cafe_ccic.c

trident tm5600的linux驱动

/*
 * A driver for the CMOS camera controller in the Marvell 88ALP01 "cafe"
 * multifunction chip.  Currently works with the Omnivision OV7670
 * sensor.
 *
 * The data sheet for this device can be found at:
 *    http://www.marvell.com/products/pcconn/88ALP01.jsp
 *
 * Copyright 2006 One Laptop Per Child Association, Inc.
 * Copyright 2006-7 Jonathan Corbet <[e-mail]>
 *
 * Written by Jonathan Corbet, [e-mail].
 *
 * 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/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pci.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/videodev2.h>
#include "compat.h"
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-chip-ident.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 0x000002


/*
 * Parameters.
 */
MODULE_AUTHOR("Jonathan Corbet <[e-mail]>");
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_read;
module_param(alloc_bufs_at_read, bool, 0444);
MODULE_PARM_DESC(alloc_bufs_at_read,
		"Non-zero value causes DMA buffers to be allocated when the "
		"video capture device is read, rather than at module load "
		"time.  This saves memory, but decreases the chances of "
		"successfully getting those buffers.");

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;
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 */
	u32 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;
	DEFINE_WAIT(the_wait);

	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);

	/*
	 * Time to wait for the write to complete.  THIS IS A RACY
	 * WAY TO DO IT, but the sad fact is that reading the TWSIC1
	 * register too quickly after starting the operation sends
	 * the device into a place that may be kinder and better, but
	 * which is absolutely useless for controlling the sensor.  In
	 * practice we have plenty of time to get into our sleep state
	 * before the interrupt hits, and the worst case is that we
	 * time out and then see that things completed, so this seems
	 * the best way for now.
	 */
	do {
		prepare_to_wait(&cam->smbus_wait, &the_wait,
				TASK_UNINTERRUPTIBLE);
		schedule_timeout(1); /* even 1 jiffy is too long */
		finish_wait(&cam->smbus_wait, &the_wait);
	} while (!cafe_smbus_write_done(cam));

#ifdef IF_THE_CAFE_HARDWARE_WORKED_RIGHT
	wait_event_timeout(cam->smbus_wait, cafe_smbus_write_done(cam),
			CAFE_SMBUS_TIMEOUT);
#endif
	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 0  /* client needs to talk during attach process */
	if (! cam->sensor) {
		cam_err(cam, "SMBUS xfer with no client\n");
		return -EINVAL;
	}
#endif
	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;