[WATCHDOG] Add support for SB1 hardware watchdog (75c752e6) · Commits · e / devices / android_kernel_sony_msm8994

drivers/watchdog/Kconfig

+13 −0

Original line number	Diff line number	Diff line
		@@ -633,6 +633,19 @@ config WDT_RM9K_GPI
		To compile this driver as a module, choose M here: the
		module will be called rm9k_wdt.

		config SIBYTE_WDOG
		tristate "Sibyte SoC hardware watchdog"
		depends on CPU_SB1
		help
		Watchdog driver for the built in watchdog hardware in Sibyte
		SoC processors. There are apparently two watchdog timers
		on such processors; this driver supports only the first one,
		because currently Linux only supports exporting one watchdog
		to userspace.

		To compile this driver as a loadable module, choose M here.
		The module will be called sb_wdog.

		config AR7_WDT
		tristate "TI AR7 Watchdog Timer"
		depends on AR7

drivers/watchdog/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -92,6 +92,7 @@ obj-$(CONFIG_SBC_EPX_C3_WATCHDOG) += sbc_epx_c3.o
		obj-$(CONFIG_INDYDOG) += indydog.o
		obj-$(CONFIG_WDT_MTX1) += mtx-1_wdt.o
		obj-$(CONFIG_WDT_RM9K_GPI) += rm9k_wdt.o
		obj-$(CONFIG_SIBYTE_WDOG) += sb_wdog.o
		obj-$(CONFIG_AR7_WDT) += ar7_wdt.o
		obj-$(CONFIG_TXX9_WDT) += txx9wdt.o

drivers/watchdog/sb_wdog.c

0 → 100644

+353 −0

Original line number	Diff line number	Diff line
		/*
		* Watchdog driver for SiByte SB1 SoCs
		*
		* Copyright (C) 2007 OnStor, Inc. * Andrew Sharp <andy.sharp@onstor.com>
		*
		* This driver is intended to make the second of two hardware watchdogs
		* on the Sibyte 12XX and 11XX SoCs available to the user. There are two
		* such devices available on the SoC, but it seems that there isn't an
		* enumeration class for watchdogs in Linux like there is for RTCs.
		* The second is used rather than the first because it uses IRQ 1,
		* thereby avoiding all that IRQ 0 problematic nonsense.
		*
		* I have not tried this driver on a 1480 processor; it might work
		* just well enough to really screw things up.
		*
		* It is a simple timer, and there is an interrupt that is raised the
		* first time the timer expires. The second time it expires, the chip
		* is reset and there is no way to redirect that NMI. Which could
		* be problematic in some cases where this chip is sitting on the HT
		* bus and has just taken responsibility for providing a cache block.
		* Since the reset can't be redirected to the external reset pin, it is
		* possible that other HT connected processors might hang and not reset.
		* For Linux, a soft reset would probably be even worse than a hard reset.
		* There you have it.
		*
		* The timer takes 23 bits of a 64 bit register (?) as a count value,
		* and decrements the count every microsecond, for a max value of
		* 0x7fffff usec or about 8.3ish seconds.
		*
		* This watchdog borrows some user semantics from the softdog driver,
		* in that if you close the fd, it leaves the watchdog running, unless
		* you previously wrote a 'V' to the fd, in which case it disables
		* the watchdog when you close the fd like some other drivers.
		*
		* Based on various other watchdog drivers, which are probably all
		* loosely based on something Alan Cox wrote years ago.
		*
		* (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
		* http://www.redhat.com
		*
		* This program is free software; you can redistribute it and/or
		* modify it under the terms of the GNU General Public License
		* version 1 or 2 as published by the Free Software Foundation.
		*
		*/
		#include <linux/module.h>
		#include <linux/io.h>
		#include <linux/uaccess.h>
		#include <linux/fs.h>
		#include <linux/reboot.h>
		#include <linux/miscdevice.h>
		#include <linux/watchdog.h>
		#include <linux/interrupt.h>

