watchdog: Add support for sp5100 chipset TCO

This driver adds /dev/watchdog support for the AMD sp5100 aka SB7x0 chipsets.

It follows the same conventions found in other /dev/watchdog drivers.

Signed-off-by: Priyanka Gupta <priyankag@google.com>
Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

4 files changed, 533 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 3c6607ddcd20..c48faa5ade73 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -418,6 +418,17 @@ config F71808E_WDT
           You can compile this driver directly into the kernel, or use
           it as a module.  The module will be called f71808e_wdt.
 
+config SP5100_TCO
+        tristate "AMD/ATI SP5100 TCO Timer/Watchdog"
+        depends on X86 && PCI
+        ---help---
+          Hardware watchdog driver for the AMD/ATI SP5100 chipset. The TCO
+          (Total Cost of Ownership) timer is a watchdog timer that will reboot
+          the machine after its expiration. The expiration time can be
+          configured with the "heartbeat" parameter.
+
+          To compile this driver as a module, choose M here: the
+          module will be called sp5100_tco.
 
 config GEODE_WDT
         tristate "AMD Geode CS5535/CS5536 Watchdog"
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 4b0ef386229d..12e6c1e32671 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_ADVANTECH_WDT) += advantechwdt.o
 obj-$(CONFIG_ALIM1535_WDT) += alim1535_wdt.o
 obj-$(CONFIG_ALIM7101_WDT) += alim7101_wdt.o
 obj-$(CONFIG_F71808E_WDT) += f71808e_wdt.o
+obj-$(CONFIG_SP5100_TCO) += sp5100_tco.o
 obj-$(CONFIG_GEODE_WDT) += geodewdt.o
 obj-$(CONFIG_SC520_WDT) += sc520_wdt.o
 obj-$(CONFIG_SBC_FITPC2_WATCHDOG) += sbc_fitpc2_wdt.o
diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
new file mode 100644
index 000000000000..808372883e88
--- /dev/null
+++ b/drivers/watchdog/sp5100_tco.c
@@ -0,0 +1,480 @@
+/*
+ *      sp5100_tco :    TCO timer driver for sp5100 chipsets
+ *
+ *      (c) Copyright 2009 Google Inc., All Rights Reserved.
+ *
+ *      Based on i8xx_tco.c:
+ *      (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
+ *      Reserved.
+ *                              http://www.kernelconcepts.de
+ *
+ *      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.
+ *
+ *      See AMD Publication 43009 "AMD SB700/710/750 Register Reference Guide"
+ */
+
+/*
+ *      Includes, defines, variables, module parameters, ...
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/pci.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+
+#include "sp5100_tco.h"
+
+/* Module and version information */
+#define TCO_VERSION "0.01"
+#define TCO_MODULE_NAME "SP5100 TCO timer"
+#define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
+#define PFX TCO_MODULE_NAME ": "
+
+/* internal variables */
+static void __iomem *tcobase;
+static unsigned int pm_iobase;
+static DEFINE_SPINLOCK(tco_lock);       /* Guards the hardware */
+static unsigned long timer_alive;
+static char tco_expect_close;
+static struct pci_dev *sp5100_tco_pci;
+
+/* the watchdog platform device */
+static struct platform_device *sp5100_tco_platform_device;
+
+/* module parameters */
+
+#define WATCHDOG_HEARTBEAT 60   /* 60 sec default heartbeat. */
+static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
+                 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
+
+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) ")");
+
+/*
+ * Some TCO specific functions
+ */
+static void tco_timer_start(void)
+{
+        u32 val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&tco_lock, flags);
+        val = readl(SP5100_WDT_CONTROL(tcobase));
+        val |= SP5100_WDT_START_STOP_BIT;
+        writel(val, SP5100_WDT_CONTROL(tcobase));
+        spin_unlock_irqrestore(&tco_lock, flags);
+}
+
+static void tco_timer_stop(void)
+{
+        u32 val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&tco_lock, flags);
+        val = readl(SP5100_WDT_CONTROL(tcobase));
+        val &= ~SP5100_WDT_START_STOP_BIT;
+        writel(val, SP5100_WDT_CONTROL(tcobase));
+        spin_unlock_irqrestore(&tco_lock, flags);
+}
+
+static void tco_timer_keepalive(void)
+{
