| /* |
| * 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/platform_device.h> |
| #include <linux/watchdog.h> |
| #include <linux/fs.h> |
| #include <linux/ioport.h> |
| #include <linux/io.h> |
| #include <linux/uaccess.h> |
| #include <linux/clk.h> |
| |
| #include <asm/addrspace.h> |
| #include <asm/mach-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 unsigned long wdt_is_open; |
| static spinlock_t wdt_lock; |
| static unsigned expect_close; |
| |
| /* XXX currently fixed, allows max margin ~68.72 secs */ |
| #define prescale_value 0xffff |
| |
| /* Resource of the WDT registers */ |
| static struct resource *ar7_regs_wdt; |
| /* Pointer to the remapped WDT IO space */ |
| static struct ar7_wdt *ar7_wdt; |
| |
| static struct clk *vbus_clk; |
| |
| 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; |
| u32 vbus_rate; |
| |
| vbus_rate = clk_get_rate(vbus_clk); |
| change = new_margin * (vbus_rate / prescale_value); |
| if (change < 1) |
| change = 1; |
| if (change > 0xffff) |
| change = 0xffff; |
| ar7_wdt_change(change); |
| margin = change * prescale_value / vbus_rate; |
| printk(KERN_INFO DRVNAME |
| ": timer margin %d seconds (prescale %d, change %d, freq %d)\n", |
| margin, prescale_value, change, vbus_rate); |
| } |
| |
| 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 (test_and_set_bit(0, &wdt_is_open)) |
| 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(); |
| clear_bit(0, &wdt_is_open); |
| return 0; |
| } |
| |
| 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; |
| |
| spin_lock(&wdt_lock); |
| ar7_wdt_kick(1); |
| spin_unlock(&wdt_lock); |
| |
| 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 long ar7_wdt_ioctl(struct file *file, |
| unsigned int cmd, unsigned long arg) |
| { |
| static const struct watchdog_info ident = { |
| .identity = LONGNAME, |
| .firmware_version = 1, |
| .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
| WDIOF_MAGICCLOSE), |
| }; |
| int new_margin; |
| |
| switch (cmd) { |
| 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; |
| |
| spin_lock(&wdt_lock); |
| ar7_wdt_update_margin(new_margin); |
| ar7_wdt_kick(1); |
| spin_unlock(&wdt_lock); |
| |
| case WDIOC_GETTIMEOUT: |
| if (put_user(margin, (int *)arg)) |
| return -EFAULT; |
| return 0; |
| default: |
| return -ENOTTY; |
| } |
| } |
| |
| static const struct file_operations ar7_wdt_fops = { |
| .owner = THIS_MODULE, |
| .write = ar7_wdt_write, |
| .unlocked_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 __devinit ar7_wdt_probe(struct platform_device *pdev) |
| { |
| int rc; |
| |
| spin_lock_init(&wdt_lock); |
| |
| ar7_regs_wdt = |
| platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs"); |
| if (!ar7_regs_wdt) { |
| printk(KERN_ERR DRVNAME ": could not get registers resource\n"); |
| rc = -ENODEV; |
| goto out; |
| } |
| |
| if (!request_mem_region(ar7_regs_wdt->start, |
| resource_size(ar7_regs_wdt), LONGNAME)) { |
| printk(KERN_WARNING DRVNAME ": watchdog I/O region busy\n"); |
| rc = -EBUSY; |
| goto out; |
| } |
| |
| ar7_wdt = ioremap(ar7_regs_wdt->start, resource_size(ar7_regs_wdt)); |
| if (!ar7_wdt) { |
| printk(KERN_ERR DRVNAME ": could not ioremap registers\n"); |
| rc = -ENXIO; |
| goto out_mem_region; |
| } |
| |
| vbus_clk = clk_get(NULL, "vbus"); |
| if (IS_ERR(vbus_clk)) { |
| printk(KERN_ERR DRVNAME ": could not get vbus clock\n"); |
| rc = PTR_ERR(vbus_clk); |
| goto out_mem_region; |
| } |
| |
| ar7_wdt_disable_wdt(); |
| ar7_wdt_prescale(prescale_value); |
| ar7_wdt_update_margin(margin); |
| |
| rc = misc_register(&ar7_wdt_miscdev); |
| if (rc) { |
| printk(KERN_ERR DRVNAME ": unable to register misc device\n"); |
| goto out_alloc; |
| } |
| goto out; |
| |
| out_alloc: |
| iounmap(ar7_wdt); |
| out_mem_region: |
| release_mem_region(ar7_regs_wdt->start, resource_size(ar7_regs_wdt)); |
| out: |
| return rc; |
| } |
| |
| static int __devexit ar7_wdt_remove(struct platform_device *pdev) |
| { |
| misc_deregister(&ar7_wdt_miscdev); |
| iounmap(ar7_wdt); |
| release_mem_region(ar7_regs_wdt->start, resource_size(ar7_regs_wdt)); |
| |
| return 0; |
| } |
| |
| static void ar7_wdt_shutdown(struct platform_device *pdev) |
| { |
| if (!nowayout) |
| ar7_wdt_disable_wdt(); |
| } |
| |
| static struct platform_driver ar7_wdt_driver = { |
| .probe = ar7_wdt_probe, |
| .remove = __devexit_p(ar7_wdt_remove), |
| .shutdown = ar7_wdt_shutdown, |
| .driver = { |
| .owner = THIS_MODULE, |
| .name = "ar7_wdt", |
| }, |
| }; |
| |
| static int __init ar7_wdt_init(void) |
| { |
| return platform_driver_register(&ar7_wdt_driver); |
| } |
| |
| static void __exit ar7_wdt_cleanup(void) |
| { |
| platform_driver_unregister(&ar7_wdt_driver); |
| } |
| |
| module_init(ar7_wdt_init); |
| module_exit(ar7_wdt_cleanup); |