为什么我这个代码现在在按下reset键后因为非法内存访问错误导致系统重启？
/*
* GPIO Button Hotplug driver
*
* Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
* Copyright (C)
2008-2010 Gabor Juhos <juhosg@openwrt.org>
*
* Based on the diag.c
- GPIO interface driver for Broadcom boards
* Copyright (C) 2006 Mike Baker <mbm@openwrt.org>,
* Copyright (C) 2006
-2007 Felix Fietkau <nbd@openwrt.org>
* Copyright (C)
2008 Andy Boyett <agb@openwrt.org>
*
* 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.
*/
#include <linux/module.h>
#include <linux/version.h>
#include <linux/kmod.h>
#include <linux/workqueue.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/kobject.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/of_gpio.h>
#include <linux/gpio_keys.h>
#include <net/sock.h>
#include <net/net_namespace.h>
#define DRV_NAME "gpio
-keys"
#define BH_SKB_SIZE 2048
#define PFX DRV_NAME ": "
#define BH_DEBUG 1
#ifdef BH_DEBUG
#define BH_DBG(fmt, args...) printk(KERN_DEBUG "%s: " fmt, DRV_NAME, ##args )
#else
#define BH_DBG(fmt, args...) do {} while (0)
#endif
#define BH_ERR(fmt, args...) printk(KERN_ERR "%s: " fmt, DRV_NAME, ##args )
struct bh_priv {
unsigned long seen;
};
struct bh_event {
const char *name;
unsigned int type;
char *action;
unsigned long seen;
struct sk_buff *skb;
struct work_struct work;
};
struct bh_map {
unsigned int code;
const char *name;
};
struct gpio_keys_button_data {
struct delayed_work work;
struct bh_priv bh;
int last_state;
int count;
int threshold;
int can_sleep;
struct gpio_keys_button *b;
struct timer_list reset_timer;
bool reset_pressed;
};
#define NETLINK_GPIO_EVENT 31
struct gpio_netlink_msg{
char button_name[32];
unsigned int event_type;
int value;
unsigned long timestamp;
};
static struct sock *gpio_nl_sk = NULL;
extern u64 uevent_next_seqnum(void);
#define BH_MAP(_code, _name) \
{ \
.code = (_code), \
.name = (_name), \
}
static struct bh_map button_map[] = {
BH_MAP(BTN_0, "BTN_0"),
BH_MAP(BTN_1, "BTN_1"),
BH_MAP(BTN_2, "BTN_2"),
BH_MAP(BTN_3, "BTN_3"),
BH_MAP(BTN_4, "BTN_4"),
BH_MAP(BTN_5, "BTN_5"),
BH_MAP(BTN_6, "BTN_6"),
BH_MAP(BTN_7, "BTN_7"),
BH_MAP(BTN_8, "BTN_8"),
BH_MAP(BTN_9, "BTN_9"),
BH_MAP(KEY_POWER, "power"),
BH_MAP(KEY_RESTART, "reset"),
BH_MAP(KEY_RFKILL, "rfkill"),
BH_MAP(KEY_WPS_BUTTON, "wps"),
BH_MAP(KEY_WIMAX, "wwan"),
};
/*
-------------------------------------------------------------------------*/
static void reset_timer_callback(unsigned long data)
{
struct gpio_keys_button_data *bdata = (struct gpio_keys_button_data *)data;
if (bdata
->reset_pressed) {
send_gpio_netlink_event("reset", EV_KEY, 1);
}
}
static int bh_event_add_var(struct bh_event *event, int argv,
const char *format, ...)
