[PATCH RFC] watchdog: add a new driver for VIA chipsets

From: Marc Vertes
Date: Tue Nov 22 2011 - 06:25:50 EST


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@xxxxxxxxxx>
---

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@xxxxxxxxxx>
+ * Based on a preliminary version from Harald Welte <HaraldWelte@xxxxxxxxxxx>
+ *
+ * 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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