+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * AMD Elan SC520 processor Watchdog Timer driver
- *
- * Based on acquirewdt.c by Alan Cox,
- * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
- *
- * The authors do NOT admit liability nor provide warranty for
- * any of this software. This material is provided "AS-IS" in
- * the hope that it may be useful for others.
- *
- * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net>
- * 9/27 - 2001 [Initial release]
- *
- * Additional fixes Alan Cox
- * - Fixed formatting
- * - Removed debug printks
- * - Fixed SMP built kernel deadlock
- * - Switched to private locks not lock_kernel
- * - Used ioremap/writew/readw
- * - Added NOWAYOUT support
- * 4/12 - 2002 Changes by Rob Radez <rob@osinvestor.com>
- * - Change comments
- * - Eliminate fop_llseek
- * - Change CONFIG_WATCHDOG_NOWAYOUT semantics
- * - Add KERN_* tags to printks
- * - fix possible wdt_is_open race
- * - Report proper capabilities in watchdog_info
- * - Add WDIOC_{GETSTATUS, GETBOOTSTATUS, SETTIMEOUT,
- * GETTIMEOUT, SETOPTIONS} ioctls
- * 09/8 - 2003 Changes by Wim Van Sebroeck <wim@iguana.be>
- * - cleanup of trailing spaces
- * - added extra printk's for startup problems
- * - use module_param
- * - made timeout (the emulated heartbeat) a module_param
- * - made the keepalive ping an internal subroutine
- * 3/27 - 2004 Changes by Sean Young <sean@mess.org>
- * - set MMCR_BASE to 0xfffef000
- * - CBAR does not need to be read
- * - removed debugging printks
- *
- * This WDT driver is different from most other Linux WDT
- * drivers in that the driver will ping the watchdog by itself,
- * because this particular WDT has a very short timeout (1.6
- * seconds) and it would be insane to count on any userspace
- * daemon always getting scheduled within that time frame.
- *
- * This driver uses memory mapped IO, and spinlock.
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/module.h>
-#include <linux/moduleparam.h>
-#include <linux/types.h>
-#include <linux/timer.h>
-#include <linux/miscdevice.h>
-#include <linux/watchdog.h>
-#include <linux/fs.h>
-#include <linux/ioport.h>
-#include <linux/notifier.h>
-#include <linux/reboot.h>
-#include <linux/init.h>
-#include <linux/jiffies.h>
-#include <linux/io.h>
-#include <linux/uaccess.h>
-
-
-/*
- * The AMD Elan SC520 timeout value is 492us times a power of 2 (0-7)
- *
- * 0: 492us 2: 1.01s 4: 4.03s 6: 16.22s
- * 1: 503ms 3: 2.01s 5: 8.05s 7: 32.21s
- *
- * We will program the SC520 watchdog for a timeout of 2.01s.
- * If we reset the watchdog every ~250ms we should be safe.
- */
-
-#define WDT_INTERVAL (HZ/4+1)
-
-/*
- * We must not require too good response from the userspace daemon.
- * Here we require the userspace daemon to send us a heartbeat
- * char to /dev/watchdog every 30 seconds.
