drivers/char/csdio.c

/*
 * Copyright (c) 2010, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/serial_reg.h>
#include <linux/circ_buf.h>
#include <linux/gfp.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/platform_device.h>

/* Char device */
#include <linux/cdev.h>
#include <linux/fs.h>

/* Sdio device */
#include <linux/mmc/core.h>
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/sdio.h>
#include <linux/mmc/sdio_func.h>
#include <linux/mmc/sdio_ids.h>

#include <linux/csdio.h>

#define FALSE   0
#define TRUE    1

#define VERSION                     "0.5"
#define CSDIO_NUM_OF_SDIO_FUNCTIONS 7
#define CSDIO_DEV_NAME              "csdio"
#define TP_DEV_NAME                 CSDIO_DEV_NAME"f"
#define CSDIO_DEV_PERMISSIONS       0666

#define CSDIO_SDIO_BUFFER_SIZE      (64*512)

int csdio_major;
int csdio_minor;
int csdio_transport_nr_devs = CSDIO_NUM_OF_SDIO_FUNCTIONS;
static uint csdio_vendor_id;
static uint csdio_device_id;
static char *host_name;

static struct csdio_func_t {
	struct sdio_func   *m_func;
	int                 m_enabled;
	struct cdev         m_cdev;      /* char device structure */
	struct device      *m_device;
	u32                 m_block_size;
} *g_csdio_func_table[CSDIO_NUM_OF_SDIO_FUNCTIONS] = {0};

struct csdio_t {
	struct cdev             m_cdev;
	struct device          *m_device;
	struct class           *m_driver_class;
	struct fasync_struct   *m_async_queue;
	unsigned char           m_current_irq_mask; /* currently enabled irqs */
	struct mmc_host        *m_host;
	unsigned int            m_num_of_func;
} g_csdio;

struct csdio_file_descriptor {
	struct csdio_func_t    *m_port;
	u32                     m_block_mode;/* data tran. byte(0)/block(1) */
	u32                     m_op_code;   /* address auto increment flag */
	u32                     m_address;
};

static void *g_sdio_buffer;

/*
 * Open and release
 */
static int csdio_transport_open(struct inode *inode, struct file *filp)
{
	int ret = 0;
	struct csdio_func_t *port = NULL; /*  device information */
	struct sdio_func *func = NULL;
	struct csdio_file_descriptor *descriptor = NULL;

	port = container_of(inode->i_cdev, struct csdio_func_t, m_cdev);
	func = port->m_func;
	descriptor = kzalloc(sizeof(struct csdio_file_descriptor), GFP_KERNEL);
	if (!descriptor) {
		ret = -ENOMEM;
		goto exit;
	}

	pr_info(TP_DEV_NAME"%d: open: func=%p, port=%p\n",
			func->num, func, port);
	sdio_claim_host(func);
	ret = sdio_enable_func(func);
	if (ret) {
		pr_err(TP_DEV_NAME"%d:Enable func failed (%d)\n",
				func->num, ret);
		ret = -EIO;
		goto free_descriptor;
	}
	descriptor->m_port = port;
	filp->private_data = descriptor;
	goto release_host;

free_descriptor:
	kfree(descriptor);
release_host:
	sdio_release_host(func);
exit:
	return ret;
}

static int csdio_transport_release(struct inode *inode, struct file *filp)
{
	int ret = 0;
	struct csdio_file_descriptor *descriptor = filp->private_data;
	struct csdio_func_t *port = descriptor->m_port;
	struct sdio_func *func = port->m_func;

	pr_info(TP_DEV_NAME"%d: release\n", func->num);
	sdio_claim_host(func);
	ret = sdio_disable_func(func);
	if (ret) {
		pr_err(TP_DEV_NAME"%d:Disable func failed(%d)\n",
				func->num, ret);
		ret = -EIO;
	}
	sdio_release_host(func);
	kfree(descriptor);
	return ret;
}

