forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
363 lines
8.6 KiB
363 lines
8.6 KiB
/* |
|
* Watchdog driver for SiByte SB1 SoCs |
|
* |
|
* Copyright (C) 2007 OnStor, Inc. * Andrew Sharp <[email protected]> |
|
* |
|
* This driver is intended to make the second of two hardware watchdogs |
|
* on the Sibyte 12XX and 11XX SoCs available to the user. There are two |
|
* such devices available on the SoC, but it seems that there isn't an |
|
* enumeration class for watchdogs in Linux like there is for RTCs. |
|
* The second is used rather than the first because it uses IRQ 1, |
|
* thereby avoiding all that IRQ 0 problematic nonsense. |
|
* |
|
* I have not tried this driver on a 1480 processor; it might work |
|
* just well enough to really screw things up. |
|
* |
|
* It is a simple timer, and there is an interrupt that is raised the |
|
* first time the timer expires. The second time it expires, the chip |
|
* is reset and there is no way to redirect that NMI. Which could |
|
* be problematic in some cases where this chip is sitting on the HT |
|
* bus and has just taken responsibility for providing a cache block. |
|
* Since the reset can't be redirected to the external reset pin, it is |
|
* possible that other HT connected processors might hang and not reset. |
|
* For Linux, a soft reset would probably be even worse than a hard reset. |
|
* There you have it. |
|
* |
|
* The timer takes 23 bits of a 64 bit register (?) as a count value, |
|
* and decrements the count every microsecond, for a max value of |
|
* 0x7fffff usec or about 8.3ish seconds. |
|
* |
|
* This watchdog borrows some user semantics from the softdog driver, |
|
* in that if you close the fd, it leaves the watchdog running, unless |
|
* you previously wrote a 'V' to the fd, in which case it disables |
|
* the watchdog when you close the fd like some other drivers. |
|
* |
|
* Based on various other watchdog drivers, which are probably all |
|
* loosely based on something Alan Cox wrote years ago. |
|
* |
|
* (c) Copyright 1996 Alan Cox <[email protected]>, |
|
* All Rights Reserved. |
|
* |
|
* This program is free software; you can redistribute it and/or |
|
* modify it under the terms of the GNU General Public License |
|
* version 1 or 2 as published by the Free Software Foundation. |
|
* |
|
*/ |
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
|
|
|
#include <linux/module.h> |
|
#include <linux/io.h> |
|
#include <linux/uaccess.h> |
|
#include <linux/fs.h> |
|
#include <linux/reboot.h> |
|
#include <linux/miscdevice.h> |
|
#include <linux/watchdog.h> |
|
#include <linux/interrupt.h> |
|
|
|
#include <asm/sibyte/sb1250.h> |
|
#include <asm/sibyte/sb1250_regs.h> |
|
#include <asm/sibyte/sb1250_int.h> |
|
#include <asm/sibyte/sb1250_scd.h> |
|
|
|
static DEFINE_SPINLOCK(sbwd_lock); |
|
|
|
/* |
|
* set the initial count value of a timer |
|
* |
|
* wdog is the iomem address of the cfg register |
|
*/ |
|
static void sbwdog_set(char __iomem *wdog, unsigned long t) |
|
{ |
|
spin_lock(&sbwd_lock); |
|
__raw_writeb(0, wdog); |
|
__raw_writeq(t & 0x7fffffUL, wdog - 0x10); |
|
spin_unlock(&sbwd_lock); |
|
} |
|
|
|
/* |
|
* cause the timer to [re]load it's initial count and start counting |
|
* all over again |
|
* |
|
* wdog is the iomem address of the cfg register |
|
*/ |
