Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 22 Feb 2002 05:26:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 22 Feb 2002 05:26:37 -0500 Received: from netfinity.realnet.co.sz ([196.28.7.2]:4782 "HELO netfinity.realnet.co.sz") by vger.kernel.org with SMTP id ; Fri, 22 Feb 2002 05:26:20 -0500 Date: Fri, 22 Feb 2002 12:15:13 +0200 (SAST) From: Zwane Mwaikambo X-X-Sender: zwane@netfinity.realnet.co.sz To: Linux Kernel Cc: Alan Cox , Jeff Garzik , Christer Weinigel Subject: Re: [DRIVER][RFC] SC1200 Watchdog driver Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Here's a finalised version, with the recommended changes (including probe). ISAPNP to follow shortly. Alan, regarding that race in ioctl, read/write. Wouldn't the open semaphore protect against that in this case. Otherwise irq safe spinlocks could be added to read/write. /* * National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver * (c) Copyright 2002 Zwane Mwaikambo , * All Rights Reserved. * Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively. * * 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. * * The author(s) of this software shall not be held liable for damages * of any nature resulting due to the use of this software. This * software is provided AS-IS with no warranties. * * Changelog: * 20020220 Zwane Mwaikambo Code based on datasheet, no hardware. * 20020221 Zwane Mwaikambo Cleanups as suggested by Jeff Garzik and Alan Cox. * 20020222 Zwane Mwaikambo Added probing. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #define SC1200_MODULE_VER "build 20020222" #define SC1200_MODULE_NAME "sc1200wdt" #define PFX SC1200q_MODULE_NAME ": " #define MAX_TIMEOUT 255 /* 255 minutes */ #define PMIR (io) /* Power Management Index Register */ #define PMDR (io+1) /* Power Management Data Register */ /* Data Register indexes */ #define FER1 0x00 /* Function enable register 1 */ #define FER2 0x01 /* Function enable register 2 */ #define PMC1 0x02 /* Power Management Ctrl 1 */ #define PMC2 0x03 /* Power Management Ctrl 2 */ #define PMC3 0x04 /* Power Management Ctrl 3 */ #define WDTO 0x05 /* Watchdog timeout register */ #define WDCF 0x06 /* Watchdog config register */ #define WDST 0x07 /* Watchdog status register */ /* WDO Status */ #define WDO_ENABLED 0x00 #define WDO_DISABLED 0x01 /* WDCF bitfields - which devices assert WDO */ #define KBC_IRQ 0x01 /* Keyboard Controller */ #define MSE_IRQ 0x02 /* Mouse */ #define UART1_IRQ 0x03 /* Serial0 */ #define UART2_IRQ 0x04 /* Serial1 */ /* 5 -7 are reserved */ static char banner[] __initdata = KERN_INFO PFX SC1200_MODULE_VER " timeout = %d min(s)\n"; static int timeout = 1; /* default to 1 minute (0 - 255), 0 disables it */ static int io; struct semaphore open_sem; MODULE_PARM(io, "i"); MODULE_PARM_DESC(io, "io port"); MODULE_PARM(timeout, "i"); MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1"); /* Read from Data Register */ static inline void sc1200wdt_read_data(unsigned char index, unsigned char *data) { outb_p(index, PMIR); *data = inb(PMDR); } /* Write to Data Register */ static inline void sc1200wdt_write_data(unsigned char index, unsigned char data) { outb_p(index, PMIR); outb(data, PMDR); } /* this returns the status of the WDO signal, inactive high * returns WDO_ENABLED or WDO_DISABLED */ static inline int sc1200wdt_status(void) { unsigned char ret; sc1200wdt_read_data(WDST, &ret); return (ret & 0x01); /* bits 1 - 7 are undefined */ } static int sc1200wdt_open(struct inode *inode, struct file *file) { unsigned char reg; /* allow one at a time */ if (down_trylock(&open_sem)) return -EBUSY; #ifdef CONFIG_WATCHDOG_NOWAYOUT MOD_INC_USE_COUNT; #endif if (timeout > MAX_TIMEOUT) timeout = MAX_TIMEOUT; sc1200wdt_read_data(WDCF, ®); /* assert WDO when any of the following interrupts are triggered too */ reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ); sc1200wdt_write_data(WDCF, reg); /* set the timeout and