183 lines
4.5 KiB
C
183 lines
4.5 KiB
C
/*
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* Watchdog driver for Cirrus Logic EP93xx family of devices.
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*
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* Copyright (c) 2004 Ray Lehtiniemi
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* Copyright (c) 2006 Tower Technologies
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* Based on ep93xx driver, bits from alim7101_wdt.c
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*
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* Authors: Ray Lehtiniemi <rayl@mail.com>,
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* Alessandro Zummo <a.zummo@towertech.it>
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*
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* Copyright (c) 2012 H Hartley Sweeten <hsweeten@visionengravers.com>
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* Convert to a platform device and use the watchdog framework API
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*
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* This watchdog fires after 250msec, which is a too short interval
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* for us to rely on the user space daemon alone. So we ping the
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* wdt each ~200msec and eventually stop doing it if the user space
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* daemon dies.
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*
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* TODO:
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*
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* - Test last reset from watchdog status
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* - Add a few missing ioctls
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*/
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#include <linux/platform_device.h>
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#include <linux/module.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/timer.h>
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#include <linux/io.h>
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#define WDT_VERSION "0.4"
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/* default timeout (secs) */
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#define WDT_TIMEOUT 30
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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");
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static unsigned int timeout = WDT_TIMEOUT;
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module_param(timeout, uint, 0);
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MODULE_PARM_DESC(timeout,
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"Watchdog timeout in seconds. (1<=timeout<=3600, default="
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__MODULE_STRING(WDT_TIMEOUT) ")");
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static void __iomem *mmio_base;
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static struct timer_list timer;
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static unsigned long next_heartbeat;
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#define EP93XX_WATCHDOG 0x00
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#define EP93XX_WDSTATUS 0x04
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/* reset the wdt every ~200ms - the heartbeat of the device is 0.250 seconds*/
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#define WDT_INTERVAL (HZ/5)
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static void ep93xx_wdt_timer_ping(unsigned long data)
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{
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if (time_before(jiffies, next_heartbeat))
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writel(0x5555, mmio_base + EP93XX_WATCHDOG);
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/* Re-set the timer interval */
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mod_timer(&timer, jiffies + WDT_INTERVAL);
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}
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static int ep93xx_wdt_start(struct watchdog_device *wdd)
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{
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next_heartbeat = jiffies + (timeout * HZ);
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writel(0xaaaa, mmio_base + EP93XX_WATCHDOG);
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mod_timer(&timer, jiffies + WDT_INTERVAL);
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return 0;
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}
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static int ep93xx_wdt_stop(struct watchdog_device *wdd)
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{
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del_timer_sync(&timer);
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writel(0xaa55, mmio_base + EP93XX_WATCHDOG);
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return 0;
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}
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static int ep93xx_wdt_keepalive(struct watchdog_device *wdd)
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{
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/* user land ping */
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next_heartbeat = jiffies + (timeout * HZ);
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return 0;
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}
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static const struct watchdog_info ep93xx_wdt_ident = {
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.options = WDIOF_CARDRESET |
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WDIOF_MAGICCLOSE |
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WDIOF_KEEPALIVEPING,
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.identity = "EP93xx Watchdog",
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};
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static struct watchdog_ops ep93xx_wdt_ops = {
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.owner = THIS_MODULE,
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.start = ep93xx_wdt_start,
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.stop = ep93xx_wdt_stop,
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.ping = ep93xx_wdt_keepalive,
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};
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static struct watchdog_device ep93xx_wdt_wdd = {
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.info = &ep93xx_wdt_ident,
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.ops = &ep93xx_wdt_ops,
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};
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static int ep93xx_wdt_probe(struct platform_device *pdev)
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{
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struct resource *res;
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unsigned long val;
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int err;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res)
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return -ENXIO;
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if (!devm_request_mem_region(&pdev->dev, res->start,
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resource_size(res), pdev->name))
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return -EBUSY;
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mmio_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
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if (!mmio_base)
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return -ENXIO;
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if (timeout < 1 || timeout > 3600) {
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timeout = WDT_TIMEOUT;
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dev_warn(&pdev->dev,
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"timeout value must be 1<=x<=3600, using %d\n",
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timeout);
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}
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val = readl(mmio_base + EP93XX_WATCHDOG);
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ep93xx_wdt_wdd.bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0;
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ep93xx_wdt_wdd.timeout = timeout;
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watchdog_set_nowayout(&ep93xx_wdt_wdd, nowayout);
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setup_timer(&timer, ep93xx_wdt_timer_ping, 1);
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err = watchdog_register_device(&ep93xx_wdt_wdd);
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if (err)
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return err;
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dev_info(&pdev->dev,
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"EP93XX watchdog, driver version " WDT_VERSION "%s\n",
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(val & 0x08) ? " (nCS1 disable detected)" : "");
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return 0;
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}
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static int ep93xx_wdt_remove(struct platform_device *pdev)
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{
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watchdog_unregister_device(&ep93xx_wdt_wdd);
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return 0;
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}
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static struct platform_driver ep93xx_wdt_driver = {
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.driver = {
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.owner = THIS_MODULE,
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.name = "ep93xx-wdt",
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},
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.probe = ep93xx_wdt_probe,
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.remove = ep93xx_wdt_remove,
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};
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module_platform_driver(ep93xx_wdt_driver);
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MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>,"
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"Alessandro Zummo <a.zummo@towertech.it>,"
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"H Hartley Sweeten <hsweeten@visionengravers.com>");
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MODULE_DESCRIPTION("EP93xx Watchdog");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(WDT_VERSION);
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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