linux/drivers/watchdog/intel-mid_wdt.c
Andy Shevchenko 954351e870 watchdog: intel-mid_wdt: Keep watchdog running
Firmware followed by bootloader leaves watchdog running.

Keep it running in the driver.

User will not need any additional options to reboot in case of panic
during boot.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2017-06-05 20:37:35 +02:00

189 lines
4.6 KiB
C

/*
* intel-mid_wdt: generic Intel MID SCU watchdog driver
*
* Platforms supported so far:
* - Merrifield only
*
* Copyright (C) 2014 Intel Corporation. All rights reserved.
* Contact: David Cohen <david.a.cohen@linux.intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General
* Public License as published by the Free Software Foundation.
*/
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/nmi.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/platform_data/intel-mid_wdt.h>
#include <asm/intel_scu_ipc.h>
#include <asm/intel-mid.h>
#define IPC_WATCHDOG 0xf8
#define MID_WDT_PRETIMEOUT 15
#define MID_WDT_TIMEOUT_MIN (1 + MID_WDT_PRETIMEOUT)
#define MID_WDT_TIMEOUT_MAX 170
#define MID_WDT_DEFAULT_TIMEOUT 90
/* SCU watchdog messages */
enum {
SCU_WATCHDOG_START = 0,
SCU_WATCHDOG_STOP,
SCU_WATCHDOG_KEEPALIVE,
};
static inline int wdt_command(int sub, u32 *in, int inlen)
{
return intel_scu_ipc_command(IPC_WATCHDOG, sub, in, inlen, NULL, 0);
}
static int wdt_start(struct watchdog_device *wd)
{
struct device *dev = watchdog_get_drvdata(wd);
int ret, in_size;
int timeout = wd->timeout;
struct ipc_wd_start {
u32 pretimeout;
u32 timeout;
} ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout };
/*
* SCU expects the input size for watchdog IPC to
* be based on 4 bytes
*/
in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4);
ret = wdt_command(SCU_WATCHDOG_START, (u32 *)&ipc_wd_start, in_size);
if (ret)
dev_crit(dev, "error starting watchdog: %d\n", ret);
return ret;
}
static int wdt_ping(struct watchdog_device *wd)
{
struct device *dev = watchdog_get_drvdata(wd);
int ret;
ret = wdt_command(SCU_WATCHDOG_KEEPALIVE, NULL, 0);
if (ret)
dev_crit(dev, "Error executing keepalive: %d\n", ret);
return ret;
}
static int wdt_stop(struct watchdog_device *wd)
{
struct device *dev = watchdog_get_drvdata(wd);
int ret;
ret = wdt_command(SCU_WATCHDOG_STOP, NULL, 0);
if (ret)
dev_crit(dev, "Error stopping watchdog: %d\n", ret);
return ret;
}
static irqreturn_t mid_wdt_irq(int irq, void *dev_id)
{
panic("Kernel Watchdog");
/* This code should not be reached */
return IRQ_HANDLED;
}
static const struct watchdog_info mid_wdt_info = {
.identity = "Intel MID SCU watchdog",
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops mid_wdt_ops = {
.owner = THIS_MODULE,
.start = wdt_start,
.stop = wdt_stop,
.ping = wdt_ping,
};
static int mid_wdt_probe(struct platform_device *pdev)
{
struct watchdog_device *wdt_dev;
struct intel_mid_wdt_pdata *pdata = pdev->dev.platform_data;
int ret;
if (!pdata) {
dev_err(&pdev->dev, "missing platform data\n");
return -EINVAL;
}
if (pdata->probe) {
ret = pdata->probe(pdev);
if (ret)
return ret;
}
wdt_dev = devm_kzalloc(&pdev->dev, sizeof(*wdt_dev), GFP_KERNEL);
if (!wdt_dev)
return -ENOMEM;
wdt_dev->info = &mid_wdt_info;
wdt_dev->ops = &mid_wdt_ops;
wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN;
wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX;
wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT;
wdt_dev->parent = &pdev->dev;
watchdog_set_drvdata(wdt_dev, &pdev->dev);
ret = devm_request_irq(&pdev->dev, pdata->irq, mid_wdt_irq,
IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog",
wdt_dev);
if (ret) {
dev_err(&pdev->dev, "error requesting warning irq %d\n",
pdata->irq);
return ret;
}
/*
* The firmware followed by U-Boot leaves the watchdog running
* with the default threshold which may vary. When we get here
* we should make a decision to prevent any side effects before
* user space daemon will take care of it. The best option,
* taking into consideration that there is no way to read values
* back from hardware, is to enforce watchdog being run with
* deterministic values.
*/
ret = wdt_start(wdt_dev);
if (ret)
return ret;
/* Make sure the watchdog is serviced */
set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
ret = devm_watchdog_register_device(&pdev->dev, wdt_dev);
if (ret) {
dev_err(&pdev->dev, "error registering watchdog device\n");
return ret;
}
dev_info(&pdev->dev, "Intel MID watchdog device probed\n");
return 0;
}
static struct platform_driver mid_wdt_driver = {
.probe = mid_wdt_probe,
.driver = {
.name = "intel_mid_wdt",
},
};
module_platform_driver(mid_wdt_driver);
MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>");
MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform");
MODULE_LICENSE("GPL");