+/*
+ * Blackfin On-Chip Watchdog Driver
+ * Supports BF53[123]/BF53[467]/BF54[2489]/BF561
+ *
+ * Originally based on softdog.c
+ * Copyright 2006-2007 Analog Devices Inc.
+ * Copyright 2006-2007 Michele d'Amico
+ * Copyright 1996 Alan Cox <alan@redhat.com>
+ *
+ * Enter bugs at http://blackfin.uclinux.org/
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/timer.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <asm/blackfin.h>
+#include <asm/uaccess.h>
+
+#define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
+#define stampit() stamp("here i am")
+
+#define WATCHDOG_NAME "bfin-wdt"
+#define PFX WATCHDOG_NAME ": "
+
+/* The BF561 has two watchdogs (one per core), but since Linux
+ * only runs on core A, we'll just work with that one.
+ */
+#ifdef BF561_FAMILY
+# define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL()
+# define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT()
+# define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT()
+# define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x)
+# define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x)
+# define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
+#endif
+
+/* Bit in SWRST that indicates boot caused by watchdog */
+#define SWRST_RESET_WDOG 0x4000
+
+/* Bit in WDOG_CTL that indicates watchdog has expired (WDR0) */
+#define WDOG_EXPIRED 0x8000
+
+/* Masks for WDEV field in WDOG_CTL register */
+#define ICTL_RESET 0x0
+#define ICTL_NMI 0x2
+#define ICTL_GPI 0x4
+#define ICTL_NONE 0x6
+#define ICTL_MASK 0x6
+
+/* Masks for WDEN field in WDOG_CTL register */
+#define WDEN_MASK 0x0FF0
+#define WDEN_ENABLE 0x0000
+#define WDEN_DISABLE 0x0AD0
+
+/* some defaults */
+#define WATCHDOG_TIMEOUT 20
+
+static unsigned int timeout = WATCHDOG_TIMEOUT;
+static int nowayout = WATCHDOG_NOWAYOUT;
+static struct watchdog_info bfin_wdt_info;
+static unsigned long open_check;
+static char expect_close;
+static spinlock_t bfin_wdt_spinlock = SPIN_LOCK_UNLOCKED;
+
+/**
+ * bfin_wdt_keepalive - Keep the Userspace Watchdog Alive
+ *
+ * The Userspace watchdog got a KeepAlive: schedule the next timeout.
+ */
+static int bfin_wdt_keepalive(void)
+{
+ stampit();
+ bfin_write_WDOG_STAT(0);
+ return 0;
+}
+
+/**
+ * bfin_wdt_stop - Stop the Watchdog
+ *
+ * Stops the on-chip watchdog.
+ */
+static int bfin_wdt_stop(void)
+{
+ stampit();
+ bfin_write_WDOG_CTL(WDEN_DISABLE);
+ return 0;
+}
+
+/**
+ * bfin_wdt_start - Start the Watchdog
+ *
+ * Starts the on-chip watchdog. Automatically loads WDOG_CNT
+ * into WDOG_STAT for us.
+ */
+static int bfin_wdt_start(void)
+{
+ stampit();
+ bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET);
+ return 0;
+}
+
+/**
+ * bfin_wdt_running - Check Watchdog status
+ *
+ * See if the watchdog is running.
+ */
+static int bfin_wdt_running(void)
+{
+ stampit();
+ return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
+}
+
+/**
+ * bfin_wdt_set_timeout - Set the Userspace Watchdog timeout
+ * @t: new timeout value (in seconds)
+ *
+ * Translate the specified timeout in seconds into System Clock
+ * terms which is what the on-chip Watchdog requires.
+ */
+static int bfin_wdt_set_timeout(unsigned long t)
+{
+ u32 cnt;
+ unsigned long flags;
+
+ stampit();
+
+ cnt = t * get_sclk();
+ if (cnt < get_sclk()) {
+ printk(KERN_WARNING PFX "timeout value is too large\n");
+ return -EINVAL;
+ }
+
+ spin_lock_irqsave(&bfin_wdt_spinlock, flags);
+ {
+ int run = bfin_wdt_running();
+ bfin_wdt_stop();
+ bfin_write_WDOG_CNT(cnt);
+ if (run) bfin_wdt_start();
+ }
+ spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
+
+ timeout = t;
+
+ return 0;
+}
+
+/**
+ * bfin_wdt_open - Open the Device
+ * @inode: inode of device
+ * @file: file handle of device
+ *
+ * Watchdog device is opened and started.
