arch/arm/mach-msm/hsic_sysmon.c - kernel/msm - Gitiles

 /* Copyright (c) 2012, 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.
  */

 /* add additional information to our printk's */
 #define pr_fmt(fmt) "%s: " fmt "\n", __func__

 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/kref.h>
 #include <linux/platform_device.h>
 #include <linux/uaccess.h>
 #include <linux/usb.h>
 #include <linux/debugfs.h>

 #include "hsic_sysmon.h"
 #include "sysmon.h"

 #define DRIVER_DESC	"HSIC System monitor driver"

 enum hsic_sysmon_op {
 	HSIC_SYSMON_OP_READ = 0,
 	HSIC_SYSMON_OP_WRITE,
 	NUM_OPS
 };

 struct hsic_sysmon {
 	struct usb_device	*udev;
 	struct usb_interface	*ifc;
 	__u8			in_epaddr;
 	__u8			out_epaddr;
 	unsigned int		pipe[NUM_OPS];
 	struct kref		kref;
 	struct platform_device	pdev;
 	int			id;

 	/* debugging counters */
 	atomic_t		dbg_bytecnt[NUM_OPS];
 	atomic_t		dbg_pending[NUM_OPS];
 };
 static struct hsic_sysmon *hsic_sysmon_devices[NUM_HSIC_SYSMON_DEVS];

 static void hsic_sysmon_delete(struct kref *kref)
 {
 	struct hsic_sysmon *hs = container_of(kref, struct hsic_sysmon, kref);

 	usb_put_dev(hs->udev);
 	hsic_sysmon_devices[hs->id] = NULL;
 	kfree(hs);
 }

 /**
  * hsic_sysmon_open() - Opens the system monitor bridge.
  * @id: the HSIC system monitor device to open
  *
  * This should only be called after the platform_device "sys_mon" with id
  * SYSMON_SS_EXT_MODEM has been added. The simplest way to do that is to
  * register a platform_driver and its probe will be called when the HSIC
  * device is ready.
  */
 int hsic_sysmon_open(enum hsic_sysmon_device_id id)
 {
 	struct hsic_sysmon	*hs;

 	if (id >= NUM_HSIC_SYSMON_DEVS) {
 		pr_err("invalid dev id(%d)", id);
 		return -ENODEV;
 	}

 	hs = hsic_sysmon_devices[id];
 	if (!hs) {
 		pr_err("dev is null");
 		return -ENODEV;
 	}

 	kref_get(&hs->kref);

 	return 0;
 }
 EXPORT_SYMBOL(hsic_sysmon_open);

 /**
  * hsic_sysmon_close() - Closes the system monitor bridge.
  * @id: the HSIC system monitor device to close
  */
 void hsic_sysmon_close(enum hsic_sysmon_device_id id)
 {
 	struct hsic_sysmon	*hs;

 	if (id >= NUM_HSIC_SYSMON_DEVS) {
 		pr_err("invalid dev id(%d)", id);
 		return;
 	}

 	hs = hsic_sysmon_devices[id];
 	kref_put(&hs->kref, hsic_sysmon_delete);
 }
 EXPORT_SYMBOL(hsic_sysmon_close);

 /**
  * hsic_sysmon_readwrite() - Common function to send read/write over HSIC
  */
 static int hsic_sysmon_readwrite(enum hsic_sysmon_device_id id, void *data,
 				 size_t len, size_t *actual_len, int timeout,
 				 enum hsic_sysmon_op op)
 {
 	struct hsic_sysmon	*hs;
 	int			ret;
 	const char		*opstr = (op == HSIC_SYSMON_OP_READ) ?
 						"read" : "write";

 	pr_debug("%s: id:%d, data len:%d, timeout:%d", opstr, id, len, timeout);

 	if (id >= NUM_HSIC_SYSMON_DEVS) {
 		pr_err("invalid dev id(%d)", id);
 		return -ENODEV;
 	}

 	if (!len) {
 		pr_err("length(%d) must be greater than 0", len);
 		return -EINVAL;
 	}

 	hs = hsic_sysmon_devices[id];
 	if (!hs) {
 		pr_err("device was not opened");
 		return -ENODEV;
 	}

 	if (!hs->ifc) {
 		pr_err("can't %s, device disconnected", opstr);
 		return -ENODEV;
 	}