		#include <asm/sibyte/sb1250.h>
		#include <asm/sibyte/sb1250_regs.h>
		#include <asm/sibyte/sb1250_int.h>
		#include <asm/sibyte/sb1250_scd.h>


		/*
		* set the initial count value of a timer
		*
		* wdog is the iomem address of the cfg register
		*/
		void sbwdog_set(char __iomem *wdog, unsigned long t)
		{
		__raw_writeb(0, wdog - 0x10);
		__raw_writeq(t & 0x7fffffUL, wdog);
		}

		/*
		* cause the timer to [re]load it's initial count and start counting
		* all over again
		*
		* wdog is the iomem address of the cfg register
		*/
		void sbwdog_pet(char __iomem *wdog)
		{
		__raw_writeb(__raw_readb(wdog) \| 1, wdog);
		}

		static unsigned long sbwdog_gate; /* keeps it to one thread only */
		static char __iomem kern_dog = (char __iomem )(IO_BASE + (A_SCD_WDOG_CFG_0));
		static char __iomem user_dog = (char __iomem )(IO_BASE + (A_SCD_WDOG_CFG_1));
		static unsigned long timeout = 0x7fffffUL; /* useconds: 8.3ish secs. */
		static int expect_close;

		static struct watchdog_info ident = {
		.options = WDIOF_CARDRESET \| WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
		.identity = "SiByte Watchdog",
		};

		/*
		* Allow only a single thread to walk the dog
		*/
		static int sbwdog_open(struct inode inode, struct file file)
		{
		nonseekable_open(inode, file);
		if (test_and_set_bit(0, &sbwdog_gate)) {
		return -EBUSY;
		}
		__module_get(THIS_MODULE);

		/*
		* Activate the timer
		*/
		sbwdog_set(user_dog, timeout);
		__raw_writeb(1, user_dog);

		return 0;
		}

		/*
		* Put the dog back in the kennel.
		*/
		static int sbwdog_release(struct inode inode, struct file file)
		{
		if (expect_close == 42) {
		__raw_writeb(0, user_dog);
		module_put(THIS_MODULE);
		} else {
		printk(KERN_CRIT "%s: Unexpected close, not stopping watchdog!\n",
		ident.identity);
		sbwdog_pet(user_dog);
		}
		clear_bit(0, &sbwdog_gate);
		expect_close = 0;

		return 0;
		}

		/*
		* 42 - the answer
		*/
		static ssize_t sbwdog_write(struct file file, const char __user data,
		size_t len, loff_t *ppos)
		{
		int i;

		if (len) {
		/*
		* restart the timer
		*/
		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;
		}
		}
		sbwdog_pet(user_dog);
		}

		return len;
		}

		static int sbwdog_ioctl(struct inode inode, struct file file,
		unsigned int cmd, unsigned long arg)
		{
		int ret = -ENOTTY;
		unsigned long time;
		void __user argp = (void __user )arg;
		int __user *p = argp;

		switch (cmd) {
		case WDIOC_GETSUPPORT:
		ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
		break;

		case WDIOC_GETSTATUS:
		case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, p);
		break;

		case WDIOC_SETTIMEOUT:
		ret = get_user(time, p);
		if (ret) {
		break;
		}

		time *= 1000000;
		if (time > 0x7fffffUL) {
		ret = -EINVAL;
		break;
		}
		timeout = time;
		sbwdog_set(user_dog, timeout);
		sbwdog_pet(user_dog);

		case WDIOC_GETTIMEOUT:
		/*
		* get the remaining count from the ... count register
		* which is 1*8 before the config register
		*/
		ret = put_user(__raw_readq(user_dog - 8) / 1000000, p);
		break;

		case WDIOC_KEEPALIVE:
		sbwdog_pet(user_dog);
		ret = 0;
		break;
		}
		return ret;
		}

