*
 * The default format we use until somebody says otherwise.
 */
static struct v4l2_pix_format cafe_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 int cafe_vidioc_enum_fmt_cap(struct file *filp,
                void *priv, struct v4l2_fmtdesc *fmt)
{
        struct cafe_camera *cam = priv;
        int ret;

        if (fmt->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;
        mutex_lock(&cam->s_mutex);
        ret = __cafe_cam_cmd(cam, VIDIOC_ENUM_FMT, fmt);
        mutex_unlock(&cam->s_mutex);
        return ret;
}


static int cafe_vidioc_try_fmt_cap (struct file *filp, void *priv,
                struct v4l2_format *fmt)
{
        struct cafe_camera *cam = priv;
        int ret;

        mutex_lock(&cam->s_mutex);
        ret = __cafe_cam_cmd(cam, VIDIOC_TRY_FMT, fmt);
        mutex_unlock(&cam->s_mutex);
        return ret;
}

static int cafe_vidioc_s_fmt_cap(struct file *filp, void *priv,
                struct v4l2_format *fmt)
{
        struct cafe_camera *cam = priv;
        int ret;

        /*
         * Can't do anything if the device is not idle
         * Also can't if there are streaming buffers in place.
         */
        if (cam->state != S_IDLE || cam->n_sbufs > 0)
                return -EBUSY;
        /*
         * See if the formatting works in principle.
         */
        ret = cafe_vidioc_try_fmt_cap(filp, priv, fmt);
        if (ret)
                return ret;
        /*
         * Now we start to change things for real, so let's do it
         * under lock.
         */
        mutex_lock(&cam->s_mutex);
        cam->pix_format = fmt->fmt.pix;
        /*
         * Make sure we have appropriate DMA buffers.
         */
        ret = -ENOMEM;
        if (cam->nbufs > 0 && cam->dma_buf_size < cam->pix_format.sizeimage)
                cafe_free_dma_bufs(cam);
        if (cam->nbufs == 0) {
                if (cafe_alloc_dma_bufs(cam, 0))
                        goto out;
        }
        /*
         * It looks like this might work, so let's program the sensor.
         */
        ret = cafe_cam_configure(cam);
        if (! ret)
                ret = cafe_ctlr_configure(cam);
  out:
        mutex_unlock(&cam->s_mutex);
        return ret;
}

/*
 * Return our stored notion of how the camera is/should be configured.
 * The V4l2 spec wants us to be smarter, and actually get this from
 * the camera (and not mess with it at open time).  Someday.
 */
static int cafe_vidioc_g_fmt_cap(struct file *filp, void *priv,
                struct v4l2_format *f)
{
        struct cafe_camera *cam = priv;

        f->fmt.pix = cam->pix_format;
        return 0;
}

/*
 * We only have one input - the sensor - so minimize the nonsense here.
 */
static int cafe_vidioc_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 cafe_vidioc_g_input(struct file *filp, void *priv, unsigned int *i)
{
        *i = 0;
        return 0;
}

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

/* from vivi.c */
static int cafe_vidioc_s_std(struct file *filp, void *priv, v4l2_std_id *a)
{
        return 0;
}

/*
 * G/S_PARM.  Most of this is done by the sensor, but we are
 * the level which controls the number of read buffers.
 */
static int cafe_vidioc_g_parm(struct file *filp, void *priv,
                struct v4l2_streamparm *parms)
{
        struct cafe_camera *cam = priv;
        int ret;

        mutex_lock(&cam->s_mutex);
        ret = __cafe_cam_cmd(cam, VIDIOC_G_PARM, parms);
        mutex_unlock(&cam->s_mutex);
        parms->parm.capture.readbuffers = n_dma_bufs;
        return ret;
}

static int cafe_vidioc_s_parm(struct file *filp, void *priv,
                struct v4l2_streamparm *parms)
{
        struct cafe_camera *cam = priv;
        int ret;

        mutex_lock(&cam->s_mutex);
        ret = __cafe_cam_cmd(cam, VIDIOC_S_PARM, parms);
        mutex_unlock(&cam->s_mutex);
        parms->parm.capture.readbuffers = n_dma_bufs;
        return ret;
}


static void cafe_v4l_dev_release(struct video_device *vd)
{
        struct cafe_camera *cam = container_of(vd, struct cafe_camera, v4ldev);

        kfree(cam);
}


/*
 * This template device holds all of those v4l2 methods; we
 * clone it for specific real devices.
 */

