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