{
static char buf[128];
char *s;
va_list args;
int len;
if (argv)
return 0;
va_start(args, format);
len = vsnprintf(buf, sizeof(buf), format, args);
va_end(args);
if (len >= sizeof(buf)) {
BH_ERR("buffer size too small\n");
WARN_ON(1);
return
-ENOMEM;
}
s = skb_put(event
->skb, len + 1);
strcpy(s, buf);
BH_DBG("added variable '%s'\n", s);
return 0;
}
static int button_hotplug_fill_event(struct bh_event *event)
{
int ret;
ret = bh_event_add_var(event, 0, "HOME=%s", "/");
if (ret)
return ret;
ret = bh_event_add_var(event, 0, "PATH=%s",
"/sbin:/bin:/usr/sbin:/usr/bin");
if (ret)
return ret;
ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
if (ret)
return ret;
ret = bh_event_add_var(event, 0, "ACTION=%s", event
->action);
if (ret)
return ret;
ret = bh_event_add_var(event, 0, "BUTTON=%s", event
->name);
if (ret)
return ret;
if (event
->type == EV_SW) {
ret = bh_event_add_var(event, 0, "TYPE=%s", "switch");
if (ret)
return ret;
}
ret = bh_event_add_var(event, 0, "SEEN=%ld", event
->seen);
if (ret)
return ret;
ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
return ret;
}
static void button_hotplug_work(struct work_struct *work)
{
struct bh_event *event = container_of(work, struct bh_event, work);
int ret = 0;
event
->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
if (!event
->skb)
goto out_free_event;
ret = bh_event_add_var(event, 0, "%s@", event
->action);
if (ret)
goto out_free_skb;
ret = button_hotplug_fill_event(event);
if (ret)
goto out_free_skb;
NETLINK_CB(event
->skb).dst_group = 1;
broadcast_uevent(event
->skb, 0, 1, GFP_KERNEL);
out_free_skb:
if (ret) {
BH_ERR("work error %d\n", ret);
kfree_skb(event
->skb);
}
out_free_event:
kfree(event);
}
static int button_hotplug_create_event(const char *name, unsigned int type,
unsigned long seen, int pressed)
{
struct bh_event *event;
BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
name, seen, pressed);
event = kzalloc(sizeof(*event), GFP_KERNEL);
if (!event)
return
-ENOMEM;
event
->name = name;
event
->type = type;
event
->seen = seen;
event
->action = pressed ? "pressed" : "released";
INIT_WORK(&event
->work, (void *)(void *)button_hotplug_work);
schedule_work(&event
->work);
return 0;
}
/*
-------------------------------------------------------------------------*/
static int button_get_index(unsigned int code)
{
int i;
for (i = 0; i < ARRAY_SIZE(button_map); i++)
if (button_map[i].code == code)
return i;
return
-1;
}
static void send_gpio_netlink_event(const char *name, unsigned int type, int value)
{
struct sk_buff* skb;
struct nlmsghdr *nlh;
struct gpio_netlink_msg *msg;
int size = sizeof(struct gpio_netlink_msg);
int len;
int ret = 0;
if(!gpio_nl_sk){
BH_ERR("Netlink socket not intialized\n");
return;
}
len = NLMSG_SPACE(size);
skb = alloc_skb(len, GFP_ATOMIC);
if(!skb){
BH_ERR("Failed to allocate netlink skb\n");
return;
}
nlh = (struct nlmsghdr *)skb
->data;
nlh
->nlmsg_len = NLMSG_SPACE(size);
nlh
->nlmsg_type = 1;
nlh
->nlmsg_flags = 0;
nlh
->nlmsg_seq = 0;
nlh
->nlmsg_pid = 0;
msg = (struct gpio_netlink_msg *)NLMSG_DATA(nlh);
strncpy(msg
->button_name, name, sizeof(msg
->button_name)
-1);
msg
->button_name[sizeof(msg
->button_name)
-1] = '\0';
msg
->event_type = type;
msg
->value = value;
msg
->timestamp = jiffies;
skb_put(skb, NLMSG_SPACE(size));
ret = netlink_broadcast(gpio_nl_sk, skb, 0, 1, GFP_ATOMIC);
if(ret < 0){
BH_DBG("Netlink broadcast failed: %d ", ret);
kfree_skb(skb);
}
BH_DBG(" Netlink message send for %s ,value = %d\n", name, value);
}
static int create_netlink_socket(void)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 6, 0)
