diff options
Diffstat (limited to 'drivers/watchdog/diag288_wdt.c')
| -rw-r--r-- | drivers/watchdog/diag288_wdt.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/drivers/watchdog/diag288_wdt.c b/drivers/watchdog/diag288_wdt.c new file mode 100644 index 000000000000..ea2b0171e70b --- /dev/null +++ b/drivers/watchdog/diag288_wdt.c @@ -0,0 +1,184 @@ +// 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 with LPAR. + * + * On LPAR, the watchdog will always trigger a system restart. The module + * parameter cmd is meaningless here. + * + * + * Copyright IBM Corp. 2004, 2013 + * Author(s): Arnd Bergmann (arndb@de.ibm.com) + * Philipp Hachtmann (phacht@de.ibm.com) + * + */ + +#define pr_fmt(fmt) "diag288_wdt: " 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 <asm/machine.h> +#include <asm/ebcdic.h> +#include <asm/diag288.h> +#include <asm/diag.h> +#include <linux/io.h> + +#define MAX_CMDLEN 240 +#define DEFAULT_CMD "SYSTEM RESTART" + +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 char *cmd_buf; + +static int diag288(unsigned int func, unsigned int timeout, + unsigned long action, unsigned int len) +{ + diag_stat_inc(DIAG_STAT_X288); + return __diag288(func, timeout, action, len); +} + +static int diag288_str(unsigned int func, unsigned int timeout, char *cmd) +{ + ssize_t len; + + len = strscpy(cmd_buf, cmd, MAX_CMDLEN); + if (len < 0) + return len; + ASCEBC(cmd_buf, MAX_CMDLEN); + EBC_TOUPPER(cmd_buf, MAX_CMDLEN); + + return diag288(func, timeout, virt_to_phys(cmd_buf), len); +} + +static int wdt_start(struct watchdog_device *dev) +{ + int ret; + unsigned int func; + + if (machine_is_vm()) { + func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) + : WDT_FUNC_INIT; + ret = diag288_str(func, dev->timeout, wdt_cmd); + WARN_ON(ret != 0); + } else { + ret = diag288(WDT_FUNC_INIT, dev->timeout, LPARWDT_RESTART, 0); + } + + if (ret) { + pr_err("The watchdog cannot be activated\n"); + return ret; + } + return 0; +} + +static int wdt_stop(struct watchdog_device *dev) +{ + return diag288(WDT_FUNC_CANCEL, 0, 0, 0); +} + +static int wdt_ping(struct watchdog_device *dev) +{ + int ret; + unsigned int func; + + if (machine_is_vm()) { + /* + * 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_str(func, dev->timeout, wdt_cmd); + WARN_ON(ret != 0); + } else { + ret = diag288(WDT_FUNC_CHANGE, dev->timeout, 0, 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, +}; + +static int __init diag288_init(void) +{ + watchdog_set_nowayout(&wdt_dev, nowayout_info); + + if (machine_is_vm()) { + cmd_buf = kmalloc(MAX_CMDLEN, GFP_KERNEL); + if (!cmd_buf) { + pr_err("The watchdog cannot be initialized\n"); + return -ENOMEM; + } + } + + return watchdog_register_device(&wdt_dev); +} + +static void __exit diag288_exit(void) +{ + watchdog_unregister_device(&wdt_dev); + kfree(cmd_buf); +} + +module_cpu_feature_match(S390_CPU_FEATURE_D288, diag288_init); +module_exit(diag288_exit); |