|
static void sbwdog_pet(char __iomem *wdog) |
|
{ |
|
spin_lock(&sbwd_lock); |
|
__raw_writeb(__raw_readb(wdog) | 1, wdog); |
|
spin_unlock(&sbwd_lock); |
|
} |
|
|
|
static unsigned long sbwdog_gate; /* keeps it to one thread only */ |
|
static char __iomem *kern_dog = (char __iomem *)(IO_BASE + (A_SCD_WDOG_CFG_0)); |
|
static char __iomem *user_dog = (char __iomem *)(IO_BASE + (A_SCD_WDOG_CFG_1)); |
|
static unsigned long timeout = 0x7fffffUL; /* useconds: 8.3ish secs. */ |
|
static int expect_close; |
|
|
|
static const struct watchdog_info ident = { |
|
.options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | |
|
WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
|
.identity = "SiByte Watchdog", |
|
}; |
|
|
|
/* |
|
* Allow only a single thread to walk the dog |
|
*/ |
|
static int sbwdog_open(struct inode *inode, struct file *file) |
|
{ |
|
stream_open(inode, file); |
|
if (test_and_set_bit(0, &sbwdog_gate)) |
|
return -EBUSY; |
|
__module_get(THIS_MODULE); |
|
|
|
/* |
|
* Activate the timer |
|
*/ |
|
sbwdog_set(user_dog, timeout); |
|
__raw_writeb(1, user_dog); |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* Put the dog back in the kennel. |
|
*/ |
|
static int sbwdog_release(struct inode *inode, struct file *file) |
|
{ |
|
if (expect_close == 42) { |
|
__raw_writeb(0, user_dog); |
|
module_put(THIS_MODULE); |
|
} else { |
|
pr_crit("%s: Unexpected close, not stopping watchdog!\n", |
|
ident.identity); |
|
sbwdog_pet(user_dog); |
|
} |
|
clear_bit(0, &sbwdog_gate); |
|
expect_close = 0; |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* 42 - the answer |
|
*/ |
|
static ssize_t sbwdog_write(struct file *file, const char __user *data, |
|
size_t len, loff_t *ppos) |
|
{ |
|
int i; |
|
|
|
if (len) { |
|
/* |
|
* restart the timer |
|
*/ |
|
expect_close = 0; |
|
|
|
for (i = 0; i != len; i++) { |
|
char c; |
|
|
|
if (get_user(c, data + i)) |
|
return -EFAULT; |
|
if (c == 'V') |
|
expect_close = 42; |
|
} |
|
sbwdog_pet(user_dog); |
|
} |
|
|
|
return len; |
|
} |
|
|
|
static long sbwdog_ioctl(struct file *file, unsigned int cmd, |
|
unsigned long arg) |
|
{ |
|
int ret = -ENOTTY; |
|
unsigned long time; |
|
void __user *argp = (void __user *)arg; |
|
int __user *p = argp; |
|
|
|
switch (cmd) { |
|
case WDIOC_GETSUPPORT: |
|
ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
|
break; |
|
|
|
case WDIOC_GETSTATUS: |
|
case WDIOC_GETBOOTSTATUS: |
|
ret = put_user(0, p); |
|
break; |
|
|
|
case WDIOC_KEEPALIVE: |
|
sbwdog_pet(user_dog); |
|
ret = 0; |
|
break; |
|
|
|
case WDIOC_SETTIMEOUT: |
|
ret = get_user(time, p); |
|
if (ret) |
|
break; |
|
|
|
time *= 1000000; |
|
if (time > 0x7fffffUL) { |
|
ret = -EINVAL; |
|
break; |
|
} |
|
timeout = time; |
|
sbwdog_set(user_dog, timeout); |
|
sbwdog_pet(user_dog); |
|
fallthrough; |
|
|
|
case WDIOC_GETTIMEOUT: |
|
/* |
|
* get the remaining count from the ... count register |
|
* which is 1*8 before the config register |
|
*/ |
|
ret = put_user((u32)__raw_readq(user_dog - 8) / 1000000, p); |
|
break; |
|
} |
|
return ret; |
|
} |
|
|
|
/* |
|
* Notifier for system down |
|
*/ |
|
static int sbwdog_notify_sys(struct notifier_block *this, unsigned long code, |
|
void *erf) |
|
{ |
|
if (code == SYS_DOWN || code == SYS_HALT) { |
|
/* |
|
* sit and sit |
|
*/ |
|
