--- /dev/null
+/*
+ * 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.
+ */
+
+#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 int 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_MBAR + 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_MBAR + MCF_GPT_GMS0);
+ __raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) |
+ MCF_GPT_GCIR_CNT(0xffff), MCF_MBAR + MCF_GPT_GCIR0);
+ gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE;
+ __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
+}
+
+static void wdt_disable(void)
+{
+ unsigned int gms0;
+
+ /* disable watchdog */
+ gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
+ gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE);
+ __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
+}
+
+static void wdt_keepalive(void)
+{
+ unsigned int gms0;
+
+ gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
+ gms0 |= MCF_GPT_GMS_OCPW(0xA5);
+ __raw_writel(gms0, MCF_MBAR + 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 {
+ printk(KERN_CRIT "WATCHDOG: 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_MBAR + MCF_GPT_GCIR0, 4,
+ "Coldfire M54xx Watchdog")) {
+ printk(KERN_WARNING
+ "Coldfire M54xx Watchdog : I/O region busy\n");
+ return -EBUSY;
+ }
+ printk(KERN_INFO "ColdFire watchdog 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_MBAR + 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, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
projects / mv-sheeva.git / blobdiff