static const struct file_operations cafe_v4l_fops = {
        .owner = THIS_MODULE,
        .open = cafe_v4l_open,
        .release = cafe_v4l_release,
        .read = cafe_v4l_read,
        .poll = cafe_v4l_poll,
        .mmap = cafe_v4l_mmap,
        .ioctl = video_ioctl2,
        .llseek = no_llseek,
};

static struct video_device cafe_v4l_template = {
        .name = "cafe",
        .type = VFL_TYPE_GRABBER,
        .type2 = VID_TYPE_CAPTURE,
        .minor = -1, /* Get one dynamically */
        .tvnorms = V4L2_STD_NTSC_M,
        .current_norm = V4L2_STD_NTSC_M,  /* make mplayer happy */

        .fops = &cafe_v4l_fops,
        .release = cafe_v4l_dev_release,

        .vidioc_querycap        = cafe_vidioc_querycap,
        .vidioc_enum_fmt_cap    = cafe_vidioc_enum_fmt_cap,
        .vidioc_try_fmt_cap     = cafe_vidioc_try_fmt_cap,
        .vidioc_s_fmt_cap       = cafe_vidioc_s_fmt_cap,
        .vidioc_g_fmt_cap       = cafe_vidioc_g_fmt_cap,
        .vidioc_enum_input      = cafe_vidioc_enum_input,
        .vidioc_g_input         = cafe_vidioc_g_input,
        .vidioc_s_input         = cafe_vidioc_s_input,
        .vidioc_s_std           = cafe_vidioc_s_std,
        .vidioc_reqbufs         = cafe_vidioc_reqbufs,
        .vidioc_querybuf        = cafe_vidioc_querybuf,
        .vidioc_qbuf            = cafe_vidioc_qbuf,
        .vidioc_dqbuf           = cafe_vidioc_dqbuf,
        .vidioc_streamon        = cafe_vidioc_streamon,
        .vidioc_streamoff       = cafe_vidioc_streamoff,
        .vidioc_queryctrl       = cafe_vidioc_queryctrl,
        .vidioc_g_ctrl          = cafe_vidioc_g_ctrl,
        .vidioc_s_ctrl          = cafe_vidioc_s_ctrl,
        .vidioc_g_parm          = cafe_vidioc_g_parm,
        .vidioc_s_parm          = cafe_vidioc_s_parm,
};







/* ---------------------------------------------------------------------- */
/*
 * Interrupt handler stuff
 */



static void cafe_frame_tasklet(unsigned long data)
{
        struct cafe_camera *cam = (struct cafe_camera *) data;
        int i;
        unsigned long flags;
        struct cafe_sio_buffer *sbuf;

        spin_lock_irqsave(&cam->dev_lock, flags);
        for (i = 0; i < cam->nbufs; i++) {
                int bufno = cam->next_buf;
                if (bufno < 0) {  /* "will never happen" */
                        cam_err(cam, "No valid bufs in tasklet!\n");
                        break;
                }
                if (++(cam->next_buf) >= cam->nbufs)
                        cam->next_buf = 0;
                if (! test_bit(bufno, &cam->flags))
                        continue;
                if (list_empty(&cam->sb_avail))
                        break;  /* Leave it valid, hope for better later */
                clear_bit(bufno, &cam->flags);
                /*
                 * We could perhaps drop the spinlock during this
                 * big copy.  Something to consider.
                 */
                sbuf = list_entry(cam->sb_avail.next,
                                struct cafe_sio_buffer, list);
                memcpy(sbuf->buffer, cam->dma_bufs[bufno],
                                cam->pix_format.sizeimage);
                sbuf->v4lbuf.bytesused = cam->pix_format.sizeimage;
                sbuf->v4lbuf.sequence = cam->buf_seq[bufno];
                sbuf->v4lbuf.flags &= ~V4L2_BUF_FLAG_QUEUED;
                sbuf->v4lbuf.flags |= V4L2_BUF_FLAG_DONE;
                list_move_tail(&sbuf->list, &cam->sb_full);
        }
        if (! list_empty(&cam->sb_full))
                wake_up(&cam->iowait);
        spin_unlock_irqrestore(&cam->dev_lock, flags);
}



static void cafe_frame_complete(struct cafe_camera *cam, int frame)
{
        /*
         * Basic frame housekeeping.
         */
        if (test_bit(frame, &cam->flags) && printk_ratelimit())
                cam_err(cam, "Frame overrun on %d, frames lost\n", frame);
        set_bit(frame, &cam->flags);
        clear_bit(CF_DMA_ACTIVE, &cam->flags);
        if (cam->next_buf < 0)
                cam->next_buf = frame;
        cam->buf_seq[frame] = ++(cam->sequence);

        switch (cam->state) {
        /*
         * If in single read mode, try going speculative.
         */
            case S_SINGLEREAD:
                cam->state = S_SPECREAD;
                cam->specframes = 0;
                wake_up(&cam->iowait);
                break;

