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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Intel Atom E6xx Watchdog driver4 *5 * Copyright (C) 2011 Alexander Stein6 * <alexander.stein@systec-electronic.com>7 */8 9#include <linux/module.h>10#include <linux/moduleparam.h>11#include <linux/platform_device.h>12#include <linux/io.h>13#include <linux/kernel.h>14#include <linux/types.h>15#include <linux/watchdog.h>16#include <linux/seq_file.h>17#include <linux/debugfs.h>18#include <linux/uaccess.h>19#include <linux/spinlock.h>20 21#define DRIVER_NAME "ie6xx_wdt"22 23#define PV1 0x0024#define PV2 0x0425 26#define RR0 0x0c27#define RR1 0x0d28#define WDT_RELOAD 0x0129#define WDT_TOUT 0x0230 31#define WDTCR 0x1032#define WDT_PRE_SEL 0x0433#define WDT_RESET_SEL 0x0834#define WDT_RESET_EN 0x1035#define WDT_TOUT_EN 0x2036 37#define DCR 0x1438 39#define WDTLR 0x1840#define WDT_LOCK 0x0141#define WDT_ENABLE 0x0242#define WDT_TOUT_CNF 0x0343 44#define MIN_TIME 145#define MAX_TIME (10 * 60) /* 10 minutes */46#define DEFAULT_TIME 6047 48static unsigned int timeout = DEFAULT_TIME;49module_param(timeout, uint, 0);50MODULE_PARM_DESC(timeout,51 "Default Watchdog timer setting ("52 __MODULE_STRING(DEFAULT_TIME) "s)."53 "The range is from 1 to 600");54 55static bool nowayout = WATCHDOG_NOWAYOUT;56module_param(nowayout, bool, 0);57MODULE_PARM_DESC(nowayout,58 "Watchdog cannot be stopped once started (default="59 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");60 61static u8 resetmode = 0x10;62module_param(resetmode, byte, 0);63MODULE_PARM_DESC(resetmode,64 "Resetmode bits: 0x08 warm reset (cold reset otherwise), "65 "0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)");66 67static struct {68 unsigned short sch_wdtba;69 spinlock_t unlock_sequence;70#ifdef CONFIG_DEBUG_FS71 struct dentry *debugfs;72#endif73} ie6xx_wdt_data;74 75/*76 * This is needed to write to preload and reload registers77 * struct ie6xx_wdt_data.unlock_sequence must be used78 * to prevent sequence interrupts79 */80static void ie6xx_wdt_unlock_registers(void)81{82 outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0);83 outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0);84}85 86static int ie6xx_wdt_ping(struct watchdog_device *wdd)87{88 spin_lock(&ie6xx_wdt_data.unlock_sequence);89 ie6xx_wdt_unlock_registers();90 outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1);91 spin_unlock(&ie6xx_wdt_data.unlock_sequence);92 return 0;93}94 95static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)96{97 u32 preload;98 u64 clock;99 u8 wdtcr;100 101 /* Watchdog clock is PCI Clock (33MHz) */102 clock = 33000000;103 /* and the preload value is loaded into [34:15] of the down counter */104 preload = (t * clock) >> 15;105 /*106 * Manual states preload must be one less.107 * Does not wrap as t is at least 1108 */109 preload -= 1;110 111 spin_lock(&ie6xx_wdt_data.unlock_sequence);112 113 /* Set ResetMode & Enable prescaler for range 10ms to 10 min */114 wdtcr = resetmode & 0x38;115 outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR);116 117 ie6xx_wdt_unlock_registers();118 outl(0, ie6xx_wdt_data.sch_wdtba + PV1);119 120 ie6xx_wdt_unlock_registers();121 outl(preload, ie6xx_wdt_data.sch_wdtba + PV2);122 123 ie6xx_wdt_unlock_registers();124 outb(WDT_RELOAD | WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1);125 126 spin_unlock(&ie6xx_wdt_data.unlock_sequence);127 128 wdd->timeout = t;129 return 0;130}131 132static int ie6xx_wdt_start(struct watchdog_device *wdd)133{134 ie6xx_wdt_set_timeout(wdd, wdd->timeout);135 136 /* Enable the watchdog timer */137 spin_lock(&ie6xx_wdt_data.unlock_sequence);138 outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR);139 spin_unlock(&ie6xx_wdt_data.unlock_sequence);140 141 return 0;142}143 144static int ie6xx_wdt_stop(struct watchdog_device *wdd)145{146 if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK)147 return -1;148 149 /* Disable the watchdog timer */150 spin_lock(&ie6xx_wdt_data.unlock_sequence);151 outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR);152 spin_unlock(&ie6xx_wdt_data.unlock_sequence);153 154 