--- /dev/null
+++ b/Documentation/csdio.txt
@@ -0,0 +1,189 @@
+Introduction
+============
+The Char SDIO Device Driver is an interface which exposes an SDIO
+card/function from kernel space as a char device in user space.
+
+The driver doesn't interact with any HW directly. It relies on SDIO
+card/function interface provided as a part of Linux kernel.
+
+Hardware description
+====================
+Each SDIO device/card contains an SDIO client HW block.
+The host interacts with the device by sending byte sequences called
+command (CMD). Some commands can be followed by data blocks. The
+device sends back a byte sequence called response (R) and a data
+block if required. CMD3, CMD5 and CMD7 are used to initialize the
+device. CMD52 and CMD53 are used to access the device. Command
+format and properties are defined by SDIO Specification document
+published by SD Association:
+    http://www.sdcard.org/developers/tech/sdio/.
+
+CMD52 and CMD53 can access up to 8 address spaces called Functions.
+Function 0 contains system information predefined by SD/SDIO
+standard and Functions 1-7 are defined by the SDIO device
+manufacturer.
+
+An SDIO device/card can send an interrupt to SDIO host. This
+interrupt is intercepted and handled by SDIO host.
+
+Software description
+====================
+Linux provides a framework for handling SDIO devices. It implements
+kind of plug-and-play model in which the Linux SDIO Host Driver is
+responsible for initializing an SDIO device upon insertion. It also
+reads device/card identification information and enumerates functions
+provided by the device and then looks up in the list of
+preregistered user SDIO drivers for a suitable one.
+
+During its lifecycle the user SDIO driver interacts with the Linux
+SDIO Host Driver in order to send/receive information to/from SDIO
+device/card. The user SDIO driver doesn't work with CMD52/CMD53
+directly. Instead it uses an abstraction provided by the Linux SDIO
+Host Driver.
+
+The Linux SDIO Host Driver is also in charge of handling SDIO
+interrupts. User SDIO driver can register its own callback in SDIO
+Host Driver and get a notification about interrupt event.
+
+The Char SDIO Device Driver follows the design guidelines mentioned
+above. It provides the following functionality:
+
+ - Register itself in the user SDIO drivers list;
+ - Handle Probe event upon insertion of supported card/device;
+ - Creates and maintains a char device driver for each SDIO Function
+   found in the card/device;
+ - Translates read/write/ioctl calls to appropriate SDIO call
+   sequences;
+
+In order to handle general SDIO configuration functionality and
+Function 0 the Char SDIO Device Driver provides additional
+simplified char device driver.
+
+The Manufacturer and Device IDs of handled SDIO device should be
+provided as parameters for kernel module or as configuration
+parameters in case of statically linked driver.
+
+Design
+======
+The main goal of the Char SDIO Device Driver is to expose an SDIO
+card/device from kernel space to user space as a char device driver.
+The driver should be generic and simple as far as possible.
+
+The biggest design tradeoff is maintaining a balance between the
+system call overhead required to initiate an SDIO transaction from
+user space and overall SDIO communication performance. But luckily,
+because of nature of SDIO protocol, this overhead is negligible
+comparing to time required to execute SDIO transaction itself. So,
+each CMD52 (read or write) consists from single ioctl system call.
+And each CMD53 invokes single ioctl system call followed by read or
+write system call.
+
+The Char SDIO Device Driver registers its own class of the devices
+called 'csdio'. This class will serve as a common roof for all SDIO
+devices served by different instances of the Char SDIO Device Driver.
+Additional benefit from maintaining its own class is the driver
+ability to overwrite default permissions of the dev nodes created by
+the driver.
+
+Power Management
+================
+None
+
+SMP/multi-core
+==============
+The driver does not anticipate any issues related to multi-core
+since it is expected to run on one core only.
+
+Security
+========
+None
+
+Performance
+===========
+None
+
+Interface
+=========
+The Char SDIO Device Driver has two char device interfaces:
+ - Control Interface;
+ - Function Interface.