 	ret = usb_autopm_get_interface(hs->ifc);
 	if (ret < 0) {
 		dev_err(&hs->ifc->dev, "can't %s, autopm_get failed:%d\n",
 			opstr, ret);
 		return ret;
 	}

 	atomic_inc(&hs->dbg_pending[op]);

 	ret = usb_bulk_msg(hs->udev, hs->pipe[op], data, len, actual_len,
 				timeout);

 	atomic_dec(&hs->dbg_pending[op]);

 	if (ret)
 		dev_err(&hs->ifc->dev,
 			"can't %s, usb_bulk_msg failed, err:%d\n", opstr, ret);
 	else
 		atomic_add(*actual_len, &hs->dbg_bytecnt[op]);

 	usb_autopm_put_interface(hs->ifc);
 	return ret;
 }

 /**
  * hsic_sysmon_read() - Read data from the HSIC sysmon interface.
  * @id: the HSIC system monitor device to open
  * @data: pointer to caller-allocated buffer to fill in
  * @len: length in bytes of the buffer
  * @actual_len: pointer to a location to put the actual length read
  *	in bytes
  * @timeout: time in msecs to wait for the message to complete before
  *	timing out (if 0 the wait is forever)
  *
  * Context: !in_interrupt ()
  *
  * Synchronously reads data from the HSIC interface. The call will return
  * after the read has completed, encountered an error, or timed out. Upon
  * successful return actual_len will reflect the number of bytes read.
  *
  * If successful, it returns 0, otherwise a negative error number.  The number
  * of actual bytes transferred will be stored in the actual_len paramater.
  */
 int hsic_sysmon_read(enum hsic_sysmon_device_id id, char *data, size_t len,
 		     size_t *actual_len, int timeout)
 {
 	return hsic_sysmon_readwrite(id, data, len, actual_len,
 					timeout, HSIC_SYSMON_OP_READ);
 }
 EXPORT_SYMBOL(hsic_sysmon_read);

 /**
  * hsic_sysmon_write() - Write data to the HSIC sysmon interface.
  * @id: the HSIC system monitor device to open
  * @data: pointer to caller-allocated buffer to write
  * @len: length in bytes of the data in buffer to write
  * @actual_len: pointer to a location to put the actual length written
  *	in bytes
  * @timeout: time in msecs to wait for the message to complete before
  *	timing out (if 0 the wait is forever)
  *
  * Context: !in_interrupt ()
  *
  * Synchronously writes data to the HSIC interface. The call will return
  * after the write has completed, encountered an error, or timed out. Upon
  * successful return actual_len will reflect the number of bytes written.
  *
  * If successful, it returns 0, otherwise a negative error number.  The number
  * of actual bytes transferred will be stored in the actual_len paramater.
  */
 int hsic_sysmon_write(enum hsic_sysmon_device_id id, const char *data,
 		      size_t len, int timeout)
 {
 	size_t actual_len;
 	return hsic_sysmon_readwrite(id, (void *)data, len, &actual_len,
 					timeout, HSIC_SYSMON_OP_WRITE);
 }
 EXPORT_SYMBOL(hsic_sysmon_write);

 #if defined(CONFIG_DEBUG_FS)
 #define DEBUG_BUF_SIZE	512
 static ssize_t sysmon_debug_read_stats(struct file *file, char __user *ubuf,
 					size_t count, loff_t *ppos)
 {
 	char	*buf;
 	int	i, ret = 0;

 	buf = kzalloc(sizeof(char) * DEBUG_BUF_SIZE, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	for (i = 0; i < NUM_HSIC_SYSMON_DEVS; i++) {
 		struct hsic_sysmon *hs = hsic_sysmon_devices[i];
 		if (!hs)
 			continue;

 		ret += scnprintf(buf, DEBUG_BUF_SIZE,
 				"---HSIC Sysmon #%d---\n"
 				"epin:%d, epout:%d\n"
 				"bytes to host: %d\n"
 				"bytes to mdm: %d\n"
 				"pending reads: %d\n"
 				"pending writes: %d\n",
 				i, hs->in_epaddr & ~0x80, hs->out_epaddr,
 				atomic_read(
 				    &hs->dbg_bytecnt[HSIC_SYSMON_OP_READ]),
 				atomic_read(
 				    &hs->dbg_bytecnt[HSIC_SYSMON_OP_WRITE]),
 				atomic_read(
 				    &hs->dbg_pending[HSIC_SYSMON_OP_READ]),
 				atomic_read(
 				    &hs->dbg_pending[HSIC_SYSMON_OP_WRITE])
 				);
 	}

