linux/drivers/usb/misc/cytherm.c
Oliver Neukum d718d2b178 USB: fix read vs. disconnect race in cytherm driver
the disconnect method of this driver set intfdata to NULL before
removing attribute files. The attributes' read methods will happily
follow the NULL pointer. Here's the correct ordering.

Signed-off-by : Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-25 12:18:44 -07:00

447 lines
11 KiB
C

/* -*- linux-c -*-
* Cypress USB Thermometer driver
*
* Copyright (c) 2004 Erik Rigtorp <erkki@linux.nu> <erik@rigtorp.com>
*
* This driver works with Elektor magazine USB Interface as published in
* issue #291. It should also work with the original starter kit/demo board
* from Cypress.
*
* 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, version 2.
*
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/usb.h>
#define DRIVER_VERSION "v1.0"
#define DRIVER_AUTHOR "Erik Rigtorp"
#define DRIVER_DESC "Cypress USB Thermometer driver"
#define USB_SKEL_VENDOR_ID 0x04b4
#define USB_SKEL_PRODUCT_ID 0x0002
static struct usb_device_id id_table [] = {
{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
{ }
};
MODULE_DEVICE_TABLE (usb, id_table);
/* Structure to hold all of our device specific stuff */
struct usb_cytherm {
struct usb_device *udev; /* save off the usb device pointer */
struct usb_interface *interface; /* the interface for this device */
int brightness;
};
/* local function prototypes */
static int cytherm_probe(struct usb_interface *interface,
const struct usb_device_id *id);
static void cytherm_disconnect(struct usb_interface *interface);
/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver cytherm_driver = {
.name = "cytherm",
.probe = cytherm_probe,
.disconnect = cytherm_disconnect,
.id_table = id_table,
};
/* Vendor requests */
/* They all operate on one byte at a time */
#define PING 0x00
#define READ_ROM 0x01 /* Reads form ROM, value = address */
#define READ_RAM 0x02 /* Reads form RAM, value = address */
#define WRITE_RAM 0x03 /* Write to RAM, value = address, index = data */
#define READ_PORT 0x04 /* Reads from port, value = address */
#define WRITE_PORT 0x05 /* Write to port, value = address, index = data */
/* Send a vendor command to device */
static int vendor_command(struct usb_device *dev, unsigned char request,
unsigned char value, unsigned char index,
void *buf, int size)
{
return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
request,
USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_OTHER,
value,
index, buf, size,
USB_CTRL_GET_TIMEOUT);
}
#define BRIGHTNESS 0x2c /* RAM location for brightness value */
#define BRIGHTNESS_SEM 0x2b /* RAM location for brightness semaphore */
static ssize_t show_brightness(struct device *dev, struct device_attribute *attr, char *buf)
{
struct usb_interface *intf = to_usb_interface(dev);
struct usb_cytherm *cytherm = usb_get_intfdata(intf);
return sprintf(buf, "%i", cytherm->brightness);
}
static ssize_t set_brightness(struct device *dev, struct device_attribute *attr, const char *buf,
size_t count)
{
struct usb_interface *intf = to_usb_interface(dev);
struct usb_cytherm *cytherm = usb_get_intfdata(intf);
unsigned char *buffer;
int retval;
buffer = kmalloc(8, GFP_KERNEL);
if (!buffer) {
dev_err(&cytherm->udev->dev, "out of memory\n");
return 0;
}
cytherm->brightness = simple_strtoul(buf, NULL, 10);
if (cytherm->brightness > 0xFF)
cytherm->brightness = 0xFF;
else if (cytherm->brightness < 0)
cytherm->brightness = 0;
/* Set brightness */
retval = vendor_command(cytherm->udev, WRITE_RAM, BRIGHTNESS,
