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