 	ret = simple_read_from_buffer(ubuf, count, ppos, buf, ret);
 	kfree(buf);
 	return ret;
 }

 static ssize_t sysmon_debug_reset_stats(struct file *file,
 					const char __user *buf,
 					size_t count, loff_t *ppos)
 {
 	int	i;

 	for (i = 0; i < NUM_HSIC_SYSMON_DEVS; i++) {
 		struct hsic_sysmon *hs = hsic_sysmon_devices[i];
 		if (hs) {
 			atomic_set(&hs->dbg_bytecnt[HSIC_SYSMON_OP_READ], 0);
 			atomic_set(&hs->dbg_bytecnt[HSIC_SYSMON_OP_WRITE], 0);
 			atomic_set(&hs->dbg_pending[HSIC_SYSMON_OP_READ], 0);
 			atomic_set(&hs->dbg_pending[HSIC_SYSMON_OP_WRITE], 0);
 		}
 	}

 	return count;
 }

 const struct file_operations sysmon_stats_ops = {
 	.read = sysmon_debug_read_stats,
 	.write = sysmon_debug_reset_stats,
 };

 static struct dentry *dent;

 static void hsic_sysmon_debugfs_init(void)
 {
 	struct dentry *dfile;

 	dent = debugfs_create_dir("hsic_sysmon", 0);
 	if (IS_ERR(dent))
 		return;

 	dfile = debugfs_create_file("status", 0444, dent, 0, &sysmon_stats_ops);
 	if (!dfile || IS_ERR(dfile))
 		debugfs_remove(dent);
 }

 static void hsic_sysmon_debugfs_cleanup(void)
 {
 	if (dent) {
 		debugfs_remove_recursive(dent);
 		dent = NULL;
 	}
 }
 #else
 static inline void hsic_sysmon_debugfs_init(void) { }
 static inline void hsic_sysmon_debugfs_cleanup(void) { }
 #endif

 static void hsic_sysmon_pdev_release(struct device *dev) { }

 static int
 hsic_sysmon_probe(struct usb_interface *ifc, const struct usb_device_id *id)
 {
 	struct hsic_sysmon		*hs;
 	struct usb_host_interface	*ifc_desc;
 	struct usb_endpoint_descriptor	*ep_desc;
 	int				i;
 	int				ret = -ENOMEM;
 	__u8				ifc_num;

 	pr_debug("id:%lu", id->driver_info);

 	ifc_num = ifc->cur_altsetting->desc.bInterfaceNumber;

 	/* is this the interface we're looking for? */
 	if (ifc_num != id->driver_info)
 		return -ENODEV;

 	hs = kzalloc(sizeof(*hs), GFP_KERNEL);
 	if (!hs) {
 		pr_err("unable to allocate hsic_sysmon");
 		return -ENOMEM;
 	}

 	hs->udev = usb_get_dev(interface_to_usbdev(ifc));
 	hs->ifc = ifc;
 	kref_init(&hs->kref);

 	ifc_desc = ifc->cur_altsetting;
 	for (i = 0; i < ifc_desc->desc.bNumEndpoints; i++) {
 		ep_desc = &ifc_desc->endpoint[i].desc;

 		if (!hs->in_epaddr && usb_endpoint_is_bulk_in(ep_desc)) {
 			hs->in_epaddr = ep_desc->bEndpointAddress;
 			hs->pipe[HSIC_SYSMON_OP_READ] =
 				usb_rcvbulkpipe(hs->udev, hs->in_epaddr);
 		}

 		if (!hs->out_epaddr && usb_endpoint_is_bulk_out(ep_desc)) {
 			hs->out_epaddr = ep_desc->bEndpointAddress;
 			hs->pipe[HSIC_SYSMON_OP_WRITE] =
 				usb_sndbulkpipe(hs->udev, hs->out_epaddr);
 		}
 	}

 	if (!(hs->in_epaddr && hs->out_epaddr)) {
 		pr_err("could not find bulk in and bulk out endpoints");
 		ret = -ENODEV;
 		goto error;
 	}

 	hs->id = HSIC_SYSMON_DEV_EXT_MODEM;
 	hsic_sysmon_devices[HSIC_SYSMON_DEV_EXT_MODEM] = hs;
 	usb_set_intfdata(ifc, hs);