get the ball rolling */ sc1200wdt_write_data(WDTO, timeout); printk(KERN_INFO PFX "Watchdog enabled"); return 0; } static int sc1200wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int new_timeout; static struct watchdog_info ident = { options: WDIOF_SETTIMEOUT, firmware_version: 0, identity: "PC87307/PC97307" }; switch (cmd) { default: return -ENOTTY; /* Keep Pavel Machek amused ;) */ case WDIOC_GETSUPPORT: if (copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))) return -EFAULT; return 0; case WDIOC_GETSTATUS: return put_user(sc1200wdt_status(), (int *)arg); case WDIOC_KEEPALIVE: sc1200wdt_write_data(WDTO, timeout); return 0; case WDIOC_SETTIMEOUT: if (get_user(new_timeout, (int *)arg)) return -EFAULT; /* the API states this is given in secs */ new_timeout /= 60; if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) return -EINVAL; timeout = new_timeout; sc1200wdt_write_data(WDTO, timeout); /* fall through and return the new timeout */ case WDIOC_GETTIMEOUT: return put_user(timeout * 60, (int *)arg); } } static int sc1200wdt_release(struct inode *inode, struct file *file) { #ifndef CONFIG_WATCHDOG_NOWAYOUT /* Disable it on the way out */ sc1200wdt_write_data(WDTO, 0); printk(KERN_INFO PFX "Watchdog disabled\n"); #endif up(&open_sem); return 0; } static ssize_t sc1200wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) { if (ppos != &file->f_pos) return -ESPIPE; if (len) { sc1200wdt_write_data(WDTO, timeout); return 1; } return 0; } static int sc1200wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) sc1200wdt_write_data(WDTO, 0); return NOTIFY_DONE; } static struct notifier_block sc1200wdt_notifier = { notifier_call: sc1200wdt_notify_sys, notifier_block: NULL, priority: 0 }; #ifndef MODULE static int __init sc1200wdt_setup(char *str) { int ints[4]; str = get_options (str, ARRAY_SIZE(ints), ints); if (ints[0] > 0) { io = ints[1]; if (ints[0] > 1) timeout = ints[2]; } return 1; } __setup("sc1200wdt=", sc1200wdt_setup); #endif /* MODULE */ static struct file_operations sc1200wdt_fops = { owner: THIS_MODULE, write: sc1200wdt_write, ioctl: sc1200wdt_ioctl, open: sc1200wdt_open, release: sc1200wdt_release, }; static struct miscdevice sc1200wdt_miscdev = { minor: WATCHDOG_MINOR, name: "watchdog", fops: &sc1200wdt_fops, }; static int __init sc1200wdt_probe(void) { /* The probe works by reading the PMC3 register's default value of 0x0e * there is one caveat, if the device disables the parallel port or any * of the UARTs we won't be able to detect it. * Nb. This could be done with accuracy by reading the SID registers, but * we don't have access to those io regions. */ unsigned char reg; sc1200wdt_read_data(PMC3, ®); reg &= 0x0f; /* we don't want the UART busy bits */ return (reg == 0x0e) ? 0 : -ENODEV; } static int __init sc1200wdt_init(void) { int ret; printk(banner, timeout); if (!request_region(io, 2, SC1200_MODULE_NAME)) { printk(KERN_ERR PFX "IO port %#x not free.\n", io); ret = -EBUSY; goto out_clean; } ret = sc1200wdt_probe(); if (ret == -ENODEV) goto out_io; ret = register_reboot_notifier(&sc1200wdt_notifier); if (ret) { printk(KERN_ERR PFX "Unable to register reboot notifier err = %d\n", ret); goto out_io; } sema_init(&open_sem, 1); ret = misc_register(&sc1200wdt_miscdev); if (ret) { printk(KERN_ERR PFX "Unable to register miscdev on minor %d\n", WATCHDOG_MINOR); goto out_rbt; } out_clean: return ret; out_rbt: unregister_reboot_notifier(&sc1200wdt_notifier); out_io: release_region(io, 2); goto out_clean; } static void __exit sc1200wdt_exit(void) { misc_deregister(&sc1200wdt_miscdev); unregister_reboot_notifier(&sc1200wdt_notifier); release_region(io, 2); } module_init(sc1200wdt_init); module_exit(sc1200wdt_exit); MODULE_AUTHOR("Zwane Mwaikambo "); MODULE_DESCRIPTION("Driver for National Semiconductor PC87307/PC97307 watchdog component"); MODULE_LICENSE("GPL"); EXPORT_NO_SYMBOLS; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/