return 0;155}156 157static const struct watchdog_info ie6xx_wdt_info = {158 .identity = "Intel Atom E6xx Watchdog",159 .options = WDIOF_SETTIMEOUT |160 WDIOF_MAGICCLOSE |161 WDIOF_KEEPALIVEPING,162};163 164static const struct watchdog_ops ie6xx_wdt_ops = {165 .owner = THIS_MODULE,166 .start = ie6xx_wdt_start,167 .stop = ie6xx_wdt_stop,168 .ping = ie6xx_wdt_ping,169 .set_timeout = ie6xx_wdt_set_timeout,170};171 172static struct watchdog_device ie6xx_wdt_dev = {173 .info = &ie6xx_wdt_info,174 .ops = &ie6xx_wdt_ops,175 .min_timeout = MIN_TIME,176 .max_timeout = MAX_TIME,177};178 179#ifdef CONFIG_DEBUG_FS180 181static int ie6xx_wdt_show(struct seq_file *s, void *unused)182{183 seq_printf(s, "PV1 = 0x%08x\n",184 inl(ie6xx_wdt_data.sch_wdtba + PV1));185 seq_printf(s, "PV2 = 0x%08x\n",186 inl(ie6xx_wdt_data.sch_wdtba + PV2));187 seq_printf(s, "RR = 0x%08x\n",188 inw(ie6xx_wdt_data.sch_wdtba + RR0));189 seq_printf(s, "WDTCR = 0x%08x\n",190 inw(ie6xx_wdt_data.sch_wdtba + WDTCR));191 seq_printf(s, "DCR = 0x%08x\n",192 inl(ie6xx_wdt_data.sch_wdtba + DCR));193 seq_printf(s, "WDTLR = 0x%08x\n",194 inw(ie6xx_wdt_data.sch_wdtba + WDTLR));195 196 seq_printf(s, "\n");197 return 0;198}199 200DEFINE_SHOW_ATTRIBUTE(ie6xx_wdt);201 202static void ie6xx_wdt_debugfs_init(void)203{204 /* /sys/kernel/debug/ie6xx_wdt */205 ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt",206 S_IFREG | S_IRUGO, NULL, NULL, &ie6xx_wdt_fops);207}208 209static void ie6xx_wdt_debugfs_exit(void)210{211 debugfs_remove(ie6xx_wdt_data.debugfs);212}213 214#else215static void ie6xx_wdt_debugfs_init(void)216{217}218 219static void ie6xx_wdt_debugfs_exit(void)220{221}222#endif223 224static int ie6xx_wdt_probe(struct platform_device *pdev)225{226 struct resource *res;227 u8 wdtlr;228 int ret;229 230 res = platform_get_resource(pdev, IORESOURCE_IO, 0);231 if (!res)232 return -ENODEV;233 234 if (!request_region(res->start, resource_size(res), pdev->name)) {235 dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n",236 (u64)res->start);237 return -EBUSY;238 }239 240 ie6xx_wdt_data.sch_wdtba = res->start;241 dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba);242 243 ie6xx_wdt_dev.timeout = timeout;244 watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout);245 ie6xx_wdt_dev.parent = &pdev->dev;246 247 spin_lock_init(&ie6xx_wdt_data.unlock_sequence);248 249 wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR);250 if (wdtlr & WDT_LOCK)251 dev_warn(&pdev->dev,252 "Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr);253 254 ie6xx_wdt_debugfs_init();255 256 ret = watchdog_register_device(&ie6xx_wdt_dev);257 if (ret)258 goto misc_register_error;259 260 return 0;261 262misc_register_error:263 ie6xx_wdt_debugfs_exit();264 release_region(res->start, resource_size(res));265 ie6xx_wdt_data.sch_wdtba = 0;266 return ret;267}268 269static void ie6xx_wdt_remove(struct platform_device *pdev)270{271 struct resource *res;272 273 res = platform_get_resource(pdev, IORESOURCE_IO, 0);274 ie6xx_wdt_stop(NULL);275 watchdog_unregister_device(&ie6xx_wdt_dev);276 ie6xx_wdt_debugfs_exit();277 release_region(res->start, resource_size(res));278 ie6xx_wdt_data.sch_wdtba = 0;279}280 281static struct platform_driver ie6xx_wdt_driver = {282 .probe = ie6xx_wdt_probe,283 .remove_new = ie6xx_wdt_remove,284 .driver = {285 .name = DRIVER_NAME,286 },287};288 289static int __init ie6xx_wdt_init(void)290{291 /* Check boot parameters to verify that their initial values */292 /* are in range. */293 if ((timeout < MIN_TIME) ||294 (timeout > MAX_TIME)) {295 pr_err("Watchdog timer: value of timeout %d (dec) "296 "is out of range from %d to %d (dec)\n",297 timeout, MIN_TIME, MAX_TIME);298 return -EINVAL;299 }300 301 return platform_driver_register(&ie6xx_wdt_driver);302}303 304static void __exit ie6xx_wdt_exit(void)305{306 platform_driver_unregister(&ie6xx_wdt_driver);307}308 309late_initcall(ie6xx_wdt_init);310module_exit(ie6xx_wdt_exit);311 312MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");313MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");314MODULE_LICENSE("GPL");315MODULE_ALIAS("platform:" DRIVER_NAME);316