cytherm->brightness, buffer, 8);
if (retval)
dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
/* Inform µC that we have changed the brightness setting */
retval = vendor_command(cytherm->udev, WRITE_RAM, BRIGHTNESS_SEM,
0x01, buffer, 8);
if (retval)
dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
kfree(buffer);
return count;
}
static DEVICE_ATTR(brightness, S_IRUGO | S_IWUSR | S_IWGRP,
show_brightness, set_brightness);
#define TEMP 0x33 /* RAM location for temperature */
#define SIGN 0x34 /* RAM location for temperature sign */
static ssize_t show_temp(struct device *dev, struct device_attribute *attr, char *buf)
{
struct usb_interface *intf = to_usb_interface(dev);
struct usb_cytherm *cytherm = usb_get_intfdata(intf);
int retval;
unsigned char *buffer;
int temp, sign;
buffer = kmalloc(8, GFP_KERNEL);
if (!buffer) {
dev_err(&cytherm->udev->dev, "out of memory\n");
return 0;
}
/* read temperature */
retval = vendor_command(cytherm->udev, READ_RAM, TEMP, 0, buffer, 8);
if (retval)
dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
temp = buffer[1];
/* read sign */
retval = vendor_command(cytherm->udev, READ_RAM, SIGN, 0, buffer, 8);
if (retval)
dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
sign = buffer[1];
kfree(buffer);
return sprintf(buf, "%c%i.%i", sign ? '-' : '+', temp >> 1,
5*(temp - ((temp >> 1) << 1)));
}
static ssize_t set_temp(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
return count;
}
static DEVICE_ATTR(temp, S_IRUGO, show_temp, set_temp);
#define BUTTON 0x7a
static ssize_t show_button(struct device *dev, struct device_attribute *attr, char *buf)
{
struct usb_interface *intf = to_usb_interface(dev);
struct usb_cytherm *cytherm = usb_get_intfdata(intf);
int retval;
unsigned char *buffer;
buffer = kmalloc(8, GFP_KERNEL);
if (!buffer) {
dev_err(&cytherm->udev->dev, "out of memory\n");
return 0;
}
/* check button */
retval = vendor_command(cytherm->udev, READ_RAM, BUTTON, 0, buffer, 8);
if (retval)
dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
retval = buffer[1];
kfree(buffer);
if (retval)
return sprintf(buf, "1");
else
return sprintf(buf, "0");
}
static ssize_t set_button(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
return count;
}
static DEVICE_ATTR(button, S_IRUGO, show_button, set_button);
static ssize_t show_port0(struct device *dev, struct device_attribute *attr, char *buf)
{
struct usb_interface *intf = to_usb_interface(dev);
struct usb_cytherm *cytherm = usb_get_intfdata(intf);
int retval;
unsigned char *buffer;
buffer = kmalloc(8, GFP_KERNEL);
if (!buffer) {
dev_err(&cytherm->udev->dev, "out of memory\n");
return 0;
}
retval = vendor_command(cytherm->udev, READ_PORT, 0, 0, buffer, 8);
if (retval)
dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
retval = buffer[1];
kfree(buffer);
return sprintf(buf, "%d", retval);
}
static ssize_t set_port0(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
struct usb_interface *intf = to_usb_interface(dev);
struct usb_cytherm *cytherm = usb_get_intfdata(intf);
unsigned char *buffer;
int retval;
int tmp;
buffer = kmalloc(8, GFP_KERNEL);
if (!buffer) {
dev_err(&cytherm->udev->dev, "out of memory\n");
return 0;
}
tmp = simple_strtoul(buf, NULL, 10);
if (tmp > 0xFF)
tmp = 0xFF;
else if (tmp < 0)
tmp = 0;
retval = vendor_command(cytherm->udev, WRITE_PORT, 0,
tmp, buffer, 8);
if (retval)
dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
kfree(buffer);
return count;
}
static DEVICE_ATTR(port0, S_IRUGO | S_IWUSR | S_IWGRP, show_port0, set_port0);
