/* * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface * * Authors: Dave Updegraff * Kumar Gala * Attribution: from 83xx_wst: Florian Schirmer * ..and from sc520_wdt * Copyright (c) 2008 MontaVista Software, Inc. * Anton Vorontsov * * Note: it appears that you can only actually ENABLE or DISABLE the thing * once after POR. Once enabled, you cannot disable, and vice versa. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include struct mpc8xxx_wdt { __be32 res0; __be32 swcrr; /* System watchdog control register */ #define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */ #define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */ #define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/ #define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */ __be32 swcnr; /* System watchdog count register */ u8 res1[2]; __be16 swsrr; /* System watchdog service register */ u8 res2[0xF0]; }; struct mpc8xxx_wdt_type { int prescaler; bool hw_enabled; }; static struct mpc8xxx_wdt __iomem *wd_base; static int mpc8xxx_wdt_init_late(void); static u16 timeout = 0xffff; module_param(timeout, ushort, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in ticks. (0swsrr, 0x556c); out_be16(&wd_base->swsrr, 0xaa39); spin_unlock(&wdt_spinlock); } static struct watchdog_device mpc8xxx_wdt_dev; static void mpc8xxx_wdt_timer_ping(unsigned long arg); static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0, (unsigned long)&mpc8xxx_wdt_dev); static void mpc8xxx_wdt_timer_ping(unsigned long arg) { struct watchdog_device *w = (struct watchdog_device *)arg; mpc8xxx_wdt_keepalive(); /* We're pinging it twice faster than needed, just to be sure. */ mod_timer(&wdt_timer, jiffies + HZ * w->timeout / 2); } static int mpc8xxx_wdt_start(struct watchdog_device *w) { u32 tmp = SWCRR_SWEN; /* Good, fire up the show */ if (prescale) tmp |= SWCRR_SWPR; if (reset) tmp |= SWCRR_SWRI; tmp |= timeout << 16; out_be32(&wd_base->swcrr, tmp); del_timer_sync(&wdt_timer); return 0; } static int mpc8xxx_wdt_ping(struct watchdog_device *w) { mpc8xxx_wdt_keepalive(); return 0; } static int mpc8xxx_wdt_stop(struct watchdog_device *w) { mod_timer(&wdt_timer, jiffies); return 0; } static struct watchdog_info mpc8xxx_wdt_info = { .options = WDIOF_KEEPALIVEPING, .firmware_version = 1, .identity = "MPC8xxx", }; static struct watchdog_ops mpc8xxx_wdt_ops = { .owner = THIS_MODULE, .start = mpc8xxx_wdt_start, .ping = mpc8xxx_wdt_ping, .stop = mpc8xxx_wdt_stop, }; static struct watchdog_device mpc8xxx_wdt_dev = { .info = &mpc8xxx_wdt_info, .ops = &mpc8xxx_wdt_ops, }; static const struct of_device_id mpc8xxx_wdt_match[]; static int mpc8xxx_wdt_probe(struct platform_device *ofdev) { int ret; const struct of_device_id *match; struct device_node *np = ofdev->dev.of_node; const struct mpc8xxx_wdt_type *wdt_type; u32 freq = fsl_get_sys_freq(); bool enabled; unsigned int timeout_sec; match = of_match_device(mpc8xxx_wdt_match, &ofdev->dev); if (!match) return -EINVAL; wdt_type = match->data; if (!freq || freq == -1) return -EINVAL; wd_base = of_iomap(np, 0); if (!wd_base) return -ENOMEM; enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN; if (!enabled && wdt_type->hw_enabled) { pr_info("could not be enabled in software\n"); ret = -ENOSYS; goto err_unmap; } /* Calculate the timeout in seconds */ if (prescale) timeout_sec = (timeout * wdt_type->prescaler) / freq; else timeout_sec = timeout / freq; mpc8xxx_wdt_dev.timeout = timeout_sec; #ifdef MODULE ret = mpc8xxx_wdt_init_late(); if (ret) goto err_unmap; #endif pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d (%d seconds)\n", reset ? "reset" : "interrupt", timeout, timeout_sec); /* * If the watchdog was previously enabled or we're running on * MPC8xxx, we should ping the wdt from the kernel until the * userspace handles it. */ if (enabled) mod_timer(&wdt_timer, jiffies); return 0; err_unmap: iounmap(wd_base); wd_base = NULL; return ret; } static int mpc8xxx_wdt_remove(struct platform_device *ofdev) { pr_crit("Watchdog removed, expect the %s soon!\n", reset ? "reset" : "machine check exception"); del_timer_sync(&wdt_timer); watchdog_unregister_device(&mpc8xxx_wdt_dev); iounmap(wd_base); return 0; } static const struct of_device_id mpc8xxx_wdt_match[] = { { .compatible = "mpc83xx_wdt", .data = &(struct mpc8xxx_wdt_type) { .prescaler = 0x10000, }, }, { .compatible = "fsl,mpc8610-wdt", .data = &(struct mpc8xxx_wdt_type) { .prescaler = 0x10000, .hw_enabled = true, }, }, { .compatible = "fsl,mpc823-wdt", .data = &(struct mpc8xxx_wdt_type) { .prescaler = 0x800, .hw_enabled = true, }, }, {}, }; MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match); static struct platform_driver mpc8xxx_wdt_driver = { .probe = mpc8xxx_wdt_probe, .remove = mpc8xxx_wdt_remove, .driver = { .name = "mpc8xxx_wdt", .of_match_table = mpc8xxx_wdt_match, }, }; /* * We do wdt initialization in two steps: arch_initcall probes the wdt * very early to start pinging the watchdog (misc devices are not yet * available), and later module_init() just registers the misc device. */ static int mpc8xxx_wdt_init_late(void) { int ret; if (!wd_base) return -ENODEV; watchdog_set_nowayout(&mpc8xxx_wdt_dev, nowayout); ret = watchdog_register_device(&mpc8xxx_wdt_dev); if (ret) { pr_err("cannot register watchdog device (err=%d)\n", ret); return ret; } return 0; } #ifndef MODULE module_init(mpc8xxx_wdt_init_late); #endif static int __init mpc8xxx_wdt_init(void) { return platform_driver_register(&mpc8xxx_wdt_driver); } arch_initcall(mpc8xxx_wdt_init); static void __exit mpc8xxx_wdt_exit(void) { platform_driver_unregister(&mpc8xxx_wdt_driver); } module_exit(mpc8xxx_wdt_exit); MODULE_AUTHOR("Dave Updegraff, Kumar Gala"); MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx " "uProcessors"); MODULE_LICENSE("GPL");