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- /*
- * drivers/watchdog/m54xx_wdt.c
- *
- * Watchdog driver for ColdFire MCF547x & MCF548x processors
- * Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be>
- *
- * Adapted from the IXP4xx watchdog driver, which carries these notices:
- *
- * Author: Deepak Saxena <dsaxena@plexity.net>
- *
- * Copyright 2004 (c) MontaVista, Software, Inc.
- * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
- *
- * This file is licensed under the terms of the GNU General Public
- * License version 2. This program is licensed "as is" without any
- * warranty of any kind, whether express or implied.
- */
- #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
- #include <linux/module.h>
- #include <linux/moduleparam.h>
- #include <linux/types.h>
- #include <linux/kernel.h>
- #include <linux/fs.h>
- #include <linux/miscdevice.h>
- #include <linux/watchdog.h>
- #include <linux/init.h>
- #include <linux/bitops.h>
- #include <linux/ioport.h>
- #include <linux/uaccess.h>
- #include <asm/coldfire.h>
- #include <asm/m54xxsim.h>
- #include <asm/m54xxgpt.h>
- static bool nowayout = WATCHDOG_NOWAYOUT;
- static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */
- static unsigned long wdt_status;
- #define WDT_IN_USE 0
- #define WDT_OK_TO_CLOSE 1
- static void wdt_enable(void)
- {
- unsigned int gms0;
- /* preserve GPIO usage, if any */
- gms0 = __raw_readl(MCF_GPT_GMS0);
- if (gms0 & MCF_GPT_GMS_TMS_GPIO)
- gms0 &= (MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_GPIO_MASK
- | MCF_GPT_GMS_OD);
- else
- gms0 = MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_OD;
- __raw_writel(gms0, MCF_GPT_GMS0);
- __raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) |
- MCF_GPT_GCIR_CNT(0xffff), MCF_GPT_GCIR0);
- gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE;
- __raw_writel(gms0, MCF_GPT_GMS0);
- }
- static void wdt_disable(void)
- {
- unsigned int gms0;
- /* disable watchdog */
- gms0 = __raw_readl(MCF_GPT_GMS0);
- gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE);
- __raw_writel(gms0, MCF_GPT_GMS0);
- }
- static void wdt_keepalive(void)
- {
- unsigned int gms0;
- gms0 = __raw_readl(MCF_GPT_GMS0);
- gms0 |= MCF_GPT_GMS_OCPW(0xA5);
- __raw_writel(gms0, MCF_GPT_GMS0);
- }
- static int m54xx_wdt_open(struct inode *inode, struct file *file)
- {
- if (test_and_set_bit(WDT_IN_USE, &wdt_status))
- return -EBUSY;
- clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
- wdt_enable();
- return nonseekable_open(inode, file);
- }
- static ssize_t m54xx_wdt_write(struct file *file, const char *data,
- size_t len, loff_t *ppos)
- {
- if (len) {
- if (!nowayout) {
- size_t i;
- clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
- for (i = 0; i != len; i++) {
- char c;
- if (get_user(c, data + i))
- return -EFAULT;
- if (c == 'V')
- set_bit(WDT_OK_TO_CLOSE, &wdt_status);
- }
- }
- wdt_keepalive();
- }
- return len;
- }
- static const struct watchdog_info ident = {
- .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
- WDIOF_KEEPALIVEPING,
- .identity = "Coldfire M54xx Watchdog",
- };
- static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd,
- unsigned long arg)
- {
- int ret = -ENOTTY;
- int time;
- switch (cmd) {
- case WDIOC_GETSUPPORT:
- ret = copy_to_user((struct watchdog_info *)arg, &ident,
- sizeof(ident)) ? -EFAULT : 0;
- break;
- case WDIOC_GETSTATUS:
- ret = put_user(0, (int *)arg);
- break;
- case WDIOC_GETBOOTSTATUS:
- ret = put_user(0, (int *)arg);
- break;
- case WDIOC_KEEPALIVE:
- wdt_keepalive();
- ret = 0;
- break;
- case WDIOC_SETTIMEOUT:
- ret = get_user(time, (int *)arg);
- if (ret)
- break;
- if (time <= 0 || time > 30) {
- ret = -EINVAL;
- break;
- }
- heartbeat = time;
- wdt_enable();
- /* Fall through */
- case WDIOC_GETTIMEOUT:
- ret = put_user(heartbeat, (int *)arg);
- break;
- }
- return ret;
- }
- static int m54xx_wdt_release(struct inode *inode, struct file *file)
- {
- if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
- wdt_disable();
- else {
- pr_crit("Device closed unexpectedly - timer will not stop\n");
- wdt_keepalive();
- }
- clear_bit(WDT_IN_USE, &wdt_status);
- clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
- return 0;
- }
- static const struct file_operations m54xx_wdt_fops = {
- .owner = THIS_MODULE,
- .llseek = no_llseek,
- .write = m54xx_wdt_write,
- .unlocked_ioctl = m54xx_wdt_ioctl,
- .open = m54xx_wdt_open,
- .release = m54xx_wdt_release,
- };
- static struct miscdevice m54xx_wdt_miscdev = {
- .minor = WATCHDOG_MINOR,
- .name = "watchdog",
- .fops = &m54xx_wdt_fops,
- };
- static int __init m54xx_wdt_init(void)
- {
- if (!request_mem_region(MCF_GPT_GCIR0, 4, "Coldfire M54xx Watchdog")) {
- pr_warn("I/O region busy\n");
- return -EBUSY;
- }
- pr_info("driver is loaded\n");
- return misc_register(&m54xx_wdt_miscdev);
- }
- static void __exit m54xx_wdt_exit(void)
- {
- misc_deregister(&m54xx_wdt_miscdev);
- release_mem_region(MCF_GPT_GCIR0, 4);
- }
- module_init(m54xx_wdt_init);
- module_exit(m54xx_wdt_exit);
- MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
- MODULE_DESCRIPTION("Coldfire M54xx Watchdog");
- module_param(heartbeat, int, 0);
- MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)");
- module_param(nowayout, bool, 0);
- MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
- MODULE_LICENSE("GPL");
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