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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da9055_wdt.c (4136B)

      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * System monitoring driver for DA9055 PMICs.
      4 *
      5 * Copyright(c) 2012 Dialog Semiconductor Ltd.
      6 *
      7 * Author: David Dajun Chen <dchen@diasemi.com>
      8 *
      9 */
     10
     11#include <linux/module.h>
     12#include <linux/types.h>
     13#include <linux/kernel.h>
     14#include <linux/slab.h>
     15#include <linux/platform_device.h>
     16#include <linux/watchdog.h>
     17#include <linux/delay.h>
     18
     19#include <linux/mfd/da9055/core.h>
     20#include <linux/mfd/da9055/reg.h>
     21
     22static bool nowayout = WATCHDOG_NOWAYOUT;
     23module_param(nowayout, bool, 0);
     24MODULE_PARM_DESC(nowayout,
     25		 "Watchdog cannot be stopped once started (default="
     26		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
     27
     28#define DA9055_DEF_TIMEOUT	4
     29#define DA9055_TWDMIN		256
     30
     31struct da9055_wdt_data {
     32	struct watchdog_device wdt;
     33	struct da9055 *da9055;
     34};
     35
     36static const struct {
     37	u8 reg_val;
     38	int user_time;  /* In seconds */
     39} da9055_wdt_maps[] = {
     40	{ 0, 0 },
     41	{ 1, 2 },
     42	{ 2, 4 },
     43	{ 3, 8 },
     44	{ 4, 16 },
     45	{ 5, 32 },
     46	{ 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
     47	{ 6, 65 },
     48	{ 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
     49	{ 7, 131 },
     50};
     51
     52static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev,
     53				  unsigned int timeout)
     54{
     55	struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
     56	struct da9055 *da9055 = driver_data->da9055;
     57	int ret, i;
     58
     59	for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++)
     60		if (da9055_wdt_maps[i].user_time == timeout)
     61			break;
     62
     63	if (i == ARRAY_SIZE(da9055_wdt_maps))
     64		ret = -EINVAL;
     65	else
     66		ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
     67					DA9055_TWDSCALE_MASK,
     68					da9055_wdt_maps[i].reg_val <<
     69					DA9055_TWDSCALE_SHIFT);
     70	if (ret < 0) {
     71		dev_err(da9055->dev,
     72			"Failed to update timescale bit, %d\n", ret);
     73		return ret;
     74	}
     75
     76	wdt_dev->timeout = timeout;
     77
     78	return 0;
     79}
     80
     81static int da9055_wdt_ping(struct watchdog_device *wdt_dev)
     82{
     83	struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
     84	struct da9055 *da9055 = driver_data->da9055;
     85
     86	/*
     87	 * We have a minimum time for watchdog window called TWDMIN. A write
     88	 * to the watchdog before this elapsed time will cause an error.
     89	 */
     90	mdelay(DA9055_TWDMIN);
     91
     92	/* Reset the watchdog timer */
     93	return da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
     94				 DA9055_WATCHDOG_MASK, 1);
     95}
     96
     97static int da9055_wdt_start(struct watchdog_device *wdt_dev)
     98{
     99	return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
    100}
    101
    102static int da9055_wdt_stop(struct watchdog_device *wdt_dev)
    103{
    104	return da9055_wdt_set_timeout(wdt_dev, 0);
    105}
    106
    107static const struct watchdog_info da9055_wdt_info = {
    108	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
    109	.identity	= "DA9055 Watchdog",
    110};
    111
    112static const struct watchdog_ops da9055_wdt_ops = {
    113	.owner = THIS_MODULE,
    114	.start = da9055_wdt_start,
    115	.stop = da9055_wdt_stop,
    116	.ping = da9055_wdt_ping,
    117	.set_timeout = da9055_wdt_set_timeout,
    118};
    119
    120static int da9055_wdt_probe(struct platform_device *pdev)
    121{
    122	struct device *dev = &pdev->dev;
    123	struct da9055 *da9055 = dev_get_drvdata(dev->parent);
    124	struct da9055_wdt_data *driver_data;
    125	struct watchdog_device *da9055_wdt;
    126	int ret;
    127
    128	driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
    129	if (!driver_data)
    130		return -ENOMEM;
    131
    132	driver_data->da9055 = da9055;
    133
    134	da9055_wdt = &driver_data->wdt;
    135
    136	da9055_wdt->timeout = DA9055_DEF_TIMEOUT;
    137	da9055_wdt->info = &da9055_wdt_info;
    138	da9055_wdt->ops = &da9055_wdt_ops;
    139	da9055_wdt->parent = dev;
    140	watchdog_set_nowayout(da9055_wdt, nowayout);
    141	watchdog_set_drvdata(da9055_wdt, driver_data);
    142
    143	ret = da9055_wdt_stop(da9055_wdt);
    144	if (ret < 0) {
    145		dev_err(dev, "Failed to stop watchdog, %d\n", ret);
    146		return ret;
    147	}
    148
    149	ret = devm_watchdog_register_device(dev, &driver_data->wdt);
    150	if (ret != 0)
    151		dev_err(da9055->dev, "watchdog_register_device() failed: %d\n",
    152			ret);
    153
    154	return ret;
    155}
    156
    157static struct platform_driver da9055_wdt_driver = {
    158	.probe = da9055_wdt_probe,
    159	.driver = {
    160		.name	= "da9055-watchdog",
    161	},
    162};
    163
    164module_platform_driver(da9055_wdt_driver);
    165
    166MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
    167MODULE_DESCRIPTION("DA9055 watchdog");
    168MODULE_LICENSE("GPL");
    169MODULE_ALIAS("platform:da9055-watchdog");