+        u32 val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&tco_lock, flags);
+        val = readl(SP5100_WDT_CONTROL(tcobase));
+        val |= SP5100_WDT_TRIGGER_BIT;
+        writel(val, SP5100_WDT_CONTROL(tcobase));
+        spin_unlock_irqrestore(&tco_lock, flags);
+}
+
+static int tco_timer_set_heartbeat(int t)
+{
+        unsigned long flags;
+
+        if (t < 0 || t > 0xffff)
+                return -EINVAL;
+
+        /* Write new heartbeat to watchdog */
+        spin_lock_irqsave(&tco_lock, flags);
+        writel(t, SP5100_WDT_COUNT(tcobase));
+        spin_unlock_irqrestore(&tco_lock, flags);
+
+        heartbeat = t;
+        return 0;
+}
+
+/*
+ *      /dev/watchdog handling
+ */
+
+static int sp5100_tco_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 */
+        tco_timer_start();
+        tco_timer_keepalive();
+        return nonseekable_open(inode, file);
+}
+
+static int sp5100_tco_release(struct inode *inode, struct file *file)
+{
+        /* Shut off the timer. */
+        if (tco_expect_close == 42) {
+                tco_timer_stop();
+        } else {
+                printk(KERN_CRIT PFX
+                        "Unexpected close, not stopping watchdog!\n");
+                tco_timer_keepalive();
+        }
+        clear_bit(0, &timer_alive);
+        tco_expect_close = 0;
+        return 0;
+}
+
+static ssize_t sp5100_tco_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... */
+                        tco_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')
+                                        tco_expect_close = 42;
+                        }
+                }
+
+                /* someone wrote to us, we should reload the timer */
+                tco_timer_keepalive();
+        }
+        return len;
+}
+
+static long sp5100_tco_ioctl(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 const struct watchdog_info ident = {
+                .options =              WDIOF_SETTIMEOUT |
+                                        WDIOF_KEEPALIVEPING |
+                                        WDIOF_MAGICCLOSE,
+                .firmware_version =     0,
+                .identity =             TCO_MODULE_NAME,
+        };
+
+        switch (cmd) {
+        case WDIOC_GETSUPPORT:
+                return copy_to_user(argp, &ident,
+                        sizeof(ident)) ? -EFAULT : 0;
+        case WDIOC_GETSTATUS:
+        case WDIOC_GETBOOTSTATUS:
+                return put_user(0, p);
+        case WDIOC_SETOPTIONS:
+                if (get_user(new_options, p))
+                        return -EFAULT;
+                if (new_options & WDIOS_DISABLECARD) {
+                        tco_timer_stop();
+                        retval = 0;
+                }
+                if (new_options & WDIOS_ENABLECARD) {
+                        tco_timer_start();
+                        tco_timer_keepalive();
+                        retval = 0;
+                }
+                return retval;
+        case WDIOC_KEEPALIVE:
+                tco_timer_keepalive();
+                return 0;
+        case WDIOC_SETTIMEOUT:
+                if (get_user(new_heartbeat, p))
+                        return -EFAULT;
+                if (tco_timer_set_heartbeat(new_heartbeat))
+                        return -EINVAL;
+                tco_timer_keepalive();
+                /* Fall through */
+        case WDIOC_GETTIMEOUT:
+                return put_user(heartbeat, p);
+        default:
+                return -ENOTTY;
+        }
+}
+
+/*
+ * Kernel Interfaces
+ */
+
+static const struct file_operations sp5100_tco_fops = {
+        .owner =                THIS_MODULE,
+        .llseek =               no_llseek,
+        .write =                sp5100_tco_write,
+        .unlocked_ioctl =       sp5100_tco_ioctl,
+        .open =                 sp5100_tco_open,
+        .release =              sp5100_tco_release,
+};
+
+static struct miscdevice sp5100_tco_miscdev = {
+        .minor =        WATCHDOG_MINOR,
+        .name =         "watchdog",
+        .fops =         &sp5100_tco_fops,
+};
+
+/*
+ * 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
+ * want to register another driver on the same PCI id.