        /*
         * If we are already doing speculative reads, and nobody is
         * reading them, just stop.
         */
            case S_SPECREAD:
                if (++(cam->specframes) >= cam->nbufs) {
                        cafe_ctlr_stop(cam);
                        cafe_ctlr_irq_disable(cam);
                        cam->state = S_IDLE;
                }
                wake_up(&cam->iowait);
                break;
        /*
         * For the streaming case, we defer the real work to the
         * camera tasklet.
         *
         * FIXME: if the application is not consuming the buffers,
         * we should eventually put things on hold and restart in
         * vidioc_dqbuf().
         */
            case S_STREAMING:
                tasklet_schedule(&cam->s_tasklet);
                break;

            default:
                cam_err(cam, "Frame interrupt in non-operational state\n");
                break;
        }
}




static void cafe_frame_irq(struct cafe_camera *cam, unsigned int irqs)
{
        unsigned int frame;

        cafe_reg_write(cam, REG_IRQSTAT, FRAMEIRQS); /* Clear'em all */
        /*
         * Handle any frame completions.  There really should
         * not be more than one of these, or we have fallen
         * far behind.
         */
        for (frame = 0; frame < cam->nbufs; frame++)
                if (irqs & (IRQ_EOF0 << frame))
                        cafe_frame_complete(cam, frame);
        /*
         * If a frame starts, note that we have DMA active.  This
         * code assumes that we won't get multiple frame interrupts
         * at once; may want to rethink that.
         */
        if (irqs & (IRQ_SOF0 | IRQ_SOF1 | IRQ_SOF2))
                set_bit(CF_DMA_ACTIVE, &cam->flags);
}



static irqreturn_t cafe_irq(int irq, void *data)
{
        struct cafe_camera *cam = data;
        unsigned int irqs;

        spin_lock(&cam->dev_lock);
        irqs = cafe_reg_read(cam, REG_IRQSTAT);
        if ((irqs & ALLIRQS) == 0) {
                spin_unlock(&cam->dev_lock);
                return IRQ_NONE;
        }
        if (irqs & FRAMEIRQS)
                cafe_frame_irq(cam, irqs);
        if (irqs & TWSIIRQS) {
                cafe_reg_write(cam, REG_IRQSTAT, TWSIIRQS);
                wake_up(&cam->smbus_wait);
        }
        spin_unlock(&cam->dev_lock);
        return IRQ_HANDLED;
}


/* -------------------------------------------------------------------------- */
#ifdef CONFIG_VIDEO_ADV_DEBUG
/*
 * Debugfs stuff.
 */

static char cafe_debug_buf[1024];
static struct dentry *cafe_dfs_root;

static void cafe_dfs_setup(void)
{
        cafe_dfs_root = debugfs_create_dir("cafe_ccic", NULL);
        if (IS_ERR(cafe_dfs_root)) {
                cafe_dfs_root = NULL;  /* Never mind */
                printk(KERN_NOTICE "cafe_ccic unable to set up debugfs\n");
        }
}

static void cafe_dfs_shutdown(void)
{
        if (cafe_dfs_root)
                debugfs_remove(cafe_dfs_root);
}

static int cafe_dfs_open(struct inode *inode, struct file *file)
{
        file->private_data = inode->i_private;
        return 0;
}

static ssize_t cafe_dfs_read_regs(struct file *file,
                char __user *buf, size_t count, loff_t *ppos)
{
        struct cafe_camera *cam = file->private_data;
        char *s = cafe_debug_buf;
        int offset;