 	hs->pdev.name = "sys_mon";
 	hs->pdev.id = SYSMON_SS_EXT_MODEM;
 	hs->pdev.dev.release = hsic_sysmon_pdev_release;
 	platform_device_register(&hs->pdev);

 	pr_debug("complete");

 	return 0;

 error:
 	if (hs)
 		kref_put(&hs->kref, hsic_sysmon_delete);

 	return ret;
 }

 static void hsic_sysmon_disconnect(struct usb_interface *ifc)
 {
 	struct hsic_sysmon	*hs = usb_get_intfdata(ifc);

 	platform_device_unregister(&hs->pdev);
 	kref_put(&hs->kref, hsic_sysmon_delete);
 	usb_set_intfdata(ifc, NULL);
 }

 static int hsic_sysmon_suspend(struct usb_interface *ifc, pm_message_t message)
 {
 	return 0;
 }

 static int hsic_sysmon_resume(struct usb_interface *ifc)
 {
 	return 0;
 }

 /* driver_info maps to the interface number corresponding to sysmon */
 static const struct usb_device_id hsic_sysmon_ids[] = {
 	{ USB_DEVICE(0x5c6, 0x9048), .driver_info = 1, },
 	{ USB_DEVICE(0x5c6, 0x904C), .driver_info = 1, },
 	{} /* terminating entry */
 };
 MODULE_DEVICE_TABLE(usb, hsic_sysmon_ids);

 static struct usb_driver hsic_sysmon_driver = {
 	.name =		"hsic_sysmon",
 	.probe =	hsic_sysmon_probe,
 	.disconnect =	hsic_sysmon_disconnect,
 	.suspend =	hsic_sysmon_suspend,
 	.resume =	hsic_sysmon_resume,
 	.id_table =	hsic_sysmon_ids,
 	.supports_autosuspend = 1,
 };

 static int __init hsic_sysmon_init(void)
 {
 	int ret;

 	ret = usb_register(&hsic_sysmon_driver);
 	if (ret) {
 		pr_err("unable to register " DRIVER_DESC);
 		return ret;
 	}

 	hsic_sysmon_debugfs_init();
 	return 0;
 }

 static void __exit hsic_sysmon_exit(void)
 {
 	hsic_sysmon_debugfs_cleanup();
 	usb_deregister(&hsic_sysmon_driver);
 }

 module_init(hsic_sysmon_init);
 module_exit(hsic_sysmon_exit);

 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL v2");
	/* Copyright (c) 2012, 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.
	*/

	/* add additional information to our printk's */
	#define pr_fmt(fmt) "%s: " fmt "\n", __func__

	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/kref.h>
	#include <linux/platform_device.h>
	#include <linux/uaccess.h>
	#include <linux/usb.h>
	#include <linux/debugfs.h>

	#include "hsic_sysmon.h"
	#include "sysmon.h"

	#define DRIVER_DESC "HSIC System monitor driver"

	enum hsic_sysmon_op {
	HSIC_SYSMON_OP_READ = 0,
	HSIC_SYSMON_OP_WRITE,
	NUM_OPS
	};

	struct hsic_sysmon {
	struct usb_device *udev;
	struct usb_interface *ifc;
	__u8 in_epaddr;
	__u8 out_epaddr;
	unsigned int pipe[NUM_OPS];
	struct kref kref;
	struct platform_device pdev;
	int id;

	/* debugging counters */
	atomic_t dbg_bytecnt[NUM_OPS];
	atomic_t dbg_pending[NUM_OPS];
	};
	static struct hsic_sysmon *hsic_sysmon_devices[NUM_HSIC_SYSMON_DEVS];

	static void hsic_sysmon_delete(struct kref *kref)
	{
	struct hsic_sysmon *hs = container_of(kref, struct hsic_sysmon, kref);

	usb_put_dev(hs->udev);
	hsic_sysmon_devices[hs->id] = NULL;
	kfree(hs);
	}

	/**
	* hsic_sysmon_open() - Opens the system monitor bridge.
	* @id: the HSIC system monitor device to open
	*
	* This should only be called after the platform_device "sys_mon" with id
	* SYSMON_SS_EXT_MODEM has been added. The simplest way to do that is to
	* register a platform_driver and its probe will be called when the HSIC
	* device is ready.
	*/
	int hsic_sysmon_open(enum hsic_sysmon_device_id id)
	{
	struct hsic_sysmon *hs;

	if (id >= NUM_HSIC_SYSMON_DEVS) {
	pr_err("invalid dev id(%d)", id);
	return -ENODEV;
	}

	hs = hsic_sysmon_devices[id];
	if (!hs) {
	pr_err("dev is null");
	return -ENODEV;
	}

	kref_get(&hs->kref);

	return 0;
	}
	EXPORT_SYMBOL(hsic_sysmon_open);