static ssize_t show_port1(struct device *dev, struct device_attribute *attr, char *buf)
{
struct usb_interface *intf = to_usb_interface(dev);
struct usb_cytherm *cytherm = usb_get_intfdata(intf);
int retval;
unsigned char *buffer;
buffer = kmalloc(8, GFP_KERNEL);
if (!buffer) {
dev_err(&cytherm->udev->dev, "out of memory\n");
return 0;
}
retval = vendor_command(cytherm->udev, READ_PORT, 1, 0, buffer, 8);
if (retval)
dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
retval = buffer[1];
kfree(buffer);
return sprintf(buf, "%d", retval);
}
static ssize_t set_port1(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
struct usb_interface *intf = to_usb_interface(dev);
struct usb_cytherm *cytherm = usb_get_intfdata(intf);
unsigned char *buffer;
int retval;
int tmp;
buffer = kmalloc(8, GFP_KERNEL);
if (!buffer) {
dev_err(&cytherm->udev->dev, "out of memory\n");
return 0;
}
tmp = simple_strtoul(buf, NULL, 10);
if (tmp > 0xFF)
tmp = 0xFF;
else if (tmp < 0)
tmp = 0;
retval = vendor_command(cytherm->udev, WRITE_PORT, 1,
tmp, buffer, 8);
if (retval)
dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
kfree(buffer);
return count;
}
static DEVICE_ATTR(port1, S_IRUGO | S_IWUSR | S_IWGRP, show_port1, set_port1);
static int cytherm_probe(struct usb_interface *interface,
const struct usb_device_id *id)
{
struct usb_device *udev = interface_to_usbdev(interface);
struct usb_cytherm *dev = NULL;
int retval = -ENOMEM;
dev = kzalloc (sizeof(struct usb_cytherm), GFP_KERNEL);
if (dev == NULL) {
dev_err (&interface->dev, "Out of memory\n");
goto error_mem;
}
dev->udev = usb_get_dev(udev);
usb_set_intfdata (interface, dev);
dev->brightness = 0xFF;
retval = device_create_file(&interface->dev, &dev_attr_brightness);
if (retval)
goto error;
retval = device_create_file(&interface->dev, &dev_attr_temp);
if (retval)
goto error;
retval = device_create_file(&interface->dev, &dev_attr_button);
if (retval)
goto error;
retval = device_create_file(&interface->dev, &dev_attr_port0);
if (retval)
goto error;
retval = device_create_file(&interface->dev, &dev_attr_port1);
if (retval)
goto error;
dev_info (&interface->dev,
"Cypress thermometer device now attached\n");
return 0;
error:
device_remove_file(&interface->dev, &dev_attr_brightness);
device_remove_file(&interface->dev, &dev_attr_temp);
device_remove_file(&interface->dev, &dev_attr_button);
device_remove_file(&interface->dev, &dev_attr_port0);
device_remove_file(&interface->dev, &dev_attr_port1);
usb_set_intfdata (interface, NULL);
usb_put_dev(dev->udev);
kfree(dev);
error_mem:
return retval;
}
static void cytherm_disconnect(struct usb_interface *interface)
{
struct usb_cytherm *dev;
dev = usb_get_intfdata (interface);
device_remove_file(&interface->dev, &dev_attr_brightness);
device_remove_file(&interface->dev, &dev_attr_temp);
device_remove_file(&interface->dev, &dev_attr_button);
device_remove_file(&interface->dev, &dev_attr_port0);
device_remove_file(&interface->dev, &dev_attr_port1);
/* first remove the files, then NULL the pointer */
usb_set_intfdata (interface, NULL);
usb_put_dev(dev->udev);
kfree(dev);
dev_info(&interface->dev, "Cypress thermometer now disconnected\n");
}
static int __init usb_cytherm_init(void)
{
int result;
result = usb_register(&cytherm_driver);
if (result)
{
err("usb_register failed. Error number %d", result);
return result;
}
info(DRIVER_VERSION ":" DRIVER_DESC);
return 0;
}
static void __exit usb_cytherm_exit(void)
{
usb_deregister(&cytherm_driver);
}
module_init (usb_cytherm_init);
module_exit (usb_cytherm_exit);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");