diff options
Diffstat (limited to 'drivers/watchdog/ebc-c384_wdt.c')
| -rw-r--r-- | drivers/watchdog/ebc-c384_wdt.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/watchdog/ebc-c384_wdt.c b/drivers/watchdog/ebc-c384_wdt.c new file mode 100644 index 000000000..77fda0b4b --- /dev/null +++ b/drivers/watchdog/ebc-c384_wdt.c @@ -0,0 +1,188 @@ +/* + * 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); |