--- /dev/null
+/*
+ * 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/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/suspend.h>
+#include <asm/ebcdic.h>
+#include <linux/io.h>
+#include <linux/uaccess.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_MISCDEV(WATCHDOG_MINOR);
+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");
+ return err;
+}
+
+static int __diag288_vm(unsigned int func, unsigned int timeout,
+ char *cmd, size_t len)
+{
+ return __diag288(func, timeout, virt_to_phys(cmd), len);
+}
+
+static int __diag288_lpar(unsigned int func, unsigned int timeout,
+ unsigned long action)
+{
+ return __diag288(func, timeout, action, 0);
+}
+
+static int wdt_start(struct watchdog_device *dev)
+{
+ char *ebc_cmd;
+ size_t len;
+ int ret;
+ unsigned int func;
+
+ ret = -ENODEV;
+
+ 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);
+
+ 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");
+ return ret;
+ }
+ return 0;
+}
+
+static int wdt_stop(struct watchdog_device *dev)
+{
+ int ret;
+
+ ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
+ return ret;
+}
+
+static int wdt_ping(struct watchdog_device *dev)
+{
+ char *ebc_cmd;
+ size_t len;
+ int ret;
+ unsigned int func;
+
+ ret = -ENODEV;
+
+ 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 struct watchdog_ops wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = wdt_start,
+ .stop = wdt_stop,
+ .ping = wdt_ping,
+ .set_timeout = wdt_set_timeout,
+};
+
+static 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.
+ * We reuse the open flag to ensure that suspend and watchdog open are
+ * exclusive operations
+ */
+static int wdt_suspend(void)
+{
+ if (test_and_set_bit(WDOG_DEV_OPEN, &wdt_dev.status)) {
+ pr_err("Linux cannot be suspended while the watchdog is in use\n");
+ return notifier_from_errno(-EBUSY);
+ }
+ if (test_bit(WDOG_ACTIVE, &wdt_dev.status)) {
+ clear_bit(WDOG_DEV_OPEN, &wdt_dev.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(WDOG_DEV_OPEN, &wdt_dev.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
+ };
+
+ watchdog_set_nowayout(&wdt_dev, nowayout_info);
+
+ if (MACHINE_IS_VM) {
+ if (__diag288_vm(WDT_FUNC_INIT, 15,
+ ebc_begin, sizeof(ebc_begin)) != 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);
Code Review / kvmfornfv.git / blobdiff