struct netlink_kernel_cfg cfg ={
.input = NULL,
.groups = 1,
};
gpio_nl_sk = netlink_kernel_create(&init_net, NETLINK_GPIO_EVENT, &cfg);
#else
gpio_nl_sk = netlink_kernel_create(&init_net, NETLINK_GPIO_EVENT, 1, NULL, NULL, THIS_MODULE);
#endif
if(!gpio_nl_sk){
BH_ERR("Failed to create netlink socket\n");
return
-ENOMEM;
}
BH_DBG("Netlink socket created successfully\n");
return 0;
}
static void release_netlink_socket(void)
{
if(gpio_nl_sk){
netlink_kernel_release(gpio_nl_sk);
gpio_nl_sk = NULL;
}
}
static void button_hotplug_event(struct gpio_keys_button_data *data,
unsigned int type, int value)
{
struct bh_priv *priv = &data
->bh;
unsigned long seen = jiffies;
int btn;
BH_DBG("event type=%u, code=%u, value=%d\n", type, data
->b
->code, value);
if(data
->b
->code == KEY_RESTART){
if (value) { // 按键按下
data
->reset_pressed = true;
mod_timer(&data
->reset_timer, jiffies + msecs_to_jiffies(6000)); // 6秒计时
BH_DBG("Reset button pressed, timer started");
} else { // 按键释放
if (data
->reset_pressed) {
del_timer(&data
->reset_timer);
data
->reset_pressed = false;
BH_DBG("Reset button released early, timer canceled");
}
}
priv
->seen = seen;
return;
}
if ((type != EV_KEY) && (type != EV_SW))
return;
btn = button_get_index(data
->b
->code);
if (btn < 0)
return;
button_hotplug_create_event(button_map[btn].name, type,
(seen
- priv
->seen) / HZ, value);
priv
->seen = seen;
}
struct gpio_keys_button_dev {
int polled;
struct delayed_work work;
struct device *dev;
struct gpio_keys_platform_data *pdata;
struct gpio_keys_button_data data[0];
};
static int gpio_button_get_value(struct gpio_keys_button_data *bdata)
{
int val;
if (bdata
->can_sleep)
val = !!gpio_get_value_cansleep(bdata
->b
->gpio);
else
val = !!gpio_get_value(bdata
->b
->gpio);
return val ^ bdata
->b
->active_low;
}
static void gpio_keys_polled_check_state(struct gpio_keys_button_data *bdata)
{
int state = gpio_button_get_value(bdata);
if (state != bdata
->last_state) {
unsigned int type = bdata
->b
->type ?: EV_KEY;
if (bdata
->count < bdata
->threshold) {
bdata
->count++;
return;
}
if ((bdata
->last_state !=
-1) || (type == EV_SW))
button_hotplug_event(bdata, type, state);
bdata
->last_state = state;
}
bdata
->count = 0;
}
static void gpio_keys_polled_queue_work(struct gpio_keys_button_dev *bdev)
{
struct gpio_keys_platform_data *pdata = bdev
->pdata;
unsigned long delay = msecs_to_jiffies(pdata
->poll_interval);
if (delay >= HZ)
delay = round_jiffies_relative(delay);
schedule_delayed_work(&bdev
->work, delay);
}
static void gpio_keys_polled_poll(struct work_struct *work)
{
struct gpio_keys_button_dev *bdev =
container_of(work, struct gpio_keys_button_dev, work.work);
int i;
for (i = 0; i < bdev
->pdata
->nbuttons; i++) {
struct gpio_keys_button_data *bdata = &bdev
->data[i];
gpio_keys_polled_check_state(bdata);
}
gpio_keys_polled_queue_work(bdev);
}
static void gpio_keys_polled_close(struct gpio_keys_button_dev *bdev)
{
struct gpio_keys_platform_data *pdata = bdev
->pdata;
cancel_delayed_work_sync(&bdev
->work);
if (pdata
->disable)
pdata
->disable(bdev
->dev);
}
static irqreturn_t button_handle_irq(int irq, void *_bdata)
{
struct gpio_keys_button_data *bdata = (struct gpio_keys_button_data *) _bdata;
button_hotplug_event(bdata, bdata
->b
->type ?: EV_KEY, gpio_button_get_value(bdata));
return IRQ_HANDLED;
}
#ifdef CONFIG_OF
static struct gpio_keys_platform_data *
gpio_keys_get_devtree_pdata(struct device *dev)
{
struct device_node *node, *pp;
struct gpio_keys_platform_data *pdata;
struct gpio_keys_button *button;
int error;
