/* * linux/drivers/char/watchdog/omap_wdt.c * * Watchdog driver for the TI OMAP 16xx & 24xx 32KHz (non-secure) watchdog * * Author: MontaVista Software, Inc. * <gdavis@mvista.com> or <source@mvista.com> * * 2003 (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. * * History: * * 20030527: George G. Davis <gdavis@mvista.com> * Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> * Based on SoftDog driver by Alan Cox <alan@redhat.com> * * Copyright (c) 2004 Texas Instruments. * 1. Modified to support OMAP1610 32-KHz watchdog timer * 2. Ported to 2.6 kernel * * Copyright (c) 2005 David Brownell * Use the driver model and standard identifiers; handle bigger timeouts. */ #include <linux/module.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/reboot.h> #include <linux/init.h> #include <linux/err.h> #include <linux/platform_device.h> #include <linux/moduleparam.h> #include <linux/clk.h> #include <linux/bitops.h> #include <asm/io.h> #include <asm/uaccess.h> #include <asm/hardware.h> #include <asm/arch/prcm.h> #include "omap_wdt.h" static unsigned timer_margin; module_param(timer_margin, uint, 0); MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)"); static int omap_wdt_users; static struct clk *armwdt_ck = NULL; static struct clk *mpu_wdt_ick = NULL; static struct clk *mpu_wdt_fck = NULL; static unsigned int wdt_trgr_pattern = 0x1234; static void omap_wdt_ping(void) { /* wait for posted write to complete */ while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08) cpu_relax(); wdt_trgr_pattern = ~wdt_trgr_pattern; omap_writel(wdt_trgr_pattern, (OMAP_WATCHDOG_TGR)); /* wait for posted write to complete */ while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08) cpu_relax(); /* reloaded WCRR from WLDR */ } static void omap_wdt_enable(void) { /* Sequence to enable the watchdog */ omap_writel(0xBBBB, OMAP_WATCHDOG_SPR); while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10) cpu_relax(); omap_writel(0x4444, OMAP_WATCHDOG_SPR); while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10) cpu_relax(); } static void omap_wdt_disable(void) { /* sequence required to disable watchdog */ omap_writel(0xAAAA, OMAP_WATCHDOG_SPR); /* TIMER_MODE */ while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10) cpu_relax(); omap_writel(0x5555, OMAP_WATCHDOG_SPR); /* TIMER_MODE */ while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10) cpu_relax(); } static void omap_wdt_adjust_timeout(unsigned new_timeout) { if (new_timeout < TIMER_MARGIN_MIN) new_timeout = TIMER_MARGIN_DEFAULT; if (new_timeout > TIMER_MARGIN_MAX) new_timeout = TIMER_MARGIN_MAX; timer_margin = new_timeout; } static void omap_wdt_set_timeout(void) { u32 pre_margin = GET_WLDR_VAL(timer_margin); /* just count up at 32 KHz */ while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04) cpu_relax(); omap_writel(pre_margin, OMAP_WATCHDOG_LDR); while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04) cpu_relax(); } /* * Allow only one task to hold it open */ static int omap_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(1, (unsigned long *)&omap_wdt_users)) return -EBUSY; if (cpu_is_omap16xx()) clk_enable(armwdt_ck); /* Enable the clock */ if (cpu_is_omap24xx()) { clk_enable(mpu_wdt_ick); /* Enable the interface clock */ clk_enable(mpu_wdt_fck); /* Enable the functional clock */ } /* initialize prescaler */ while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01) cpu_relax(); omap_writel((1 << 5) | (PTV << 2), OMAP_WATCHDOG_CNTRL); while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01) cpu_relax(); omap_wdt_set_timeout(); omap_wdt_enable(); return nonseekable_open(inode, file); } static int omap_wdt_release(struct inode *inode, struct file *file) { /* * Shut off the timer unless NOWAYOUT is defined. */ #ifndef CONFIG_WATCHDOG_NOWAYOUT omap_wdt_disable(); if (cpu_is_omap16xx()) { clk_disable(armwdt_ck); /* Disable the clock */ clk_put(armwdt_ck); armwdt_ck = NULL; } if (cpu_is_omap24xx()) { clk_disable(mpu_wdt_ick); /* Disable the clock */ clk_disable(mpu_wdt_fck); /* Disable the clock */ clk_put(mpu_wdt_ick); clk_put(mpu_wdt_fck); mpu_wdt_ick = NULL; mpu_wdt_fck = NULL; } #else printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n"); #endif omap_wdt_users = 0; return 0; } static ssize_t