f1f5bda4e9
This patch reworks the probe() function in the at32ap700x_wdt driver, this to make sure the miscdev is properly initialized and the driver is ready to be accessed. Reported-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Signed-off-by: Wim Van sebroeck <wim@iguana.be>
454 lines
10 KiB
C
454 lines
10 KiB
C
/*
|
|
* Watchdog driver for Atmel AT32AP700X devices
|
|
*
|
|
* Copyright (C) 2005-2006 Atmel Corporation
|
|
*
|
|
* 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.
|
|
*
|
|
*
|
|
* Errata: WDT Clear is blocked after WDT Reset
|
|
*
|
|
* A watchdog timer event will, after reset, block writes to the WDT_CLEAR
|
|
* register, preventing the program to clear the next Watchdog Timer Reset.
|
|
*
|
|
* If you still want to use the WDT after a WDT reset a small code can be
|
|
* insterted at the startup checking the AVR32_PM.rcause register for WDT reset
|
|
* and use a GPIO pin to reset the system. This method requires that one of the
|
|
* GPIO pins are available and connected externally to the RESET_N pin. After
|
|
* the GPIO pin has pulled down the reset line the GPIO will be reset and leave
|
|
* the pin tristated with pullup.
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/watchdog.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/io.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/slab.h>
|
|
|
|
#define TIMEOUT_MIN 1
|
|
#define TIMEOUT_MAX 2
|
|
#define TIMEOUT_DEFAULT TIMEOUT_MAX
|
|
|
|
/* module parameters */
|
|
static int timeout = TIMEOUT_DEFAULT;
|
|
module_param(timeout, int, 0);
|
|
MODULE_PARM_DESC(timeout,
|
|
"Timeout value. Limited to be 1 or 2 seconds. (default="
|
|
__MODULE_STRING(TIMEOUT_DEFAULT) ")");
|
|
|
|
static int nowayout = WATCHDOG_NOWAYOUT;
|
|
module_param(nowayout, int, 0);
|
|
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
|
|
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
|
|
|
|
/* Watchdog registers and write/read macro */
|
|
#define WDT_CTRL 0x00
|
|
#define WDT_CTRL_EN 0
|
|
#define WDT_CTRL_PSEL 8
|
|
#define WDT_CTRL_KEY 24
|
|
|
|
#define WDT_CLR 0x04
|
|
|
|
#define WDT_RCAUSE 0x10
|
|
#define WDT_RCAUSE_POR 0
|
|
#define WDT_RCAUSE_EXT 2
|
|
#define WDT_RCAUSE_WDT 3
|
|
#define WDT_RCAUSE_JTAG 4
|
|
#define WDT_RCAUSE_SERP 5
|
|
|
|
#define WDT_BIT(name) (1 << WDT_##name)
|
|
#define WDT_BF(name, value) ((value) << WDT_##name)
|
|
|
|
#define wdt_readl(dev, reg) \
|
|
__raw_readl((dev)->regs + WDT_##reg)
|
|
#define wdt_writel(dev, reg, value) \
|
|
__raw_writel((value), (dev)->regs + WDT_##reg)
|
|
|
|
struct wdt_at32ap700x {
|
|
void __iomem *regs;
|
|
spinlock_t io_lock;
|
|
int timeout;
|
|
int boot_status;
|
|
unsigned long users;
|
|
struct miscdevice miscdev;
|
|
};
|
|
|
|
static struct wdt_at32ap700x *wdt;
|
|
static char expect_release;
|
|
|
|
/*
|
|
* Disable the watchdog.
|
|
*/
|
|
static inline void at32_wdt_stop(void)
|
|
{
|
|
unsigned long psel;
|
|
|
|
spin_lock(&wdt->io_lock);
|
|
psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
|
|
wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55));
|
|
wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa));
|
|
spin_unlock(&wdt->io_lock);
|
|
}
|
|
|
|
/*
|
|
* Enable and reset the watchdog.
|
|
*/
|
|
static inline void at32_wdt_start(void)
|
|
{
|
|
/* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
|
|
unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
|
|
|
|
spin_lock(&wdt->io_lock);
|
|
wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
|
|
| WDT_BF(CTRL_PSEL, psel)
|
|
| WDT_BF(CTRL_KEY, 0x55));
|
|
wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
|
|
| WDT_BF(CTRL_PSEL, psel)
|
|
| WDT_BF(CTRL_KEY, 0xaa));
|
|
spin_unlock(&wdt->io_lock);
|
|
}
|
|
|
|
/*
|
|
* Pat the watchdog timer.
|
|
*/
|
|
static inline void at32_wdt_pat(void)
|
|
{
|
|
spin_lock(&wdt->io_lock);
|
|
wdt_writel(wdt, CLR, 0x42);
|
|
spin_unlock(&wdt->io_lock);
|
|
}
|
|
|
|
/*
|
|
* Watchdog device is opened, and watchdog starts running.