	/**
	* hsic_sysmon_close() - Closes the system monitor bridge.
	* @id: the HSIC system monitor device to close
	*/
	void hsic_sysmon_close(enum hsic_sysmon_device_id id)
	{
	struct hsic_sysmon *hs;

	if (id >= NUM_HSIC_SYSMON_DEVS) {
	pr_err("invalid dev id(%d)", id);
	return;
	}

	hs = hsic_sysmon_devices[id];
	kref_put(&hs->kref, hsic_sysmon_delete);
	}
	EXPORT_SYMBOL(hsic_sysmon_close);

	/**
	* hsic_sysmon_readwrite() - Common function to send read/write over HSIC
	*/
	static int hsic_sysmon_readwrite(enum hsic_sysmon_device_id id, void *data,
	size_t len, size_t *actual_len, int timeout,
	enum hsic_sysmon_op op)
	{
	struct hsic_sysmon *hs;
	int ret;
	const char *opstr = (op == HSIC_SYSMON_OP_READ) ?
	"read" : "write";

	pr_debug("%s: id:%d, data len:%d, timeout:%d", opstr, id, len, timeout);

	if (id >= NUM_HSIC_SYSMON_DEVS) {
	pr_err("invalid dev id(%d)", id);
	return -ENODEV;
	}

	if (!len) {
	pr_err("length(%d) must be greater than 0", len);
	return -EINVAL;
	}

	hs = hsic_sysmon_devices[id];
	if (!hs) {
	pr_err("device was not opened");
	return -ENODEV;
	}

	if (!hs->ifc) {
	pr_err("can't %s, device disconnected", opstr);
	return -ENODEV;
	}

	ret = usb_autopm_get_interface(hs->ifc);
	if (ret < 0) {
	dev_err(&hs->ifc->dev, "can't %s, autopm_get failed:%d\n",
	opstr, ret);
	return ret;
	}

	atomic_inc(&hs->dbg_pending[op]);

	ret = usb_bulk_msg(hs->udev, hs->pipe[op], data, len, actual_len,
	timeout);

	atomic_dec(&hs->dbg_pending[op]);

	if (ret)
	dev_err(&hs->ifc->dev,
	"can't %s, usb_bulk_msg failed, err:%d\n", opstr, ret);
	else
	atomic_add(*actual_len, &hs->dbg_bytecnt[op]);

	usb_autopm_put_interface(hs->ifc);
	return ret;
	}

	/**
	* hsic_sysmon_read() - Read data from the HSIC sysmon interface.
	* @id: the HSIC system monitor device to open
	* @data: pointer to caller-allocated buffer to fill in
	* @len: length in bytes of the buffer
	* @actual_len: pointer to a location to put the actual length read
	* in bytes
	* @timeout: time in msecs to wait for the message to complete before
	* timing out (if 0 the wait is forever)
	*
	* Context: !in_interrupt ()
	*
	* Synchronously reads data from the HSIC interface. The call will return
	* after the read has completed, encountered an error, or timed out. Upon
	* successful return actual_len will reflect the number of bytes read.
	*
	* If successful, it returns 0, otherwise a negative error number. The number
	* of actual bytes transferred will be stored in the actual_len paramater.
	*/
	int hsic_sysmon_read(enum hsic_sysmon_device_id id, char *data, size_t len,
	size_t *actual_len, int timeout)
	{
	return hsic_sysmon_readwrite(id, data, len, actual_len,
	timeout, HSIC_SYSMON_OP_READ);
	}
	EXPORT_SYMBOL(hsic_sysmon_read);