/*
 * Data management: read and write
 */
static ssize_t csdio_transport_read(struct file *filp,
		char __user *buf,
		size_t count,
		loff_t *f_pos)
{
	ssize_t ret = 0;
	struct csdio_file_descriptor *descriptor = filp->private_data;
	struct csdio_func_t *port = descriptor->m_port;
	struct sdio_func *func = port->m_func;
	size_t t_count = count;

	if (descriptor->m_block_mode) {
		pr_info(TP_DEV_NAME "%d: CMD53 read, Md:%d, Addr:0x%04X,"
				" Un:%d (Bl:%d, BlSz:%d)\n", func->num,
				descriptor->m_block_mode,
				descriptor->m_address,
				count*port->m_block_size,
				count, port->m_block_size);
		/* recalculate size */
		count *= port->m_block_size;
	}
	sdio_claim_host(func);
	if (descriptor->m_op_code) {
		/* auto increment */
		ret = sdio_memcpy_fromio(func, g_sdio_buffer,
				descriptor->m_address, count);
	} else { /* FIFO */
		ret = sdio_readsb(func, g_sdio_buffer,
				descriptor->m_address, count);
	}
	sdio_release_host(func);
	if (!ret) {
		if (copy_to_user(buf, g_sdio_buffer, count))
			ret = -EFAULT;
		else
			ret = t_count;
	}
	if (ret < 0) {
		pr_err(TP_DEV_NAME "%d: CMD53 read failed (%d)"
				"(Md:%d, Addr:0x%04X, Sz:%d)\n",
				func->num, ret,
				descriptor->m_block_mode,
				descriptor->m_address, count);
	}
	return ret;
}

static ssize_t csdio_transport_write(struct file *filp,
		const char __user *buf,
		size_t count,
		loff_t *f_pos)
{
	ssize_t ret = 0;
	struct csdio_file_descriptor *descriptor = filp->private_data;
	struct csdio_func_t *port = descriptor->m_port;
	struct sdio_func *func = port->m_func;
	size_t t_count = count;

	if (descriptor->m_block_mode)
		count *= port->m_block_size;

	if (copy_from_user(g_sdio_buffer, buf, count)) {
		pr_err(TP_DEV_NAME"%d:copy_from_user failed\n", func->num);
		ret = -EFAULT;
	} else {
		sdio_claim_host(func);
		if (descriptor->m_op_code) {
			/* auto increment */
			ret = sdio_memcpy_toio(func, descriptor->m_address,
					g_sdio_buffer, count);
		} else {
			/* FIFO */
			ret = sdio_writesb(func, descriptor->m_address,
					g_sdio_buffer, count);
		}
		sdio_release_host(func);
		if (!ret) {
			ret = t_count;
		} else {
			pr_err(TP_DEV_NAME "%d: CMD53 write failed (%d)"
				"(Md:%d, Addr:0x%04X, Sz:%d)\n",
				func->num, ret, descriptor->m_block_mode,
				descriptor->m_address, count);
		}
	}
	return ret;
}

/* disable interrupt for sdio client */
static int disable_sdio_client_isr(struct sdio_func *func)
{
	int ret;

	/* disable for all functions, to restore interrupts
	 * use g_csdio.m_current_irq_mask */
	sdio_f0_writeb(func, 0, SDIO_CCCR_IENx, &ret);
	if (ret)
		pr_err(CSDIO_DEV_NAME" Can't sdio_f0_writeb (%d)\n", ret);

	return ret;
}

/*
 * This handles the interrupt from SDIO.
 */
static void csdio_sdio_irq(struct sdio_func *func)
{
	int ret;

	pr_info(CSDIO_DEV_NAME" csdio_sdio_irq: func=%d\n", func->num);
	ret = disable_sdio_client_isr(func);
	if (ret) {
		pr_err(CSDIO_DEV_NAME" Can't disable client isr(%d)\n", ret);
		return;
	}
	/*  signal asynchronous readers */
	if (g_csdio.m_async_queue)
		kill_fasync(&g_csdio.m_async_queue, SIGIO, POLL_IN);
}

/*
 * The ioctl() implementation
 */
static int csdio_transport_ioctl(struct inode *inode,
		struct file *filp,
		unsigned int cmd,
		unsigned long arg)
{
	int err = 0;
	int ret = 0;
	struct csdio_file_descriptor *descriptor = filp->private_data;
	struct csdio_func_t *port = descriptor->m_port;
	struct sdio_func *func = port->m_func;

	/*  extract the type and number bitfields
	    sanity check: return ENOTTY (inappropriate ioctl) before
	    access_ok()
	*/
	if ((_IOC_TYPE(cmd) != CSDIO_IOC_MAGIC) ||
			(_IOC_NR(cmd) > CSDIO_IOC_MAXNR)) {
		pr_err(TP_DEV_NAME "Wrong ioctl command parameters\n");
		ret = -ENOTTY;
		goto exit;
	}

