[WATCHDOG] Winbond SMsC37B787 watchdog driver

New watchdog driver for the Winbond SMsC37B787 chipset.
 
Signed-off-by: Sven Anders <anders@anduras.de>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 614 insertions, 0 deletions

diff --git a/drivers/char/watchdog/smsc37b787_wdt.c b/drivers/char/watchdog/smsc37b787_wdt.c
new file mode 100644
index 000000000000..47141c0b6f25
--- /dev/null
+++ b/drivers/char/watchdog/smsc37b787_wdt.c
@@ -0,0 +1,614 @@
+/*
+ *      SMsC 37B787 Watchdog Timer driver for Linux 2.6.x.x
+ *
+ *      Based on acquirewdt.c by Alan Cox <alan@redhat.com>
+ *       and some other existing drivers
+ *
+ *      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 authors do NOT admit liability nor provide warranty for
+ *      any of this software. This material is provided "AS-IS" in
+ *      the hope that it may be useful for others.
+ *
+ *      (C) Copyright 2003-2006  Sven Anders <anders@anduras.de>
+ *
+ *  History:
+ *      2003 - Created version 1.0 for Linux 2.4.x.
+ *      2006 - Ported to Linux 2.6, added nowayout and MAGICCLOSE
+ *             features. Released version 1.1
+ *
+ *  Theory of operation:
+ *
+ *      A Watchdog Timer (WDT) is a hardware circuit that can
+ *      reset the computer system in case of a software fault.
+ *      You probably knew that already.
+ *
+ *      Usually a userspace daemon will notify the kernel WDT driver
+ *      via the /dev/watchdog special device file that userspace is
+ *      still alive, at regular intervals.  When such a notification
+ *      occurs, the driver will usually tell the hardware watchdog
+ *      that everything is in order, and that the watchdog should wait
+ *      for yet another little while to reset the system.
+ *      If userspace fails (RAM error, kernel bug, whatever), the
+ *      notifications cease to occur, and the hardware watchdog will
+ *      reset the system (causing a reboot) after the timeout occurs.
+ *
+ * Create device with:
+ *  mknod /dev/watchdog c 10 130
+ *
+ * For an example userspace keep-alive daemon, see:
+ *   Documentation/watchdog/watchdog.txt
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/ioport.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+/* enable support for minutes as units? */
+/* (does not always work correctly, so disabled by default!) */
+#define SMSC_SUPPORT_MINUTES
+#undef SMSC_SUPPORT_MINUTES
+
+#define MAX_TIMEOUT     255
+
+#define UNIT_SECOND     0
+#define UNIT_MINUTE     1
+
+#define MODNAME         "smsc37b787_wdt: "
+#define VERSION         "1.1"
+
+#define WATCHDOG_MINOR  130
+
+#define IOPORT          0x3F0
+#define IOPORT_SIZE     2
+#define IODEV_NO        8
+
+static int unit = UNIT_SECOND;  /* timer's unit */
+static int timeout = 60;        /* timeout value: default is 60 "units" */
+static int timer_enabled = 0;   /* is the timer enabled? */
+
+static char expect_close;       /* is the close expected? */
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+
+/* -- Low level function ----------------------------------------*/
+
+/* unlock the IO chip */
+
+static inline void open_io_config(void)
+{
+        outb(0x55, IOPORT);
+        mdelay(1);
+        outb(0x55, IOPORT);
+}
+
+/* lock the IO chip */
+static inline void close_io_config(void)
+{
+        outb(0xAA, IOPORT);
