// SPDX-License-Identifier: GPL-2.0-only /* * Intel Atom E6xx Watchdog driver * * Copyright (C) 2011 Alexander Stein * <alexander.stein@systec-electronic.com> */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/platform_device.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/types.h> #include <linux/watchdog.h> #include <linux/seq_file.h> #include <linux/debugfs.h> #include <linux/uaccess.h> #include <linux/spinlock.h> #define DRIVER_NAME "ie6xx_wdt" #define PV1 0x00 #define PV2 0x04 #define RR0 0x0c #define RR1 0x0d #define WDT_RELOAD 0x01 #define WDT_TOUT 0x02 #define WDTCR 0x10 #define WDT_PRE_SEL 0x04 #define WDT_RESET_SEL 0x08 #define WDT_RESET_EN 0x10 #define WDT_TOUT_EN 0x20 #define DCR 0x14 #define WDTLR 0x18 #define WDT_LOCK 0x01 #define WDT_ENABLE 0x02 #define WDT_TOUT_CNF 0x03 #define MIN_TIME 1 #define MAX_TIME (10 * 60) /* 10 minutes */ #define DEFAULT_TIME 60 static unsigned int timeout = DEFAULT_TIME; module_param(timeout, uint, 0); MODULE_PARM_DESC(timeout, "Default Watchdog timer setting (" __MODULE_STRING(DEFAULT_TIME) "s)." "The range is from 1 to 600"); static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static u8 resetmode = 0x10; module_param(resetmode, byte, 0); MODULE_PARM_DESC(resetmode, "Resetmode bits: 0x08 warm reset (cold reset otherwise), " "0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)"); static struct { unsigned short sch_wdtba; spinlock_t unlock_sequence; #ifdef CONFIG_DEBUG_FS struct dentry *debugfs; #endif } ie6xx_wdt_data; /* * This is needed to write to preload and reload registers * struct ie6xx_wdt_data.unlock_sequence must be used * to prevent sequence interrupts */ static void ie6xx_wdt_unlock_registers(void) { outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0); outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0); } static int ie6xx_wdt_ping(struct watchdog_device *wdd) { spin_lock(&ie6xx_wdt_data.unlock_sequence); ie6xx_wdt_unlock_registers(); outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1); spin_unlock(&ie6xx_wdt_data.unlock_sequence); return 0; } static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) { u32 preload; u64 clock; u8 wdtcr; /* Watchdog clock is PCI Clock (33MHz) */ clock = 33000000; /* and the preload value is loaded into [34:15] of the down counter */ preload = (t * clock) >> 15; /* * Manual states preload must be one less. * Does not wrap as t is at least 1 */ preload -= 1; spin_lock(&ie6xx_wdt_data.unlock_sequence); /* Set ResetMode & Enable prescaler for range 10ms to 10 min */ wdtcr = resetmode & 0x38; outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR); ie6xx_wdt_unlock_registers(); outl(0, ie6xx_wdt_data.sch_wdtba + PV1); ie6xx_wdt_unlock_registers(); outl(preload, ie6xx_wdt_data.sch_wdtba + PV2); ie6xx_wdt_unlock_registers(); outb(WDT_RELOAD | WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1); spin_unlock(&ie6xx_wdt_data.unlock_sequence); wdd->timeout = t; return 0; } static int ie6xx_wdt_start(struct watchdog_device *wdd) { ie6xx_wdt_set_timeout(wdd, wdd->timeout); /* Enable the watchdog timer */ spin_lock(&ie6xx_wdt_data.unlock_sequence); outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR); spin_unlock(&ie6xx_wdt_data.unlock_sequence); return 0; } static int ie6xx_wdt_stop(struct watchdog_device *wdd) { if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK) return -1; /* Disable the watchdog timer */ spin_lock(&ie6xx_wdt_data.unlock_sequence); outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR); spin_unlock(&ie6xx_wdt_data.unlock_sequence); return 0; } static const struct watchdog_info ie6xx_wdt_info = { .identity = "Intel Atom E6xx Watchdog", .