	/*  the direction is a bitmask, and VERIFY_WRITE catches R/W
	 *  transfers. `Type' is user-oriented, while access_ok is
	    kernel-oriented, so the concept of "read" and "write" is reversed
	*/
	if (_IOC_DIR(cmd) & _IOC_READ) {
		err = !access_ok(VERIFY_WRITE, (void __user *)arg,
				_IOC_SIZE(cmd));
	} else {
		if (_IOC_DIR(cmd) & _IOC_WRITE) {
			err =  !access_ok(VERIFY_READ, (void __user *)arg,
					_IOC_SIZE(cmd));
		}
	}
	if (err) {
		pr_err(TP_DEV_NAME "Wrong ioctl access direction\n");
		ret = -EFAULT;
		goto exit;
	}

	switch (cmd) {
	case CSDIO_IOC_SET_OP_CODE:
		{
			pr_info(TP_DEV_NAME"%d:SET_OP_CODE=%d\n",
					func->num, descriptor->m_op_code);
			ret = get_user(descriptor->m_op_code,
					(unsigned char __user *)arg);
			if (ret) {
				pr_err(TP_DEV_NAME"%d:SET_OP_CODE get data"
						" from user space failed(%d)\n",
						func->num, ret);
				ret = -ENOTTY;
				break;
			}
		}
		break;
	case CSDIO_IOC_FUNCTION_SET_BLOCK_SIZE:
		{
			unsigned block_size;

			ret = get_user(block_size, (unsigned __user *)arg);
			if (ret) {
				pr_err(TP_DEV_NAME"%d:SET_BLOCK_SIZE get data"
						" from user space failed(%d)\n",
						func->num, ret);
				ret = -ENOTTY;
				break;
			}
			pr_info(TP_DEV_NAME"%d:SET_BLOCK_SIZE=%d\n",
					func->num, block_size);
			sdio_claim_host(func);
			ret = sdio_set_block_size(func, block_size);
			if (!ret) {
				port->m_block_size = block_size;
			} else {
				pr_err(TP_DEV_NAME"%d:SET_BLOCK_SIZE set block"
						" size to %d failed (%d)\n",
						func->num, block_size, ret);
				ret = -ENOTTY;
				break;
			}
			sdio_release_host(func);
		}
		break;
	case CSDIO_IOC_SET_BLOCK_MODE:
		{
			pr_info(TP_DEV_NAME"%d:SET_BLOCK_MODE=%d\n",
					func->num, descriptor->m_block_mode);
			ret = get_user(descriptor->m_block_mode,
					(unsigned char __user *)arg);
			if (ret) {
				pr_err(TP_DEV_NAME"%d:SET_BLOCK_MODE get data"
						" from user space failed\n",
						func->num);
				ret = -ENOTTY;
				break;
			}
		}
		break;
	case CSDIO_IOC_CMD52:
		{
			struct csdio_cmd52_ctrl_t cmd52ctrl;
			int cmd52ret;

			if (copy_from_user(&cmd52ctrl,
					(const unsigned char __user *)arg,
					sizeof(cmd52ctrl))) {
				pr_err(TP_DEV_NAME"%d:IOC_CMD52 get data"
						" from user space failed\n",
						func->num);
				ret = -ENOTTY;
				break;
			}
			sdio_claim_host(func);
			if (cmd52ctrl.m_write)
				sdio_writeb(func, cmd52ctrl.m_data,
						cmd52ctrl.m_address, &cmd52ret);
			else
				cmd52ctrl.m_data = sdio_readb(func,
						cmd52ctrl.m_address, &cmd52ret);

			cmd52ctrl.m_ret = cmd52ret;
			sdio_release_host(func);
			if (cmd52ctrl.m_ret)
				pr_err(TP_DEV_NAME"%d:IOC_CMD52 failed (%d)\n",
						func->num, cmd52ctrl.m_ret);

			if (copy_to_user((unsigned char __user *)arg,
						&cmd52ctrl,
						sizeof(cmd52ctrl))) {
				pr_err(TP_DEV_NAME"%d:IOC_CMD52 put data"
						" to user space failed\n",
						func->num);
				ret = -ENOTTY;
				break;
			}
		}
		break;
	case CSDIO_IOC_CMD53:
		{
			struct csdio_cmd53_ctrl_t csdio_cmd53_ctrl;