+}
+
+/* select the IO device */
+static inline void select_io_device(unsigned char devno)
+{
+        outb(0x07, IOPORT);
+        outb(devno, IOPORT+1);
+}
+
+/* write to the control register */
+static inline void write_io_cr(unsigned char reg, unsigned char data)
+{
+        outb(reg, IOPORT);
+        outb(data, IOPORT+1);
+}
+
+/* read from the control register */
+static inline char read_io_cr(unsigned char reg)
+{
+        outb(reg, IOPORT);
+        return inb(IOPORT+1);
+}
+
+/* -- Medium level functions ------------------------------------*/
+
+static inline void gpio_bit12(unsigned char reg)
+{
+        // -- General Purpose I/O Bit 1.2 --
+        // Bit 0,   In/Out: 0 = Output, 1 = Input
+        // Bit 1,   Polarity: 0 = No Invert, 1 = Invert
+        // Bit 2,   Group Enable Intr.: 0 = Disable, 1 = Enable
+        // Bit 3/4, Function select: 00 = GPI/O, 01 = WDT, 10 = P17,
+        //                           11 = Either Edge Triggered Intr. 2
+        // Bit 5/6  (Reserved)
+        // Bit 7,   Output Type: 0 = Push Pull Bit, 1 = Open Drain
+        write_io_cr(0xE2, reg);
+}
+
+static inline void gpio_bit13(unsigned char reg)
+{
+        // -- General Purpose I/O Bit 1.3 --
+        // Bit 0,  In/Out: 0 = Output, 1 = Input
+        // Bit 1,  Polarity: 0 = No Invert, 1 = Invert
+        // Bit 2,  Group Enable Intr.: 0 = Disable, 1 = Enable
+        // Bit 3,  Function select: 0 = GPI/O, 1 = LED
+        // Bit 4-6 (Reserved)
+        // Bit 7,  Output Type: 0 = Push Pull Bit, 1 = Open Drain
+        write_io_cr(0xE3, reg);
+}
+
+static inline void wdt_timer_units(unsigned char new_units)
+{
+        // -- Watchdog timer units --
+        // Bit 0-6 (Reserved)
+        // Bit 7,  WDT Time-out Value Units Select
+        //         (0 = Minutes, 1 = Seconds)
+        write_io_cr(0xF1, new_units);
+}
+
+static inline void wdt_timeout_value(unsigned char new_timeout)
+{
+        // -- Watchdog Timer Time-out Value --
+        // Bit 0-7 Binary coded units (0=Disabled, 1..255)
+        write_io_cr(0xF2, new_timeout);
+}
+
+static inline void wdt_timer_conf(unsigned char conf)
+{
+        // -- Watchdog timer configuration --
+        // Bit 0   Joystick enable: 0* = No Reset, 1 = Reset WDT upon Gameport I/O
+        // Bit 1   Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
+        // Bit 2   Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr.
+        // Bit 3   Reset the timer
+        //         (Wrong in SMsC documentation? Given as: PowerLED Timout Enabled)
+        // Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
+        //            0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
+        write_io_cr(0xF3, conf);
+}
+
+static inline void wdt_timer_ctrl(unsigned char reg)
+{
+        // -- Watchdog timer control --
+        // Bit 0   Status Bit: 0 = Timer counting, 1 = Timeout occured
+        // Bit 1   Power LED Toggle: 0 = Disable Toggle, 1 = Toggle at 1 Hz
+        // Bit 2   Force Timeout: 1 = Forces WD timeout event (self-cleaning)
+        // Bit 3   P20 Force Timeout enabled:
+        //          0 = P20 activity does not generate the WD timeout event
+        //          1 = P20 Allows rising edge of P20, from the keyboard
+        //              controller, to force the WD timeout event.