omap_wdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { /* Refresh LOAD_TIME. */ if (len) omap_wdt_ping(); return len; } static int omap_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int new_margin; static struct watchdog_info ident = { .identity = "OMAP Watchdog", .options = WDIOF_SETTIMEOUT, .firmware_version = 0, }; switch (cmd) { default: return -ENOTTY; case WDIOC_GETSUPPORT: return copy_to_user((struct watchdog_info __user *)arg, &ident, sizeof(ident)); case WDIOC_GETSTATUS: return put_user(0, (int __user *)arg); case WDIOC_GETBOOTSTATUS: if (cpu_is_omap16xx()) return put_user(omap_readw(ARM_SYSST), (int __user *)arg); if (cpu_is_omap24xx()) return put_user(omap_prcm_get_reset_sources(), (int __user *)arg); case WDIOC_KEEPALIVE: omap_wdt_ping(); return 0; case WDIOC_SETTIMEOUT: if (get_user(new_margin, (int __user *)arg)) return -EFAULT; omap_wdt_adjust_timeout(new_margin); omap_wdt_disable(); omap_wdt_set_timeout(); omap_wdt_enable(); omap_wdt_ping(); /* Fall */ case WDIOC_GETTIMEOUT: return put_user(timer_margin, (int __user *)arg); } } static const struct file_operations omap_wdt_fops = { .owner = THIS_MODULE, .write = omap_wdt_write, .ioctl = omap_wdt_ioctl, .open = omap_wdt_open, .release = omap_wdt_release, }; static struct miscdevice omap_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &omap_wdt_fops }; static int __init omap_wdt_probe(struct platform_device *pdev) { struct resource *res, *mem; int ret; /* reserve static register mappings */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) return -ENOENT; mem = request_mem_region(res->start, res->end - res->start + 1, pdev->name); if (mem == NULL) return -EBUSY; platform_set_drvdata(pdev, mem); omap_wdt_users = 0; if (cpu_is_omap16xx()) { armwdt_ck = clk_get(&pdev->dev, "armwdt_ck"); if (IS_ERR(armwdt_ck)) { ret = PTR_ERR(armwdt_ck); armwdt_ck = NULL; goto fail; } } if (cpu_is_omap24xx()) { mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick"); if (IS_ERR(mpu_wdt_ick)) { ret = PTR_ERR(mpu_wdt_ick); mpu_wdt_ick = NULL; goto fail; } mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck"); if (IS_ERR(mpu_wdt_fck)) { ret = PTR_ERR(mpu_wdt_fck); mpu_wdt_fck = NULL; goto fail; } } omap_wdt_disable(); omap_wdt_adjust_timeout(timer_margin); omap_wdt_miscdev.parent = &pdev->dev; ret = misc_register(&omap_wdt_miscdev); if (ret) goto fail; pr_info("OMAP Watchdog Timer: initial timeout %d sec\n", timer_margin); /* autogate OCP interface clock */ omap_writel(0x01, OMAP_WATCHDOG_SYS_CONFIG); return 0; fail: if (armwdt_ck) clk_put(armwdt_ck); if (mpu_wdt_ick) clk_put(mpu_wdt_ick); if (mpu_wdt_fck) clk_put(mpu_wdt_fck); release_resource(mem); return ret; } static void omap_wdt_shutdown(struct platform_device *pdev) { omap_wdt_disable(); } static int omap_wdt_remove(struct platform_device *pdev) { struct resource *mem = platform_get_drvdata(pdev); misc_deregister(&omap_wdt_miscdev); release_resource(mem); if (armwdt_ck) clk_put(armwdt_ck); if (mpu_wdt_ick) clk_put(mpu_wdt_ick); if (mpu_wdt_fck) clk_put(mpu_wdt_fck); return 0; } #ifdef CONFIG_PM /* REVISIT ... not clear this is the best way to handle system suspend; and * it's very inappropriate for selective device suspend (e.g. suspending this * through sysfs rather than by stopping the watchdog daemon). Also, this * may not play well enough with NOWAYOUT... */ static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state) { if (omap_wdt_users) omap_wdt_disable(); return 0; } static int omap_wdt_resume(struct platform_device *pdev) { if (omap_wdt_users) { omap_wdt_enable(); omap_wdt_ping(); } return 0; } #else #define omap_wdt_suspend NULL #define omap_wdt_resume NULL #endif static struct platform_driver omap_wdt_driver = { .probe = omap_wdt_probe, .remove = omap_wdt_remove, .shutdown = omap_wdt_shutdown, .suspend = omap_wdt_suspend, .resume = omap_wdt_resume, .driver = { .owner = THIS_MODULE, .name = "omap_wdt", }, }; static int __init omap_wdt_init(void) { return platform_driver_register(&omap_wdt_driver); } static void __exit omap_wdt_exit(void) { platform_driver_unregister(&omap_wdt_driver); } module_init(omap_wdt_init); module_exit(omap_wdt_exit); MODULE_AUTHOR("George G. Davis"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); MODULE_ALIAS("platform:omap_wdt");