			if (copy_from_user(&csdio_cmd53_ctrl,
						(const char __user *)arg,
						sizeof(csdio_cmd53_ctrl))) {
				ret = -EPERM;
				pr_err(TP_DEV_NAME"%d:"
					"Get data from user space failed\n",
					func->num);
				break;
			}
			descriptor->m_block_mode =
				csdio_cmd53_ctrl.m_block_mode;
			descriptor->m_op_code = csdio_cmd53_ctrl.m_op_code;
			descriptor->m_address = csdio_cmd53_ctrl.m_address;
		}
		break;
	case CSDIO_IOC_CONNECT_ISR:
		{
			pr_info(CSDIO_DEV_NAME" SDIO_CONNECT_ISR"
				" func=%d, csdio_sdio_irq=%x\n",
				func->num, (unsigned int)csdio_sdio_irq);
			sdio_claim_host(func);
			ret = sdio_claim_irq(func, csdio_sdio_irq);
			sdio_release_host(func);
			if (ret) {
				pr_err(CSDIO_DEV_NAME" SDIO_CONNECT_ISR"
						" claim irq failed(%d)\n", ret);
			} else {
				/* update current irq mask for disable/enable */
				g_csdio.m_current_irq_mask |= (1 << func->num);
			}
		}
		break;
	case CSDIO_IOC_DISCONNECT_ISR:
		{
			pr_info(CSDIO_DEV_NAME " SDIO_DISCONNECT_ISR func=%d\n",
					func->num);
			sdio_claim_host(func);
			sdio_release_irq(func);
			sdio_release_host(func);
			/* update current irq mask for disable/enable */
			g_csdio.m_current_irq_mask &= ~(1 << func->num);
		}
		break;
	default:  /*  redundant, as cmd was checked against MAXNR */
		pr_warning(TP_DEV_NAME"%d: Redundant IOCTL\n",
				func->num);
		ret = -ENOTTY;
	}
exit:
	return ret;
}

static const struct file_operations csdio_transport_fops = {
	.owner =    THIS_MODULE,
	.read =     csdio_transport_read,
	.write =    csdio_transport_write,
	.ioctl =    csdio_transport_ioctl,
	.open =     csdio_transport_open,
	.release =  csdio_transport_release,
};

static void csdio_transport_cleanup(struct csdio_func_t *port)
{
	int devno = MKDEV(csdio_major, csdio_minor + port->m_func->num);
	device_destroy(g_csdio.m_driver_class, devno);
	port->m_device = NULL;
	cdev_del(&port->m_cdev);
}

#if defined(CONFIG_DEVTMPFS)
static inline int csdio_cdev_update_permissions(
    const char *devname, int dev_minor)
{
	return 0;
}
#else
static int csdio_cdev_update_permissions(
    const char *devname, int dev_minor)
{
	int ret = 0;
	mm_segment_t fs;
	struct file *file;
	struct inode *inode;
	struct iattr newattrs;
	int mode = CSDIO_DEV_PERMISSIONS;
	char dev_file[64];

	fs = get_fs();
	set_fs(get_ds());

	snprintf(dev_file, sizeof(dev_file), "/dev/%s%d",
		devname, dev_minor);
	file = filp_open(dev_file, O_RDWR, 0);
	if (IS_ERR(file)) {
		ret = -EFAULT;
		goto exit;
	}

	inode = file->f_path.dentry->d_inode;

	mutex_lock(&inode->i_mutex);
	newattrs.ia_mode =
		(mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
	ret = notify_change(file->f_path.dentry, &newattrs);
	mutex_unlock(&inode->i_mutex);

	filp_close(file, NULL);

exit:
	set_fs(fs);
	return ret;
}
#endif

static struct device *csdio_cdev_init(struct cdev *char_dev,
		const struct file_operations *file_op, int dev_minor,
		const char *devname, struct device *parent)
{
	int ret = 0;
	struct device *new_device = NULL;
	dev_t devno = MKDEV(csdio_major, dev_minor);

	/*  Initialize transport device */
	cdev_init(char_dev, file_op);
	char_dev->owner = THIS_MODULE;
	char_dev->ops = file_op;
	ret = cdev_add(char_dev, devno, 1);

	/*  Fail gracefully if need be */
	if (ret) {
		pr_warning("Error %d adding CSDIO char device '%s%d'",
				ret, devname, dev_minor);
		goto exit;
	}
	pr_info("'%s%d' char driver registered\n", devname, dev_minor);