	/**
	* hsic_sysmon_write() - Write data to the HSIC sysmon interface.
	* @id: the HSIC system monitor device to open
	* @data: pointer to caller-allocated buffer to write
	* @len: length in bytes of the data in buffer to write
	* @actual_len: pointer to a location to put the actual length written
	* in bytes
	* @timeout: time in msecs to wait for the message to complete before
	* timing out (if 0 the wait is forever)
	*
	* Context: !in_interrupt ()
	*
	* Synchronously writes data to the HSIC interface. The call will return
	* after the write has completed, encountered an error, or timed out. Upon
	* successful return actual_len will reflect the number of bytes written.
	*
	* If successful, it returns 0, otherwise a negative error number. The number
	* of actual bytes transferred will be stored in the actual_len paramater.
	*/
	int hsic_sysmon_write(enum hsic_sysmon_device_id id, const char *data,
	size_t len, int timeout)
	{
	size_t actual_len;
	return hsic_sysmon_readwrite(id, (void *)data, len, &actual_len,
	timeout, HSIC_SYSMON_OP_WRITE);
	}
	EXPORT_SYMBOL(hsic_sysmon_write);

	#if defined(CONFIG_DEBUG_FS)
	#define DEBUG_BUF_SIZE 512
	static ssize_t sysmon_debug_read_stats(struct file file, char __user ubuf,
	size_t count, loff_t *ppos)
	{
	char *buf;
	int i, ret = 0;

	buf = kzalloc(sizeof(char) * DEBUG_BUF_SIZE, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	for (i = 0; i < NUM_HSIC_SYSMON_DEVS; i++) {
	struct hsic_sysmon *hs = hsic_sysmon_devices[i];
	if (!hs)
	continue;

	ret += scnprintf(buf, DEBUG_BUF_SIZE,
	"---HSIC Sysmon #%d---\n"
	"epin:%d, epout:%d\n"
	"bytes to host: %d\n"
	"bytes to mdm: %d\n"
	"pending reads: %d\n"
	"pending writes: %d\n",
	i, hs->in_epaddr & ~0x80, hs->out_epaddr,
	atomic_read(
	&hs->dbg_bytecnt[HSIC_SYSMON_OP_READ]),
	atomic_read(
	&hs->dbg_bytecnt[HSIC_SYSMON_OP_WRITE]),
	atomic_read(
	&hs->dbg_pending[HSIC_SYSMON_OP_READ]),
	atomic_read(
	&hs->dbg_pending[HSIC_SYSMON_OP_WRITE])
	);
	}

	ret = simple_read_from_buffer(ubuf, count, ppos, buf, ret);
	kfree(buf);
	return ret;
	}

	static ssize_t sysmon_debug_reset_stats(struct file *file,
	const char __user *buf,
	size_t count, loff_t *ppos)
	{
	int i;

	for (i = 0; i < NUM_HSIC_SYSMON_DEVS; i++) {
	struct hsic_sysmon *hs = hsic_sysmon_devices[i];
	if (hs) {
	atomic_set(&hs->dbg_bytecnt[HSIC_SYSMON_OP_READ], 0);
	atomic_set(&hs->dbg_bytecnt[HSIC_SYSMON_OP_WRITE], 0);
	atomic_set(&hs->dbg_pending[HSIC_SYSMON_OP_READ], 0);
	atomic_set(&hs->dbg_pending[HSIC_SYSMON_OP_WRITE], 0);
	}
	}

	return count;
	}

	const struct file_operations sysmon_stats_ops = {
	.read = sysmon_debug_read_stats,
	.write = sysmon_debug_reset_stats,
	};

	static struct dentry *dent;

	static void hsic_sysmon_debugfs_init(void)
	{
	struct dentry *dfile;

	dent = debugfs_create_dir("hsic_sysmon", 0);
	if (IS_ERR(dent))
	return;

	dfile = debugfs_create_file("status", 0444, dent, 0, &sysmon_stats_ops);
	if (!dfile \|\| IS_ERR(dfile))
	debugfs_remove(dent);
	}

	static void hsic_sysmon_debugfs_cleanup(void)
	{
	if (dent) {
	debugfs_remove_recursive(dent);
	dent = NULL;
	}
	}
	#else
	static inline void hsic_sysmon_debugfs_init(void) { }
	static inline void hsic_sysmon_debugfs_cleanup(void) { }
	#endif

	static void hsic_sysmon_pdev_release(struct device *dev) { }

	static int
	hsic_sysmon_probe(struct usb_interface ifc, const struct usb_device_id id)
	{
	struct hsic_sysmon *hs;
	struct usb_host_interface *ifc_desc;
	struct usb_endpoint_descriptor *ep_desc;
	int i;
	int ret = -ENOMEM;
	__u8 ifc_num;

	pr_debug("id:%lu", id->driver_info);

	ifc_num = ifc->cur_altsetting->desc.bInterfaceNumber;

