From 16366feafb3e5df1878d2651ab8bffbec2cca7bc Mon Sep 17 00:00:00 2001 From: Gabor Juhos Date: Wed, 26 Jan 2011 20:48:41 +0000 Subject: ramips: add watchdog driver SVN-Revision: 25126 --- .../ramips/files/drivers/watchdog/ramips_wdt.c | 355 +++++++++++++++++++++ 1 file changed, 355 insertions(+) create mode 100644 target/linux/ramips/files/drivers/watchdog/ramips_wdt.c (limited to 'target/linux/ramips/files/drivers') diff --git a/target/linux/ramips/files/drivers/watchdog/ramips_wdt.c b/target/linux/ramips/files/drivers/watchdog/ramips_wdt.c new file mode 100644 index 0000000000..a0b56c8cb1 --- /dev/null +++ b/target/linux/ramips/files/drivers/watchdog/ramips_wdt.c @@ -0,0 +1,355 @@ +/* + * Ralink RT288X/RT305X built-in hardware watchdog timer + * + * Copyright (C) 2011 Gabor Juhos + * + * This driver was based on: drivers/watchdog/ixp4xx_wdt.c + * Author: Deepak Saxena + * Copyright 2004 (c) MontaVista, Software, Inc. + * + * which again was based on sa1100 driver, + * Copyright (C) 2000 Oleg Drokin + * + * parts of the driver are based on Ralink's 2.6.21 BSP + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define DRIVER_NAME "ramips-wdt" + +#define RAMIPS_WDT_TIMEOUT 20 /* seconds */ +#define RAMIPS_WDT_PRESCALE 65536 + +#define TIMER_REG_TMRSTAT 0x00 +#define TIMER_REG_TMR1LOAD 0x20 +#define TIMER_REG_TMR1CTL 0x28 + +#define TMRSTAT_TMR1RST BIT(5) + +#define TMR1CTL_ENABLE BIT(7) +#define TMR1CTL_MODE_SHIFT 4 +#define TMR1CTL_MODE_MASK 0x3 +#define TMR1CTL_MODE_FREE_RUNNING 0x0 +#define TMR1CTL_MODE_PERIODIC 0x1 +#define TMR1CTL_MODE_TIMEOUT 0x2 +#define TMR1CTL_MODE_WDT 0x3 +#define TMR1CTL_PRESCALE_MASK 0xf +#define TMR1CTL_PRESCALE_65536 0xf + +static int nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " + "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +static int ramips_wdt_timeout = RAMIPS_WDT_TIMEOUT; +module_param_named(timeout, ramips_wdt_timeout, int, 0); +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds " + "(default=" __MODULE_STRING(RAMIPS_WDT_TIMEOUT) "s)"); + +static unsigned long ramips_wdt_flags; + +#define WDT_FLAGS_BUSY 0 +#define WDT_FLAGS_EXPECT_CLOSE 1 + +static struct clk *ramips_wdt_clk; +static unsigned long ramips_wdt_freq; +static int ramips_wdt_max_timeout; +static void __iomem *ramips_wdt_base; + +static inline void ramips_wdt_wr(unsigned reg, u32 val) +{ + __raw_writel(val, ramips_wdt_base + reg); +} + +static inline u32 ramips_wdt_rr(unsigned reg) +{ + return __raw_readl(ramips_wdt_base + reg); +} + +static inline void ramips_wdt_keepalive(void) +{ + ramips_wdt_wr(TIMER_REG_TMR1LOAD, ramips_wdt_timeout * ramips_wdt_freq); +} + +static inline void ramips_wdt_enable(void) +{ + u32 t; + + ramips_wdt_keepalive(); + + t = ramips_wdt_rr(TIMER_REG_TMR1CTL); + t |= TMR1CTL_ENABLE; + ramips_wdt_wr(TIMER_REG_TMR1CTL, t); +} + +static inline void ramips_wdt_disable(void) +{ + u32 t; + + ramips_wdt_keepalive(); + + t = ramips_wdt_rr(TIMER_REG_TMR1CTL); + t &= ~TMR1CTL_ENABLE; + ramips_wdt_wr(TIMER_REG_TMR1CTL, t); +} + +static int ramips_wdt_set_timeout(int val) +{ + if (val < 1 || val > ramips_wdt_max_timeout) { + pr_crit(DRIVER_NAME + ": timeout value %d must be 0 < timeout < %d\n", + val, ramips_wdt_max_timeout); + return -EINVAL; + } + + ramips_wdt_timeout = val; + ramips_wdt_keepalive(); + + return 0; +} + +static int ramips_wdt_open(struct inode *inode, struct file *file) +{ + u32 t; + + if (test_and_set_bit(WDT_FLAGS_BUSY, &ramips_wdt_flags)) + return -EBUSY; + + clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags); + + t = ramips_wdt_rr(TIMER_REG_TMR1CTL); + t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT | + TMR1CTL_PRESCALE_MASK); + t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT | + TMR1CTL_PRESCALE_65536); + ramips_wdt_wr(TIMER_REG_TMR1CTL, t); + + ramips_wdt_enable(); + + return nonseekable_open(inode, file); +} + +static int ramips_wdt_release(struct inode *inode, struct file *file) +{ + if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags)) + ramips_wdt_disable(); + else { + pr_crit(DRIVER_NAME ": device closed unexpectedly, " + "watchdog timer will not stop!