+ */
+static struct pci_device_id sp5100_tco_pci_tbl[] = {
+        { PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS, PCI_ANY_ID,
+          PCI_ANY_ID, },
+        { 0, },                 /* End of list */
+};
+MODULE_DEVICE_TABLE(pci, sp5100_tco_pci_tbl);
+
+/*
+ * Init & exit routines
+ */
+
+static unsigned char __devinit sp5100_tco_setupdevice(void)
+{
+        struct pci_dev *dev = NULL;
+        u32 val;
+
+        /* Match the PCI device */
+        for_each_pci_dev(dev) {
+                if (pci_match_id(sp5100_tco_pci_tbl, dev) != NULL) {
+                        sp5100_tco_pci = dev;
+                        break;
+                }
+        }
+
+        if (!sp5100_tco_pci)
+                return 0;
+
+        /* Request the IO ports used by this driver */
+        pm_iobase = SP5100_IO_PM_INDEX_REG;
+        if (!request_region(pm_iobase, SP5100_PM_IOPORTS_SIZE, "SP5100 TCO")) {
+                printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
+                        pm_iobase);
+                goto exit;
+        }
+
+        /* Find the watchdog base address. */
+        outb(SP5100_PM_WATCHDOG_BASE3, SP5100_IO_PM_INDEX_REG);
+        val = inb(SP5100_IO_PM_DATA_REG);
+        outb(SP5100_PM_WATCHDOG_BASE2, SP5100_IO_PM_INDEX_REG);
+        val = val << 8 | inb(SP5100_IO_PM_DATA_REG);
+        outb(SP5100_PM_WATCHDOG_BASE1, SP5100_IO_PM_INDEX_REG);
+        val = val << 8 | inb(SP5100_IO_PM_DATA_REG);
+        outb(SP5100_PM_WATCHDOG_BASE0, SP5100_IO_PM_INDEX_REG);
+        /* Low three bits of BASE0 are reserved. */
+        val = val << 8 | (inb(SP5100_IO_PM_DATA_REG) & 0xf8);
+
+        tcobase = ioremap(val, SP5100_WDT_MEM_MAP_SIZE);
+        if (tcobase == 0) {
+                printk(KERN_ERR PFX "failed to get tcobase address\n");
+                goto unreg_region;
+        }
+
+        /* Enable watchdog decode bit */
+        pci_read_config_dword(sp5100_tco_pci,
+                              SP5100_PCI_WATCHDOG_MISC_REG,
+                              &val);
+
+        val |= SP5100_PCI_WATCHDOG_DECODE_EN;
+
+        pci_write_config_dword(sp5100_tco_pci,
+                               SP5100_PCI_WATCHDOG_MISC_REG,
+                               val);
+
+        /* Enable Watchdog timer and set the resolution to 1 sec. */
+        outb(SP5100_PM_WATCHDOG_CONTROL, SP5100_IO_PM_INDEX_REG);
+        val = inb(SP5100_IO_PM_DATA_REG);
+        val |= SP5100_PM_WATCHDOG_SECOND_RES;
+        val &= ~SP5100_PM_WATCHDOG_DISABLE;
+        outb(val, SP5100_IO_PM_DATA_REG);
+
+        /* Check that the watchdog action is set to reset the system. */
+        val = readl(SP5100_WDT_CONTROL(tcobase));
+        val &= ~SP5100_PM_WATCHDOG_ACTION_RESET;
+        writel(val, SP5100_WDT_CONTROL(tcobase));
+
+        /* Set a reasonable heartbeat before we stop the timer */
+        tco_timer_set_heartbeat(heartbeat);
+
+        /*
+         * Stop the TCO before we change anything so we don't race with
+         * a zeroed timer.
+         */
+        tco_timer_stop();
+
+        /* Done */
+        return 1;
+
+        iounmap(tcobase);
+unreg_region:
+        release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
+exit:
+        return 0;
+}
+
+static int __devinit sp5100_tco_init(struct platform_device *dev)
+{
+        int ret;
+        u32 val;
+
+        /* Check whether or not the hardware watchdog is there. If found, then
+         * set it up.
+         */
+        if (!sp5100_tco_setupdevice())
+                return -ENODEV;
+
+        /* Check to see if last reboot was due to watchdog timeout */
+        printk(KERN_INFO PFX "Watchdog reboot %sdetected.\n",
+               readl(SP5100_WDT_CONTROL(tcobase)) & SP5100_PM_WATCHDOG_FIRED ?
+                      "" : "not ");
+
+        /* Clear out the old status */
+        val = readl(SP5100_WDT_CONTROL(tcobase));
+        val &= ~SP5100_PM_WATCHDOG_FIRED;
+        writel(val, SP5100_WDT_CONTROL(tcobase));
+
+        /*
+         * Check that the heartbeat value is within it's range.
+         * If not, reset to the default.
