cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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moxart_wdt.c (4339B)

      1/*
      2 * MOXA ART SoCs watchdog driver.
      3 *
      4 * Copyright (C) 2013 Jonas Jensen
      5 *
      6 * Jonas Jensen <jonas.jensen@gmail.com>
      7 *
      8 * This file is licensed under the terms of the GNU General Public
      9 * License version 2.  This program is licensed "as is" without any
     10 * warranty of any kind, whether express or implied.
     11 */
     12
     13#include <linux/clk.h>
     14#include <linux/io.h>
     15#include <linux/module.h>
     16#include <linux/mod_devicetable.h>
     17#include <linux/err.h>
     18#include <linux/kernel.h>
     19#include <linux/platform_device.h>
     20#include <linux/watchdog.h>
     21#include <linux/moduleparam.h>
     22
     23#define REG_COUNT			0x4
     24#define REG_MODE			0x8
     25#define REG_ENABLE			0xC
     26
     27struct moxart_wdt_dev {
     28	struct watchdog_device dev;
     29	void __iomem *base;
     30	unsigned int clock_frequency;
     31};
     32
     33static int heartbeat;
     34
     35static int moxart_wdt_restart(struct watchdog_device *wdt_dev,
     36			      unsigned long action, void *data)
     37{
     38	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
     39
     40	writel(1, moxart_wdt->base + REG_COUNT);
     41	writel(0x5ab9, moxart_wdt->base + REG_MODE);
     42	writel(0x03, moxart_wdt->base + REG_ENABLE);
     43
     44	return 0;
     45}
     46
     47static int moxart_wdt_stop(struct watchdog_device *wdt_dev)
     48{
     49	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
     50
     51	writel(0, moxart_wdt->base + REG_ENABLE);
     52
     53	return 0;
     54}
     55
     56static int moxart_wdt_start(struct watchdog_device *wdt_dev)
     57{
     58	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
     59
     60	writel(moxart_wdt->clock_frequency * wdt_dev->timeout,
     61	       moxart_wdt->base + REG_COUNT);
     62	writel(0x5ab9, moxart_wdt->base + REG_MODE);
     63	writel(0x03, moxart_wdt->base + REG_ENABLE);
     64
     65	return 0;
     66}
     67
     68static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev,
     69				  unsigned int timeout)
     70{
     71	wdt_dev->timeout = timeout;
     72
     73	return 0;
     74}
     75
     76static const struct watchdog_info moxart_wdt_info = {
     77	.identity       = "moxart-wdt",
     78	.options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
     79			  WDIOF_MAGICCLOSE,
     80};
     81
     82static const struct watchdog_ops moxart_wdt_ops = {
     83	.owner          = THIS_MODULE,
     84	.start          = moxart_wdt_start,
     85	.stop           = moxart_wdt_stop,
     86	.set_timeout    = moxart_wdt_set_timeout,
     87	.restart        = moxart_wdt_restart,
     88};
     89
     90static int moxart_wdt_probe(struct platform_device *pdev)
     91{
     92	struct moxart_wdt_dev *moxart_wdt;
     93	struct device *dev = &pdev->dev;
     94	struct clk *clk;
     95	int err;
     96	unsigned int max_timeout;
     97	bool nowayout = WATCHDOG_NOWAYOUT;
     98
     99	moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL);
    100	if (!moxart_wdt)
    101		return -ENOMEM;
    102
    103	platform_set_drvdata(pdev, moxart_wdt);
    104
    105	moxart_wdt->base = devm_platform_ioremap_resource(pdev, 0);
    106	if (IS_ERR(moxart_wdt->base))
    107		return PTR_ERR(moxart_wdt->base);
    108
    109	clk = devm_clk_get(dev, NULL);
    110	if (IS_ERR(clk)) {
    111		pr_err("%s: of_clk_get failed\n", __func__);
    112		return PTR_ERR(clk);
    113	}
    114
    115	moxart_wdt->clock_frequency = clk_get_rate(clk);
    116	if (moxart_wdt->clock_frequency == 0) {
    117		pr_err("%s: incorrect clock frequency\n", __func__);
    118		return -EINVAL;
    119	}
    120
    121	max_timeout = UINT_MAX / moxart_wdt->clock_frequency;
    122
    123	moxart_wdt->dev.info = &moxart_wdt_info;
    124	moxart_wdt->dev.ops = &moxart_wdt_ops;
    125	moxart_wdt->dev.timeout = max_timeout;
    126	moxart_wdt->dev.min_timeout = 1;
    127	moxart_wdt->dev.max_timeout = max_timeout;
    128	moxart_wdt->dev.parent = dev;
    129
    130	watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev);
    131	watchdog_set_nowayout(&moxart_wdt->dev, nowayout);
    132	watchdog_set_restart_priority(&moxart_wdt->dev, 128);
    133
    134	watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt);
    135
    136	watchdog_stop_on_unregister(&moxart_wdt->dev);
    137	err = devm_watchdog_register_device(dev, &moxart_wdt->dev);
    138	if (err)
    139		return err;
    140
    141	dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",
    142		moxart_wdt->dev.timeout, nowayout);
    143
    144	return 0;
    145}
    146
    147static const struct of_device_id moxart_watchdog_match[] = {
    148	{ .compatible = "moxa,moxart-watchdog" },
    149	{ },
    150};
    151MODULE_DEVICE_TABLE(of, moxart_watchdog_match);
    152
    153static struct platform_driver moxart_wdt_driver = {
    154	.probe      = moxart_wdt_probe,
    155	.driver     = {
    156		.name		= "moxart-watchdog",
    157		.of_match_table	= moxart_watchdog_match,
    158	},
    159};
    160module_platform_driver(moxart_wdt_driver);
    161
    162module_param(heartbeat, int, 0);
    163MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
    164
    165MODULE_DESCRIPTION("MOXART watchdog driver");
    166MODULE_LICENSE("GPL");
    167MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");