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/*
* Watchdog timer driver for the WinSystems EBC-C384
* Copyright (C) 2016 William Breathitt Gray
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <linux/device.h>
#include <linux/dmi.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#define MODULE_NAME "ebc-c384_wdt"
#define WATCHDOG_TIMEOUT 60
/*
* The timeout value in minutes must fit in a single byte when sent to the
* watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds.
*/
#define WATCHDOG_MAX_TIMEOUT 15300
#define BASE_ADDR 0x564
#define ADDR_EXTENT 5
#define CFG_ADDR (BASE_ADDR + 1)
#define PET_ADDR (BASE_ADDR + 2)
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 unsigned timeout;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
static int ebc_c384_wdt_start(struct watchdog_device *wdev)
{
unsigned t = wdev->timeout;
/* resolution is in minutes for timeouts greater than 255 seconds */
if (t > 255)
t = DIV_ROUND_UP(t, 60);
outb(t, PET_ADDR);
return 0;
}
static int ebc_c384_wdt_stop(struct watchdog_device *wdev)
{
outb(0x00, PET_ADDR);
return 0;
}
static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t)
{
/* resolution is in minutes for timeouts greater than 255 seconds */
if (t > 255) {
/* round second resolution up to minute granularity */
wdev->timeout = roundup(t, 60);
/* set watchdog timer for minutes */
outb(0x00, CFG_ADDR);
} else {
wdev->timeout = t;
/* set watchdog timer for seconds */
outb(0x80, CFG_ADDR);
}
return 0;
}
static const struct watchdog_ops ebc_c384_wdt_ops = {
.start = ebc_c384_wdt_start,
.stop = ebc_c384_wdt_stop,
.set_timeout = ebc_c384_wdt_set_timeout
};
static const struct watchdog_info ebc_c384_wdt_info = {
.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT,
.identity = MODULE_NAME
};
static int __init ebc_c384_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct watchdog_device *wdd;
if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
BASE_ADDR, BASE_ADDR + ADDR_EXTENT);
return -EBUSY;
}
wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
if (!wdd)
return -ENOMEM;
wdd->info = &ebc_c384_wdt_info;
wdd->ops = &ebc_c384_wdt_ops;
wdd->timeout = WATCHDOG_TIMEOUT;
wdd->min_timeout = 1;
wdd->max_timeout = WATCHDOG_MAX_TIMEOUT;
watchdog_set_nowayout(wdd, nowayout);
if (watchdog_init_timeout(wdd, timeout, dev))
dev_warn(dev, "Invalid timeout (%u seconds), using default (%u seconds)\n",
timeout, WATCHDOG_TIMEOUT);
platform_set_drvdata(pdev, wdd);
return watchdog_register_device(wdd);
}
static int ebc_c384_wdt_remove(struct platform_device *pdev)
{
struct watchdog_device *wdd = platform_get_drvdata(pdev);
watchdog_unregister_device(wdd);
return 0;
}
static struct platform_driver ebc_c384_wdt_driver = {
.driver = {
.name = MODULE_NAME
},
.remove = ebc_c384_wdt_remove
};
static struct platform_device *ebc_c384_wdt_device;
static int __init ebc_c384_wdt_init(void)
{
int err;
if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC"))
return -ENODEV;
ebc_c384_wdt_device = platform_device_alloc(MODULE_NAME, -1);
if (!ebc_c384_wdt_device)
return -ENOMEM;
err = platform_device_add(ebc_c384_wdt_device);
if (err)
goto err_platform_device;
err = platform_driver_probe(&ebc_c384_wdt_driver, ebc_c384_wdt_probe);
if (err)
goto err_platform_driver;
return 0;
err_platform_driver:
platform_device_del(ebc_c384_wdt_device);
err_platform_device:
platform_device_put(ebc_c384_wdt_device);
return err;
}
static void __exit ebc_c384_wdt_exit(void)
{
platform_device_unregister(ebc_c384_wdt_device);
platform_driver_unregister(&ebc_c384_wdt_driver);
}
module_init(ebc_c384_wdt_init);
module_exit(ebc_c384_wdt_exit);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" MODULE_NAME);
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