|
|
*/
|
|
static int at32_wdt_open(struct inode *inode, struct file *file)
|
|
{
|
|
if (test_and_set_bit(1, &wdt->users))
|
|
return -EBUSY;
|
|
|
|
at32_wdt_start();
|
|
return nonseekable_open(inode, file);
|
|
}
|
|
|
|
/*
|
|
* Close the watchdog device.
|
|
*/
|
|
static int at32_wdt_close(struct inode *inode, struct file *file)
|
|
{
|
|
if (expect_release == 42) {
|
|
at32_wdt_stop();
|
|
} else {
|
|
dev_dbg(wdt->miscdev.parent,
|
|
"unexpected close, not stopping watchdog!\n");
|
|
at32_wdt_pat();
|
|
}
|
|
clear_bit(1, &wdt->users);
|
|
expect_release = 0;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Change the watchdog time interval.
|
|
*/
|
|
static int at32_wdt_settimeout(int time)
|
|
{
|
|
/*
|
|
* All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
|
|
* 2 ^ 16 allowing up to 2 seconds timeout.
|
|
*/
|
|
if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX))
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Set new watchdog time. It will be used when at32_wdt_start() is
|
|
* called.
|
|
*/
|
|
wdt->timeout = time;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Get the watchdog status.
|
|
*/
|
|
static int at32_wdt_get_status(void)
|
|
{
|
|
int rcause;
|
|
int status = 0;
|
|
|
|
rcause = wdt_readl(wdt, RCAUSE);
|
|
|
|
switch (rcause) {
|
|
case WDT_BIT(RCAUSE_EXT):
|
|
status = WDIOF_EXTERN1;
|
|
break;
|
|
case WDT_BIT(RCAUSE_WDT):
|
|
status = WDIOF_CARDRESET;
|
|
break;
|
|
case WDT_BIT(RCAUSE_POR): /* fall through */
|
|
case WDT_BIT(RCAUSE_JTAG): /* fall through */
|
|
case WDT_BIT(RCAUSE_SERP): /* fall through */
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return status;
|
|
}
|
|
|
|
static const struct watchdog_info at32_wdt_info = {
|
|
.identity = "at32ap700x watchdog",
|
|
.options = WDIOF_SETTIMEOUT |
|
|
WDIOF_KEEPALIVEPING |
|
|
WDIOF_MAGICCLOSE,
|
|
};
|
|
|
|
/*
|
|
* Handle commands from user-space.
|
|
*/
|
|
static long at32_wdt_ioctl(struct file *file,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
int ret = -ENOTTY;
|
|
int time;
|
|
void __user *argp = (void __user *)arg;
|
|
int __user *p = argp;
|
|
|
|
switch (cmd) {
|
|
case WDIOC_GETSUPPORT:
|
|
ret = copy_to_user(argp, &at32_wdt_info,
|
|
sizeof(at32_wdt_info)) ? -EFAULT : 0;
|
|
break;
|
|
case WDIOC_GETSTATUS:
|
|
ret = put_user(0, p);
|
|
break;
|
|
case WDIOC_GETBOOTSTATUS:
|
|
ret = put_user(wdt->boot_status, p);
|
|
break;
|
|
case WDIOC_SETOPTIONS:
|
|
ret = get_user(time, p);
|
|
if (ret)
|
|
break;
|
|
if (time & WDIOS_DISABLECARD)
|
|
at32_wdt_stop();
|
|
if (time & WDIOS_ENABLECARD)
|
|
at32_wdt_start();
|
|
ret = 0;
|
|
break;
|
|
case WDIOC_KEEPALIVE:
|
|
at32_wdt_pat();
|
|
ret = 0;
|
|
break;
|
|
case WDIOC_SETTIMEOUT:
|
|
ret = get_user(time, p);
|
|
if (ret)
|
|
break;
|
|
ret = at32_wdt_settimeout(time);
|
|
if (ret)
|
|
break;
|
|
/* Enable new time value */
|
|
at32_wdt_start();
|
|
/* fall through */
|
|
case WDIOC_GETTIMEOUT:
|
|
ret = put_user(wdt->timeout, p);
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t at32_wdt_write(struct file *file, const char __user *data,
|
|
size_t len, loff_t *ppos)
|
|
{
|
|
/* See if we got the magic character 'V' and reload the timer */
|
|
if (len) {
|
|
if (!nowayout) {
|
|
size_t i;
|
|
|
|
/*
|
|
* note: just in case someone wrote the magic
|
|
* character five months ago...
