--- /dev/null
+/*
+ * mpc83xx_wdt.c - MPC83xx watchdog userspace interface
+ *
+ * Authors: Dave Updegraff <dave@cray.org>
+ * Kumar Gala <galak@kernel.crashing.org>
+ * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
+ * ..and from sc520_wdt
+ *
+ * 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.
+ */
+
+#include <linux/config.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/watchdog.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+struct mpc83xx_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];
+};
+
+static struct mpc83xx_wdt __iomem *wd_base;
+
+static u16 timeout = 0xffff;
+module_param(timeout, ushort, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in ticks. (0<timeout<65536, default=65535");
+
+static int reset = 1;
+module_param(reset, bool, 0);
+MODULE_PARM_DESC(reset, "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
+
+/*
+ * We always prescale, but if someone really doesn't want to they can set this
+ * to 0
+ */
+static int prescale = 1;
+static unsigned int timeout_sec;
+
+static unsigned long wdt_is_open;
+static spinlock_t wdt_spinlock;
+
+static void mpc83xx_wdt_keepalive(void)
+{
+ /* Ping the WDT */
+ spin_lock(&wdt_spinlock);
+ out_be16(&wd_base->swsrr, 0x556c);
+ out_be16(&wd_base->swsrr, 0xaa39);
+ spin_unlock(&wdt_spinlock);
+}
+
+static ssize_t mpc83xx_wdt_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ if (count)
+ mpc83xx_wdt_keepalive();
+ return count;
+}
+
+static int mpc83xx_wdt_open(struct inode *inode, struct file *file)
+{
+ u32 tmp = SWCRR_SWEN;
+ if (test_and_set_bit(0, &wdt_is_open))
+ return -EBUSY;
+
+ /* Once we start the watchdog we can't stop it */
+ __module_get(THIS_MODULE);
+
+ /* Good, fire up the show */
+ if (prescale)
+ tmp |= SWCRR_SWPR;
+ if (reset)
+ tmp |= SWCRR_SWRI;
+
+ tmp |= timeout << 16;
+
+ out_be32(&wd_base->swcrr, tmp);
+
+ return nonseekable_open(inode, file);
+}
+
+static int mpc83xx_wdt_release(struct inode *inode, struct file *file)
+{
+ printk(KERN_CRIT "Unexpected close, not stopping watchdog!\n");
+ mpc83xx_wdt_keepalive();
+ clear_bit(0, &wdt_is_open);
+ return 0;
+}
+
+static int mpc83xx_wdt_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ static struct watchdog_info ident = {
+ .options = WDIOF_KEEPALIVEPING,
+ .firmware_version = 1,
+ .identity = "MPC83xx",
+ };
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+ case WDIOC_KEEPALIVE:
+ mpc83xx_wdt_keepalive();
+ return 0;
+ case WDIOC_GETTIMEOUT:
+ return put_user(timeout_sec, p);
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+
+static struct file_operations mpc83xx_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = mpc83xx_wdt_write,
+ .ioctl = mpc83xx_wdt_ioctl,
+ .open = mpc83xx_wdt_open,
+ .release = mpc83xx_wdt_release,
+};
+
+static struct miscdevice mpc83xx_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &mpc83xx_wdt_fops,
+};
+
+static int __devinit mpc83xx_wdt_probe(struct platform_device *dev)
+{
+ struct resource *r;
+ int ret;
+ unsigned int *freq = dev->dev.platform_data;
+
+ /* get a pointer to the register memory */
+ r = platform_get_resource(dev, IORESOURCE_MEM, 0);
+
+ if (!r) {
+ ret = -ENODEV;
+ goto err_out;
+ }
+
+ wd_base = ioremap(r->start, sizeof (struct mpc83xx_wdt));
+
+ if (wd_base == NULL) {
+ ret = -ENOMEM;
+ goto err_out;
+ }
+
+ ret = misc_register(&mpc83xx_wdt_miscdev);
+ if (ret) {
+ printk(KERN_ERR "cannot register miscdev on minor=%d "
+ "(err=%d)\n",
+ WATCHDOG_MINOR, ret);
+ goto err_unmap;
+ }
+
+ /* Calculate the timeout in seconds */
+ if (prescale)
+ timeout_sec = (timeout * 0x10000) / (*freq);
+ else
+ timeout_sec = timeout / (*freq);
+
+ printk(KERN_INFO "WDT driver for MPC83xx initialized. "
+ "mode:%s timeout=%d (%d seconds)\n",
+ reset ? "reset":"interrupt", timeout, timeout_sec);
+
+ spin_lock_init(&wdt_spinlock);
+
+ return 0;
+
+err_unmap:
+ iounmap(wd_base);
+err_out:
+ return ret;
+}
+
+static int __devexit mpc83xx_wdt_remove(struct platform_device *dev)
+{
+ misc_deregister(&mpc83xx_wdt_miscdev);
+ iounmap(wd_base);
+
+ return 0;
+}
+
+static struct platform_driver mpc83xx_wdt_driver = {
+ .probe = mpc83xx_wdt_probe,
+ .remove = __devexit_p(mpc83xx_wdt_remove),
+ .driver = {
+ .name = "mpc83xx_wdt",
+ },
+};
+
+static int __init mpc83xx_wdt_init(void)
+{
+ return platform_driver_register(&mpc83xx_wdt_driver);
+}
+
+static void __exit mpc83xx_wdt_exit(void)
+{
+ platform_driver_unregister(&mpc83xx_wdt_driver);
+}
+
+module_init(mpc83xx_wdt_init);
+module_exit(mpc83xx_wdt_exit);
+
+MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
+MODULE_DESCRIPTION("Driver for watchdog timer in MPC83xx uProcessor");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
projects / linux-drm-fsl-dcu.git / commitdiff