[WATCHDOG] i6300esb.patch

I wrote earlier to the list[1] asking for a driver for the watchdog
included in the 6300ESB chipset.  I got a 2.4 driver via private email
from Ross Biro which I've changed into what I hope resembles a 2.6
driver (which was done by looking a lot at the watchdog drivers
already in the 2.6 tree).

I've attached the result, and I'm hoping to get some feedback on the
coding as a first step.  I can't actually test it on the hardware
right now as I won't have physical access until April. So my own tests
have been limited to "compiles-without-warnings" and
"can-be-insmodded-in-other-machine-without-oops".

[1] http://marc.theaimsgroup.com/?l=linux-kernel&m=110711079825794&w=2
[2] http://marc.theaimsgroup.com/?l=linux-kernel&m=110711973917746&w=2

Signed-off-by: David Hardeman <david@2gen.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 508 insertions, 0 deletions

diff --git a/drivers/char/watchdog/i6300esb.c b/drivers/char/watchdog/i6300esb.c
new file mode 100644
index 000000000000..87273839aead
--- /dev/null
+++ b/drivers/char/watchdog/i6300esb.c
@@ -0,0 +1,508 @@
+/*
+ *      i6300esb 0.03:  Watchdog timer driver for Intel 6300ESB chipset
+ *
+ *      (c) Copyright 2004 Google Inc.
+ *
+ *      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.
+ *
+ *      based on i810-tco.c which is
+ *
+ *      (c) Copyright 2000      kernel concepts <nils@kernelconcepts.de>
+ *                              developed for
+ *                              Jentro AG, Haar/Munich (Germany)
+ *
+ *      which is in turn based on softdog.c by Alan Cox <alan@redhat.com>
+ *
+ *      The timer is implemented in the following I/O controller hubs:
+ *      (See the intel documentation on http://developer.intel.com.)
+ *      6300ESB chip : document number 300641-003
+ *
+ *  2004YYZZ Ross Biro
+ *      Initial version 0.01
+ *  2004YYZZ Ross Biro
+ *      Version 0.02
+ *  20050210 David Härdeman <david@2gen.com>
+ *      Ported driver to kernel 2.6
+ */
+
+/*
+ *      Includes, defines, variables, module parameters, ...
+ */
+
+#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/pci.h>
+#include <linux/ioport.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#include "i6300esb.h"
+
+/* Module and version information */
+#define ESB_VERSION "0.03"
+#define ESB_MODULE_NAME "i6300ESB timer"
+#define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
+#define PFX ESB_MODULE_NAME ": "
+
+/* internal variables */
+static void __iomem *BASEADDR;
+static spinlock_t esb_lock; /* Guards the hardware */
+static unsigned long timer_alive;
+static struct pci_dev *esb_pci;
+static unsigned short triggered; /* The status of the watchdog upon boot */
+static char esb_expect_close;
+
+/* module parameters */
+#define WATCHDOG_HEARTBEAT 30   /* 30 sec default heartbeat (1<heartbeat<2*1023) */
+static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (1<heartbeat<2046, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+static int nowayout = 1;
+#else
+static int nowayout = 0;
+#endif
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
+
+/*
+ * Some i6300ESB specific functions
+ */
+
+/*
+ * Prepare for reloading the timer by unlocking the proper registers.
+ * This is performed by first writing 0x80 followed by 0x86 to the
+ * reload register. After this the appropriate registers can be written
+ * to once before they need to be unlocked again.
+ */
+static inline void esb_unlock_registers(void) {
+        writeb(ESB_UNLOCK1, ESB_RELOAD_REG);
+        writeb(ESB_UNLOCK2, ESB_RELOAD_REG);
+}
+
+static void esb_timer_start(void)
+{
+        u8 val;
+
+        /* Enable or Enable + Lock? */
+        val = 0x02 | nowayout ? 0x01 : 0x00;
+
+        pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
+}
+
+static int esb_timer_stop(void)
+{
+        u8 val;
+
+        spin_lock(&esb_lock);
+        /* First, reset timers as suggested by the docs */
+        esb_unlock_registers();
+        writew(0x10, ESB_RELOAD_REG);
+        /* Then disable the WDT */
+        pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
+        pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
+        spin_unlock(&esb_lock);
+
+        /* Returns 0 if the timer was disabled, non-zero otherwise */
+        return (val & 0x01);
+}
+
+static void esb_timer_keepalive(void)
+{
+        spin_lock(&esb_lock);
+        esb_unlock_registers();
+        writew(0x10, ESB_RELOAD_REG);
+        /* FIXME: Do we need to flush anything here? */
+        spin_unlock(&esb_lock);
+}
+
+static int esb_timer_set_heartbeat(int time)
+{
+        u32 val;
+
+        if (time < 0x1 || time > (2 * 0x03ff))
+                return -EINVAL;
+
+        spin_lock(&esb_lock);
+
+        /* We shift by 9, so if we are passed a value of 1 sec,
+         * val will be 1 << 9 = 512, then write that to two
+         * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
+         */
+        val = time << 9;
+
+        /* Write timer 1 */
+        esb_unlock_registers();
+        writel(val, ESB_TIMER1_REG);
+
+        /* Write timer 2 */
+        esb_unlock_registers();
+        writel(val, ESB_TIMER2_REG);
+
+        /* Reload */
+        esb_unlock_registers();
+        writew(0x10, ESB_RELOAD_REG);
+
+        /* FIXME: Do we need to flush everything out? */
