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    Subject[PATCH RFC] watchdog: add a new driver for VIA chipsets
    Add a new driver for the hardware watchdog timer on VIA chipsets.
    Tested on a Artigo A1100, VX855 chipset.

    Signed-off-by: Marc Vertes <marc.vertes@sigfox.com>
    ---
    Kconfig | 13 ++++
    Makefile | 1
    via_wdt.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    3 files changed, 190 insertions(+)
    --- linux-3.2-rc2/drivers/watchdog/Makefile.orig 2011-11-15 18:02:59.000000000 +0100
    +++ linux-3.2-rc2/drivers/watchdog/Makefile 2011-11-18 18:13:36.594534635 +0100
    @@ -100,6 +100,7 @@ obj-$(CONFIG_SBC7240_WDT) += sbc7240_wdt
    obj-$(CONFIG_CPU5_WDT) += cpu5wdt.o
    obj-$(CONFIG_SMSC_SCH311X_WDT) += sch311x_wdt.o
    obj-$(CONFIG_SMSC37B787_WDT) += smsc37b787_wdt.o
    +obj-$(CONFIG_VIA_WDT) += via_wdt.o
    obj-$(CONFIG_W83627HF_WDT) += w83627hf_wdt.o
    obj-$(CONFIG_W83697HF_WDT) += w83697hf_wdt.o
    obj-$(CONFIG_W83697UG_WDT) += w83697ug_wdt.o
    --- linux-3.2-rc2/drivers/watchdog/via_wdt.c.orig 2011-11-18 18:14:45.358174874 +0100
    +++ linux-3.2-rc2/drivers/watchdog/via_wdt.c 2011-11-22 11:49:33.169408728 +0100
    @@ -0,0 +1,176 @@
    +/*
    + * VIA Chipset Watchdog Driver
    + *
    + * Copyright (C) 2011 Sigfox
    + * License terms: GNU General Public License (GPL) version 2
    + * Author: Marc Vertes <marc.vertes@sigfox.com>
    + * Based on a preliminary version from Harald Welte <HaraldWelte@viatech.com>
    + *
    + * The only way to activate the watchdog timer or to set its period is
    + * through BIOS setup.
    + */
    +#include <linux/device.h>
    +#include <linux/fs.h>
    +#include <linux/io.h>
    +#include <linux/miscdevice.h>
    +#include <linux/module.h>
    +#include <linux/pci.h>
    +#include <linux/uaccess.h>
    +#include <linux/watchdog.h>
    +
    +#define VIA_WDT_MB_OFFSET 0xe8 /* memory base offset */
    +#define VIA_WDT_TRIGGER 0x80 /* start a new countdown */
    +#define VIA_WDT_FIRED 0x02 /* set if last restart was caused
    + by expired watchdog timer */
    +
    +static void *wdt_mem; /* watchdog memory region address */
    +static unsigned long open_lock;
    +
    +static unsigned int wdt_ping(void)
    +{
    + unsigned int res = readl(wdt_mem); /* get status bits */
    + writel(res | VIA_WDT_TRIGGER, wdt_mem);
    + return res;
    +}
    +
    +static ssize_t wdt_write(struct file *file, const char __user *buf,
    + size_t count, loff_t *ppos)
    +{
    + if (count <= 0)
    + return 0;
    + wdt_ping();
    + return 1;
    +}
    +
    +static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
    +{
    + int ret;
    + static struct watchdog_info ident = {
    + .options = WDIOF_CARDRESET,
    + .identity = "VIA Southbridge WDT",
    + };
    +
    + switch (cmd) {
    + case WDIOC_GETSUPPORT:
    + ret = copy_to_user((struct watchdog_info *)arg, &ident,
    + sizeof(ident)) ? -EFAULT : 0;
    + break;
    + case WDIOC_GETSTATUS:
    + ret = put_user(0, (int __user *)arg);
    + break;
    + case WDIOC_GETBOOTSTATUS:
    + if (wdt_ping() & VIA_WDT_FIRED)
    + ret = put_user(WDIOF_CARDRESET, (int __user *)arg);
    + else
    + ret = put_user(0, (int __user *)arg);
    + break;
    + case WDIOC_KEEPALIVE:
    + wdt_ping();
    + ret = 0;
    + break;
    + default:
    + ret = -ENOTTY;
    + }
    + return ret;
    +}
    +
    +static int wdt_open(struct inode *inode, struct file *file)
    +{
    + if (test_and_set_bit(0, &open_lock))
    + return -EBUSY;
