linux/drivers/watchdog/alim1535_wdt.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

451 lines
9.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Watchdog for the 7101 PMU version found in the ALi M1535 chipsets
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#define WATCHDOG_NAME "ALi_M1535"
#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
/* internal variables */
static unsigned long ali_is_open;
static char ali_expect_release;
static struct pci_dev *ali_pci;
static u32 ali_timeout_bits; /* stores the computed timeout */
static DEFINE_SPINLOCK(ali_lock); /* Guards the hardware */
/* module parameters */
static int timeout = WATCHDOG_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. (0 < timeout < 18000, default="
__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/*
* ali_start - start watchdog countdown
*
* Starts the timer running providing the timer has a counter
* configuration set.
*/
static void ali_start(void)
{
u32 val;
spin_lock(&ali_lock);
pci_read_config_dword(ali_pci, 0xCC, &val);
val &= ~0x3F; /* Mask count */
val |= (1 << 25) | ali_timeout_bits;
pci_write_config_dword(ali_pci, 0xCC, val);
spin_unlock(&ali_lock);
}
/*
* ali_stop - stop the timer countdown
*
* Stop the ALi watchdog countdown
*/
static void ali_stop(void)
{
u32 val;
spin_lock(&ali_lock);
pci_read_config_dword(ali_pci, 0xCC, &val);
val &= ~0x3F; /* Mask count to zero (disabled) */
val &= ~(1 << 25); /* and for safety mask the reset enable */
pci_write_config_dword(ali_pci, 0xCC, val);
spin_unlock(&ali_lock);
}
/*
* ali_keepalive - send a keepalive to the watchdog
*
* Send a keepalive to the timer (actually we restart the timer).
*/
static void ali_keepalive(void)
{
ali_start();
}
/*
* ali_settimer - compute the timer reload value
* @t: time in seconds
*
* Computes the timeout values needed
*/
static int ali_settimer(int t)
{
if (t < 0)
return -EINVAL;
else if (t < 60)
ali_timeout_bits = t|(1 << 6);
else if (t < 3600)
ali_timeout_bits = (t / 60)|(1 << 7);
else if (t < 18000)
ali_timeout_bits = (t / 300)|(1 << 6)|(1 << 7);
else
return -EINVAL;
timeout = t;
return 0;
}
/*
* /dev/watchdog handling
*/
/*
* ali_write - writes to ALi watchdog
* @file: file from VFS
* @data: user address of data
* @len: length of data
* @ppos: pointer to the file offset
*
* Handle a write to the ALi watchdog. Writing to the file pings
* the watchdog and resets it. Writing the magic 'V' sequence allows
* the next close to turn off the watchdog.
*/
static ssize_t ali_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... */
ali_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')
ali_expect_release = 42;
}
}
/* someone wrote to us, we should reload the timer */
ali_start();
}
return len;
}
/*
* ali_ioctl - handle watchdog ioctls
* @file: VFS file pointer
* @cmd: ioctl number
* @arg: arguments to the ioctl
*
* Handle the watchdog ioctls supported by the ALi driver. Really
* we want an extension to enable irq ack monitoring and the like
*/
static long ali_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING |
WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = "ALi M1535 WatchDog Timer",
};
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_SETOPTIONS:
{
int new_options, retval = -EINVAL;
if (get_user(new_options, p))
return -EFAULT;
if (new_options & WDIOS_DISABLECARD) {
ali_stop();
retval = 0;
}
if (new_options & WDIOS_ENABLECARD) {
ali_start();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
ali_keepalive();
return 0;
case WDIOC_SETTIMEOUT:
{
int new_timeout;
if (get_user(new_timeout, p))
return -EFAULT;
if (ali_settimer(new_timeout))
return -EINVAL;
ali_keepalive();
}
/* fall through */
case WDIOC_GETTIMEOUT:
return put_user(timeout, p);
default:
return -ENOTTY;
}
}
/*
* ali_open - handle open of ali watchdog
* @inode: inode from VFS
* @file: file from VFS
*
* Open the ALi watchdog device. Ensure only one person opens it
* at a time. Also start the watchdog running.
*/
static int ali_open(struct inode *inode, struct file *file)
{
/* /dev/watchdog can only be opened once */
if (test_and_set_bit(0, &ali_is_open))
return -EBUSY;
/* Activate */
ali_start();
return stream_open(inode, file);
}
/*
* ali_release - close an ALi watchdog
* @inode: inode from VFS
* @file: file from VFS
*
* Close the ALi watchdog device. Actual shutdown of the timer
* only occurs if the magic sequence has been set.
