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Diffstat (limited to '')
| -rw-r--r-- | drivers/watchdog/pseries-wdt.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/drivers/watchdog/pseries-wdt.c b/drivers/watchdog/pseries-wdt.c new file mode 100644 index 000000000..7f53b5293 --- /dev/null +++ b/drivers/watchdog/pseries-wdt.c @@ -0,0 +1,239 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2022 International Business Machines, Inc. + */ + +#include <linux/bitops.h> +#include <linux/kernel.h> +#include <linux/limits.h> +#include <linux/math.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/platform_device.h> +#include <linux/time64.h> +#include <linux/watchdog.h> + +#define DRV_NAME "pseries-wdt" + +/* + * H_WATCHDOG Input + * + * R4: "flags": + * + * Bits 48-55: "operation" + */ +#define PSERIES_WDTF_OP_START 0x100UL /* start timer */ +#define PSERIES_WDTF_OP_STOP 0x200UL /* stop timer */ +#define PSERIES_WDTF_OP_QUERY 0x300UL /* query timer capabilities */ + +/* + * Bits 56-63: "timeoutAction" (for "Start Watchdog" only) + */ +#define PSERIES_WDTF_ACTION_HARD_POWEROFF 0x1UL /* poweroff */ +#define PSERIES_WDTF_ACTION_HARD_RESTART 0x2UL /* restart */ +#define PSERIES_WDTF_ACTION_DUMP_RESTART 0x3UL /* dump + restart */ + +/* + * H_WATCHDOG Output + * + * R3: Return code + * + * H_SUCCESS The operation completed. + * + * H_BUSY The hypervisor is too busy; retry the operation. + * + * H_PARAMETER The given "flags" are somehow invalid. Either the + * "operation" or "timeoutAction" is invalid, or a + * reserved bit is set. + * + * H_P2 The given "watchdogNumber" is zero or exceeds the + * supported maximum value. + * + * H_P3 The given "timeoutInMs" is below the supported + * minimum value. + * + * H_NOOP The given "watchdogNumber" is already stopped. + * + * H_HARDWARE The operation failed for ineffable reasons. + * + * H_FUNCTION The H_WATCHDOG hypercall is not supported by this + * hypervisor. + * + * R4: + * + * - For the "Query Watchdog Capabilities" operation, a 64-bit + * structure: + */ +#define PSERIES_WDTQ_MIN_TIMEOUT(cap) (((cap) >> 48) & 0xffff) +#define PSERIES_WDTQ_MAX_NUMBER(cap) (((cap) >> 32) & 0xffff) + +static const unsigned long pseries_wdt_action[] = { + [0] = PSERIES_WDTF_ACTION_HARD_POWEROFF, + [1] = PSERIES_WDTF_ACTION_HARD_RESTART, + [2] = PSERIES_WDTF_ACTION_DUMP_RESTART, +}; + +#define WATCHDOG_ACTION 1 +static unsigned int action = WATCHDOG_ACTION; +module_param(action, uint, 0444); +MODULE_PARM_DESC(action, "Action taken when watchdog expires (default=" + __MODULE_STRING(WATCHDOG_ACTION) ")"); + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0444); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +#define WATCHDOG_TIMEOUT 60 +static unsigned int timeout = WATCHDOG_TIMEOUT; +module_param(timeout, uint, 0444); +MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds (default=" + __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); + +struct pseries_wdt { + struct watchdog_device wd; + unsigned long action; + unsigned long num; /* Watchdog numbers are 1-based */ +}; + +static int pseries_wdt_start(struct watchdog_device *wdd) +{ + struct pseries_wdt *pw = watchdog_get_drvdata(wdd); + struct device *dev = wdd->parent; + unsigned long flags, msecs; + long rc; + + flags = pw->action | PSERIES_WDTF_OP_START; + msecs = wdd->timeout * MSEC_PER_SEC; + rc = plpar_hcall_norets(H_WATCHDOG, flags, pw->num, msecs); + if (rc != H_SUCCESS) { + dev_crit(dev, "H_WATCHDOG: %ld: failed to start timer %lu", + rc, pw->num); + return -EIO; + } + return 0; +} + +static int pseries_wdt_stop(struct watchdog_device *wdd) +{ + struct pseries_wdt *pw = watchdog_get_drvdata(wdd); + struct device *dev = wdd->parent; + long rc; + + rc = plpar_hcall_norets(H_WATCHDOG, PSERIES_WDTF_OP_STOP, pw->num); + if (rc != H_SUCCESS && rc != H_NOOP) { + dev_crit(dev, "H_WATCHDOG: %ld: failed to stop timer %lu", + rc, pw->num); + return -EIO; + } + return 0; +} + +static struct watchdog_info pseries_wdt_info = { + .identity = DRV_NAME, + .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT + | WDIOF_PRETIMEOUT, +}; + +static const struct watchdog_ops pseries_wdt_ops = { + .owner = THIS_MODULE, + .start = pseries_wdt_start, + .stop = pseries_wdt_stop, +}; + +static int pseries_wdt_probe(struct platform_device *pdev) +{ + unsigned long ret[PLPAR_HCALL_BUFSIZE] = { 0 }; + struct pseries_wdt *pw; + unsigned long cap; + long msecs, rc; + int err; + + rc = plpar_hcall(H_WATCHDOG, ret, PSERIES_WDTF_OP_QUERY); + if (rc == H_FUNCTION) + return -ENODEV; + if (rc != H_SUCCESS) + return -EIO; + cap = ret[0]; + + pw = devm_kzalloc(&pdev->dev, sizeof(*pw), GFP_KERNEL); + if (!pw) + return -ENOMEM; + + /* + * Assume watchdogNumber 1 for now. If we ever support + * multiple timers we will need to devise a way to choose a + * distinct watchdogNumber for each platform device at device + * registration time. + */ + pw->num = 1; + if (PSERIES_WDTQ_MAX_NUMBER(cap) < pw->num) + return -ENODEV; + + if (action >= ARRAY_SIZE(pseries_wdt_action)) + return -EINVAL; + pw->action = pseries_wdt_action[action]; + + pw->wd.parent = &pdev->dev; + pw->wd.info = &pseries_wdt_info; + pw->wd.ops = &pseries_wdt_ops; + msecs = PSERIES_WDTQ_MIN_TIMEOUT(cap); + pw->wd.min_timeout = DIV_ROUND_UP(msecs, MSEC_PER_SEC); + pw->wd.max_timeout = UINT_MAX / 1000; /* from linux/watchdog.h */ + pw->wd.timeout = timeout; + if (watchdog_init_timeout(&pw->wd, 0, NULL)) + return -EINVAL; + watchdog_set_nowayout(&pw->wd, nowayout); + watchdog_stop_on_reboot(&pw->wd); + watchdog_stop_on_unregister(&pw->wd); + watchdog_set_drvdata(&pw->wd, pw); + + err = devm_watchdog_register_device(&pdev->dev, &pw->wd); + if (err) + return err; + + platform_set_drvdata(pdev, &pw->wd); + + return 0; +} + +static int pseries_wdt_suspend(struct platform_device *pdev, pm_message_t state) +{ + struct watchdog_device *wd = platform_get_drvdata(pdev); + + if (watchdog_active(wd)) + return pseries_wdt_stop(wd); + return 0; +} + +static int pseries_wdt_resume(struct platform_device *pdev) +{ + struct watchdog_device *wd = platform_get_drvdata(pdev); + + if (watchdog_active(wd)) + return pseries_wdt_start(wd); + return 0; +} + +static const struct platform_device_id pseries_wdt_id[] = { + { .name = "pseries-wdt" }, + {} +}; +MODULE_DEVICE_TABLE(platform, pseries_wdt_id); + +static struct platform_driver pseries_wdt_driver = { + .driver = { + .name = DRV_NAME, + }, + .id_table = pseries_wdt_id, + .probe = pseries_wdt_probe, + .resume = pseries_wdt_resume, + .suspend = pseries_wdt_suspend, +}; +module_platform_driver(pseries_wdt_driver); + +MODULE_AUTHOR("Alexey Kardashevskiy"); +MODULE_AUTHOR("Scott Cheloha"); +MODULE_DESCRIPTION("POWER Architecture Platform Watchdog Driver"); +MODULE_LICENSE("GPL"); |