        for (offset = 0; offset < 0x44; offset += 4)
                s += sprintf(s, "%02x: %08x\n", offset,
                                cafe_reg_read(cam, offset));
        for (offset = 0x88; offset <= 0x90; offset += 4)
                s += sprintf(s, "%02x: %08x\n", offset,
                                cafe_reg_read(cam, offset));
        for (offset = 0xb4; offset <= 0xbc; offset += 4)
                s += sprintf(s, "%02x: %08x\n", offset,
                                cafe_reg_read(cam, offset));
        for (offset = 0x3000; offset <= 0x300c; offset += 4)
                s += sprintf(s, "%04x: %08x\n", offset,
                                cafe_reg_read(cam, offset));
        return simple_read_from_buffer(buf, count, ppos, cafe_debug_buf,
                        s - cafe_debug_buf);
}

static const struct file_operations cafe_dfs_reg_ops = {
        .owner = THIS_MODULE,
        .read = cafe_dfs_read_regs,
        .open = cafe_dfs_open
};

static ssize_t cafe_dfs_read_cam(struct file *file,
                char __user *buf, size_t count, loff_t *ppos)
{
        struct cafe_camera *cam = file->private_data;
        char *s = cafe_debug_buf;
        int offset;

        if (! cam->sensor)
                return -EINVAL;
        for (offset = 0x0; offset < 0x8a; offset++)
        {
                u8 v;

                cafe_smbus_read_data(cam, cam->sensor->addr, offset, &v);
                s += sprintf(s, "%02x: %02x\n", offset, v);
        }
        return simple_read_from_buffer(buf, count, ppos, cafe_debug_buf,
                        s - cafe_debug_buf);
}

static const struct file_operations cafe_dfs_cam_ops = {
        .owner = THIS_MODULE,
        .read = cafe_dfs_read_cam,
        .open = cafe_dfs_open
};



static void cafe_dfs_cam_setup(struct cafe_camera *cam)
{
        char fname[40];

        if (!cafe_dfs_root)
                return;
        sprintf(fname, "regs-%d", cam->v4ldev.minor);
        cam->dfs_regs = debugfs_create_file(fname, 0444, cafe_dfs_root,
                        cam, &cafe_dfs_reg_ops);
        sprintf(fname, "cam-%d", cam->v4ldev.minor);
        cam->dfs_cam_regs = debugfs_create_file(fname, 0444, cafe_dfs_root,
                        cam, &cafe_dfs_cam_ops);
}


static void cafe_dfs_cam_shutdown(struct cafe_camera *cam)
{
        if (! IS_ERR(cam->dfs_regs))
                debugfs_remove(cam->dfs_regs);
        if (! IS_ERR(cam->dfs_cam_regs))
                debugfs_remove(cam->dfs_cam_regs);
}

#else

#define cafe_dfs_setup()
#define cafe_dfs_shutdown()
#define cafe_dfs_cam_setup(cam)
#define cafe_dfs_cam_shutdown(cam)
#endif    /* CONFIG_VIDEO_ADV_DEBUG */




/* ------------------------------------------------------------------------*/
/*
 * PCI interface stuff.
 */

static int cafe_pci_probe(struct pci_dev *pdev,
                const struct pci_device_id *id)
{
        int ret;
        u16 classword;
        struct cafe_camera *cam;
        /*
         * Make sure we have a camera here - we'll get calls for
         * the other cafe devices as well.
         */
        pci_read_config_word(pdev, PCI_CLASS_DEVICE, &classword);
        if (classword != PCI_CLASS_MULTIMEDIA_VIDEO)
                return -ENODEV;
        /*
         * Start putting together one of our big camera structures.
         */
        ret = -ENOMEM;
        cam = kzalloc(sizeof(struct cafe_camera), GFP_KERNEL);
        if (cam == NULL)
                goto out;
        mutex_init(&cam->s_mutex);
        mutex_lock(&cam->s_mutex);
        spin_lock_init(&cam->dev_lock);
        cam->state = S_NOTREADY;
        cafe_set_config_needed(cam, 1);
        init_waitqueue_head(&cam->smbus_wait);
        init_waitqueue_head(&cam->iowait);
        cam->pdev = pdev;
        cam->pix_format = cafe_def_pix_format;
        INIT_LIST_HEAD(&cam->dev_list);
        INIT_LIST_HEAD(&cam->sb_avail);
        INIT_LIST_HEAD(&cam->sb_full);
        tasklet_init(&cam->s_tasklet, cafe_frame_tasklet, (unsigned long) cam);
        /*
         * Get set up on the PCI bus.
         */
        ret = pci_enable_device(pdev);
        if (ret)
                goto out_free;
        pci_set_master(pdev);