+ */
+static int bfin_wdt_open(struct inode *inode, struct file *file)
+{
+ stampit();
+
+ if (test_and_set_bit(0, &open_check))
+ return -EBUSY;
+
+ if (nowayout)
+ __module_get(THIS_MODULE);
+
+ bfin_wdt_keepalive();
+ bfin_wdt_start();
+
+ return nonseekable_open(inode, file);
+}
+
+/**
+ * bfin_wdt_close - Close the Device
+ * @inode: inode of device
+ * @file: file handle of device
+ *
+ * Watchdog device is closed and stopped.
+ */
+static int bfin_wdt_release(struct inode *inode, struct file *file)
+{
+ stampit();
+
+ if (expect_close == 42) {
+ bfin_wdt_stop();
+ } else {
+ printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
+ bfin_wdt_keepalive();
+ }
+
+ expect_close = 0;
+ clear_bit(0, &open_check);
+
+ return 0;
+}
+
+/**
+ * bfin_wdt_write - Write to Device
+ * @file: file handle of device
+ * @buf: buffer to write
+ * @count: length of buffer
+ * @ppos: offset
+ *
+ * Pings the watchdog on write.
+ */
+static ssize_t bfin_wdt_write(struct file *file, const char __user *data,
+ size_t len, loff_t *ppos)
+{
+ stampit();
+
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ /* In case it was set long ago */
+ expect_close = 0;
+
+ for (i = 0; i != len; i++) {
+ char c;
+ if (get_user(c, data + i))
+ return -EFAULT;
+ if (c == 'V')
+ expect_close = 42;
+ }
+ }
+ bfin_wdt_keepalive();
+ }
+
+ return len;
+}
+
+/**
+ * bfin_wdt_ioctl - Query Device
+ * @inode: inode of device
+ * @file: file handle of device
+ * @cmd: watchdog command
+ * @arg: argument
+ *
+ * Query basic information from the device or ping it, as outlined by the
+ * watchdog API.
+ */
+static int bfin_wdt_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+
+ stampit();
+
+ switch (cmd) {
+ default:
+ return -ENOTTY;
+
+ case WDIOC_GETSUPPORT:
+ if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info)))
+ return -EFAULT;
+ else
+ return 0;
+
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p);
+
+ case WDIOC_KEEPALIVE:
+ bfin_wdt_keepalive();
+ return 0;
+
+ case WDIOC_SETTIMEOUT: {
+ int new_timeout;
+
+ if (get_user(new_timeout, p))
+ return -EFAULT;
+
+ if (bfin_wdt_set_timeout(new_timeout))
+ return -EINVAL;
+ }
+ /* Fall */
+ case WDIOC_GETTIMEOUT:
+ return put_user(timeout, p);
+
+ case WDIOC_SETOPTIONS: {
+ unsigned long flags;
+ int options, ret = -EINVAL;
+
+ if (get_user(options, p))
+ return -EFAULT;
+
+ spin_lock_irqsave(&bfin_wdt_spinlock, flags);
+
+ if (options & WDIOS_DISABLECARD) {
+ bfin_wdt_stop();
+ ret = 0;
+ }
+
+ if (options & WDIOS_ENABLECARD) {
+ bfin_wdt_start();
+ ret = 0;
+ }
+
+ spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
+
+ return ret;
+ }
+ }
+}
+
+/**
+ * bfin_wdt_notify_sys - Notifier Handler
+ * @this: notifier block
+ * @code: notifier event
+ * @unused: unused
+ *
+ * Handles specific events, such as turning off the watchdog during a
+ * shutdown event.