	/*  create a /dev entry for transport drivers */
	new_device = device_create(g_csdio.m_driver_class, parent, devno, NULL,
			"%s%d", devname, dev_minor);
	if (!new_device) {
		pr_err("Can't create device node '/dev/%s%d'\n",
				devname, dev_minor);
		goto cleanup;
	}
	/* no irq attached */
	g_csdio.m_current_irq_mask = 0;

	if (csdio_cdev_update_permissions(devname, dev_minor)) {
		pr_warning("%s%d: Unable to update access permissions of the"
			" '/dev/%s%d'\n",
			devname, dev_minor, devname, dev_minor);
	}

	pr_info("%s%d: Device node '/dev/%s%d' created successfully\n",
			devname, dev_minor, devname, dev_minor);
	goto exit;
cleanup:
	cdev_del(char_dev);
exit:
	return new_device;
}

/* Looks for first non empty function, returns NULL otherwise */
static struct sdio_func *get_active_func(void)
{
	int i;

	for (i = 0; i < CSDIO_NUM_OF_SDIO_FUNCTIONS; i++) {
		if (g_csdio_func_table[i])
			return g_csdio_func_table[i]->m_func;
	}
	return NULL;
}

static ssize_t
show_vdd(struct device *dev, struct device_attribute *attr, char *buf)
{
	if (NULL == g_csdio.m_host)
		return snprintf(buf, PAGE_SIZE, "N/A\n");
	return snprintf(buf, PAGE_SIZE, "%d\n",
		g_csdio.m_host->ios.vdd);
}

static int
set_vdd_helper(int value)
{
	struct mmc_ios *ios = NULL;

	if (NULL == g_csdio.m_host) {
		pr_err("%s0: Set VDD, no MMC host assigned\n", CSDIO_DEV_NAME);
		return -ENXIO;
	}

	mmc_claim_host(g_csdio.m_host);
	ios = &g_csdio.m_host->ios;
	ios->vdd = value;
	g_csdio.m_host->ops->set_ios(g_csdio.m_host, ios);
	mmc_release_host(g_csdio.m_host);
	return 0;
}

static ssize_t
set_vdd(struct device *dev, struct device_attribute *att,
	const char *buf, size_t count)
{
	int value = 0;

	sscanf(buf, "%d", &value);
	if (set_vdd_helper(value))
		return -ENXIO;
	return count;
}

static DEVICE_ATTR(vdd, S_IRUGO | S_IWUSR,
	show_vdd, set_vdd);

static struct attribute *dev_attrs[] = {
	&dev_attr_vdd.attr,
	NULL,
};

static struct attribute_group dev_attr_grp = {
	.attrs = dev_attrs,
};

/*
 * The ioctl() implementation for control device
 */
static int csdio_ctrl_ioctl(struct inode *inode, struct file *filp,
		unsigned int cmd, unsigned long arg)
{
	int err = 0;
	int ret = 0;

	pr_info("CSDIO ctrl ioctl.\n");

	/*  extract the type and number bitfields
	    sanity check: return ENOTTY (inappropriate ioctl) before
	    access_ok()
	*/
	if ((_IOC_TYPE(cmd) != CSDIO_IOC_MAGIC) ||
			(_IOC_NR(cmd) > CSDIO_IOC_MAXNR)) {
		pr_err(CSDIO_DEV_NAME "Wrong ioctl command parameters\n");
		ret = -ENOTTY;
		goto exit;
	}

	/*  the direction is a bitmask, and VERIFY_WRITE catches R/W
	  transfers. `Type' is user-oriented, while access_ok is
	  kernel-oriented, so the concept of "read" and "write" is reversed
	  */
	if (_IOC_DIR(cmd) & _IOC_READ) {
		err = !access_ok(VERIFY_WRITE, (void __user *)arg,
				_IOC_SIZE(cmd));
	} else {
		if (_IOC_DIR(cmd) & _IOC_WRITE)
			err =  !access_ok(VERIFY_READ, (void __user *)arg,
					_IOC_SIZE(cmd));
	}
	if (err) {
		pr_err(CSDIO_DEV_NAME "Wrong ioctl access direction\n");
		ret = -EFAULT;
		goto exit;
	}

	switch (cmd) {
	case CSDIO_IOC_ENABLE_HIGHSPEED_MODE:
		pr_info(CSDIO_DEV_NAME" ENABLE_HIGHSPEED_MODE\n");
		break;
	case CSDIO_IOC_SET_DATA_TRANSFER_CLOCKS:
		{
			struct mmc_host *host = g_csdio.m_host;
			struct mmc_ios *ios = NULL;