+        // Bit 4   (Reserved)
+        // -- Soft power management --
+        // Bit 5   Stop Counter: 1 = Stop software power down counter
+        //            set via register 0xB8, (self-cleaning)
+        //            (Upon read: 0 = Counter running, 1 = Counter stopped)
+        // Bit 6   Restart Counter: 1 = Restart software power down counter
+        //            set via register 0xB8, (self-cleaning)
+        // Bit 7   SPOFF: 1 = Force software power down (self-cleaning)
+
+        write_io_cr(0xF4, reg);
+}
+
+/* -- Higher level functions ------------------------------------*/
+
+/* initialize watchdog */
+
+static void wb_smsc_wdt_initialize(void)
+{
+        unsigned char old;
+
+        open_io_config();
+        select_io_device(IODEV_NO);
+
+        // enable the watchdog
+        gpio_bit13(0x08);  // Select pin 80 = LED not GPIO
+        gpio_bit12(0x0A);  // Set pin 79 = WDT not GPIO/Output/Polarity=Invert
+
+        // disable the timeout
+        wdt_timeout_value(0);
+
+        // reset control register
+        wdt_timer_ctrl(0x00);
+
+        // reset configuration register
+        wdt_timer_conf(0x00);
+
+        // read old (timer units) register
+        old = read_io_cr(0xF1) & 0x7F;
+        if (unit == UNIT_SECOND) old |= 0x80; // set to seconds
+
+        // set the watchdog timer units
+        wdt_timer_units(old);
+
+        close_io_config();
+}
+
+/* shutdown the watchdog */
+
+static void wb_smsc_wdt_shutdown(void)
+{
+        open_io_config();
+        select_io_device(IODEV_NO);
+
+        // disable the watchdog
+        gpio_bit13(0x09);
+        gpio_bit12(0x09);
+
+        // reset watchdog config register
+        wdt_timer_conf(0x00);
+
+        // reset watchdog control register
+        wdt_timer_ctrl(0x00);
+
+        // disable timeout
+        wdt_timeout_value(0x00);
+
+        close_io_config();
+}
+
+/* set timeout => enable watchdog */
+
+static void wb_smsc_wdt_set_timeout(unsigned char new_timeout)
+{
+        open_io_config();
+        select_io_device(IODEV_NO);
+
+        // set Power LED to blink, if we enable the timeout
+        wdt_timer_ctrl((new_timeout == 0) ? 0x00 : 0x02);
+
+        // set timeout value
+        wdt_timeout_value(new_timeout);
+
+        close_io_config();
+}
+
+/* get timeout */
+
+static unsigned char wb_smsc_wdt_get_timeout(void)
+{
+        unsigned char set_timeout;
+
+        open_io_config();
+        select_io_device(IODEV_NO);
+        set_timeout = read_io_cr(0xF2);
+        close_io_config();
+
+        return set_timeout;
+}
+
+/* disable watchdog */
+
+static void wb_smsc_wdt_disable(void)
+{
+        // set the timeout to 0 to disable the watchdog
+        wb_smsc_wdt_set_timeout(0);
+}
+
+/* enable watchdog by setting the current timeout */
+
+static void wb_smsc_wdt_enable(void)
+{
+        // set the current timeout...
+        wb_smsc_wdt_set_timeout(timeout);
+}
+
+/* reset the timer */
+
+static void wb_smsc_wdt_reset_timer(void)
+{
+        open_io_config();
+        select_io_device(IODEV_NO);
+
+        // reset the timer
+        wdt_timeout_value(timeout);
+        wdt_timer_conf(0x08);
+
+        close_io_config();
+}
+
+/* return, if the watchdog is enabled (timeout is set...) */
+
+static int wb_smsc_wdt_status(void)
+{
+        return (wb_smsc_wdt_get_timeout() == 0) ? 0 : WDIOF_KEEPALIVEPING;
+}
+
+
+/* -- File operations -------------------------------------------*/
+
+/* open => enable watchdog and set initial timeout */
+
+static int wb_smsc_wdt_open(struct inode *inode, struct file *file)
+{
+        /* /dev/watchdog can only be opened once */
+
+        if (timer_enabled)
+                return -EBUSY;
+
+        if (nowayout)
+                __module_get(THIS_MODULE);
+
