// SPDX-License-Identifier: GPL-2.0-only
/*
* VIA Chipset Watchdog Driver
*
* Copyright (C) 2011 Sigfox
* Author: Marc Vertes <[email protected]>
* Based on a preliminary version from Harald Welte <[email protected]>
* Timer code by Wim Van Sebroeck <[email protected]>
*
* Caveat: PnP must be enabled in BIOS to allow full access to watchdog
* control registers. If not, the watchdog must be configured in BIOS manually.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/device.h>
#include <linux/io.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/timer.h>
#include <linux/watchdog.h>
/* Configuration registers relative to the pci device */
#define VIA_WDT_MMIO_BASE 0xe8 /* MMIO region base address */
#define VIA_WDT_CONF 0xec /* watchdog enable state */
/* Relevant bits for the VIA_WDT_CONF register */
#define VIA_WDT_CONF_ENABLE 0x01 /* 1: enable watchdog */
#define VIA_WDT_CONF_MMIO 0x02 /* 1: enable watchdog MMIO */
/*
* The MMIO region contains the watchdog control register and the
* hardware timer counter.
*/
#define VIA_WDT_MMIO_LEN 8 /* MMIO region length in bytes */
#define VIA_WDT_CTL 0 /* MMIO addr+0: state/control reg. */
#define VIA_WDT_COUNT 4 /* MMIO addr+4: timer counter reg. */
/* Bits for the VIA_WDT_CTL register */
#define VIA_WDT_RUNNING 0x01 /* 0: stop, 1: running */
#define VIA_WDT_FIRED 0x02 /* 1: restarted by expired watchdog */
#define VIA_WDT_PWROFF 0x04 /* 0: reset, 1: poweroff */
#define VIA_WDT_DISABLED 0x08 /* 1: timer is disabled */
#define VIA_WDT_TRIGGER 0x80 /* 1: start a new countdown */
/* Hardware heartbeat in seconds */
#define WDT_HW_HEARTBEAT 1
/* Timer heartbeat (500ms) */
#define WDT_HEARTBEAT (HZ/2) /* should be <= ((WDT_HW_HEARTBEAT*HZ)/2) */
/* User space timeout in seconds */
#define WDT_TIMEOUT_MAX 1023 /* approx. 17 min. */
#define WDT_TIMEOUT 60
static int timeout = WDT_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, between 1 and 1023 "
"(default = " __MODULE_STRING(WDT_TIMEOUT) ")");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default = " __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static struct watchdog_device wdt_dev;
static struct resource wdt_res;
static void __iomem *wdt_mem;
static unsigned int mmio;
static void wdt_timer_tick(struct timer_list *unused);
static DEFINE_TIMER(timer, wdt_timer_tick);
/* The timer that pings the watchdog */
static unsigned long next_heartbeat; /* the next_heartbeat for the timer */
static inline void wdt_reset(void)
{
unsigned int ctl = readl(wdt_mem);
writel(ctl | VIA_WDT_TRIGGER, wdt_mem);
}
/*
* Timer tick: the timer will make sure that the watchdog timer hardware
* is being reset in time. The conditions to do this are:
* 1) the watchdog timer has been started and /dev/watchdog is open
* and there is still time left before userspace should send the
* next heartbeat/ping. (note: the internal heartbeat is much smaller
* then the external/userspace heartbeat).
* 2) the watchdog timer has been stopped by userspace.
