Commit 3cc36157 authored by Bjørn Mork's avatar Bjørn Mork Committed by Greg Kroah-Hartman
Browse files

usb: cdc-wdm: adding usb_cdc_wdm_register subdriver support 



This driver can be used as a subdriver of another USB driver, allowing
it to export a Device Managment interface consisting of a single interrupt
endpoint with no dedicated USB interface.

Some devices provide a Device Management function combined with a wwan
function in a single USB interface having three endpoints (bulk in/out
+ interrupt).  If the interrupt endpoint is used exclusively for DM
notifications, then this driver can support that as a subdriver
provided that the wwan driver calls the appropriate entry points on
probe, suspend, resume, pre_reset, post_reset and disconnect.

The main driver must have full control over all interface related
settings, including the needs_remote_wakeup flag. A manage_power
function must be provided by the main driver.

A manage_power stub doing direct flag manipulation is used in normal
driver mode.

Signed-off-by: default avatarBjørn Mork <bjorn@mork.no>
Acked-by: default avatarOliver Neukum <oneukum@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b0c13860

drivers/usb/class/cdc-wdm.c

+59 −4
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <linux/usb/cdc.h>

#include <asm/byteorder.h>

#include <asm/unaligned.h>

#include <linux/usb/cdc-wdm.h>



/*

 * Version Information
@@ -116,6 +117,7 @@ struct wdm_device { 
	int			rerr;



	struct list_head	device_list;

	int			(*manage_power)(struct usb_interface *, int);

};



static struct usb_driver wdm_driver;
@@ -580,7 +582,6 @@ static int wdm_open(struct inode *inode, struct file *file) 
		dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);

		goto out;

	}

	intf->needs_remote_wakeup = 1;



	/* using write lock to protect desc->count */

	mutex_lock(&desc->wlock);
@@ -597,6 +598,8 @@ static int wdm_open(struct inode *inode, struct file *file) 
		rv = 0;

	}

	mutex_unlock(&desc->wlock);

	if (desc->count == 1)

		desc->manage_power(intf, 1);

	usb_autopm_put_interface(desc->intf);

out:

	mutex_unlock(&wdm_mutex);
@@ -618,7 +621,7 @@ static int wdm_release(struct inode *inode, struct file *file) 
		dev_dbg(&desc->intf->dev, "wdm_release: cleanup");

		kill_urbs(desc);

		if (!test_bit(WDM_DISCONNECTING, &desc->flags))

			desc->intf->needs_remote_wakeup = 0;

			desc->manage_power(desc->intf, 0);

	}

	mutex_unlock(&wdm_mutex);

	return 0;
@@ -665,7 +668,8 @@ static void wdm_rxwork(struct work_struct *work) 


/* --- hotplug --- */



static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep, u16 bufsize)

static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,

		u16 bufsize, int (*manage_power)(struct usb_interface *, int))

{

	int rv = -ENOMEM;

	struct wdm_device *desc;
@@ -750,6 +754,8 @@ static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor 
		desc

	);



	desc->manage_power = manage_power;



	spin_lock(&wdm_device_list_lock);

	list_add(&desc->device_list, &wdm_device_list);

	spin_unlock(&wdm_device_list_lock);
@@ -766,6 +772,19 @@ err: 
	return rv;

}



static int wdm_manage_power(struct usb_interface *intf, int on)

{

	/* need autopm_get/put here to ensure the usbcore sees the new value */

	int rv = usb_autopm_get_interface(intf);

	if (rv < 0)

		goto err;



	intf->needs_remote_wakeup = on;

	usb_autopm_put_interface(intf);

err:

	return rv;

}



static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)

{

	int rv = -EINVAL;
@@ -809,12 +828,48 @@ next_desc: 
		goto err;

	ep = &iface->endpoint[0].desc;



	rv = wdm_create(intf, ep, maxcom);

	rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);



err:

	return rv;

}



/**

 * usb_cdc_wdm_register - register a WDM subdriver

 * @intf: usb interface the subdriver will associate with

 * @ep: interrupt endpoint to monitor for notifications

 * @bufsize: maximum message size to support for read/write

 *

 * Create WDM usb class character device and associate it with intf

 * without binding, allowing another driver to manage the interface.

 *

 * The subdriver will manage the given interrupt endpoint exclusively

 * and will issue control requests referring to the given intf. It

 * will otherwise avoid interferring, and in particular not do

 * usb_set_intfdata/usb_get_intfdata on intf.

 *

 * The return value is a pointer to the subdriver's struct usb_driver.

 * The registering driver is responsible for calling this subdriver's

 * disconnect, suspend, resume, pre_reset and post_reset methods from

 * its own.

 */

struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,

					struct usb_endpoint_descriptor *ep,

					int bufsize,

					int (*manage_power)(struct usb_interface *, int))

{

	int rv = -EINVAL;



	rv = wdm_create(intf, ep, bufsize, manage_power);

	if (rv < 0)

		goto err;



	return &wdm_driver;

err:

	return ERR_PTR(rv);

}

EXPORT_SYMBOL(usb_cdc_wdm_register);



static void wdm_disconnect(struct usb_interface *intf)

{

	struct wdm_device *desc;

include/linux/usb/cdc-wdm.h

0 → 100644
+19 −0
Original line number Diff line number Diff line 
/*

 * USB CDC Device Management subdriver

 *

 * Copyright (c) 2012  Bjørn Mork <bjorn@mork.no>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * version 2 as published by the Free Software Foundation.

 */



#ifndef __LINUX_USB_CDC_WDM_H

#define __LINUX_USB_CDC_WDM_H



extern struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,

					struct usb_endpoint_descriptor *ep,

					int bufsize,

					int (*manage_power)(struct usb_interface *, int));



#endif /* __LINUX_USB_CDC_WDM_H */

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