|
|
*/
|
|
expect_release = 0;
|
|
|
|
/*
|
|
* scan to see whether or not we got the magic
|
|
* character
|
|
*/
|
|
for (i = 0; i != len; i++) {
|
|
char c;
|
|
if (get_user(c, data + i))
|
|
return -EFAULT;
|
|
if (c == 'V')
|
|
expect_release = 42;
|
|
}
|
|
}
|
|
/* someone wrote to us, we should pat the watchdog */
|
|
at32_wdt_pat();
|
|
}
|
|
return len;
|
|
}
|
|
|
|
static const struct file_operations at32_wdt_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.unlocked_ioctl = at32_wdt_ioctl,
|
|
.open = at32_wdt_open,
|
|
.release = at32_wdt_close,
|
|
.write = at32_wdt_write,
|
|
};
|
|
|
|
static int __init at32_wdt_probe(struct platform_device *pdev)
|
|
{
|
|
struct resource *regs;
|
|
int ret;
|
|
|
|
if (wdt) {
|
|
dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
|
|
return -EBUSY;
|
|
}
|
|
|
|
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
if (!regs) {
|
|
dev_dbg(&pdev->dev, "missing mmio resource\n");
|
|
return -ENXIO;
|
|
}
|
|
|
|
wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL);
|
|
if (!wdt) {
|
|
dev_dbg(&pdev->dev, "no memory for wdt structure\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
wdt->regs = ioremap(regs->start, resource_size(regs));
|
|
if (!wdt->regs) {
|
|
ret = -ENOMEM;
|
|
dev_dbg(&pdev->dev, "could not map I/O memory\n");
|
|
goto err_free;
|
|
}
|
|
|
|
spin_lock_init(&wdt->io_lock);
|
|
wdt->boot_status = at32_wdt_get_status();
|
|
|
|
/* Work-around for watchdog silicon errata. */
|
|
if (wdt->boot_status & WDIOF_CARDRESET) {
|
|
dev_info(&pdev->dev, "CPU must be reset with external "
|
|
"reset or POR due to silicon errata.\n");
|
|
ret = -EIO;
|
|
goto err_iounmap;
|
|
} else {
|
|
wdt->users = 0;
|
|
}
|
|
|
|
wdt->miscdev.minor = WATCHDOG_MINOR;
|
|
wdt->miscdev.name = "watchdog";
|
|
wdt->miscdev.fops = &at32_wdt_fops;
|
|
wdt->miscdev.parent = &pdev->dev;
|
|
|
|
platform_set_drvdata(pdev, wdt);
|
|
|
|
if (at32_wdt_settimeout(timeout)) {
|
|
at32_wdt_settimeout(TIMEOUT_DEFAULT);
|
|
dev_dbg(&pdev->dev,
|
|
"default timeout invalid, set to %d sec.\n",
|
|
TIMEOUT_DEFAULT);
|
|
}
|
|
|
|
ret = misc_register(&wdt->miscdev);
|
|
if (ret) {
|
|
dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
|
|
goto err_register;
|
|
}
|
|
|
|
dev_info(&pdev->dev,
|
|
"AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n",
|
|
wdt->regs, wdt->timeout, nowayout);
|
|
|
|
return 0;
|
|
|
|
err_register:
|
|
platform_set_drvdata(pdev, NULL);
|
|
err_iounmap:
|
|
iounmap(wdt->regs);
|
|
err_free:
|
|
kfree(wdt);
|
|
wdt = NULL;
|
|
return ret;
|
|
}
|
|
|
|
static int __exit at32_wdt_remove(struct platform_device *pdev)
|
|
{
|
|
if (wdt && platform_get_drvdata(pdev) == wdt) {
|
|
/* Stop the timer before we leave */
|
|
if (!nowayout)
|
|
at32_wdt_stop();
|
|
|
|
misc_deregister(&wdt->miscdev);
|
|
iounmap(wdt->regs);
|
|
kfree(wdt);
|
|
wdt = NULL;
|
|
platform_set_drvdata(pdev, NULL);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void at32_wdt_shutdown(struct platform_device *pdev)
|
|
{
|
|
at32_wdt_stop();
|
|
}
|
|
|
|
#ifdef CONFIG_PM
|
|
static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
|
|
{
|
|
at32_wdt_stop();
|
|
return 0;
|
|
}
|
|
|
|
static int at32_wdt_resume(struct platform_device *pdev)
|
|
{
|
|
if (wdt->users)
|
|
at32_wdt_start();
|
|
return 0;
|
|
}
|
|
#else
|
|
#define at32_wdt_suspend NULL
|
|
#define at32_wdt_resume NULL
|
|
#endif
|
|
|
|
/* work with hotplug and coldplug */
|
|
MODULE_ALIAS("platform:at32_wdt");
|
|
|
|
static struct platform_driver at32_wdt_driver = {
|
|
.remove = __exit_p(at32_wdt_remove),
|
|
.suspend = at32_wdt_suspend,
|
|
.resume = at32_wdt_resume,
|
|
.driver = {
|
|
.name = "at32_wdt",
|
|
.owner = THIS_MODULE,
|
|
},
|
|
.shutdown = at32_wdt_shutdown,
|
|
};
|
|
|
|
static int __init at32_wdt_init(void)
|
|
{
|
|
return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe);
|
|
}
|
|
module_init(at32_wdt_init);
|
|
|
|
static void __exit at32_wdt_exit(void)
|
|
{
|
|
platform_driver_unregister(&at32_wdt_driver);
|
|
}
|
|
module_exit(at32_wdt_exit);
|
|
|
|
MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
|
|
MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|