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path: root/drivers/watchdog/booke_wdt.c
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Diffstat (limited to 'drivers/watchdog/booke_wdt.c')
-rw-r--r--drivers/watchdog/booke_wdt.c194
1 files changed, 194 insertions, 0 deletions
diff --git a/drivers/watchdog/booke_wdt.c b/drivers/watchdog/booke_wdt.c
new file mode 100644
index 000000000000..d362f5bf658a
--- /dev/null
+++ b/drivers/watchdog/booke_wdt.c
@@ -0,0 +1,194 @@
+/*
+ * drivers/char/watchdog/booke_wdt.c
+ *
+ * Watchdog timer for PowerPC Book-E systems
+ *
+ * Author: Matthew McClintock
+ * Maintainer: Kumar Gala <galak@kernel.crashing.org>
+ *
+ * Copyright 2005 Freescale Semiconductor Inc.
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/notifier.h>
+#include <linux/watchdog.h>
+
+#include <asm/reg_booke.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+/* If the kernel parameter wdt=1, the watchdog will be enabled at boot.
+ * Also, the wdt_period sets the watchdog timer period timeout.
+ * For E500 cpus the wdt_period sets which bit changing from 0->1 will
+ * trigger a watchog timeout. This watchdog timeout will occur 3 times, the
+ * first time nothing will happen, the second time a watchdog exception will
+ * occur, and the final time the board will reset.
+ */
+
+#ifdef CONFIG_FSL_BOOKE
+#define WDT_PERIOD_DEFAULT 63 /* Ex. wdt_period=28 bus=333Mhz , reset=~40sec */
+#else
+#define WDT_PERIOD_DEFAULT 3 /* Refer to the PPC40x and PPC4xx manuals */
+#endif /* for timing information */
+
+u32 booke_wdt_enabled = 0;
+u32 booke_wdt_period = WDT_PERIOD_DEFAULT;
+
+#ifdef CONFIG_FSL_BOOKE
+#define WDTP(x) ((((63-x)&0x3)<<30)|(((63-x)&0x3c)<<15))
+#else
+#define WDTP(x) (TCR_WP(x))
+#endif
+
+/*
+ * booke_wdt_ping:
+ */
+static __inline__ void booke_wdt_ping(void)
+{
+ mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
+}
+
+/*
+ * booke_wdt_enable:
+ */
+static __inline__ void booke_wdt_enable(void)
+{
+ u32 val;
+
+ /* clear status before enabling watchdog */
+ booke_wdt_ping();
+ val = mfspr(SPRN_TCR);
+ val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
+
+ mtspr(SPRN_TCR, val);
+}
+
+/*
+ * booke_wdt_write:
+ */
+static ssize_t booke_wdt_write (struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ booke_wdt_ping();
+ return count;
+}
+
+static struct watchdog_info ident = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+ .firmware_version = 0,
+ .identity = "PowerPC Book-E Watchdog",
+};
+
+/*
+ * booke_wdt_ioctl:
+ */
+static int booke_wdt_ioctl (struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ u32 tmp = 0;
+ u32 __user *p = (u32 __user *)arg;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ if (copy_to_user ((struct watchdog_info __user *) arg, &ident,
+ sizeof(struct watchdog_info)))
+ return -EFAULT;
+ case WDIOC_GETSTATUS:
+ return put_user(ident.options, p);
+ case WDIOC_GETBOOTSTATUS:
+ /* XXX: something is clearing TSR */
+ tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
+ /* returns 1 if last reset was caused by the WDT */
+ return (tmp ? 1 : 0);
+ case WDIOC_KEEPALIVE:
+ booke_wdt_ping();
+ return 0;
+ case WDIOC_SETTIMEOUT:
+ if (get_user(booke_wdt_period, p))
+ return -EFAULT;
+ mtspr(SPRN_TCR, (mfspr(SPRN_TCR)&~WDTP(0))|WDTP(booke_wdt_period));
+ return 0;
+ case WDIOC_GETTIMEOUT:
+ return put_user(booke_wdt_period, p);
+ case WDIOC_SETOPTIONS:
+ if (get_user(tmp, p))
+ return -EINVAL;
+ if (tmp == WDIOS_ENABLECARD) {
+ booke_wdt_ping();
+ break;
+ } else
+ return -EINVAL;
+ return 0;
+ default:
+ return -ENOTTY;
+ }
+
+ return 0;
+}
+/*
+ * booke_wdt_open:
+ */
+static int booke_wdt_open (struct inode *inode, struct file *file)
+{
+ if (booke_wdt_enabled == 0) {
+ booke_wdt_enabled = 1;
+ booke_wdt_enable();
+ printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
+ booke_wdt_period);
+ }
+
+ return nonseekable_open(inode, file);
+}
+
+static const struct file_operations booke_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = booke_wdt_write,
+ .ioctl = booke_wdt_ioctl,
+ .open = booke_wdt_open,
+};
+
+static struct miscdevice booke_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &booke_wdt_fops,
+};
+
+static void __exit booke_wdt_exit(void)
+{
+ misc_deregister(&booke_wdt_miscdev);
+}
+
+/*
+ * booke_wdt_init:
+ */
+static int __init booke_wdt_init(void)
+{
+ int ret = 0;
+
+ printk (KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n");
+ ident.firmware_version = cur_cpu_spec->pvr_value;
+
+ ret = misc_register(&booke_wdt_miscdev);
+ if (ret) {
+ printk (KERN_CRIT "Cannot register miscdev on minor=%d (err=%d)\n",
+ WATCHDOG_MINOR, ret);
+ return ret;
+ }
+
+ if (booke_wdt_enabled == 1) {
+ printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
+ booke_wdt_period);
+ booke_wdt_enable();
+ }
+
+ return ret;
+}
+device_initcall(booke_wdt_init);