- */
-
-#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
-/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
-static int timeout = WATCHDOG_TIMEOUT;
-module_param(timeout, int, 0);
-MODULE_PARM_DESC(timeout,
- "Watchdog timeout in seconds. (1 <= timeout <= 3600, 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) ")");
-
-/*
- * AMD Elan SC520 - Watchdog Timer Registers
- */
-#define MMCR_BASE 0xfffef000 /* The default base address */
-#define OFFS_WDTMRCTL 0xCB0 /* Watchdog Timer Control Register */
-
-/* WDT Control Register bit definitions */
-#define WDT_EXP_SEL_01 0x0001 /* [01] Time-out = 496 us (with 33 Mhz clk). */
-#define WDT_EXP_SEL_02 0x0002 /* [02] Time-out = 508 ms (with 33 Mhz clk). */
-#define WDT_EXP_SEL_03 0x0004 /* [03] Time-out = 1.02 s (with 33 Mhz clk). */
-#define WDT_EXP_SEL_04 0x0008 /* [04] Time-out = 2.03 s (with 33 Mhz clk). */
-#define WDT_EXP_SEL_05 0x0010 /* [05] Time-out = 4.07 s (with 33 Mhz clk). */
-#define WDT_EXP_SEL_06 0x0020 /* [06] Time-out = 8.13 s (with 33 Mhz clk). */
-#define WDT_EXP_SEL_07 0x0040 /* [07] Time-out = 16.27s (with 33 Mhz clk). */
-#define WDT_EXP_SEL_08 0x0080 /* [08] Time-out = 32.54s (with 33 Mhz clk). */
-#define WDT_IRQ_FLG 0x1000 /* [12] Interrupt Request Flag */
-#define WDT_WRST_ENB 0x4000 /* [14] Watchdog Timer Reset Enable */
-#define WDT_ENB 0x8000 /* [15] Watchdog Timer Enable */
-
-static __u16 __iomem *wdtmrctl;
-
-static void wdt_timer_ping(struct timer_list *);
-static DEFINE_TIMER(timer, wdt_timer_ping);
-static unsigned long next_heartbeat;
-static unsigned long wdt_is_open;
-static char wdt_expect_close;
-static DEFINE_SPINLOCK(wdt_spinlock);
-
-/*
- * Whack the dog
- */
-
-static void wdt_timer_ping(struct timer_list *unused)
-{
- /* If we got a heartbeat pulse within the WDT_US_INTERVAL
- * we agree to ping the WDT
- */
- if (time_before(jiffies, next_heartbeat)) {
- /* Ping the WDT */
- spin_lock(&wdt_spinlock);
- writew(0xAAAA, wdtmrctl);
- writew(0x5555, wdtmrctl);
- spin_unlock(&wdt_spinlock);
-
- /* Re-set the timer interval */
- mod_timer(&timer, jiffies + WDT_INTERVAL);
- } else
- pr_warn("Heartbeat lost! Will not ping the watchdog\n");
-}
-
-/*
- * Utility routines
- */
-
-static void wdt_config(int writeval)
-{
- unsigned long flags;
-
- /* buy some time (ping) */
- spin_lock_irqsave(&wdt_spinlock, flags);
- readw(wdtmrctl); /* ensure write synchronization */
- writew(0xAAAA, wdtmrctl);
- writew(0x5555, wdtmrctl);
- /* unlock WDT = make WDT configuration register writable one time */
- writew(0x3333, wdtmrctl);
- writew(0xCCCC, wdtmrctl);
- /* write WDT configuration register */
- writew(writeval, wdtmrctl);
- spin_unlock_irqrestore(&wdt_spinlock, flags);
-}
-
-static int wdt_startup(void)
-{
- next_heartbeat = jiffies + (timeout * HZ);
-
- /* Start the timer */
- mod_timer(&timer, jiffies + WDT_INTERVAL);
-
- /* Start the watchdog */
- wdt_config(WDT_ENB | WDT_WRST_ENB | WDT_EXP_SEL_04);
-
- pr_info("Watchdog timer is now enabled\n");
- return 0;
-}
-
-static int wdt_turnoff(void)
-{
- /* Stop the timer */
- timer_delete_sync(&timer);
-
- /* Stop the watchdog */
- wdt_config(0);
-
- pr_info("Watchdog timer is now disabled...\n");
- return 0;
-}
-
-static int wdt_keepalive(void)
-{
- /* user land ping */
- next_heartbeat = jiffies + (timeout * HZ);
- return 0;
-}
-
-static int wdt_set_heartbeat(int t)
-{
- if ((t < 1) || (t > 3600)) /* arbitrary upper limit */
- return -EINVAL;
-
- timeout = t;
- return 0;
-}
-
-/*
- * /dev/watchdog handling
- */
-
-static ssize_t fop_write(struct file *file, const char __user *buf,
- size_t count, loff_t *ppos)
-{
- /* See if we got the magic character 'V' and reload the timer */
- if (count) {
- if (!nowayout) {
- size_t ofs;
-
- /* note: just in case someone wrote the magic character
- * five months ago... */
