[WATCHDOG] AR7: watchdog timer (c283cf2c) · Commits · e / devices / android_kernel_fairphone_FP4

drivers/watchdog/Kconfig

+6 −0

Original line number	Diff line number	Diff line
		@@ -610,6 +610,12 @@ config WDT_RM9K_GPI
		To compile this driver as a module, choose M here: the
		module will be called rm9k_wdt.

		config AR7_WDT
		tristate "TI AR7 Watchdog Timer"
		depends on AR7
		help
		Hardware driver for the TI AR7 Watchdog Timer.

		# PARISC Architecture

		# POWERPC Architecture

drivers/watchdog/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -90,6 +90,7 @@ 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_AR7_WDT) += ar7_wdt.o

		# PARISC Architecture

drivers/watchdog/ar7_wdt.c

0 → 100644

+349 −0

Original line number	Diff line number	Diff line
		/*
		* drivers/watchdog/ar7_wdt.c
		*
		* Copyright (C) 2007 Nicolas Thill <nico@openwrt.org>
		* Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org>
		*
		* Some code taken from:
		* National Semiconductor SCx200 Watchdog support
		* Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
		*
		* 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.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to the Free Software
		* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
		*/

		#include <linux/module.h>
		#include <linux/moduleparam.h>
		#include <linux/errno.h>
		#include <linux/init.h>
		#include <linux/miscdevice.h>
		#include <linux/watchdog.h>
		#include <linux/notifier.h>
		#include <linux/reboot.h>
		#include <linux/fs.h>
		#include <linux/ioport.h>
		#include <linux/io.h>
		#include <linux/uaccess.h>

		#include <asm/addrspace.h>
		#include <asm/ar7/ar7.h>

		#define DRVNAME "ar7_wdt"
		#define LONGNAME "TI AR7 Watchdog Timer"

		MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
		MODULE_DESCRIPTION(LONGNAME);
		MODULE_LICENSE("GPL");
		MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

		static int margin = 60;
		module_param(margin, int, 0);
		MODULE_PARM_DESC(margin, "Watchdog margin in seconds");

		static int nowayout = WATCHDOG_NOWAYOUT;
		module_param(nowayout, int, 0);
		MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");

		#define READ_REG(x) readl((void __iomem *)&(x))
		#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))

		struct ar7_wdt {
		u32 kick_lock;
		u32 kick;
		u32 change_lock;
		u32 change;
		u32 disable_lock;
		u32 disable;
		u32 prescale_lock;
		u32 prescale;
		};

		static struct semaphore open_semaphore;
		static unsigned expect_close;

		/* XXX currently fixed, allows max margin ~68.72 secs */
		#define prescale_value 0xffff

		/* Offset of the WDT registers */
		static unsigned long ar7_regs_wdt;
		/* Pointer to the remapped WDT IO space */
		static struct ar7_wdt *ar7_wdt;
		static void ar7_wdt_get_regs(void)
		{
		u16 chip_id = ar7_chip_id();
		switch (chip_id) {
		case AR7_CHIP_7100:
		case AR7_CHIP_7200:
		ar7_regs_wdt = AR7_REGS_WDT;
		break;
		default:
		ar7_regs_wdt = UR8_REGS_WDT;
		break;
		}
		}


		static void ar7_wdt_kick(u32 value)
		{
		WRITE_REG(ar7_wdt->kick_lock, 0x5555);
		if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
		WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
		if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
		WRITE_REG(ar7_wdt->kick, value);
		return;
		}
		}
		printk(KERN_ERR DRVNAME ": failed to unlock WDT kick reg\n");
		}

		static void ar7_wdt_prescale(u32 value)
		{
		WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
		if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
		WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
		if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
		WRITE_REG(ar7_wdt->prescale, value);
		return;
		}
		}
		printk(KERN_ERR DRVNAME ": failed to unlock WDT prescale reg\n");
		}

		static void ar7_wdt_change(u32 value)
		{
		WRITE_REG(ar7_wdt->change_lock, 0x6666);
		if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
		WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
		if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
		WRITE_REG(ar7_wdt->change, value);
		return;
		}
		}
		printk(KERN_ERR DRVNAME ": failed to unlock WDT change reg\n");
		}

		static void ar7_wdt_disable(u32 value)
		{
		WRITE_REG(ar7_wdt->disable_lock, 0x7777);
		if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
		WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
		if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
		WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
		if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
		WRITE_REG(ar7_wdt->disable, value);
		return;
		}
		}
		}
		printk(KERN_ERR DRVNAME ": failed to unlock WDT disable reg\n");
		}

		static void ar7_wdt_update_margin(int new_margin)
		{
		u32 change;

		change = new_margin * (ar7_vbus_freq() / prescale_value);
		if (change < 1) change = 1;
		if (change > 0xffff) change = 0xffff;
		ar7_wdt_change(change);
		margin = change * prescale_value / ar7_vbus_freq();
		printk(KERN_INFO DRVNAME
		": timer margin %d seconds (prescale %d, change %d, freq %d)\n",
		margin, prescale_value, change, ar7_vbus_freq());
		}