+
+        /* Done */
+        heartbeat = time;
+        spin_unlock(&esb_lock);
+        return 0;
+}
+
+static int esb_timer_read (void)
+{
+        u32 count;
+
+        /* This isn't documented, and doesn't take into
+         * acount which stage is running, but it looks
+         * like a 20 bit count down, so we might as well report it.
+         */
+        pci_read_config_dword(esb_pci, 0x64, &count);
+        return (int)count;
+}
+
+/*
+ *      /dev/watchdog handling
+ */
+
+static int esb_open (struct inode *inode, struct file *file)
+{
+        /* /dev/watchdog can only be opened once */
+        if (test_and_set_bit(0, &timer_alive))
+                return -EBUSY;
+
+        /* Reload and activate timer */
+        esb_timer_keepalive ();
+        esb_timer_start ();
+
+        return nonseekable_open(inode, file);
+}
+
+static int esb_release (struct inode *inode, struct file *file)
+{
+        /* Shut off the timer. */
+        if (esb_expect_close == 42) {
+                esb_timer_stop ();
+        } else {
+                printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
+                esb_timer_keepalive ();
+        }
+        clear_bit(0, &timer_alive);
+        esb_expect_close = 0;
+        return 0;
+}
+
+static ssize_t esb_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;
+
+                        /* note: just in case someone wrote the magic character
+                         * five months ago... */
+                        esb_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')
+                                        esb_expect_close = 42;
+                        }
+                }
+
+                /* someone wrote to us, we should reload the timer */
+                esb_timer_keepalive ();
+        }
+        return len;
+}
+
+static int esb_ioctl (struct inode *inode, struct file *file,
+                      unsigned int cmd, unsigned long arg)
+{
+        int new_options, retval = -EINVAL;
+        int new_heartbeat;
+        void __user *argp = (void __user *)arg;
+        int __user *p = argp;
+        static struct watchdog_info ident = {
+                .options =              WDIOF_SETTIMEOUT |
+                                        WDIOF_KEEPALIVEPING |
+                                        WDIOF_MAGICCLOSE,
+                .firmware_version =     0,
+                .identity =             ESB_MODULE_NAME,
+        };
+
+        switch (cmd) {
+                case WDIOC_GETSUPPORT:
+                        return copy_to_user(argp, &ident,
+                                            sizeof (ident)) ? -EFAULT : 0;
+
+                case WDIOC_GETSTATUS:
+                        return put_user (esb_timer_read(), p);
+
+                case WDIOC_GETBOOTSTATUS:
+                        return put_user (triggered, p);
+
+                case WDIOC_KEEPALIVE:
+                        esb_timer_keepalive ();
+                        return 0;
+
+                case WDIOC_SETOPTIONS:
+                {
+                        if (get_user (new_options, p))
+                                return -EFAULT;
+
+                        if (new_options & WDIOS_DISABLECARD) {
+                                esb_timer_stop ();
+                                retval = 0;
+                        }
+
+                        if (new_options & WDIOS_ENABLECARD) {
+                                esb_timer_keepalive ();
+                                esb_timer_start ();
+                                retval = 0;
+                        }
+
+                        return retval;
+                }
+
+                case WDIOC_SETTIMEOUT:
+                {
+                        if (get_user(new_heartbeat, p))
+                                return -EFAULT;
+
+                        if (esb_timer_set_heartbeat(new_heartbeat))
+                            return -EINVAL;
+
+                        esb_timer_keepalive ();
+                        /* Fall */
+                }
+
+                case WDIOC_GETTIMEOUT:
+                        return put_user(heartbeat, p);
+
+                default:
+                        return -ENOIOCTLCMD;
+        }
+}
+
+/*
+ *      Notify system
+ */
+
+static int esb_notify_sys (struct notifier_block *this, unsigned long code, void *unused)
+{
+        if (code==SYS_DOWN || code==SYS_HALT) {
+                /* Turn the WDT off */
+                esb_timer_stop ();
+        }
+
+        return NOTIFY_DONE;
+}
+
+/*
+ *      Kernel Interfaces
+ */
+
+static struct file_operations esb_fops = {
+        .owner =        THIS_MODULE,
+        .llseek =       no_llseek,
+        .write =        esb_write,
+        .ioctl =        esb_ioctl,
+        .open =         esb_open,
+        .release =      esb_release,
+};
+
+static struct miscdevice esb_miscdev = {
+        .minor =        WATCHDOG_MINOR,
+        .name =         "watchdog",
+        .fops =         &esb_fops,
+};
+
+static struct notifier_block esb_notifier = {
+        .notifier_call =        esb_notify_sys,
+};
+
+/*
+ * Data for PCI driver interface
+ *
+ * This data only exists for exporting the supported
+ * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
+ * register a pci_driver, because someone else might one day