int nbuttons;
int i = 0;
node = dev
->of_node;
if (!node)
return NULL;
nbuttons = of_get_child_count(node);
if (nbuttons == 0)
return NULL;
pdata = devm_kzalloc(dev, sizeof(*pdata) + nbuttons * (sizeof *button),
GFP_KERNEL);
if (!pdata) {
error =
-ENOMEM;
goto err_out;
}
pdata
->buttons = (struct gpio_keys_button *)(pdata + 1);
pdata
->nbuttons = nbuttons;
pdata
->rep = !!of_get_property(node, "autorepeat", NULL);
of_property_read_u32(node, "poll
-interval", &pdata
->poll_interval);
for_each_child_of_node(node, pp) {
enum of_gpio_flags flags;
if (!of_find_property(pp, "gpios", NULL)) {
pdata
->nbuttons
--;
dev_warn(dev, "Found button without gpios\n");
continue;
}
button = &pdata
->buttons[i++];
button
->gpio = of_get_gpio_flags(pp, 0, &flags);
button
->active_low = flags & OF_GPIO_ACTIVE_LOW;
if (of_property_read_u32(pp, "linux,code", &button
->code)) {
dev_err(dev, "Button without keycode: 0x%x\n",
button
->gpio);
error =
-EINVAL;
goto err_out;
}
button
->desc = of_get_property(pp, "label", NULL);
if (of_property_read_u32(pp, "linux,input
-type", &button
->type))
button
->type = EV_KEY;
button
->wakeup = !!of_get_property(pp, "gpio
-key,wakeup", NULL);
if (of_property_read_u32(pp, "debounce
-interval",
&button
->debounce_interval))
button
->debounce_interval = 5;
}
if (pdata
->nbuttons == 0) {
error =
-EINVAL;
goto err_out;
}
return pdata;
err_out:
return ERR_PTR(error);
}
static struct of_device_id gpio_keys_of_match[] = {
{ .compatible = "gpio
-keys", },
{ },
};
MODULE_DEVICE_TABLE(of, gpio_keys_of_match);
static struct of_device_id gpio_keys_polled_of_match[] = {
{ .compatible = "gpio
-keys
-polled", },
{ },
};
MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
#else
static inline struct gpio_keys_platform_data *
gpio_keys_get_devtree_pdata(struct device *dev)
{
return NULL;
}
#endif
static int gpio_keys_button_probe(struct platform_device *pdev,
struct gpio_keys_button_dev **_bdev, int polled)
{
struct gpio_keys_platform_data *pdata = pdev
->dev.platform_data;
struct device *dev = &pdev
->dev;
struct gpio_keys_button_dev *bdev;
struct gpio_keys_button *buttons;
int error;
int i;
if (!pdata) {
pdata = gpio_keys_get_devtree_pdata(dev);
if (IS_ERR(pdata))
return PTR_ERR(pdata);
if (!pdata) {
dev_err(dev, "missing platform data\n");
return
-EINVAL;
}
pdev
->dev.platform_data = pdata;
}
if (polled && !pdata
->poll_interval) {
dev_err(dev, "missing poll_interval value\n");
return
-EINVAL;
}
buttons = devm_kzalloc(dev, pdata
->nbuttons * sizeof(struct gpio_keys_button),
GFP_KERNEL);
if (!buttons) {
dev_err(dev, "no memory for button data\n");
return
-ENOMEM;
}
memcpy(buttons, pdata
->buttons, pdata
->nbuttons * sizeof(struct gpio_keys_button));
bdev = devm_kzalloc(dev, sizeof(struct gpio_keys_button_dev) +
pdata
->nbuttons * sizeof(struct gpio_keys_button_data),
GFP_KERNEL);
if (!bdev) {
dev_err(dev, "no memory for private data\n");
return
-ENOMEM;
}
bdev
->polled = polled;
for (i = 0; i < pdata
->nbuttons; i++) {
struct gpio_keys_button *button = &buttons[i];
struct gpio_keys_button_data *bdata = &bdev
->data[i];
unsigned int gpio = button
->gpio;
if (button
->wakeup) {
dev_err(dev, DRV_NAME "does not support wakeup\n");
return
-EINVAL;
}
error = devm_gpio_request(dev, gpio,
button
->desc ? button
->desc : DRV_NAME);
if (error) {
dev_err(dev, "unable to claim gpio %u, err=%d\n",
gpio, error);
return error;
}
error = gpio_direction_input(gpio);
if (error) {
dev_err(dev,
"unable to set direction on gpio %u, err=%d\n",
gpio, error);
return error;
}
bdata
->can_sleep = gpio_cansleep(gpio);
bdata