*/
static void wdt_timer_tick(struct timer_list *unused)
{
if (time_before(jiffies, next_heartbeat) ||
(!watchdog_active(&wdt_dev))) {
wdt_reset();
mod_timer(&timer, jiffies + WDT_HEARTBEAT);
} else
pr_crit("I will reboot your machine !\n");
}
static int wdt_ping(struct watchdog_device *wdd)
{
/* calculate when the next userspace timeout will be */
next_heartbeat = jiffies + wdd->timeout * HZ;
return 0;
}
static int wdt_start(struct watchdog_device *wdd)
{
unsigned int ctl = readl(wdt_mem);
writel(wdd->timeout, wdt_mem + VIA_WDT_COUNT);
writel(ctl | VIA_WDT_RUNNING | VIA_WDT_TRIGGER, wdt_mem);
wdt_ping(wdd);
mod_timer(&timer, jiffies + WDT_HEARTBEAT);
return 0;
}
static int wdt_stop(struct watchdog_device *wdd)
{
unsigned int ctl = readl(wdt_mem);
writel(ctl & ~VIA_WDT_RUNNING, wdt_mem);
return 0;
}
static int wdt_set_timeout(struct watchdog_device *wdd,
unsigned int new_timeout)
{
writel(new_timeout, wdt_mem + VIA_WDT_COUNT);
wdd->timeout = new_timeout;
return 0;
}
static const struct watchdog_info wdt_info = {
.identity = "VIA watchdog",
.options = WDIOF_CARDRESET |
WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE |
WDIOF_KEEPALIVEPING,
};
static const struct watchdog_ops wdt_ops = {
.owner = THIS_MODULE,
.start = wdt_start,
.stop = wdt_stop,
.ping = wdt_ping,
.set_timeout = wdt_set_timeout,
};
static struct watchdog_device wdt_dev = {
.info = &wdt_info,
.ops = &wdt_ops,
.min_timeout = 1,
.max_timeout = WDT_TIMEOUT_MAX,
};
static int wdt_probe(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
unsigned char conf;
int ret = -ENODEV;
if (pci_enable_device(pdev)) {
dev_err(&pdev->dev, "cannot enable PCI device\n");
return -ENODEV;
}
/*
* Allocate a MMIO region which contains watchdog control register
* and counter, then configure the watchdog to use this region.
* This is possible only if PnP is properly enabled in BIOS.
* If not, the watchdog must be configured in BIOS manually.
*/
if (allocate_resource(&iomem_resource, &wdt_res, VIA_WDT_MMIO_LEN,
0xf0000000, 0xffffff00, 0xff, NULL, NULL)) {
dev_err(&pdev->dev, "MMIO allocation failed\n");
goto err_out_disable_device;
}
pci_write_config_dword(pdev, VIA_WDT_MMIO_BASE, wdt_res.start);
pci_read_config_byte(pdev, VIA_WDT_CONF, &conf);
conf |= VIA_WDT_CONF_ENABLE | VIA_WDT_CONF_MMIO;
pci_write_config_byte(pdev, VIA_WDT_CONF, conf);
pci_read_config_dword(pdev, VIA_WDT_MMIO_BASE, &mmio);
if (mmio) {
dev_info(&pdev->dev, "VIA Chipset watchdog MMIO: %x\n", mmio);
} else {
dev_err(&pdev->dev, "MMIO setting failed. Check BIOS.\n");
goto err_out_resource;
}
if (!request_mem_region(mmio, VIA_WDT_MMIO_LEN, "via_wdt")) {
dev_err(&pdev->dev, "MMIO region busy\n");
goto err_out_resource;
}
wdt_mem = ioremap(mmio, VIA_WDT_MMIO_LEN);
if (wdt_mem == NULL) {
dev_err(&pdev->dev, "cannot remap VIA wdt MMIO registers\n");
goto err_out_release;
}
if (timeout < 1 || timeout > WDT_TIMEOUT_MAX)
timeout = WDT_TIMEOUT;
wdt_dev.timeout = timeout;
wdt_dev.parent = &pdev->dev;
watchdog_set_nowayout(&wdt_dev, nowayout);
if (readl(wdt_mem) & VIA_WDT_FIRED)
wdt_dev.bootstatus |= WDIOF_CARDRESET;
ret = watchdog_register_device(&wdt_dev);
if (ret)
goto err_out_iounmap;
/* start triggering, in case of watchdog already enabled by BIOS */
mod_timer(&timer, jiffies + WDT_HEARTBEAT);
return 0;
err_out_iounmap:
iounmap(wdt_mem);
err_out_release:
release_mem_region(mmio, VIA_WDT_MMIO_LEN);
err_out_resource:
release_resource(&wdt_res);
err_out_disable_device:
pci_disable_device(pdev);
return ret;
}
static void wdt_remove(struct pci_dev *pdev)
{
watchdog_unregister_device(&wdt_dev);
del_timer_sync(&timer);
iounmap(wdt_mem);
release_mem_region(mmio, VIA_WDT_MMIO_LEN);
release_resource(&wdt_res);
pci_disable_device(pdev);
}
static const struct pci_device_id 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 = wdt_remove,
};
module_pci_driver(wdt_driver);
MODULE_AUTHOR("Marc Vertes");
MODULE_DESCRIPTION("Driver for watchdog timer on VIA chipset");
MODULE_LICENSE("GPL");
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