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, }; static const struct watchdog_ops ie6xx_wdt_ops = { .owner = THIS_MODULE, .start = ie6xx_wdt_start, .stop = ie6xx_wdt_stop, .ping = ie6xx_wdt_ping, .set_timeout = ie6xx_wdt_set_timeout, }; static struct watchdog_device ie6xx_wdt_dev = { .info = &ie6xx_wdt_info, .ops = &ie6xx_wdt_ops, .min_timeout = MIN_TIME, .max_timeout = MAX_TIME, }; #ifdef CONFIG_DEBUG_FS static int ie6xx_wdt_show(struct seq_file *s, void *unused) { seq_printf(s, "PV1 = 0x%08x\n", inl(ie6xx_wdt_data.sch_wdtba + PV1)); seq_printf(s, "PV2 = 0x%08x\n", inl(ie6xx_wdt_data.sch_wdtba + PV2)); seq_printf(s, "RR = 0x%08x\n", inw(ie6xx_wdt_data.sch_wdtba + RR0)); seq_printf(s, "WDTCR = 0x%08x\n", inw(ie6xx_wdt_data.sch_wdtba + WDTCR)); seq_printf(s, "DCR = 0x%08x\n", inl(ie6xx_wdt_data.sch_wdtba + DCR)); seq_printf(s, "WDTLR = 0x%08x\n", inw(ie6xx_wdt_data.sch_wdtba + WDTLR)); seq_printf(s, "\n"); return 0; } DEFINE_SHOW_ATTRIBUTE(ie6xx_wdt); static void ie6xx_wdt_debugfs_init(void) { /* /sys/kernel/debug/ie6xx_wdt */ ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt", S_IFREG | S_IRUGO, NULL, NULL, &ie6xx_wdt_fops); } static void ie6xx_wdt_debugfs_exit(void) { debugfs_remove(ie6xx_wdt_data.debugfs); } #else static void ie6xx_wdt_debugfs_init(void) { } static void ie6xx_wdt_debugfs_exit(void) { } #endif static int ie6xx_wdt_probe(struct platform_device *pdev) { struct resource *res; u8 wdtlr; int ret; res = platform_get_resource(pdev, IORESOURCE_IO, 0); if (!res) return -ENODEV; if (!request_region(res->start, resource_size(res), pdev->name)) { dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n", (u64)res->start); return -EBUSY; } ie6xx_wdt_data.sch_wdtba = res->start; dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba); ie6xx_wdt_dev.timeout = timeout; watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout); ie6xx_wdt_dev.parent = &pdev->dev; spin_lock_init(&ie6xx_wdt_data.unlock_sequence); wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR); if (wdtlr & WDT_LOCK) dev_warn(&pdev->dev, "Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr); ie6xx_wdt_debugfs_init(); ret = watchdog_register_device(&ie6xx_wdt_dev); if (ret) goto misc_register_error; return 0; misc_register_error: ie6xx_wdt_debugfs_exit(); release_region(res->start, resource_size(res)); ie6xx_wdt_data.sch_wdtba = 0; return ret; } static void ie6xx_wdt_remove(struct platform_device *pdev) { struct resource *res; res = platform_get_resource(pdev, IORESOURCE_IO, 0); ie6xx_wdt_stop(NULL); watchdog_unregister_device(&ie6xx_wdt_dev); ie6xx_wdt_debugfs_exit(); release_region(res->start, resource_size(res)); ie6xx_wdt_data.sch_wdtba = 0; } static struct platform_driver ie6xx_wdt_driver = { .probe = ie6xx_wdt_probe, .remove_new = ie6xx_wdt_remove, .driver = { .name = DRIVER_NAME, }, }; static int __init ie6xx_wdt_init(void) { /* Check boot parameters to verify that their initial values */ /* are in range. */ if ((timeout < MIN_TIME) || (timeout > MAX_TIME)) { pr_err("Watchdog timer: value of timeout %d (dec) " "is out of range from %d to %d (dec)\n", timeout, MIN_TIME, MAX_TIME); return -EINVAL; } return platform_driver_register(&ie6xx_wdt_driver); } static void __exit ie6xx_wdt_exit(void) { platform_driver_unregister(&ie6xx_wdt_driver); } late_initcall(ie6xx_wdt_init); module_exit(ie6xx_wdt_exit); MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>"); MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:" DRIVER_NAME);