168 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Watchdog driver for the MEN z069 IP-Core4 *5 * Copyright (C) 2018 Johannes Thumshirn <jth@kernel.org>6 */7#include <linux/io.h>8#include <linux/kernel.h>9#include <linux/mcb.h>10#include <linux/module.h>11#include <linux/watchdog.h>12 13struct men_z069_drv {14 struct watchdog_device wdt;15 void __iomem *base;16 struct resource *mem;17};18 19#define MEN_Z069_WTR 0x1020#define MEN_Z069_WTR_WDEN BIT(15)21#define MEN_Z069_WTR_WDET_MASK 0x7fff22#define MEN_Z069_WVR 0x1423 24#define MEN_Z069_TIMER_FREQ 500 /* 500 Hz */25#define MEN_Z069_WDT_COUNTER_MIN 126#define MEN_Z069_WDT_COUNTER_MAX 0x7fff27#define MEN_Z069_DEFAULT_TIMEOUT 3028 29static bool nowayout = WATCHDOG_NOWAYOUT;30module_param(nowayout, bool, 0);31MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="32 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");33 34static int men_z069_wdt_start(struct watchdog_device *wdt)35{36 struct men_z069_drv *drv = watchdog_get_drvdata(wdt);37 u16 val;38 39 val = readw(drv->base + MEN_Z069_WTR);40 val |= MEN_Z069_WTR_WDEN;41 writew(val, drv->base + MEN_Z069_WTR);42 43 return 0;44}45 46static int men_z069_wdt_stop(struct watchdog_device *wdt)47{48 struct men_z069_drv *drv = watchdog_get_drvdata(wdt);49 u16 val;50 51 val = readw(drv->base + MEN_Z069_WTR);52 val &= ~MEN_Z069_WTR_WDEN;53 writew(val, drv->base + MEN_Z069_WTR);54 55 return 0;56}57 58static int men_z069_wdt_ping(struct watchdog_device *wdt)59{60 struct men_z069_drv *drv = watchdog_get_drvdata(wdt);61 u16 val;62 63 /* The watchdog trigger value toggles between 0x5555 and 0xaaaa */64 val = readw(drv->base + MEN_Z069_WVR);65 val ^= 0xffff;66 writew(val, drv->base + MEN_Z069_WVR);67 68 return 0;69}70 71static int men_z069_wdt_set_timeout(struct watchdog_device *wdt,72 unsigned int timeout)73{74 struct men_z069_drv *drv = watchdog_get_drvdata(wdt);75 u16 reg, val, ena;76 77 wdt->timeout = timeout;78 val = timeout * MEN_Z069_TIMER_FREQ;79 80 reg = readw(drv->base + MEN_Z069_WTR);81 ena = reg & MEN_Z069_WTR_WDEN;82 reg = ena | val;83 writew(reg, drv->base + MEN_Z069_WTR);84 85 return 0;86}87 88static const struct watchdog_info men_z069_info = {89 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,90 .identity = "MEN z069 Watchdog",91};92 93static const struct watchdog_ops men_z069_ops = {94 .owner = THIS_MODULE,95 .start = men_z069_wdt_start,96 .stop = men_z069_wdt_stop,97 .ping = men_z069_wdt_ping,98 .set_timeout = men_z069_wdt_set_timeout,99};100 101static int men_z069_probe(struct mcb_device *dev,102 const struct mcb_device_id *id)103{104 struct men_z069_drv *drv;105 struct resource *mem;106 107 drv = devm_kzalloc(&dev->dev, sizeof(struct men_z069_drv), GFP_KERNEL);108 if (!drv)109 return -ENOMEM;110 111 mem = mcb_request_mem(dev, "z069-wdt");112 if (IS_ERR(mem))113 return PTR_ERR(mem);114 115 drv->base = devm_ioremap(&dev->dev, mem->start, resource_size(mem));116 if (drv->base == NULL)117 goto release_mem;118 119 drv->mem = mem;120 drv->wdt.info = &men_z069_info;121 drv->wdt.ops = &men_z069_ops;122 drv->wdt.timeout = MEN_Z069_DEFAULT_TIMEOUT;123 drv->wdt.min_timeout = 1;124 drv->wdt.max_timeout = MEN_Z069_WDT_COUNTER_MAX / MEN_Z069_TIMER_FREQ;125 126 watchdog_init_timeout(&drv->wdt, 0, &dev->dev);127 watchdog_set_nowayout(&drv->wdt, nowayout);128 watchdog_set_drvdata(&drv->wdt, drv);129 drv->wdt.parent = &dev->dev;130 mcb_set_drvdata(dev, drv);131 132 return watchdog_register_device(&drv->wdt);133 134release_mem:135 mcb_release_mem(mem);136 return -ENOMEM;137}138 139static void men_z069_remove(struct mcb_device *dev)140{141 struct men_z069_drv *drv = mcb_get_drvdata(dev);142 143 watchdog_unregister_device(&drv->wdt);144 mcb_release_mem(drv->mem);145}146 147static const struct mcb_device_id men_z069_ids[] = {148 { .device = 0x45 },149 { }150};151MODULE_DEVICE_TABLE(mcb, men_z069_ids);152 153static struct mcb_driver men_z069_driver = {154 .driver = {155 .name = "z069-wdt",156 },157 .probe = men_z069_probe,158 .remove = men_z069_remove,159 .id_table = men_z069_ids,160};161module_mcb_driver(men_z069_driver);162 163MODULE_AUTHOR("Johannes Thumshirn <jth@kernel.org>");164MODULE_DESCRIPTION("Watchdog driver for the MEN z069 IP-Core");165MODULE_LICENSE("GPL v2");166MODULE_ALIAS("mcb:16z069");167MODULE_IMPORT_NS(MCB);168