+ */
+static int bfin_wdt_notify_sys(struct notifier_block *this, unsigned long code,
+ void *unused)
+{
+ stampit();
+
+ if (code == SYS_DOWN || code == SYS_HALT)
+ bfin_wdt_stop();
+
+ return NOTIFY_DONE;
+}
+
+#ifdef CONFIG_PM
+static int state_before_suspend;
+
+/**
+ * bfin_wdt_suspend - suspend the watchdog
+ * @pdev: device being suspended
+ * @state: requested suspend state
+ *
+ * Remember if the watchdog was running and stop it.
+ * TODO: is this even right? Doesn't seem to be any
+ * standard in the watchdog world ...
+ */
+static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ stampit();
+
+ state_before_suspend = bfin_wdt_running();
+ bfin_wdt_stop();
+
+ return 0;
+}
+
+/**
+ * bfin_wdt_resume - resume the watchdog
+ * @pdev: device being resumed
+ *
+ * If the watchdog was running, turn it back on.
+ */
+static int bfin_wdt_resume(struct platform_device *pdev)
+{
+ stampit();
+
+ if (state_before_suspend) {
+ bfin_wdt_set_timeout(timeout);
+ bfin_wdt_start();
+ }
+
+ return 0;
+}
+#else
+# define bfin_wdt_suspend NULL
+# define bfin_wdt_resume NULL
+#endif
+
+static struct platform_device bfin_wdt_device = {
+ .name = WATCHDOG_NAME,
+ .id = -1,
+};
+
+static struct platform_driver bfin_wdt_driver = {
+ .driver = {
+ .name = WATCHDOG_NAME,
+ .owner = THIS_MODULE,
+ },
+ .suspend = bfin_wdt_suspend,
+ .resume = bfin_wdt_resume,
+};
+
+static struct file_operations bfin_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = bfin_wdt_write,
+ .ioctl = bfin_wdt_ioctl,
+ .open = bfin_wdt_open,
+ .release = bfin_wdt_release,
+};
+
+static struct miscdevice bfin_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &bfin_wdt_fops,
+};
+
+static struct watchdog_info bfin_wdt_info = {
+ .identity = "Blackfin Watchdog",
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE,
+};
+
+static struct notifier_block bfin_wdt_notifier = {
+ .notifier_call = bfin_wdt_notify_sys,
+};
+
+/**
+ * bfin_wdt_init - Initialize module
+ *
+ * Registers the device and notifier handler. Actual device
+ * initialization is handled by bfin_wdt_open().
+ */
+static int __init bfin_wdt_init(void)
+{
+ int ret;
+
+ stampit();
+
+ /* Check that the timeout value is within range */
+ if (bfin_wdt_set_timeout(timeout))
+ return -EINVAL;
+
+ /* Since this is an on-chip device and needs no board-specific
+ * resources, we'll handle all the platform device stuff here.
+ */
+ ret = platform_device_register(&bfin_wdt_device);
+ if (ret)
+ return ret;
+
+ ret = platform_driver_probe(&bfin_wdt_driver, NULL);
+ if (ret)
+ return ret;
+
+ ret = register_reboot_notifier(&bfin_wdt_notifier);
+ if (ret) {
+ printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", ret);
+ return ret;
+ }
+
+ ret = misc_register(&bfin_wdt_miscdev);
+ if (ret) {
+ printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
+ WATCHDOG_MINOR, ret);
+ unregister_reboot_notifier(&bfin_wdt_notifier);
+ return ret;
+ }
+
+ printk(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
+ timeout, nowayout);
+
+ return 0;
+}
+
+/**
+ * bfin_wdt_exit - Deinitialize module
+ *
+ * Unregisters the device and notifier handler. Actual device
+ * deinitialization is handled by bfin_wdt_close().
+ */
+static void __exit bfin_wdt_exit(void)
+{
+ misc_deregister(&bfin_wdt_miscdev);
+ unregister_reboot_notifier(&bfin_wdt_notifier);
+}
+
+module_init(bfin_wdt_init);
+module_exit(bfin_wdt_exit);
+
+MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>");
+MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
+
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / commitdiff