        ret = -EIO;
        cam->regs = pci_iomap(pdev, 0, 0);
        if (! cam->regs) {
                printk(KERN_ERR "Unable to ioremap cafe-ccic regs\n");
                goto out_free;
        }
        ret = request_irq(pdev->irq, cafe_irq, IRQF_SHARED, "cafe-ccic", cam);
        if (ret)
                goto out_iounmap;
        cafe_ctlr_init(cam);
        cafe_ctlr_power_up(cam);
        /*
         * Set up I2C/SMBUS communications
         */
        mutex_unlock(&cam->s_mutex);  /* attach can deadlock */
        ret = cafe_smbus_setup(cam);
        if (ret)
                goto out_freeirq;
        /*
         * Get the v4l2 setup done.
         */
        mutex_lock(&cam->s_mutex);
        cam->v4ldev = cafe_v4l_template;
        cam->v4ldev.debug = 0;
//      cam->v4ldev.debug = V4L2_DEBUG_IOCTL_ARG;
        ret = video_register_device(&cam->v4ldev, VFL_TYPE_GRABBER, -1);
        if (ret)
                goto out_smbus;
        /*
         * If so requested, try to get our DMA buffers now.
         */
        if (alloc_bufs_at_load) {
                if (cafe_alloc_dma_bufs(cam, 1))
                        cam_warn(cam, "Unable to alloc DMA buffers at load"
                                        " will try again later.");
        }

        cafe_dfs_cam_setup(cam);
        mutex_unlock(&cam->s_mutex);
        cafe_add_dev(cam);
        return 0;

  out_smbus:
        cafe_smbus_shutdown(cam);
  out_freeirq:
        cafe_ctlr_power_down(cam);
        free_irq(pdev->irq, cam);
  out_iounmap:
        pci_iounmap(pdev, cam->regs);
  out_free:
        kfree(cam);
  out:
        return ret;
}


/*
 * Shut down an initialized device
 */
static void cafe_shutdown(struct cafe_camera *cam)
{
/* FIXME: Make sure we take care of everything here */
        cafe_dfs_cam_shutdown(cam);
        if (cam->n_sbufs > 0)
                /* What if they are still mapped?  Shouldn't be, but... */
                cafe_free_sio_buffers(cam);
        cafe_remove_dev(cam);
        cafe_ctlr_stop_dma(cam);
        cafe_ctlr_power_down(cam);
        cafe_smbus_shutdown(cam);
        cafe_free_dma_bufs(cam);
        free_irq(cam->pdev->irq, cam);
        pci_iounmap(cam->pdev, cam->regs);
        video_unregister_device(&cam->v4ldev);
        /* kfree(cam); done in v4l_release () */
}


static void cafe_pci_remove(struct pci_dev *pdev)
{
        struct cafe_camera *cam = cafe_find_by_pdev(pdev);

        if (cam == NULL) {
                printk(KERN_WARNING "pci_remove on unknown pdev %p\n", pdev);
                return;
        }
        mutex_lock(&cam->s_mutex);
        if (cam->users > 0)
                cam_warn(cam, "Removing a device with users!\n");
        cafe_shutdown(cam);
/* No unlock - it no longer exists */
}




static struct pci_device_id cafe_ids[] = {
        { PCI_DEVICE(0x1148, 0x4340) }, /* Temporary ID on devel board */
        { PCI_DEVICE(0x11ab, 0x4100) }, /* Eventual real ID */
        { PCI_DEVICE(0x11ab, 0x4102) }, /* Really eventual real ID */
        { 0, }
};

MODULE_DEVICE_TABLE(pci, cafe_ids);

static struct pci_driver cafe_pci_driver = {
        .name = "cafe1000-ccic",
        .id_table = cafe_ids,
        .probe = cafe_pci_probe,
        .remove = cafe_pci_remove,
};




static int __init cafe_init(void)
{
        int ret;

        printk(KERN_NOTICE "Marvell M88ALP01 'CAFE' Camera Controller version %d\n",
                        CAFE_VERSION);
        cafe_dfs_setup();
        ret = pci_register_driver(&cafe_pci_driver);
        if (ret) {
                printk(KERN_ERR "Unable to register cafe_ccic driver\n");
                goto out;
        }
        request_module("ov7670");  /* FIXME want something more general */
        ret = 0;

  out:
        return ret;
}


static void __exit cafe_exit(void)
{
        pci_unregister_driver(&cafe_pci_driver);
        cafe_dfs_shutdown();
}

module_init(cafe_init);
module_exit(cafe_exit);