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