			if (NULL == host) {
				pr_err("%s0: "
					"CSDIO_IOC_SET_DATA_TRANSFER_CLOCKS,"
					" no MMC host assigned\n",
					CSDIO_DEV_NAME);
				ret = -EFAULT;
				goto exit;
			}
			ios = &host->ios;

			mmc_claim_host(host);
			ret = get_user(host->ios.clock,
					(unsigned int __user *)arg);
			if (ret) {
				pr_err(CSDIO_DEV_NAME
					" get data from user space failed\n");
			} else {
				pr_err(CSDIO_DEV_NAME
					"SET_DATA_TRANSFER_CLOCKS(%d-%d)(%d)\n",
					host->f_min, host->f_max,
					host->ios.clock);
				host->ops->set_ios(host, ios);
			}
			mmc_release_host(host);
		}
		break;
	case CSDIO_IOC_ENABLE_ISR:
		{
			int ret;
			unsigned char reg;
			struct sdio_func *func = get_active_func();

			if (!func) {
				pr_err(CSDIO_DEV_NAME " CSDIO_IOC_ENABLE_ISR"
						" no active sdio function\n");
				ret = -EFAULT;
				goto exit;
			}
			pr_info(CSDIO_DEV_NAME
					" CSDIO_IOC_ENABLE_ISR func=%d\n",
					func->num);
			reg = g_csdio.m_current_irq_mask | 1;

			sdio_claim_host(func);
			sdio_f0_writeb(func, reg, SDIO_CCCR_IENx, &ret);
			sdio_release_host(func);
			if (ret) {
				pr_err(CSDIO_DEV_NAME
						" Can't sdio_f0_writeb (%d)\n",
						ret);
				goto exit;
			}
		}
		break;
	case CSDIO_IOC_DISABLE_ISR:
		{
			int ret;
			struct sdio_func *func = get_active_func();
			if (!func) {
				pr_err(CSDIO_DEV_NAME " CSDIO_IOC_ENABLE_ISR"
						" no active sdio function\n");
				ret = -EFAULT;
				goto exit;
			}
			pr_info(CSDIO_DEV_NAME
					" CSDIO_IOC_DISABLE_ISR func=%p\n",
					func);

			sdio_claim_host(func);
			ret = disable_sdio_client_isr(func);
			sdio_release_host(func);
			if (ret) {
				pr_err("%s0: Can't disable client isr (%d)\n",
					CSDIO_DEV_NAME, ret);
				goto exit;
			}
		}
	break;
	case CSDIO_IOC_SET_VDD:
		{
			unsigned int vdd = 0;

			ret = get_user(vdd, (unsigned int __user *)arg);
			if (ret) {
				pr_err("%s0: CSDIO_IOC_SET_VDD,"
					" get data from user space failed\n",
					CSDIO_DEV_NAME);
				goto exit;
			}
			pr_info(CSDIO_DEV_NAME" CSDIO_IOC_SET_VDD - %d\n", vdd);

			ret = set_vdd_helper(vdd);
			if (ret)
				goto exit;
		}
	break;
	case CSDIO_IOC_GET_VDD:
		{
			if (NULL == g_csdio.m_host) {
				pr_err("%s0: CSDIO_IOC_GET_VDD,"
					" no MMC host assigned\n",
					CSDIO_DEV_NAME);
				ret = -EFAULT;
				goto exit;
			}
			ret = put_user(g_csdio.m_host->ios.vdd,
				(unsigned short __user *)arg);
			if (ret) {
				pr_err("%s0: CSDIO_IOC_GET_VDD, put data"
					" to user space failed\n",
					CSDIO_DEV_NAME);
				goto exit;
			}
		}
	break;
	default:  /*  redundant, as cmd was checked against MAXNR */
		pr_warning(CSDIO_DEV_NAME" Redundant IOCTL\n");
		ret = -ENOTTY;
	}
exit:
	return ret;
}

static int csdio_ctrl_fasync(int fd, struct file *filp, int mode)
{
	pr_info(CSDIO_DEV_NAME
			" csdio_ctrl_fasync: fd=%d, filp=%p, mode=%d\n",
			fd, filp, mode);
	return fasync_helper(fd, filp, mode, &g_csdio.m_async_queue);
}