*/
static int ali_release(struct inode *inode, struct file *file)
{
/*
* Shut off the timer.
*/
if (ali_expect_release == 42)
ali_stop();
else {
pr_crit("Unexpected close, not stopping watchdog!\n");
ali_keepalive();
}
clear_bit(0, &ali_is_open);
ali_expect_release = 0;
return 0;
}
/*
* ali_notify_sys - System down notifier
*
* Notifier for system down
*/
static int ali_notify_sys(struct notifier_block *this,
unsigned long code, void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
ali_stop(); /* Turn the WDT off */
return NOTIFY_DONE;
}
/*
* Data for PCI driver interface
*
* This data only exists for exporting the supported
* PCI ids via MODULE_DEVICE_TABLE. We do not actually
* register a pci_driver, because someone else might one day
* want to register another driver on the same PCI id.
*/
static const struct pci_device_id ali_pci_tbl[] __used = {
{ PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,},
{ PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,},
{ 0, },
};
MODULE_DEVICE_TABLE(pci, ali_pci_tbl);
/*
* ali_find_watchdog - find a 1535 and 7101
*
* Scans the PCI hardware for a 1535 series bridge and matching 7101
* watchdog device. This may be overtight but it is better to be safe
*/
static int __init ali_find_watchdog(void)
{
struct pci_dev *pdev;
u32 wdog;
/* Check for a 1533/1535 series bridge */
pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL);
if (pdev == NULL)
pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1533, NULL);
if (pdev == NULL)
return -ENODEV;
pci_dev_put(pdev);
/* Check for the a 7101 PMU */
pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL);
if (pdev == NULL)
return -ENODEV;
if (pci_enable_device(pdev)) {
pci_dev_put(pdev);
return -EIO;
}
ali_pci = pdev;
/*
* Initialize the timer bits
*/
pci_read_config_dword(pdev, 0xCC, &wdog);
/* Timer bits */
wdog &= ~0x3F;
/* Issued events */
wdog &= ~((1 << 27)|(1 << 26)|(1 << 25)|(1 << 24));
/* No monitor bits */
wdog &= ~((1 << 16)|(1 << 13)|(1 << 12)|(1 << 11)|(1 << 10)|(1 << 9));
pci_write_config_dword(pdev, 0xCC, wdog);
return 0;
}
/*
* Kernel Interfaces
*/
static const struct file_operations ali_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = ali_write,
.unlocked_ioctl = ali_ioctl,
.open = ali_open,
.release = ali_release,
};
static struct miscdevice ali_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ali_fops,
};
static struct notifier_block ali_notifier = {
.notifier_call = ali_notify_sys,
};
/*
* watchdog_init - module initialiser
*
* Scan for a suitable watchdog and if so initialize it. Return an error
* if we cannot, the error causes the module to unload
*/
static int __init watchdog_init(void)
{
int ret;
/* Check whether or not the hardware watchdog is there */
if (ali_find_watchdog() != 0)
return -ENODEV;
/* Check that the timeout value is within it's range;
if not reset to the default */
if (timeout < 1 || timeout >= 18000) {
timeout = WATCHDOG_TIMEOUT;
pr_info("timeout value must be 0 < timeout < 18000, using %d\n",
timeout);
}
/* Calculate the watchdog's timeout */
ali_settimer(timeout);
ret = register_reboot_notifier(&ali_notifier);
if (ret != 0) {
pr_err("cannot register reboot notifier (err=%d)\n", ret);
goto out;
}
ret = misc_register(&ali_miscdev);
if (ret != 0) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto unreg_reboot;
}
pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
timeout, nowayout);
out:
return ret;
unreg_reboot:
unregister_reboot_notifier(&ali_notifier);
goto out;
}
/*
* watchdog_exit - module de-initialiser
*
* Called while unloading a successfully installed watchdog module.
*/
static void __exit watchdog_exit(void)
{
/* Stop the timer before we leave */
ali_stop();
/* Deregister */
misc_deregister(&ali_miscdev);
unregister_reboot_notifier(&ali_notifier);
pci_dev_put(ali_pci);
}
module_init(watchdog_init);
module_exit(watchdog_exit);
MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver");
MODULE_LICENSE("GPL");