diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/watchdog/diag288_wdt.c | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/drivers/watchdog/diag288_wdt.c b/drivers/watchdog/diag288_wdt.c new file mode 100644 index 000000000..6ca5d9515 --- /dev/null +++ b/drivers/watchdog/diag288_wdt.c @@ -0,0 +1,319 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Watchdog driver for z/VM and LPAR using the diag 288 interface. + * + * Under z/VM, expiration of the watchdog will send a "system restart" command + * to CP. + * + * The command can be altered using the module parameter "cmd". This is + * not recommended because it's only supported on z/VM but not whith LPAR. + * + * On LPAR, the watchdog will always trigger a system restart. the module + * paramter cmd is meaningless here. + * + * + * Copyright IBM Corp. 2004, 2013 + * Author(s): Arnd Bergmann (arndb@de.ibm.com) + * Philipp Hachtmann (phacht@de.ibm.com) + * + */ + +#define KMSG_COMPONENT "diag288_wdt" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/slab.h> +#include <linux/watchdog.h> +#include <linux/suspend.h> +#include <asm/ebcdic.h> +#include <asm/diag.h> +#include <linux/io.h> + +#define MAX_CMDLEN 240 +#define DEFAULT_CMD "SYSTEM RESTART" + +#define MIN_INTERVAL 15 /* Minimal time supported by diag88 */ +#define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */ + +#define WDT_DEFAULT_TIMEOUT 30 + +/* Function codes - init, change, cancel */ +#define WDT_FUNC_INIT 0 +#define WDT_FUNC_CHANGE 1 +#define WDT_FUNC_CANCEL 2 +#define WDT_FUNC_CONCEAL 0x80000000 + +/* Action codes for LPAR watchdog */ +#define LPARWDT_RESTART 0 + +static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD; +static bool conceal_on; +static bool nowayout_info = WATCHDOG_NOWAYOUT; + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>"); +MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>"); + +MODULE_DESCRIPTION("System z diag288 Watchdog Timer"); + +module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644); +MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)"); + +module_param_named(conceal, conceal_on, bool, 0644); +MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)"); + +module_param_named(nowayout, nowayout_info, bool, 0444); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)"); + +MODULE_ALIAS("vmwatchdog"); + +static int __diag288(unsigned int func, unsigned int timeout, + unsigned long action, unsigned int len) +{ + register unsigned long __func asm("2") = func; + register unsigned long __timeout asm("3") = timeout; + register unsigned long __action asm("4") = action; + register unsigned long __len asm("5") = len; + int err; + + err = -EINVAL; + asm volatile( + " diag %1, %3, 0x288\n" + "0: la %0, 0\n" + "1:\n" + EX_TABLE(0b, 1b) + : "+d" (err) : "d"(__func), "d"(__timeout), + "d"(__action), "d"(__len) : "1", "cc", "memory"); + return err; +} + +static int __diag288_vm(unsigned int func, unsigned int timeout, + char *cmd, size_t len) +{ + diag_stat_inc(DIAG_STAT_X288); + return __diag288(func, timeout, virt_to_phys(cmd), len); +} + +static int __diag288_lpar(unsigned int func, unsigned int timeout, + unsigned long action) +{ + diag_stat_inc(DIAG_STAT_X288); + return __diag288(func, timeout, action, 0); +} + +static unsigned long wdt_status; + +#define DIAG_WDOG_BUSY 0 + +static int wdt_start(struct watchdog_device *dev) +{ + char *ebc_cmd; + size_t len; + int ret; + unsigned int func; + + if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status)) + return -EBUSY; + + if (MACHINE_IS_VM) { + ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL); + if (!ebc_cmd) { + clear_bit(DIAG_WDOG_BUSY, &wdt_status); + return -ENOMEM; + } + len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN); + ASCEBC(ebc_cmd, MAX_CMDLEN); + EBC_TOUPPER(ebc_cmd, MAX_CMDLEN); + + func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) + : WDT_FUNC_INIT; + ret = __diag288_vm(func, dev->timeout, ebc_cmd, len); + WARN_ON(ret != 0); + kfree(ebc_cmd); + } else { + ret = __diag288_lpar(WDT_FUNC_INIT, + dev->timeout, LPARWDT_RESTART); + } + + if (ret) { + pr_err("The watchdog cannot be activated\n"); + clear_bit(DIAG_WDOG_BUSY, &wdt_status); + return ret; + } + return 0; +} + +static int wdt_stop(struct watchdog_device *dev) +{ + int ret; + + diag_stat_inc(DIAG_STAT_X288); + ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0); + + clear_bit(DIAG_WDOG_BUSY, &wdt_status); + + return ret; +} + +static int wdt_ping(struct watchdog_device *dev) +{ + char *ebc_cmd; + size_t len; + int ret; + unsigned int func; + + if (MACHINE_IS_VM) { + ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL); + if (!ebc_cmd) + return -ENOMEM; + len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN); + ASCEBC(ebc_cmd, MAX_CMDLEN); + EBC_TOUPPER(ebc_cmd, MAX_CMDLEN); + + /* + * It seems to be ok to z/VM to use the init function to + * retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must + * be used when the watchdog is running. + */ + func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) + : WDT_FUNC_INIT; + + ret = __diag288_vm(func, dev->timeout, ebc_cmd, len); + WARN_ON(ret != 0); + kfree(ebc_cmd); + } else { + ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0); + } + + if (ret) + pr_err("The watchdog timer cannot be started or reset\n"); + return ret; +} + +static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to) +{ + dev->timeout = new_to; + return wdt_ping(dev); +} + +static const struct watchdog_ops wdt_ops = { + .owner = THIS_MODULE, + .start = wdt_start, + .stop = wdt_stop, + .ping = wdt_ping, + .set_timeout = wdt_set_timeout, +}; + +static const struct watchdog_info wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, + .firmware_version = 0, + .identity = "z Watchdog", +}; + +static struct watchdog_device wdt_dev = { + .parent = NULL, + .info = &wdt_info, + .ops = &wdt_ops, + .bootstatus = 0, + .timeout = WDT_DEFAULT_TIMEOUT, + .min_timeout = MIN_INTERVAL, + .max_timeout = MAX_INTERVAL, +}; + +/* + * It makes no sense to go into suspend while the watchdog is running. + * Depending on the memory size, the watchdog might trigger, while we + * are still saving the memory. + */ +static int wdt_suspend(void) +{ + if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status)) { + pr_err("Linux cannot be suspended while the watchdog is in use\n"); + return notifier_from_errno(-EBUSY); + } + return NOTIFY_DONE; +} + +static int wdt_resume(void) +{ + clear_bit(DIAG_WDOG_BUSY, &wdt_status); + return NOTIFY_DONE; +} + +static int wdt_power_event(struct notifier_block *this, unsigned long event, + void *ptr) +{ + switch (event) { + case PM_POST_HIBERNATION: + case PM_POST_SUSPEND: + return wdt_resume(); + case PM_HIBERNATION_PREPARE: + case PM_SUSPEND_PREPARE: + return wdt_suspend(); + default: + return NOTIFY_DONE; + } +} + +static struct notifier_block wdt_power_notifier = { + .notifier_call = wdt_power_event, +}; + +static int __init diag288_init(void) +{ + int ret; + char ebc_begin[] = { + 194, 197, 199, 201, 213 + }; + char *ebc_cmd; + + watchdog_set_nowayout(&wdt_dev, nowayout_info); + + if (MACHINE_IS_VM) { + ebc_cmd = kmalloc(sizeof(ebc_begin), GFP_KERNEL); + if (!ebc_cmd) { + pr_err("The watchdog cannot be initialized\n"); + return -ENOMEM; + } + memcpy(ebc_cmd, ebc_begin, sizeof(ebc_begin)); + ret = __diag288_vm(WDT_FUNC_INIT, 15, + ebc_cmd, sizeof(ebc_begin)); + kfree(ebc_cmd); + if (ret != 0) { + pr_err("The watchdog cannot be initialized\n"); + return -EINVAL; + } + } else { + if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) { + pr_err("The watchdog cannot be initialized\n"); + return -EINVAL; + } + } + + if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 0)) { + pr_err("The watchdog cannot be deactivated\n"); + return -EINVAL; + } + + ret = register_pm_notifier(&wdt_power_notifier); + if (ret) + return ret; + + ret = watchdog_register_device(&wdt_dev); + if (ret) + unregister_pm_notifier(&wdt_power_notifier); + + return ret; +} + +static void __exit diag288_exit(void) +{ + watchdog_unregister_device(&wdt_dev); + unregister_pm_notifier(&wdt_power_notifier); +} + +module_init(diag288_init); +module_exit(diag288_exit); |