linux/drivers/usb/otg/nop-usb-xceiv.c
Ming Lei 20831ad239 usb: otg: nop: fix oops triggered by otg_register_notifier
This patch adds BLOCKING_INIT_NOTIFIER_HEAD in nop_usb_xceiv_probe,
so that we can avoid oops caused by uninitialized
nop->otg.notifier.rwsem which will be touched in otg_register_notifier
path.

Reported-by: Gupta, Ajay Kumar <ajay.gupta@ti.com>
Tested-by: Gupta, Ajay Kumar <ajay.gupta@ti.com>
Cc: Balbi, Felipe <balbi@ti.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-22 18:32:55 -08:00

180 lines
4.0 KiB
C

/*
* drivers/usb/otg/nop-usb-xceiv.c
*
* NOP USB transceiver for all USB transceiver which are either built-in
* into USB IP or which are mostly autonomous.
*
* Copyright (C) 2009 Texas Instruments Inc
* Author: Ajay Kumar Gupta <ajay.gupta@ti.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Current status:
* This provides a "nop" transceiver for PHYs which are
* autonomous such as isp1504, isp1707, etc.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/usb/otg.h>
#include <linux/slab.h>
struct nop_usb_xceiv {
struct otg_transceiver otg;
struct device *dev;
};
static struct platform_device *pd;
void usb_nop_xceiv_register(void)
{
if (pd)
return;
pd = platform_device_register_simple("nop_usb_xceiv", -1, NULL, 0);
if (!pd) {
printk(KERN_ERR "Unable to register usb nop transceiver\n");
return;
}
}
EXPORT_SYMBOL(usb_nop_xceiv_register);
void usb_nop_xceiv_unregister(void)
{
platform_device_unregister(pd);
pd = NULL;
}
EXPORT_SYMBOL(usb_nop_xceiv_unregister);
static inline struct nop_usb_xceiv *xceiv_to_nop(struct otg_transceiver *x)
{
return container_of(x, struct nop_usb_xceiv, otg);
}
static int nop_set_suspend(struct otg_transceiver *x, int suspend)
{
return 0;
}
static int nop_set_peripheral(struct otg_transceiver *x,
struct usb_gadget *gadget)
{
struct nop_usb_xceiv *nop;
if (!x)
return -ENODEV;
nop = xceiv_to_nop(x);
if (!gadget) {
nop->otg.gadget = NULL;
return -ENODEV;
}
nop->otg.gadget = gadget;
nop->otg.state = OTG_STATE_B_IDLE;
return 0;
}
static int nop_set_host(struct otg_transceiver *x, struct usb_bus *host)
{
struct nop_usb_xceiv *nop;
if (!x)
return -ENODEV;
nop = xceiv_to_nop(x);
if (!host) {
nop->otg.host = NULL;
return -ENODEV;
}
nop->otg.host = host;
return 0;
}
static int __devinit nop_usb_xceiv_probe(struct platform_device *pdev)
{
struct nop_usb_xceiv *nop;
int err;
nop = kzalloc(sizeof *nop, GFP_KERNEL);
if (!nop)
return -ENOMEM;
nop->dev = &pdev->dev;
nop->otg.dev = nop->dev;
nop->otg.label = "nop-xceiv";
nop->otg.state = OTG_STATE_UNDEFINED;
nop->otg.set_host = nop_set_host;
nop->otg.set_peripheral = nop_set_peripheral;
nop->otg.set_suspend = nop_set_suspend;
err = otg_set_transceiver(&nop->otg);
if (err) {
dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
err);
goto exit;
}
platform_set_drvdata(pdev, nop);
BLOCKING_INIT_NOTIFIER_HEAD(&nop->otg.notifier);
return 0;
exit:
kfree(nop);
return err;
}
static int __devexit nop_usb_xceiv_remove(struct platform_device *pdev)
{
struct nop_usb_xceiv *nop = platform_get_drvdata(pdev);
otg_set_transceiver(NULL);
platform_set_drvdata(pdev, NULL);
kfree(nop);
return 0;
}
static struct platform_driver nop_usb_xceiv_driver = {
.probe = nop_usb_xceiv_probe,
.remove = __devexit_p(nop_usb_xceiv_remove),
.driver = {
.name = "nop_usb_xceiv",
.owner = THIS_MODULE,
},
};
static int __init nop_usb_xceiv_init(void)
{
return platform_driver_register(&nop_usb_xceiv_driver);
}
subsys_initcall(nop_usb_xceiv_init);
static void __exit nop_usb_xceiv_exit(void)
{
platform_driver_unregister(&nop_usb_xceiv_driver);
}
module_exit(nop_usb_xceiv_exit);
MODULE_ALIAS("platform:nop_usb_xceiv");
MODULE_AUTHOR("Texas Instruments Inc");
MODULE_DESCRIPTION("NOP USB Transceiver driver");
MODULE_LICENSE("GPL");