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1// SPDX-License-Identifier: GPL-2.02/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */3 4#include <linux/delay.h>5#include <linux/io.h>6#include <linux/module.h>7#include <linux/platform_device.h>8#include <linux/types.h>9#include <linux/watchdog.h>10 11#define MASK_WDGCS_ENABLE 0x0112#define MASK_WDGCS_RELOAD 0x0413#define MASK_WDGCS_NMIEN 0x0814#define MASK_WDGCS_WARN 0x8015 16#define WDT_MAX_TIMEOUT_MS 65535017#define WDT_DEFAULT_TIMEOUT 3018#define SECS_TO_WDOG_TICKS(x) ((x) * 100)19#define WDOG_TICKS_TO_SECS(x) ((x) / 100)20 21#define GXP_WDT_CNT_OFS 0x1022#define GXP_WDT_CTRL_OFS 0x1623 24struct gxp_wdt {25 void __iomem *base;26 struct watchdog_device wdd;27};28 29static void gxp_wdt_enable_reload(struct gxp_wdt *drvdata)30{31 u8 val;32 33 val = readb(drvdata->base + GXP_WDT_CTRL_OFS);34 val |= (MASK_WDGCS_ENABLE | MASK_WDGCS_RELOAD);35 writeb(val, drvdata->base + GXP_WDT_CTRL_OFS);36}37 38static int gxp_wdt_start(struct watchdog_device *wdd)39{40 struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);41 42 writew(SECS_TO_WDOG_TICKS(wdd->timeout), drvdata->base + GXP_WDT_CNT_OFS);43 gxp_wdt_enable_reload(drvdata);44 return 0;45}46 47static int gxp_wdt_stop(struct watchdog_device *wdd)48{49 struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);50 u8 val;51 52 val = readb_relaxed(drvdata->base + GXP_WDT_CTRL_OFS);53 val &= ~MASK_WDGCS_ENABLE;54 writeb(val, drvdata->base + GXP_WDT_CTRL_OFS);55 return 0;56}57 58static int gxp_wdt_set_timeout(struct watchdog_device *wdd,59 unsigned int timeout)60{61 struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);62 u32 actual;63 64 wdd->timeout = timeout;65 actual = min(timeout * 100, wdd->max_hw_heartbeat_ms / 10);66 writew(actual, drvdata->base + GXP_WDT_CNT_OFS);67 68 return 0;69}70 71static unsigned int gxp_wdt_get_timeleft(struct watchdog_device *wdd)72{73 struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);74 u32 val = readw(drvdata->base + GXP_WDT_CNT_OFS);75 76 return WDOG_TICKS_TO_SECS(val);77}78 79static int gxp_wdt_ping(struct watchdog_device *wdd)80{81 struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);82 83 gxp_wdt_enable_reload(drvdata);84 return 0;85}86 87static int gxp_restart(struct watchdog_device *wdd, unsigned long action,88 void *data)89{90 struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);91 92 writew(1, drvdata->base + GXP_WDT_CNT_OFS);93 gxp_wdt_enable_reload(drvdata);94 mdelay(100);95 return 0;96}97 98static const struct watchdog_ops gxp_wdt_ops = {99 .owner = THIS_MODULE,100 .start = gxp_wdt_start,101 .stop = gxp_wdt_stop,102 .ping = gxp_wdt_ping,103 .set_timeout = gxp_wdt_set_timeout,104 .get_timeleft = gxp_wdt_get_timeleft,105 .restart = gxp_restart,106};107 108static const struct watchdog_info gxp_wdt_info = {109 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,110 .identity = "HPE GXP Watchdog timer",111};112 113static int gxp_wdt_probe(struct platform_device *pdev)114{115 struct device *dev = &pdev->dev;116 struct gxp_wdt *drvdata;117 int err;118 u8 val;119 120 drvdata = devm_kzalloc(dev, sizeof(struct gxp_wdt), GFP_KERNEL);121 if (!drvdata)122 return -ENOMEM;123 124 /*125 * The register area where the timer and watchdog reside is disarranged.126 * Hence mapping individual register blocks for the timer and watchdog127 * is not recommended as they would have access to each others128 * registers. Based on feedback the watchdog is no longer part of the129 * device tree file and the timer driver now creates the watchdog as a130 * child device. During the watchdogs creation, the timer driver passes131 * the base address to the watchdog over the private interface.132 */133 134 drvdata->base = (void __iomem *)dev->platform_data;135 136 drvdata->wdd.info = &gxp_wdt_info;137 drvdata->wdd.ops = &gxp_wdt_ops;138 drvdata->wdd.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT_MS;139 drvdata->wdd.parent = dev;140 drvdata->wdd.timeout = WDT_DEFAULT_TIMEOUT;141 142 watchdog_set_drvdata(&drvdata->wdd, drvdata);143 watchdog_set_nowayout(&drvdata->wdd, WATCHDOG_NOWAYOUT);144 145 val = readb(drvdata->base + GXP_WDT_CTRL_OFS);146 147 if (val & MASK_WDGCS_ENABLE)148 set_bit(WDOG_HW_RUNNING, &drvdata->wdd.status);149 150 watchdog_set_restart_priority(&drvdata->wdd, 128);151 152 watchdog_stop_on_reboot(&drvdata->wdd);153 err = devm_watchdog_register_device(dev, &drvdata->wdd);154 if (err) {155 dev_err(dev, "Failed to register watchdog device");156 return err;157 }158 159 dev_info(dev, "HPE GXP watchdog timer");160 161 return 0;162}163 164static struct platform_driver gxp_wdt_driver = {165 .probe = gxp_wdt_probe,166 .driver = {167 .name = "gxp-wdt",168 },169};170module_platform_driver(gxp_wdt_driver);171 172MODULE_AUTHOR("Nick Hawkins <nick.hawkins@hpe.com>");173MODULE_AUTHOR("Jean-Marie Verdun <verdun@hpe.com>");174MODULE_DESCRIPTION("Driver for GXP watchdog timer");175MODULE_LICENSE("GPL");176