+
+Char SDIO Device Driver Control Interface consists of:
+ - open()   - device node is /dev/csdio0;
+ - close()
+ - ioctl()  - the following options are available:
+   - CSDIO_IOC_ENABLE_HIGHSPEED_MODE;
+   - CSDIO_IOC_SET_DATA_TRANSFER_CLOCKS;
+   - CSDIO_IOC_ENABLE_ISR;
+   - CSDIO_IOC_DISABLE_ISR.
+
+Char SDIO Device Driver Function Interface consists of:
+ - open()  - device node is /dev/csdiofX, where X is Function Id;
+ - close()
+ - read()  - send CMD53 read;
+ - write() - send CMD53 write;
+ - ioctl() - the following options are available:
+   - CSDIO_IOC_SET_OP_CODE - 0 fixed adrress, 1 autoincrement.
+   - CSDIO_IOC_FUNCTION_SET_BLOCK_SIZE;
+   - CSDIO_IOC_SET_BLOCK_MODE - 0 byte mode, 1 block mode;
+   - CSDIO_IOC_CMD52 - execute CMD52, receives the
+        following structure as a parameter:
+            struct csdio_cmd52_ctrl_t {
+	            uint32_t    m_write; // 0 - read, 1 -write
+	            uint32_t    m_address;
+	            uint32_t    m_data;  // data to write or read data
+	            uint32_t    m_ret;   // command execution status
+            }__attribute__ ((packed));
+   - CSDIO_IOC_CMD53 - setup CMD53 data transfer, receives the
+        following structure as a parameter:
+            struct csdio_cmd53_ctrl_t {
+	            uint32_t    m_block_mode;
+	            uint32_t    m_op_code;
+	            uint32_t    m_address;
+            }__attribute__ ((packed));
+   - CSDIO_IOC_CONNECT_ISR;
+   - CSDIO_IOC_DISCONNECT_ISR;
+   - CSDIO_IOC_GET_VDD;
+   - CSDIO_IOC_SET_VDD.
+
+Additionally, user space application can use fcntl system call with
+parameters F_SETOWN and F_SETFL in order to set an asynchronous
+callback for SDIO interrupt.
+
+Driver parameters
+=================
+If the driver is compiled as a kernel module, the following
+parameters can be used in order to provide Manufacturer and Device IDs
+upon module download:
+ - csdio_vendor_id;
+ - csdio_device_id.
+If the driver is intended to work with specific SDIO host the
+host_name parameter should be added followed by the name of the MMC
+host platform device.
+
+Config options
+==============
+These are the kernel configuration options:
+ - CONFIG_CSDIO_VENDOR_ID;
+ - CONFIG_CSDIO_DEVICE_ID.
+
+Dependencies
+============
+The Char SDIO Device Driver depends on Linux SDIO Host Driver.
+
+User space utilities
+====================
+None
+
+Other
+=====
+None
+
+Known issues
+============
+None
+
+To do
+=====
+Provide mechanism to support a number of SDIO devices simultaneously
+connected to different SDIO hosts.
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -600,5 +600,28 @@ config TILE_SROM
 	  device appear much like a simple EEPROM, and knows
 	  how to partition a single ROM for multiple purposes.
 
+config MMC_GENERIC_CSDIO
+	tristate "Generic sdio driver"
+	default n
+	help
+	  SDIO function driver that extends SDIO card as character device
+	  in user space.
+
+config CSDIO_VENDOR_ID
+	hex "Card VendorId"
+	depends on MMC_GENERIC_CSDIO
+	default "0"
+	help
+	  Enter vendor id for targeted sdio device, this may be overwritten by
+	  module parameters.
+
+config CSDIO_DEVICE_ID
+	hex "CardDeviceId"
+	depends on MMC_GENERIC_CSDIO
+	default "0"
+	help
+	  Enter device id for targeted sdio device, this may be overwritten by
+	  module parameters.