		static void ar7_wdt_enable_wdt(void)
		{
		printk(KERN_DEBUG DRVNAME ": enabling watchdog timer\n");
		ar7_wdt_disable(1);
		ar7_wdt_kick(1);
		}

		static void ar7_wdt_disable_wdt(void)
		{
		printk(KERN_DEBUG DRVNAME ": disabling watchdog timer\n");
		ar7_wdt_disable(0);
		}

		static int ar7_wdt_open(struct inode inode, struct file file)
		{
		/* only allow one at a time */
		if (down_trylock(&open_semaphore))
		return -EBUSY;
		ar7_wdt_enable_wdt();
		expect_close = 0;

		return nonseekable_open(inode, file);
		}

		static int ar7_wdt_release(struct inode inode, struct file file)
		{
		if (!expect_close)
		printk(KERN_WARNING DRVNAME
		": watchdog device closed unexpectedly,"
		"will not disable the watchdog timer\n");
		else if (!nowayout)
		ar7_wdt_disable_wdt();

		up(&open_semaphore);

		return 0;
		}

		static int ar7_wdt_notify_sys(struct notifier_block *this,
		unsigned long code, void *unused)
		{
		if (code == SYS_HALT \|\| code == SYS_POWER_OFF)
		if (!nowayout)
		ar7_wdt_disable_wdt();

		return NOTIFY_DONE;
		}

		static struct notifier_block ar7_wdt_notifier = {
		.notifier_call = ar7_wdt_notify_sys
		};

		static ssize_t ar7_wdt_write(struct file file, const char data,
		size_t len, loff_t *ppos)
		{
		/* check for a magic close character */
		if (len) {
		size_t i;

		ar7_wdt_kick(1);

		expect_close = 0;
		for (i = 0; i < len; ++i) {
		char c;
		if (get_user(c, data+i))
		return -EFAULT;
		if (c == 'V')
		expect_close = 1;
		}

		}
		return len;
		}

		static int ar7_wdt_ioctl(struct inode inode, struct file file,
		unsigned int cmd, unsigned long arg)
		{
		static struct watchdog_info ident = {
		.identity = LONGNAME,
		.firmware_version = 1,
		.options = (WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING),
		};
		int new_margin;

		switch (cmd) {
		default:
		return -ENOTTY;
		case WDIOC_GETSUPPORT:
		if (copy_to_user((struct watchdog_info *)arg, &ident,
		sizeof(ident)))
		return -EFAULT;
		return 0;
		case WDIOC_GETSTATUS:
		case WDIOC_GETBOOTSTATUS:
		if (put_user(0, (int *)arg))
		return -EFAULT;
		return 0;
		case WDIOC_KEEPALIVE:
		ar7_wdt_kick(1);
		return 0;
		case WDIOC_SETTIMEOUT:
		if (get_user(new_margin, (int *)arg))
		return -EFAULT;
		if (new_margin < 1)
		return -EINVAL;

		ar7_wdt_update_margin(new_margin);
		ar7_wdt_kick(1);

		case WDIOC_GETTIMEOUT:
		if (put_user(margin, (int *)arg))
		return -EFAULT;
		return 0;
		}
		}

		static struct file_operations ar7_wdt_fops = {
		.owner = THIS_MODULE,
		.write = ar7_wdt_write,
		.ioctl = ar7_wdt_ioctl,
		.open = ar7_wdt_open,
		.release = ar7_wdt_release,
		};

		static struct miscdevice ar7_wdt_miscdev = {
		.minor = WATCHDOG_MINOR,
		.name = "watchdog",
		.fops = &ar7_wdt_fops,
		};

		static int __init ar7_wdt_init(void)
		{
		int rc;

		ar7_wdt_get_regs();

		if (!request_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt),
		LONGNAME)) {
		printk(KERN_WARNING DRVNAME ": watchdog I/O region busy\n");
		return -EBUSY;
		}

		ar7_wdt = (struct ar7_wdt *)
		ioremap(ar7_regs_wdt, sizeof(struct ar7_wdt));

		ar7_wdt_disable_wdt();
		ar7_wdt_prescale(prescale_value);
		ar7_wdt_update_margin(margin);

		sema_init(&open_semaphore, 1);

		rc = register_reboot_notifier(&ar7_wdt_notifier);
		if (rc) {
		printk(KERN_ERR DRVNAME
		": unable to register reboot notifier\n");
		goto out_alloc;
		}

		rc = misc_register(&ar7_wdt_miscdev);
		if (rc) {
		printk(KERN_ERR DRVNAME ": unable to register misc device\n");
		goto out_register;
		}
		goto out;

		out_register:
		unregister_reboot_notifier(&ar7_wdt_notifier);
		out_alloc:
		iounmap(ar7_wdt);
		release_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt));
		out:
		return rc;
		}

		static void __exit ar7_wdt_cleanup(void)
		{
		misc_deregister(&ar7_wdt_miscdev);
		unregister_reboot_notifier(&ar7_wdt_notifier);
		iounmap(ar7_wdt);
		release_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt));
		}

		module_init(ar7_wdt_init);
		module_exit(ar7_wdt_cleanup);