->last_state =
-1;
if (bdev
->polled)
bdata
->threshold = DIV_ROUND_UP(button
->debounce_interval,
pdata
->poll_interval);
else
bdata
->threshold = 1;
bdata
->b = &pdata
->buttons[i];
// 初始化复位键定时器
if (button
->code == KEY_RESTART) {
setup_timer(&bdata
->reset_timer, reset_timer_callback, (unsigned long)bdata);
bdata
->reset_pressed = false;
}
bdev
->dev = &pdev
->dev;
bdev
->pdata = pdata;
platform_set_drvdata(pdev, bdev);
*_bdev = bdev;
return 0;
}
static int gpio_keys_probe(struct platform_device *pdev)
{
struct gpio_keys_platform_data *pdata;
struct gpio_keys_button_dev *bdev;
int ret, i;
ret = gpio_keys_button_probe(pdev, &bdev, 0);
if (ret)
return ret;
pdata = pdev
->dev.platform_data;
for (i = 0; i < pdata
->nbuttons; i++) {
struct gpio_keys_button *button = &pdata
->buttons[i];
struct gpio_keys_button_data *bdata = &bdev
->data[i];
if (bdata
->can_sleep) {
dev_err(&pdev
->dev, "skipping gpio:%d, it can sleep\n", button
->gpio);
continue;
}
if (!button
->irq)
button
->irq = gpio_to_irq(button
->gpio);
if (button
->irq < 0) {
dev_err(&pdev
->dev, "failed to get irq for gpio:%d\n", button
->gpio);
continue;
}
ret = devm_request_irq(&pdev
->dev, button
->irq, button_handle_irq,
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
dev_name(&pdev
->dev), bdata);
if (ret)
dev_err(&pdev
->dev, "failed to request irq:%d for gpio:%d\n", button
->irq, button
->gpio);
else
dev_dbg(&pdev
->dev, "gpio:%d has irq:%d\n", button
->gpio, button
->irq);
if (bdata
->b
->type == EV_SW)
button_hotplug_event(bdata, EV_SW, gpio_button_get_value(bdata));
}
return 0;
}
static int gpio_keys_polled_probe(struct platform_device *pdev)
{
struct gpio_keys_platform_data *pdata;
struct gpio_keys_button_dev *bdev;
int ret;
int i;
ret = gpio_keys_button_probe(pdev, &bdev, 1);
if (ret)
return ret;
INIT_DELAYED_WORK(&bdev
->work, gpio_keys_polled_poll);
pdata = bdev
->pdata;
if (pdata
->enable)
pdata
->enable(bdev
->dev);
for (i = 0; i < pdata
->nbuttons; i++)
gpio_keys_polled_check_state(&bdev
->data[i]);
gpio_keys_polled_queue_work(bdev);
return ret;
}
static int gpio_keys_remove(struct platform_device *pdev)
{
struct gpio_keys_button_dev *bdev = platform_get_drvdata(pdev);
int i;
// 清理复位键计时器
for (i = 0; i < bdev
->pdata
->nbuttons; i++) {
if (bdev
->data[i].b
->code == KEY_RESTART) {
del_timer_sync(&bdev
->data[i].reset_timer);
}
}
platform_set_drvdata(pdev, NULL);
if (bdev
->polled)
gpio_keys_polled_close(bdev);
return 0;
}
static struct platform_driver gpio_keys_driver = {
.probe = gpio_keys_probe,
.remove = gpio_keys_remove,
.driver = {
.name = "gpio
-keys",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(gpio_keys_of_match),
},
};
static struct platform_driver gpio_keys_polled_driver = {
.probe = gpio_keys_polled_probe,
.remove = gpio_keys_remove,
.driver = {
.name = "gpio
-keys
-polled",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(gpio_keys_polled_of_match),
},
};
static int __init gpio_button_init(void)
{
int ret;
ret = create_netlink_socket();
if (ret)
return ret;
ret = platform_driver_register(&gpio_keys_driver);
if (ret)
return ret;
ret = platform_driver_register(&gpio_keys_polled_driver);
if (ret)
platform_driver_unregister(&gpio_keys_driver);
return ret;
}
static void __exit gpio_button_exit(void)
{
platform_driver_unregister(&gpio_keys_driver);
platform_driver_unregister(&gpio_keys_polled_driver);
release_netlink_socket();
}
module_init(gpio_button_init);
module_exit(gpio_button_exit);
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRV_NAME);
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