\n"); + ramips_wdt_keepalive(); + } + + clear_bit(WDT_FLAGS_BUSY, &ramips_wdt_flags); + clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags); + + return 0; +} + +static ssize_t ramips_wdt_write(struct file *file, const char *data, + size_t len, loff_t *ppos) +{ + if (len) { + if (!nowayout) { + size_t i; + + clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags); + + for (i = 0; i != len; i++) { + char c; + + if (get_user(c, data + i)) + return -EFAULT; + + if (c == 'V') + set_bit(WDT_FLAGS_EXPECT_CLOSE, + &ramips_wdt_flags); + } + } + + ramips_wdt_keepalive(); + } + + return len; +} + +static const struct watchdog_info ramips_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE, + .firmware_version = 0, + .identity = "RAMIPS watchdog", +}; + +static long ramips_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + int err; + int t; + + switch (cmd) { + case WDIOC_GETSUPPORT: + err = copy_to_user(argp, &ramips_wdt_info, + sizeof(ramips_wdt_info)) ? -EFAULT : 0; + break; + + case WDIOC_GETSTATUS: + err = put_user(0, p); + break; + + case WDIOC_KEEPALIVE: + ramips_wdt_keepalive(); + err = 0; + break; + + case WDIOC_SETTIMEOUT: + err = get_user(t, p); + if (err) + break; + + err = ramips_wdt_set_timeout(t); + if (err) + break; + + /* fallthrough */ + case WDIOC_GETTIMEOUT: + err = put_user(ramips_wdt_timeout, p); + break; + + default: + err = -ENOTTY; + break; + } + + return err; +} + +static const struct file_operations ramips_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = ramips_wdt_write, + .unlocked_ioctl = ramips_wdt_ioctl, + .open = ramips_wdt_open, + .release = ramips_wdt_release, +}; + +static struct miscdevice ramips_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &ramips_wdt_fops, +}; + +static int __devinit ramips_wdt_probe(struct platform_device *pdev) +{ + struct resource *res; + int err; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "no memory resource found\n"); + return -EINVAL; + } + + ramips_wdt_base = ioremap(res->start, resource_size(res)); + if (!ramips_wdt_base) + return -ENOMEM; + + ramips_wdt_clk = clk_get(&pdev->dev, "wdt"); + if (IS_ERR(ramips_wdt_clk)) { + err = PTR_ERR(ramips_wdt_clk); + goto err_unmap; + } + + err = clk_enable(ramips_wdt_clk); + if (err) + goto err_clk_put; + + ramips_wdt_freq = clk_get_rate(ramips_wdt_clk) / RAMIPS_WDT_PRESCALE; + if (!ramips_wdt_freq) { + err = -EINVAL; + goto err_clk_disable; + } + + ramips_wdt_max_timeout = (0xfffful / ramips_wdt_freq); + if (ramips_wdt_timeout < 1 || + ramips_wdt_timeout > ramips_wdt_max_timeout) { + ramips_wdt_timeout = ramips_wdt_max_timeout; + dev_info(&pdev->dev, + "timeout value must be 0 < timeout < %d, using %d\n", + ramips_wdt_max_timeout, ramips_wdt_timeout); + } + + err = misc_register(&ramips_wdt_miscdev); + if (err) { + dev_err(&pdev->dev, + "unable to register misc device, err=%d\n", err); + goto err_clk_disable; + } + + return 0; + +err_clk_disable: + clk_disable(ramips_wdt_clk); +err_clk_put: + clk_put(ramips_wdt_clk); +err_unmap: + iounmap(ramips_wdt_base); + return err; +} + +static int __devexit ramips_wdt_remove(struct platform_device *pdev) +{ + misc_deregister(&ramips_wdt_miscdev); + clk_disable(ramips_wdt_clk); + clk_put(ramips_wdt_clk); + iounmap(ramips_wdt_base); + return 0; +} + +static void ramips_wdt_shutdown(struct platform_device *pdev) +{ + ramips_wdt_disable(); +} + +static struct platform_driver ramips_wdt_driver = { + .remove = __devexit_p(ramips_wdt_remove), + .shutdown = ramips_wdt_shutdown, + .driver = { + .name = DRIVER_NAME, + .owner = THIS_MODULE, + }, +}; + +static int __init ramips_wdt_init(void) +{ + return platform_driver_probe(&ramips_wdt_driver, ramips_wdt_probe); +} +module_init(ramips_wdt_init); + +static void __exit ramips_wdt_exit(void) +{ + platform_driver_unregister(&ramips_wdt_driver); +} +module_exit(ramips_wdt_exit); + +MODULE_DESCRIPTION("Ralink RT288X/RT305X hardware watchdog driver"); +MODULE_AUTHOR("Gabor Juhos