/* * drivers/char/watchdog/davinci_wdt.c * * Watchdog driver for DaVinci DM644x/DM646x processors * * Copyright (C) 2006 Texas Instruments. * * 2007 (c) MontaVista Software, Inc. This file is licensed under * the terms of the GNU General Public License version 2. This program * is licensed "as is" without any warranty of any kind, whether express * or implied. */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/fs.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/init.h> #include <linux/bitops.h> #include <linux/platform_device.h> #include <linux/spinlock.h> #include <asm/hardware.h> #include <asm/uaccess.h> #include <asm/io.h> #define MODULE_NAME "DAVINCI-WDT: " #define DEFAULT_HEARTBEAT 60 #define MAX_HEARTBEAT 600 /* really the max margin is 264/27MHz*/ /* Timer register set definition */ #define PID12 (0x0) #define EMUMGT (0x4) #define TIM12 (0x10) #define TIM34 (0x14) #define PRD12 (0x18) #define PRD34 (0x1C) #define TCR (0x20) #define TGCR (0x24) #define WDTCR (0x28) /* TCR bit definitions */ #define ENAMODE12_DISABLED (0 << 6) #define ENAMODE12_ONESHOT (1 << 6) #define ENAMODE12_PERIODIC (2 << 6) /* TGCR bit definitions */ #define TIM12RS_UNRESET (1 << 0) #define TIM34RS_UNRESET (1 << 1) #define TIMMODE_64BIT_WDOG (2 << 2) /* WDTCR bit definitions */ #define WDEN (1 << 14) #define WDFLAG (1 << 15) #define WDKEY_SEQ0 (0xa5c6 << 16) #define WDKEY_SEQ1 (0xda7e << 16) static int heartbeat = DEFAULT_HEARTBEAT; static DEFINE_SPINLOCK(io_lock); static unsigned long wdt_status; #define WDT_IN_USE 0 #define WDT_OK_TO_CLOSE 1 #define WDT_REGION_INITED 2 #define WDT_DEVICE_INITED 3 static struct resource *wdt_mem; static void __iomem *wdt_base; static void wdt_service(void) { spin_lock(&io_lock); /* put watchdog in service state */ davinci_writel(WDKEY_SEQ0, wdt_base + WDTCR); /* put watchdog in active state */ davinci_writel(WDKEY_SEQ1, wdt_base + WDTCR); spin_unlock(&io_lock); } static void wdt_enable(void) { u32 tgcr; u32 timer_margin; spin_lock(&io_lock); /* disable, internal clock source */ davinci_writel(0, wdt_base + TCR); /* reset timer, set mode to 64-bit watchdog, and unreset */ davinci_writel(0, wdt_base + TGCR); tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET; davinci_writel(tgcr, wdt_base + TGCR); /* clear counter regs */ davinci_writel(0, wdt_base + TIM12); davinci_writel(0, wdt_base + TIM34); /* set timeout period */ timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) & 0xffffffff); davinci_writel(timer_margin, wdt_base + PRD12); timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) >> 32); davinci_writel(timer_margin, wdt_base + PRD34); /* enable run continuously */ davinci_writel(ENAMODE12_PERIODIC, wdt_base + TCR); /* Once the WDT is in pre-active state write to * TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are * write protected (except for the WDKEY field) */ /* put watchdog in pre-active state */ davinci_writel(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR); /* put watchdog in active state */ davinci_writel(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR); spin_unlock(&io_lock); } static int davinci_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(WDT_IN_USE, &wdt_status)) return -EBUSY; wdt_enable(); return nonseekable_open(inode, file); } static ssize_t davinci_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) { if (len) wdt_service(); return len; } static struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING, .identity = "DaVinci Watchdog", }; static int davinci_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int ret = -ENOTTY; switch (cmd) { case WDIOC_GETSUPPORT: ret = copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)) ? -EFAULT : 0; break; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: ret = put_user(0, (int *)arg); break; case WDIOC_GETTIMEOUT: ret = put_user(heartbeat, (int *)arg); break; case WDIOC_KEEPALIVE: wdt_service(); ret = 0; break; } return ret; } static int davinci_wdt_release(struct inode *inode, struct file *file) { wdt_service(); clear_bit(WDT_IN_USE, &wdt_status); return 0; } static const struct file_operations davinci_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = davinci_wdt_write, .ioctl = davinci_wdt_ioctl, .open = davinci_wdt_open, .release = davinci_wdt_release, }; static struct miscdevice davinci_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &davinci_wdt_fops, }; static int davinci_wdt_probe(struct platform_device *pdev) { int ret = 0, size; struct resource *res; if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) heartbeat = DEFAULT_HEARTBEAT; printk(KERN_INFO MODULE_NAME "DaVinci Watchdog Timer: heartbeat %d sec\n", heartbeat); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (res == NULL) { printk(KERN_INFO MODULE_NAME "failed to get memory region resource\n"); return -ENOENT; } size = res->end - res->start + 1; wdt_mem = request_mem_region(res->start, size, pdev->name); if (wdt_mem == NULL) { printk(KERN_INFO MODULE_NAME "failed to get memory region\n"); return -ENOENT; } wdt_base = (void __iomem *)(res->start); ret = misc_register(&davinci_wdt_miscdev); if (ret < 0) { printk(KERN_ERR MODULE_NAME "cannot register misc device\n"); release_resource(wdt_mem); kfree(wdt_mem); } else { set_bit(WDT_DEVICE_INITED, &wdt_status); } return ret; } static int davinci_wdt_remove(struct platform_device *pdev) { misc_deregister(&davinci_wdt_miscdev); if (wdt_mem) { release_resource(wdt_mem); kfree(wdt_mem); wdt_mem = NULL; } return 0; } static struct platform_driver platform_wdt_driver = { .driver = { .name = "watchdog", .owner = THIS_MODULE, }, .probe = davinci_wdt_probe, .remove = davinci_wdt_remove, }; static int __init davinci_wdt_init(void) { return platform_driver_register(&platform_wdt_driver); } static void __exit davinci_wdt_exit(void) { platform_driver_unregister(&platform_wdt_driver); } module_init(davinci_wdt_init); module_exit(davinci_wdt_exit); MODULE_AUTHOR("Texas Instruments"); MODULE_DESCRIPTION("DaVinci Watchdog Driver"); module_param(heartbeat, int, 0); MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to " __MODULE_STRING(MAX_HEARTBEAT) ", default " __MODULE_STRING(DEFAULT_HEARTBEAT)); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); MODULE_ALIAS("platform:watchdog");