    + return nonseekable_open(inode, file);
    +}
    +
    +static int wdt_release(struct inode *inode, struct file *file)
    +{
    + clear_bit(0, &open_lock);
    + return 0;
    +}
    +
    +static const struct file_operations wdt_fops = {
    + .owner = THIS_MODULE,
    + .llseek = no_llseek,
    + .open = wdt_open,
    + .release = wdt_release,
    + .unlocked_ioctl = wdt_ioctl,
    + .write = wdt_write,
    +};
    +
    +static struct miscdevice wdt_miscdev = {
    + .minor = WATCHDOG_MINOR,
    + .name = "watchdog",
    + .fops = &wdt_fops,
    +};
    +
    +static int __devinit wdt_probe(struct pci_dev *pdev,
    + const struct pci_device_id *ent)
    +{
    + unsigned int mmio = 0;
    +
    + if (pci_enable_device(pdev)) {
    + dev_err(&pdev->dev, "cannot enable PCI device\n");
    + return -ENODEV;
    + }
    + pci_read_config_dword(pdev, VIA_WDT_MB_OFFSET, &mmio);
    + dev_info(&pdev->dev, "VIA Chipset watchdog MMIO: %x\n", mmio);
    + if (mmio == 0) {
    + dev_err(&pdev->dev, "watchdog timer is not enabled in BIOS\n");
    + return -ENODEV;
    + }
    + wdt_mem = ioremap(mmio, 8);
    + if (wdt_mem == NULL) {
    + dev_err(&pdev->dev, "cannot remap VIA wdt mmio registers\n");
    + return -ENODEV;
    + }
    + if (misc_register(&wdt_miscdev)) {
    + dev_err(&pdev->dev, "cannot register misc device\n");
    + iounmap(wdt_mem);
    + return -EIO;
    + }
    + if (wdt_ping() & VIA_WDT_FIRED)
    + dev_info(&pdev->dev "restarted by expired watchdog timer\n");
    + return 0;
    +}
    +
    +static void __devexit wdt_remove(struct pci_dev *dev)
    +{
    + misc_deregister(&wdt_miscdev);
    + iounmap(wdt_mem);
    +}
    +
    +/*
    + * The driver has not been tested yet on CX700 and VX800.
    + */
    +DEFINE_PCI_DEVICE_TABLE(wdt_pci_table) = {
    + { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_CX700) },
    + { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX800) },
    + { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX855) },
    + { 0 }
    +};
    +
    +static struct pci_driver wdt_driver = {
    + .name = "via_wdt",
    + .id_table = wdt_pci_table,
    + .probe = wdt_probe,
    + .remove = __devexit_p(wdt_remove),
    +};
    +
    +static int __init wdt_init(void)
    +{
    + if (pci_register_driver(&wdt_driver) || wdt_mem == NULL)
    + return -ENODEV;
    + return 0;
    +}
    +
    +static void __exit wdt_exit(void)
    +{
    + pci_unregister_driver(&wdt_driver);
    +}
    +
    +module_init(wdt_init);
    +module_exit(wdt_exit);
    +
    +MODULE_AUTHOR("Marc Vertes");
    +MODULE_DESCRIPTION("Driver for watchdog timer on VIA chipset");
    +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
    +MODULE_LICENSE("GPL");
    --- linux-3.2-rc2/drivers/watchdog/Kconfig.orig 2011-11-15 18:02:59.000000000 +0100
    +++ linux-3.2-rc2/drivers/watchdog/Kconfig 2011-11-18 18:13:36.595534599 +0100
    @@ -779,6 +779,19 @@ config SMSC37B787_WDT

    Most people will say N.

    +config VIA_WDT
    + tristate "VIA Watchdog Timer"
    + depends on X86
    + ---help---
    + This is the driver for the hardware watchdog timer on VIA
    + southbridge chipset CX700, VX800, VX855. Watchdog setup
    + in BIOS is required.
    +
    + To compile this driver as a module, choose M here; the module
    + will be called via_wdt.
    +
    + Most people will say N.
    +
    config W83627HF_WDT
    tristate "W83627HF/W83627DHG Watchdog Timer"
    depends on X86

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