+         */
+        if (tco_timer_set_heartbeat(heartbeat)) {
+                heartbeat = WATCHDOG_HEARTBEAT;
+                tco_timer_set_heartbeat(heartbeat);
+        }
+
+        ret = misc_register(&sp5100_tco_miscdev);
+        if (ret != 0) {
+                printk(KERN_ERR PFX "cannot register miscdev on minor="
+                       "%d (err=%d)\n",
+                       WATCHDOG_MINOR, ret);
+                goto exit;
+        }
+
+        clear_bit(0, &timer_alive);
+
+        printk(KERN_INFO PFX "initialized (0x%p). heartbeat=%d sec"
+                " (nowayout=%d)\n",
+                tcobase, heartbeat, nowayout);
+
+        return 0;
+
+exit:
+        iounmap(tcobase);
+        release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
+        return ret;
+}
+
+static void __devexit sp5100_tco_cleanup(void)
+{
+        /* Stop the timer before we leave */
+        if (!nowayout)
+                tco_timer_stop();
+
+        /* Deregister */
+        misc_deregister(&sp5100_tco_miscdev);
+        iounmap(tcobase);
+        release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
+}
+
+static int __devexit sp5100_tco_remove(struct platform_device *dev)
+{
+        if (tcobase)
+                sp5100_tco_cleanup();
+        return 0;
+}
+
+static void sp5100_tco_shutdown(struct platform_device *dev)
+{
+        tco_timer_stop();
+}
+
+static struct platform_driver sp5100_tco_driver = {
+        .probe          = sp5100_tco_init,
+        .remove         = __devexit_p(sp5100_tco_remove),
+        .shutdown       = sp5100_tco_shutdown,
+        .driver         = {
+                .owner  = THIS_MODULE,
+                .name   = TCO_MODULE_NAME,
+        },
+};
+
+static int __init sp5100_tco_init_module(void)
+{
+        int err;
+
+        printk(KERN_INFO PFX "SP5100 TCO WatchDog Timer Driver v%s\n",
+               TCO_VERSION);
+
+        err = platform_driver_register(&sp5100_tco_driver);
+        if (err)
+                return err;
+
+        sp5100_tco_platform_device = platform_device_register_simple(
+                                        TCO_MODULE_NAME, -1, NULL, 0);
+        if (IS_ERR(sp5100_tco_platform_device)) {
+                err = PTR_ERR(sp5100_tco_platform_device);
+                goto unreg_platform_driver;
+        }
+
+        return 0;
+
+unreg_platform_driver:
+        platform_driver_unregister(&sp5100_tco_driver);
+        return err;
+}
+
+static void __exit sp5100_tco_cleanup_module(void)
+{
+        platform_device_unregister(sp5100_tco_platform_device);
+        platform_driver_unregister(&sp5100_tco_driver);
+        printk(KERN_INFO PFX "SP5100 TCO Watchdog Module Unloaded.\n");
+}
+
+module_init(sp5100_tco_init_module);
+module_exit(sp5100_tco_cleanup_module);
+
+MODULE_AUTHOR("Priyanka Gupta");
+MODULE_DESCRIPTION("TCO timer driver for SP5100 chipset");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
diff --git a/drivers/watchdog/sp5100_tco.h b/drivers/watchdog/sp5100_tco.h
new file mode 100644
index 000000000000..a5a16cc90a34
--- /dev/null
+++ b/drivers/watchdog/sp5100_tco.h
@@ -0,0 +1,41 @@
+/*
+ *      sp5100_tco:     TCO timer driver for sp5100 chipsets.
+ *
+ *      (c) Copyright 2009 Google Inc., All Rights Reserved.
+ *
+ *      TCO timer driver for sp5100 chipsets
+ */
+
+/*
+ * Some address definitions for the Watchdog
+ */
+
+#define SP5100_WDT_MEM_MAP_SIZE         0x08
+#define SP5100_WDT_CONTROL(base)        ((base) + 0x00) /* Watchdog Control */
+#define SP5100_WDT_COUNT(base)          ((base) + 0x04) /* Watchdog Count */
+
+#define SP5100_WDT_START_STOP_BIT       1
+#define SP5100_WDT_TRIGGER_BIT          (1 << 7)
+
+#define SP5100_PCI_WATCHDOG_MISC_REG    0x41
+#define SP5100_PCI_WATCHDOG_DECODE_EN   (1 << 3)
+
+#define SP5100_PM_IOPORTS_SIZE          0x02
+
+/* These two IO registers are hardcoded and there doesn't seem to be a way to
+ * read them from a register.
+ */
+#define SP5100_IO_PM_INDEX_REG          0xCD6
+#define SP5100_IO_PM_DATA_REG           0xCD7
+
+#define SP5100_PM_WATCHDOG_CONTROL      0x69
+#define SP5100_PM_WATCHDOG_BASE0        0x6C
+#define SP5100_PM_WATCHDOG_BASE1        0x6D
+#define SP5100_PM_WATCHDOG_BASE2        0x6E
+#define SP5100_PM_WATCHDOG_BASE3        0x6F
+
+#define SP5100_PM_WATCHDOG_FIRED        (1 << 1)
+#define SP5100_PM_WATCHDOG_ACTION_RESET (1 << 2)
+
+#define SP5100_PM_WATCHDOG_DISABLE      1
+#define SP5100_PM_WATCHDOG_SECOND_RES   (3 << 1)