+        /* Reload and activate timer */
+        timer_enabled = 1;
+        wb_smsc_wdt_enable();
+
+        printk(KERN_INFO MODNAME "Watchdog enabled. Timeout set to %d %s.\n", timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
+
+        return nonseekable_open(inode, file);
+}
+
+/* close => shut off the timer */
+
+static int wb_smsc_wdt_release(struct inode *inode, struct file *file)
+{
+        /* Shut off the timer. */
+
+        if (expect_close == 42) {
+                wb_smsc_wdt_disable();
+                printk(KERN_INFO MODNAME "Watchdog disabled, sleeping again...\n");
+        } else {
+                printk(KERN_CRIT MODNAME "Unexpected close, not stopping watchdog!\n");
+                wb_smsc_wdt_reset_timer();
+        }
+
+        timer_enabled = 0;
+        expect_close = 0;
+        return 0;
+}
+
+/* write => update the timer to keep the machine alive */
+
+static ssize_t wb_smsc_wdt_write(struct file *file, const char __user *data,
+                                 size_t len, loff_t *ppos)
+{
+        /* See if we got the magic character 'V' and reload the timer */
+        if (len) {
+                if (!nowayout) {
+                        size_t i;
+
+                        /* reset expect flag */
+                        expect_close = 0;
+
+                        /* scan to see whether or not we got the magic character */
+                        for (i = 0; i != len; i++) {
+                                char c;
+                                if (get_user(c, data+i))
+                                        return -EFAULT;
+                                if (c == 'V')
+                                        expect_close = 42;
+                        }
+                }
+
+                /* someone wrote to us, we should reload the timer */
+                wb_smsc_wdt_reset_timer();
+        }
+        return len;
+}
+
+/* ioctl => control interface */
+
+static int wb_smsc_wdt_ioctl(struct inode *inode, struct file *file,
+                             unsigned int cmd, unsigned long arg)
+{
+        int new_timeout;
+
+        union {
+                struct watchdog_info __user *ident;
+                int __user *i;
+        } uarg;
+
+        static struct watchdog_info ident = {
+                .options =              WDIOF_KEEPALIVEPING |
+                                        WDIOF_SETTIMEOUT |
+                                        WDIOF_MAGICCLOSE,
+                .firmware_version =     0,
+                .identity =             "SMsC 37B787 Watchdog"
+        };
+
+        uarg.i = (int __user *)arg;
+
+        switch (cmd) {
+                default:
+                        return -ENOTTY; 
+
+                case WDIOC_GETSUPPORT:
+                        return copy_to_user(uarg.ident, &ident, sizeof(ident));
+
+                case WDIOC_GETSTATUS:
+                        return put_user(wb_smsc_wdt_status(), uarg.i);
+
+                case WDIOC_GETBOOTSTATUS:
+                        return put_user(0, uarg.i);
+
+                case WDIOC_KEEPALIVE:
+                        wb_smsc_wdt_reset_timer();
+                        return 0;
+
+                case WDIOC_SETTIMEOUT:
+                        if (get_user(new_timeout, uarg.i))
+                                return -EFAULT;
+
+                        // the API states this is given in secs
+                        if (unit == UNIT_MINUTE)
+                          new_timeout /= 60;
+
+                        if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
+                                return -EINVAL;
+
+                        timeout = new_timeout;
+                        wb_smsc_wdt_set_timeout(timeout);
+
+                        // fall through and return the new timeout...