	/* is this the interface we're looking for? */
	if (ifc_num != id->driver_info)
	return -ENODEV;

	hs = kzalloc(sizeof(*hs), GFP_KERNEL);
	if (!hs) {
	pr_err("unable to allocate hsic_sysmon");
	return -ENOMEM;
	}

	hs->udev = usb_get_dev(interface_to_usbdev(ifc));
	hs->ifc = ifc;
	kref_init(&hs->kref);

	ifc_desc = ifc->cur_altsetting;
	for (i = 0; i < ifc_desc->desc.bNumEndpoints; i++) {
	ep_desc = &ifc_desc->endpoint[i].desc;

	if (!hs->in_epaddr && usb_endpoint_is_bulk_in(ep_desc)) {
	hs->in_epaddr = ep_desc->bEndpointAddress;
	hs->pipe[HSIC_SYSMON_OP_READ] =
	usb_rcvbulkpipe(hs->udev, hs->in_epaddr);
	}

	if (!hs->out_epaddr && usb_endpoint_is_bulk_out(ep_desc)) {
	hs->out_epaddr = ep_desc->bEndpointAddress;
	hs->pipe[HSIC_SYSMON_OP_WRITE] =
	usb_sndbulkpipe(hs->udev, hs->out_epaddr);
	}
	}

	if (!(hs->in_epaddr && hs->out_epaddr)) {
	pr_err("could not find bulk in and bulk out endpoints");
	ret = -ENODEV;
	goto error;
	}

	hs->id = HSIC_SYSMON_DEV_EXT_MODEM;
	hsic_sysmon_devices[HSIC_SYSMON_DEV_EXT_MODEM] = hs;
	usb_set_intfdata(ifc, hs);

	hs->pdev.name = "sys_mon";
	hs->pdev.id = SYSMON_SS_EXT_MODEM;
	hs->pdev.dev.release = hsic_sysmon_pdev_release;
	platform_device_register(&hs->pdev);

	pr_debug("complete");

	return 0;

	error:
	if (hs)
	kref_put(&hs->kref, hsic_sysmon_delete);

	return ret;
	}

	static void hsic_sysmon_disconnect(struct usb_interface *ifc)
	{
	struct hsic_sysmon *hs = usb_get_intfdata(ifc);

	platform_device_unregister(&hs->pdev);
	kref_put(&hs->kref, hsic_sysmon_delete);
	usb_set_intfdata(ifc, NULL);
	}

	static int hsic_sysmon_suspend(struct usb_interface *ifc, pm_message_t message)
	{
	return 0;
	}

	static int hsic_sysmon_resume(struct usb_interface *ifc)
	{
	return 0;
	}

	/* driver_info maps to the interface number corresponding to sysmon */
	static const struct usb_device_id hsic_sysmon_ids[] = {
	{ USB_DEVICE(0x5c6, 0x9048), .driver_info = 1, },
	{ USB_DEVICE(0x5c6, 0x904C), .driver_info = 1, },
	{} /* terminating entry */
	};
	MODULE_DEVICE_TABLE(usb, hsic_sysmon_ids);

	static struct usb_driver hsic_sysmon_driver = {
	.name = "hsic_sysmon",
	.probe = hsic_sysmon_probe,
	.disconnect = hsic_sysmon_disconnect,
	.suspend = hsic_sysmon_suspend,
	.resume = hsic_sysmon_resume,
	.id_table = hsic_sysmon_ids,
	.supports_autosuspend = 1,
	};

	static int __init hsic_sysmon_init(void)
	{
	int ret;

	ret = usb_register(&hsic_sysmon_driver);
	if (ret) {
	pr_err("unable to register " DRIVER_DESC);
	return ret;
	}

	hsic_sysmon_debugfs_init();
	return 0;
	}

	static void __exit hsic_sysmon_exit(void)
	{
	hsic_sysmon_debugfs_cleanup();
	usb_deregister(&hsic_sysmon_driver);
	}

	module_init(hsic_sysmon_init);
	module_exit(hsic_sysmon_exit);

	MODULE_DESCRIPTION(DRIVER_DESC);
	MODULE_LICENSE("GPL v2");