+ * want to register another driver on the same PCI id.
+ */
+static struct pci_device_id esb_pci_tbl[] = {
+        { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9, PCI_ANY_ID, PCI_ANY_ID, },
+        { 0, },                 /* End of list */
+};
+MODULE_DEVICE_TABLE (pci, esb_pci_tbl);
+
+/*
+ *      Init & exit routines
+ */
+
+static unsigned char __init esb_getdevice (void)
+{
+        u8 val1;
+        unsigned short val2;
+
+        struct pci_dev *dev = NULL;
+        /*
+         *      Find the PCI device
+         */
+
+        while ((dev = pci_find_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
+                if (pci_match_device(esb_pci_tbl, dev)) {
+                        esb_pci = dev;
+                        break;
+                }
+        }
+
+        if (esb_pci) {
+                if (pci_enable_device(esb_pci)) {
+                        printk (KERN_ERR PFX "failed to enable device\n");
+                        goto out;
+                }
+
+                if (pci_request_region(esb_pci, 0, ESB_MODULE_NAME)) {
+                        printk (KERN_ERR PFX "failed to request region\n");
+                        goto err_disable;
+                }
+
+                BASEADDR = ioremap(pci_resource_start(esb_pci, 0),
+                                   pci_resource_len(esb_pci, 0));
+                if (BASEADDR == NULL) {
+                        /* Something's wrong here, BASEADDR has to be set */
+                        printk (KERN_ERR PFX "failed to get BASEADDR\n");
+                        goto err_release;
+                }
+
+                /*
+                 * The watchdog has two timers, it can be setup so that the
+                 * expiry of timer1 results in an interrupt and the expiry of
+                 * timer2 results in a reboot. We set it to not generate
+                 * any interrupts as there is not much we can do with it
+                 * right now.
+                 *
+                 * We also enable reboots and set the timer frequency to
+                 * the PCI clock divided by 2^15 (approx 1KHz).
+                 */
+                pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
+
+                /* Check that the WDT isn't already locked */
+                pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
+                if (val1 & ESB_WDT_LOCK)
+                        printk (KERN_WARNING PFX "nowayout already set\n");
+
+                /* Set the timer to watchdog mode and disable it for now */
+                pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
+
+                /* Check if the watchdog was previously triggered */
+                esb_unlock_registers();
+                val2 = readw(ESB_RELOAD_REG);
+                triggered = (val2 & (0x01 << 9) >> 9);
+
+                /* Reset trigger flag and timers */
+                esb_unlock_registers();
+                writew((0x11 << 8), ESB_RELOAD_REG);
+
+                /* Done */
+                return 1;
+
+err_release:
+                pci_release_region(esb_pci, 0);
+err_disable:
+                pci_disable_device(esb_pci);
+        }
+out:
+        return 0;
+}
+
+static int __init watchdog_init (void)
+{
+        int ret;
+
+        spin_lock_init(&esb_lock);
+
+        /* Check whether or not the hardware watchdog is there */
+        if (!esb_getdevice () || esb_pci == NULL)
+                return -ENODEV;
+
+        /* Check that the heartbeat value is within it's range ; if not reset to the default */
+        if (esb_timer_set_heartbeat (heartbeat)) {
+                esb_timer_set_heartbeat (WATCHDOG_HEARTBEAT);
+                printk(KERN_INFO PFX "heartbeat value must be 1<heartbeat<2046, using %d\n",
+                       heartbeat);
+        }
+
+        ret = register_reboot_notifier(&esb_notifier);
+        if (ret != 0) {
+                printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
+                        ret);
+                goto err_unmap;
+        }
+
+        ret = misc_register(&esb_miscdev);
+        if (ret != 0) {
+                printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
+                        WATCHDOG_MINOR, ret);
+                goto err_notifier;
+        }
+
+        esb_timer_stop ();
+
+        printk (KERN_INFO PFX "initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
+                BASEADDR, heartbeat, nowayout);
+
+        return 0;
+
+err_notifier:
+        unregister_reboot_notifier(&esb_notifier);
+err_unmap:
+        iounmap(BASEADDR);
+/* err_release: */
+        pci_release_region(esb_pci, 0);
+/* err_disable: */
+        pci_disable_device(esb_pci);
+/* out: */
+        return ret;
+}
+
+static void __exit watchdog_cleanup (void)
+{
+        /* Stop the timer before we leave */
+        if (!nowayout)
+                esb_timer_stop ();
+
+        /* Deregister */
+        misc_deregister(&esb_miscdev);
+        unregister_reboot_notifier(&esb_notifier);
+        iounmap(BASEADDR);
+        pci_release_region(esb_pci, 0);
+        pci_disable_device(esb_pci);
+}
+
+module_init(watchdog_init);
+module_exit(watchdog_cleanup);
+
+MODULE_AUTHOR("Ross Biro and David Härdeman");
+MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);