[WATCHDOG] Blackfin on-chip watchdog driver (1e6d320f) · Commits · e / devices / android_kernel_fairphone_FP3

MAINTAINERS

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		@@ -771,6 +771,14 @@ L: uclinux-dist-devel@blackfin.uclinux.org (subscribers-only)
		W: http://blackfin.uclinux.org
		S: Supported

		BLACKFIN WATCHDOG DRIVER
		P: Mike Frysinger
		M: michael.frysinger@analog.com
		M: vapier.adi@gmail.com
		L: uclinux-dist-devel@blackfin.uclinux.org (subscribers-only)
		W: http://blackfin.uclinux.org
		S: Supported

		BAYCOM/HDLCDRV DRIVERS FOR AX.25
		P: Thomas Sailer
		M: t.sailer@alumni.ethz.ch

drivers/char/watchdog/Kconfig

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		@@ -212,6 +212,19 @@ config AT32AP700X_WDT
		Watchdog timer embedded into AT32AP700x devices. This will reboot
		your system when the timeout is reached.

		# Blackfin Architecture

		config BFIN_WDT
		tristate "Blackfin On-Chip Watchdog Timer"
		depends on WATCHDOG && BLACKFIN
		---help---
		If you say yes here you will get support for the Blackfin On-Chip
		Watchdog Timer. If you have one of these processors and wish to
		have watchdog support enabled, say Y, otherwise say N.

		To compile this driver as a module, choose M here: the
		module will be called bfin_wdt.

		# X86 (i386 + ia64 + x86_64) Architecture

		config ACQUIRE_WDT

drivers/char/watchdog/Makefile

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		@@ -40,6 +40,9 @@ obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
		# AVR32 Architecture
		obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o

		# Blackfin Architecture
		obj-$(CONFIG_BFIN_WDT) += bfin_wdt.o

		# X86 (i386 + ia64 + x86_64) Architecture
		obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
		obj-$(CONFIG_ADVANTECH_WDT) += advantechwdt.o

drivers/char/watchdog/bfin_wdt.c

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		/*
		* 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) ")");