__raw_writeb(0, user_dog); |
|
__raw_writeb(0, kern_dog); |
|
} |
|
|
|
return NOTIFY_DONE; |
|
} |
|
|
|
static const struct file_operations sbwdog_fops = { |
|
.owner = THIS_MODULE, |
|
.llseek = no_llseek, |
|
.write = sbwdog_write, |
|
.unlocked_ioctl = sbwdog_ioctl, |
|
.compat_ioctl = compat_ptr_ioctl, |
|
.open = sbwdog_open, |
|
.release = sbwdog_release, |
|
}; |
|
|
|
static struct miscdevice sbwdog_miscdev = { |
|
.minor = WATCHDOG_MINOR, |
|
.name = "watchdog", |
|
.fops = &sbwdog_fops, |
|
}; |
|
|
|
static struct notifier_block sbwdog_notifier = { |
|
.notifier_call = sbwdog_notify_sys, |
|
}; |
|
|
|
/* |
|
* interrupt handler |
|
* |
|
* doesn't do a whole lot for user, but oh so cleverly written so kernel |
|
* code can use it to re-up the watchdog, thereby saving the kernel from |
|
* having to create and maintain a timer, just to tickle another timer, |
|
* which is just so wrong. |
|
*/ |
|
irqreturn_t sbwdog_interrupt(int irq, void *addr) |
|
{ |
|
unsigned long wd_init; |
|
char *wd_cfg_reg = (char *)addr; |
|
u8 cfg; |
|
|
|
cfg = __raw_readb(wd_cfg_reg); |
|
wd_init = __raw_readq(wd_cfg_reg - 8) & 0x7fffff; |
|
|
|
/* |
|
* if it's the second watchdog timer, it's for those users |
|
*/ |
|
if (wd_cfg_reg == user_dog) |
|
pr_crit("%s in danger of initiating system reset " |
|
"in %ld.%01ld seconds\n", |
|
ident.identity, |
|
wd_init / 1000000, (wd_init / 100000) % 10); |
|
else |
|
cfg |= 1; |
|
|
|
__raw_writeb(cfg, wd_cfg_reg); |
|
|
|
return IRQ_HANDLED; |
|
} |
|
|
|
static int __init sbwdog_init(void) |
|
{ |
|
int ret; |
|
|
|
/* |
|
* register a reboot notifier |
|
*/ |
|
ret = register_reboot_notifier(&sbwdog_notifier); |
|
if (ret) { |
|
pr_err("%s: cannot register reboot notifier (err=%d)\n", |
|
ident.identity, ret); |
|
return ret; |
|
} |
|
|
|
/* |
|
* get the resources |
|
*/ |
|
|
|
ret = request_irq(1, sbwdog_interrupt, IRQF_SHARED, |
|
ident.identity, (void *)user_dog); |
|
if (ret) { |
|
pr_err("%s: failed to request irq 1 - %d\n", |
|
ident.identity, ret); |
|
goto out; |
|
} |
|
|
|
ret = misc_register(&sbwdog_miscdev); |
|
if (ret == 0) { |
|
pr_info("%s: timeout is %ld.%ld secs\n", |
|
ident.identity, |
|
timeout / 1000000, (timeout / 100000) % 10); |
|
return 0; |
|
} |
|
free_irq(1, (void *)user_dog); |
|
out: |
|
unregister_reboot_notifier(&sbwdog_notifier); |
|
|
|
return ret; |
|
} |
|
|
|
static void __exit sbwdog_exit(void) |
|
{ |
|
misc_deregister(&sbwdog_miscdev); |
|
free_irq(1, (void *)user_dog); |
|
unregister_reboot_notifier(&sbwdog_notifier); |
|
} |
|
|
|
module_init(sbwdog_init); |
|
module_exit(sbwdog_exit); |
|
|
|
MODULE_AUTHOR("Andrew Sharp <[email protected]>"); |
|
MODULE_DESCRIPTION("SiByte Watchdog"); |
|
|
|
module_param(timeout, ulong, 0); |
|
MODULE_PARM_DESC(timeout, |
|
"Watchdog timeout in microseconds (max/default 8388607 or 8.3ish secs)"); |
|
|
|
MODULE_LICENSE("GPL"); |
|
|
|
/* |
|
* example code that can be put in a platform code area to utilize the |
|
* first watchdog timer for the kernels own purpose. |
|
|
|
void platform_wd_setup(void) |
|
{ |
|
int ret; |
|
|
|
ret = request_irq(1, sbwdog_interrupt, IRQF_SHARED, |
|
"Kernel Watchdog", IOADDR(A_SCD_WDOG_CFG_0)); |
|
if (ret) { |
|
pr_crit("Watchdog IRQ zero(0) failed to be requested - %d\n", ret); |
|
} |
|
} |
|
|
|
|
|
*/
|
|
|