		/*
		* Notifier for system down
		*/
		static int
		sbwdog_notify_sys(struct notifier_block this, unsigned long code, void erf)
		{
		if (code == SYS_DOWN \|\| code == SYS_HALT) {
		/*
		* sit and sit
		*/
		__raw_writeb(0, user_dog);
		__raw_writeb(0, kern_dog);
		}

		return NOTIFY_DONE;
		}

		static const struct file_operations sbwdog_fops =
		{
		.owner = THIS_MODULE,
		.llseek = no_llseek,
		.write = sbwdog_write,
		.ioctl = sbwdog_ioctl,
		.open = sbwdog_open,
		.release = sbwdog_release,
		};

		static struct miscdevice sbwdog_miscdev =
		{
		.minor = WATCHDOG_MINOR,
		.name = "watchdog",
		.fops = &sbwdog_fops,
		};

		static struct notifier_block sbwdog_notifier = {
		.notifier_call = sbwdog_notify_sys,
		};

		/*
		* interrupt handler
		*
		* doesn't do a whole lot for user, but oh so cleverly written so kernel
		* code can use it to re-up the watchdog, thereby saving the kernel from
		* having to create and maintain a timer, just to tickle another timer,
		* which is just so wrong.
		*/
		irqreturn_t sbwdog_interrupt(int irq, void *addr)
		{
		unsigned long wd_init;
		char wd_cfg_reg = (char )addr;
		u8 cfg;

		cfg = __raw_readb(wd_cfg_reg);
		wd_init = __raw_readq(wd_cfg_reg - 8) & 0x7fffff;

		/*
		* if it's the second watchdog timer, it's for those users
		*/
		if (wd_cfg_reg == user_dog) {
		printk(KERN_CRIT
		"%s in danger of initiating system reset in %ld.%01ld seconds\n",
		ident.identity, wd_init / 1000000, (wd_init / 100000) % 10);
		} else {
		cfg \|= 1;
		}

		__raw_writeb(cfg, wd_cfg_reg);

		return IRQ_HANDLED;
		}

		static int __init sbwdog_init(void)
		{
		int ret;

		/*
		* register a reboot notifier
		*/
		ret = register_reboot_notifier(&sbwdog_notifier);
		if (ret) {
		printk (KERN_ERR "%s: cannot register reboot notifier (err=%d)\n",
		ident.identity, ret);
		return ret;
		}

		/*
		* get the resources
		*/
		ret = misc_register(&sbwdog_miscdev);
		if (ret == 0) {
		printk(KERN_INFO "%s: timeout is %ld.%ld secs\n", ident.identity,
		timeout / 1000000, (timeout / 100000) % 10);
		}

		ret = request_irq(1, sbwdog_interrupt, IRQF_DISABLED \| IRQF_SHARED,
		ident.identity, (void *)user_dog);
		if (ret) {
		printk(KERN_ERR "%s: failed to request irq 1 - %d\n", ident.identity,
		ret);
		misc_deregister(&sbwdog_miscdev);
		}

		return ret;
		}

		static void __exit sbwdog_exit(void)
		{
		misc_deregister(&sbwdog_miscdev);
		}

		module_init(sbwdog_init);
		module_exit(sbwdog_exit);

		MODULE_AUTHOR("Andrew Sharp <andy.sharp@onstor.com>");
		MODULE_DESCRIPTION("SiByte Watchdog");

		module_param(timeout, ulong, 0);
		MODULE_PARM_DESC(timeout,
		"Watchdog timeout in microseconds (max/default 8388607 or 8.3ish secs)");

		MODULE_LICENSE("GPL");
		MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

		/*
		* example code that can be put in a platform code area to utilize the
		* first watchdog timer for the kernels own purpose.

		void
		platform_wd_setup(void)
		{
		int ret;

		ret = request_irq(0, sbwdog_interrupt, IRQF_DISABLED \| IRQF_SHARED,
		"Kernel Watchdog", IOADDR(A_SCD_WDOG_CFG_0));
		if (ret) {
		printk(KERN_CRIT "Watchdog IRQ zero(0) failed to be requested - %d\n",
		ret);
		}
		}


		*/