/*
 * Open and close
 */
static int csdio_ctrl_open(struct inode *inode, struct file *filp)
{
	int ret = 0;
	struct csdio_t *csdio_ctrl_drv = NULL; /*  device information */

	pr_info("CSDIO ctrl open.\n");
	csdio_ctrl_drv = container_of(inode->i_cdev, struct csdio_t, m_cdev);
	filp->private_data = csdio_ctrl_drv; /*  for other methods */
	return ret;
}

static int csdio_ctrl_release(struct inode *inode, struct file *filp)
{
	pr_info("CSDIO ctrl release.\n");
	/*  remove this filp from the asynchronously notified filp's */
	csdio_ctrl_fasync(-1, filp, 0);
	return 0;
}

static const struct file_operations csdio_ctrl_fops = {
	.owner =	THIS_MODULE,
	.ioctl =	csdio_ctrl_ioctl,
	.open  =	csdio_ctrl_open,
	.release =	csdio_ctrl_release,
	.fasync =	csdio_ctrl_fasync,
};

static int csdio_probe(struct sdio_func *func,
		const struct sdio_device_id *id)
{
	struct csdio_func_t *port;
	int ret = 0;
	struct mmc_host *host = func->card->host;

	if (NULL != g_csdio.m_host && g_csdio.m_host != host) {
		pr_info("%s: Device is on unexpected host\n",
			CSDIO_DEV_NAME);
		ret = -ENODEV;
		goto exit;
	}

	/* enforce single instance policy */
	if (g_csdio_func_table[func->num-1]) {
		pr_err("%s - only single SDIO device supported",
				sdio_func_id(func));
		ret = -EEXIST;
		goto exit;
	}

	port = kzalloc(sizeof(struct csdio_func_t), GFP_KERNEL);
	if (!port) {
		pr_err("Can't allocate memory\n");
		ret = -ENOMEM;
		goto exit;
	}

	/* initialize SDIO side */
	port->m_func = func;
	sdio_set_drvdata(func, port);

	pr_info("%s - SDIO device found. Function %d\n",
			sdio_func_id(func), func->num);

	port->m_device = csdio_cdev_init(&port->m_cdev, &csdio_transport_fops,
			csdio_minor + port->m_func->num,
			TP_DEV_NAME, &port->m_func->dev);

	/* create appropriate char device */
	if (!port->m_device)
		goto free;

	if (0 == g_csdio.m_num_of_func && NULL == host_name)
		g_csdio.m_host = host;
	g_csdio.m_num_of_func++;
	g_csdio_func_table[func->num-1] = port;
	port->m_enabled = TRUE;
	goto exit;
free:
	kfree(port);
exit:
	return ret;
}

static void csdio_remove(struct sdio_func *func)
{
	struct csdio_func_t *port = sdio_get_drvdata(func);

	csdio_transport_cleanup(port);
	sdio_claim_host(func);
	sdio_release_irq(func);
	sdio_disable_func(func);
	sdio_release_host(func);
	kfree(port);
	g_csdio_func_table[func->num-1] = NULL;
	g_csdio.m_num_of_func--;
	if (0 == g_csdio.m_num_of_func && NULL == host_name)
		g_csdio.m_host = NULL;
	pr_info("%s%d: Device removed (%s). Function %d\n",
		CSDIO_DEV_NAME, func->num, sdio_func_id(func), func->num);
}

/* CONFIG_CSDIO_VENDOR_ID and CONFIG_CSDIO_DEVICE_ID are defined in Kconfig.
 * Use kernel configuration to change the values or overwrite them through
 * module parameters */
static struct sdio_device_id csdio_ids[] = {
	{ SDIO_DEVICE(CONFIG_CSDIO_VENDOR_ID, CONFIG_CSDIO_DEVICE_ID) },
	{ /* end: all zeroes */},
};

MODULE_DEVICE_TABLE(sdio, csdio_ids);

static struct sdio_driver csdio_driver = {
	.probe      = csdio_probe,
	.remove     = csdio_remove,
	.name       = "csdio",
	.id_table   = csdio_ids,
};

static void __exit csdio_exit(void)
{
	dev_t devno = MKDEV(csdio_major, csdio_minor);

	sdio_unregister_driver(&csdio_driver);
	sysfs_remove_group(&g_csdio.m_device->kobj, &dev_attr_grp);
	kfree(g_sdio_buffer);
	device_destroy(g_csdio.m_driver_class, devno);
	cdev_del(&g_csdio.m_cdev);
	class_destroy(g_csdio.m_driver_class);
	unregister_chrdev_region(devno, csdio_transport_nr_devs);
	pr_info("%s: Exit driver module\n", CSDIO_DEV_NAME);
}

static char *csdio_devnode(struct device *dev, mode_t *mode)
{
	*mode = CSDIO_DEV_PERMISSIONS;
	return NULL;
}

static int __init csdio_init(void)
{
	int ret = 0;
	dev_t devno = 0;

	pr_info("Init CSDIO driver module.\n");