- wdt_expect_close = 0;
-
- /* now scan */
- for (ofs = 0; ofs != count; ofs++) {
- char c;
- if (get_user(c, buf + ofs))
- return -EFAULT;
- if (c == 'V')
- wdt_expect_close = 42;
- }
- }
-
- /* Well, anyhow someone wrote to us, we should
- return that favour */
- wdt_keepalive();
- }
- return count;
-}
-
-static int fop_open(struct inode *inode, struct file *file)
-{
- /* Just in case we're already talking to someone... */
- if (test_and_set_bit(0, &wdt_is_open))
- return -EBUSY;
- if (nowayout)
- __module_get(THIS_MODULE);
-
- /* Good, fire up the show */
- wdt_startup();
- return stream_open(inode, file);
-}
-
-static int fop_close(struct inode *inode, struct file *file)
-{
- if (wdt_expect_close == 42)
- wdt_turnoff();
- else {
- pr_crit("Unexpected close, not stopping watchdog!\n");
- wdt_keepalive();
- }
- clear_bit(0, &wdt_is_open);
- wdt_expect_close = 0;
- return 0;
-}
-
-static long fop_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 = 1,
- .identity = "SC520",
- };
-
- 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) {
- wdt_turnoff();
- retval = 0;
- }
-
- if (new_options & WDIOS_ENABLECARD) {
- wdt_startup();
- retval = 0;
- }
-
- return retval;
- }
- case WDIOC_KEEPALIVE:
- wdt_keepalive();
- return 0;
- case WDIOC_SETTIMEOUT:
- {
- int new_timeout;
-
- if (get_user(new_timeout, p))
- return -EFAULT;
-
- if (wdt_set_heartbeat(new_timeout))
- return -EINVAL;
-
- wdt_keepalive();
- }
- fallthrough;
- case WDIOC_GETTIMEOUT:
- return put_user(timeout, p);
- default:
- return -ENOTTY;
- }
-}
-
-static const struct file_operations wdt_fops = {
- .owner = THIS_MODULE,
- .write = fop_write,
- .open = fop_open,
- .release = fop_close,
- .unlocked_ioctl = fop_ioctl,
- .compat_ioctl = compat_ptr_ioctl,
-};
-
-static struct miscdevice wdt_miscdev = {
- .minor = WATCHDOG_MINOR,
- .name = "watchdog",
- .fops = &wdt_fops,
-};
-
-/*
- * Notifier for system down
- */
-
-static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
- void *unused)
-{
- if (code == SYS_DOWN || code == SYS_HALT)
- wdt_turnoff();
- return NOTIFY_DONE;
-}
-
-/*
- * The WDT needs to learn about soft shutdowns in order to
- * turn the timebomb registers off.
- */
-
-static struct notifier_block wdt_notifier = {
- .notifier_call = wdt_notify_sys,
-};
-
-static void __exit sc520_wdt_unload(void)
-{
- if (!nowayout)
- wdt_turnoff();
-
- /* Deregister */
- misc_deregister(&wdt_miscdev);
- unregister_reboot_notifier(&wdt_notifier);
- iounmap(wdtmrctl);
-}
-
-static int __init sc520_wdt_init(void)
-{
- int rc = -EBUSY;
-
- /* Check that the timeout value is within it's range ;
- if not reset to the default */
- if (wdt_set_heartbeat(timeout)) {
- wdt_set_heartbeat(WATCHDOG_TIMEOUT);
- pr_info("timeout value must be 1 <= timeout <= 3600, using %d\n",
- WATCHDOG_TIMEOUT);
- }
-
- wdtmrctl = ioremap(MMCR_BASE + OFFS_WDTMRCTL, 2);
- if (!wdtmrctl) {
- pr_err("Unable to remap memory\n");
- rc = -ENOMEM;
- goto err_out_region2;
- }
-
- rc = register_reboot_notifier(&wdt_notifier);
- if (rc) {
- pr_err("cannot register reboot notifier (err=%d)\n", rc);
- goto err_out_ioremap;
- }
-
- rc = misc_register(&wdt_miscdev);
- if (rc) {
- pr_err("cannot register miscdev on minor=%d (err=%d)\n",
- WATCHDOG_MINOR, rc);
- goto err_out_notifier;
- }
-
- pr_info("WDT driver for SC520 initialised. timeout=%d sec (nowayout=%d)\n",
- timeout, nowayout);
-
- return 0;
-
-err_out_notifier:
- unregister_reboot_notifier(&wdt_notifier);
-err_out_ioremap:
- iounmap(wdtmrctl);
-err_out_region2:
- return rc;
-}
-
-module_init(sc520_wdt_init);
-module_exit(sc520_wdt_unload);
-
-MODULE_AUTHOR("Scott and Bill Jennings");
-MODULE_DESCRIPTION(
- "Driver for watchdog timer in AMD \"Elan\" SC520 uProcessor");
-MODULE_LICENSE("GPL");
projects / thirdparty / kernel / linux.git / commitdiff