+.
 endmenu
 
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -61,3 +61,4 @@ obj-$(CONFIG_JS_RTC)		+= js-rtc.o
 js-rtc-y = rtc.o
 
 obj-$(CONFIG_TILE_SROM)		+= tile-srom.o
+obj-$(CONFIG_MMC_GENERIC_CSDIO)	+= csdio.o
--- /dev/null
+++ b/drivers/char/csdio.c
@@ -0,0 +1,1070 @@
+/*
+ * Copyright (c) 2010, Code Aurora Forum. 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 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:%zd (Bl:%zd, 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 (%zd)"
+				"(Md:%d, Addr:0x%04X, Sz:%zd)\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 (%zd)"
+				"(Md:%d, Addr:0x%04X, Sz:%zd)\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 long csdio_transport_ioctl(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=%pK\n",
+				func->num, 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,
+	.unlocked_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 long csdio_ctrl_ioctl(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,
+	.unlocked_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 = 1;
+	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("Code Aurora Forum");
+MODULE_DESCRIPTION("CSDIO device driver version " VERSION);
+MODULE_VERSION(VERSION);
+MODULE_LICENSE("GPL v2");
--- /dev/null
+++ b/include/linux/csdio.h
@@ -0,0 +1,37 @@
+#ifndef CSDIO_H
+#define CSDIO_H
+
+#include <linux/ioctl.h>
+
+#define CSDIO_IOC_MAGIC  'm'
+
+#define CSDIO_IOC_ENABLE_HIGHSPEED_MODE      _IO(CSDIO_IOC_MAGIC, 0)
+#define CSDIO_IOC_SET_DATA_TRANSFER_CLOCKS   _IO(CSDIO_IOC_MAGIC, 1)
+#define CSDIO_IOC_SET_OP_CODE                _IO(CSDIO_IOC_MAGIC, 2)
+#define CSDIO_IOC_FUNCTION_SET_BLOCK_SIZE    _IO(CSDIO_IOC_MAGIC, 3)
+#define CSDIO_IOC_SET_BLOCK_MODE             _IO(CSDIO_IOC_MAGIC, 4)
+#define CSDIO_IOC_CONNECT_ISR                _IO(CSDIO_IOC_MAGIC, 5)
+#define CSDIO_IOC_DISCONNECT_ISR             _IO(CSDIO_IOC_MAGIC, 6)
+#define CSDIO_IOC_CMD52                      _IO(CSDIO_IOC_MAGIC, 7)
+#define CSDIO_IOC_CMD53                      _IO(CSDIO_IOC_MAGIC, 8)
+#define CSDIO_IOC_ENABLE_ISR                 _IO(CSDIO_IOC_MAGIC, 9)
+#define CSDIO_IOC_DISABLE_ISR                _IO(CSDIO_IOC_MAGIC, 10)
+#define CSDIO_IOC_SET_VDD                    _IO(CSDIO_IOC_MAGIC, 11)
+#define CSDIO_IOC_GET_VDD                    _IO(CSDIO_IOC_MAGIC, 12)
+
+#define CSDIO_IOC_MAXNR   12
+
+struct csdio_cmd53_ctrl_t {
+	uint32_t    m_block_mode;   /* data tran. byte(0)/block(1) mode */
+	uint32_t    m_op_code;      /* address auto increment flag */
+	uint32_t    m_address;
+} __attribute__ ((packed));
+
+struct csdio_cmd52_ctrl_t {
+	uint32_t    m_write;
+	uint32_t    m_address;
+	uint32_t    m_data;
+	uint32_t    m_ret;
+} __attribute__ ((packed));
+
+#endif
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -86,6 +86,7 @@ header-y += coff.h
 header-y += connector.h
 header-y += const.h
 header-y += cramfs_fs.h
+header-y += csdio.h
 header-y += cuda.h
 header-y += cyclades.h
 header-y += cycx_cfm.h