	/*  Get a range of minor numbers to work with, asking for a dynamic */
	/*  major unless directed otherwise at load time. */
	if (csdio_major) {
		devno = MKDEV(csdio_major, csdio_minor);
		ret = register_chrdev_region(devno, csdio_transport_nr_devs,
				CSDIO_DEV_NAME);
	} else {
		ret = alloc_chrdev_region(&devno, csdio_minor,
				csdio_transport_nr_devs, CSDIO_DEV_NAME);
		csdio_major = MAJOR(devno);
	}
	if (ret < 0) {
		pr_err("CSDIO: can't get major %d\n", csdio_major);
		goto exit;
	}
	pr_info("CSDIO char driver major number is %d\n", csdio_major);

	/* kernel module got parameters: overwrite vendor and device id's */
	if ((csdio_vendor_id != 0) && (csdio_device_id != 0)) {
		csdio_ids[0].vendor = (u16)csdio_vendor_id;
		csdio_ids[0].device = (u16)csdio_device_id;
	}

	/*  prepare create /dev/... instance */
	g_csdio.m_driver_class = class_create(THIS_MODULE, CSDIO_DEV_NAME);
	if (IS_ERR(g_csdio.m_driver_class)) {
		ret = -ENOMEM;
		pr_err(CSDIO_DEV_NAME " class_create failed\n");
		goto unregister_region;
	}
	g_csdio.m_driver_class->devnode = csdio_devnode;

	/*  create CSDIO ctrl driver */
	g_csdio.m_device = csdio_cdev_init(&g_csdio.m_cdev,
		&csdio_ctrl_fops, csdio_minor, CSDIO_DEV_NAME, NULL);
	if (!g_csdio.m_device) {
		pr_err("%s: Unable to create ctrl driver\n",
			CSDIO_DEV_NAME);
		goto destroy_class;
	}

	g_sdio_buffer = kmalloc(CSDIO_SDIO_BUFFER_SIZE, GFP_KERNEL);
	if (!g_sdio_buffer) {
		pr_err("Unable to allocate %d bytes\n", CSDIO_SDIO_BUFFER_SIZE);
		ret = -ENOMEM;
		goto destroy_cdev;
	}

	ret = sysfs_create_group(&g_csdio.m_device->kobj, &dev_attr_grp);
	if (ret) {
		pr_err("%s: Unable to create device attribute\n",
			CSDIO_DEV_NAME);
		goto free_sdio_buff;
	}

	g_csdio.m_num_of_func = 0;
	g_csdio.m_host = NULL;

	if (NULL != host_name) {
		struct device *dev = bus_find_device_by_name(&platform_bus_type,
			NULL, host_name);
		if (NULL != dev) {
			g_csdio.m_host = dev_get_drvdata(dev);
		} else {
			pr_err("%s: Host '%s' doesn't exist!\n", CSDIO_DEV_NAME,
				host_name);
		}
	}

	pr_info("%s: Match with VendorId=0x%X, DeviceId=0x%X, Host = %s\n",
		CSDIO_DEV_NAME, csdio_device_id, csdio_vendor_id,
		(NULL == host_name) ? "Any" : host_name);

	/* register sdio driver */
	ret = sdio_register_driver(&csdio_driver);
	if (ret) {
		pr_err("%s: Unable to register as SDIO driver\n",
			CSDIO_DEV_NAME);
		goto remove_group;
	}

	goto exit;

remove_group:
	sysfs_remove_group(&g_csdio.m_device->kobj, &dev_attr_grp);
free_sdio_buff:
	kfree(g_sdio_buffer);
destroy_cdev:
	cdev_del(&g_csdio.m_cdev);
destroy_class:
	class_destroy(g_csdio.m_driver_class);
unregister_region:
	unregister_chrdev_region(devno, csdio_transport_nr_devs);
exit:
	return ret;
}
module_param(csdio_vendor_id, uint, S_IRUGO);
module_param(csdio_device_id, uint, S_IRUGO);
module_param(host_name, charp, S_IRUGO);

module_init(csdio_init);
module_exit(csdio_exit);

MODULE_AUTHOR("The Linux Foundation");
MODULE_DESCRIPTION("CSDIO device driver version " VERSION);
MODULE_VERSION(VERSION);
MODULE_LICENSE("GPL v2");