+
+                case WDIOC_GETTIMEOUT:
+
+                        new_timeout = timeout;
+
+                        if (unit == UNIT_MINUTE)
+                          new_timeout *= 60;
+
+                        return put_user(new_timeout, uarg.i);
+
+                case WDIOC_SETOPTIONS:
+                {
+                        int options, retval = -EINVAL;
+
+                        if (get_user(options, uarg.i))
+                                return -EFAULT;
+
+                        if (options & WDIOS_DISABLECARD) {
+                                wb_smsc_wdt_disable();
+                                retval = 0;
+                        }
+
+                        if (options & WDIOS_ENABLECARD) {
+                                wb_smsc_wdt_enable();
+                                retval = 0;
+                        }
+
+                        return retval;
+                }
+        }
+}
+
+/* -- Notifier funtions -----------------------------------------*/
+
+static int wb_smsc_wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
+{
+        if (code == SYS_DOWN || code == SYS_HALT)
+        {
+                // set timeout to 0, to avoid possible race-condition
+                timeout = 0;
+                wb_smsc_wdt_disable();
+        }
+        return NOTIFY_DONE;
+}
+
+/* -- Module's structures ---------------------------------------*/
+
+static struct file_operations wb_smsc_wdt_fops =
+{
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .write          = wb_smsc_wdt_write,
+        .ioctl          = wb_smsc_wdt_ioctl,
+        .open           = wb_smsc_wdt_open,
+        .release        = wb_smsc_wdt_release
+};
+
+static struct notifier_block wb_smsc_wdt_notifier =
+{
+        .notifier_call  = wb_smsc_wdt_notify_sys
+};
+
+static struct miscdevice wb_smsc_wdt_miscdev =
+{
+        .minor          = WATCHDOG_MINOR,
+        .name           = "watchdog",
+        .fops           = &wb_smsc_wdt_fops,
+};
+
+/* -- Module init functions -------------------------------------*/
+
+/* module's "constructor" */
+
+static int __init wb_smsc_wdt_init(void)
+{
+        int ret;
+
+        printk("SMsC 37B787 watchdog component driver " VERSION " initialising...\n");
+
+        if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) {
+                printk(KERN_ERR MODNAME "Unable to register IO port %#x\n", IOPORT);
+                ret = -EBUSY;
+                goto out_pnp;
+        }
+
+        ret = register_reboot_notifier(&wb_smsc_wdt_notifier);
+        if (ret) {
+                printk(KERN_ERR MODNAME "Unable to register reboot notifier err = %d\n", ret);
+                goto out_io;
+        }
+
+        ret = misc_register(&wb_smsc_wdt_miscdev);
+        if (ret) {
+                printk(KERN_ERR MODNAME "Unable to register miscdev on minor %d\n", WATCHDOG_MINOR);
+                goto out_rbt;
+        }
+
+        // init the watchdog timer
+        wb_smsc_wdt_initialize();
+
+        // set new maximum, if it's too big
+        if (timeout > MAX_TIMEOUT)
+               timeout = MAX_TIMEOUT;
+
+        // output info
+        printk(KERN_INFO MODNAME "Timeout set to %d %s.\n", timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
+        printk(KERN_INFO MODNAME "Watchdog initialized and sleeping (nowayout=%d)...\n", nowayout);
+
+        // ret = 0
+
+out_clean:
+        return ret;
+
+out_rbt:
+        unregister_reboot_notifier(&wb_smsc_wdt_notifier);
+
+out_io:
+        release_region(IOPORT, IOPORT_SIZE);
+
+out_pnp:
+        goto out_clean;
+}       
+
+/* module's "destructor" */
+
+static void __exit wb_smsc_wdt_exit(void)
+{
+        /* Stop the timer before we leave */
+        if (!nowayout)
+        {
+                wb_smsc_wdt_shutdown();
+                printk(KERN_INFO MODNAME "Watchdog disabled.\n");
+        }
+
+        misc_deregister(&wb_smsc_wdt_miscdev);
+        unregister_reboot_notifier(&wb_smsc_wdt_notifier);
+        release_region(IOPORT, IOPORT_SIZE);
+
+        printk("SMsC 37B787 watchdog component driver removed.\n");
+}
+
+module_init(wb_smsc_wdt_init);
+module_exit(wb_smsc_wdt_exit);
+
+MODULE_AUTHOR("Sven Anders <anders@anduras.de>");
+MODULE_DESCRIPTION("Driver for SMsC 37B787 watchdog component (Version " VERSION ")");
+MODULE_LICENSE("GPL");
+
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+
+#ifdef SMSC_SUPPORT_MINUTES
+module_param(unit, int, 0);
+MODULE_PARM_DESC(unit, "set unit to use, 0=seconds or 1=minutes, default is 0");
+#endif
+
+module_param(timeout, int, 60);
+MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60");
+
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");