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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ebc-c384_wdt.c (3563B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Watchdog timer driver for the WinSystems EBC-C384
      4 * Copyright (C) 2016 William Breathitt Gray
      5 */
      6#include <linux/device.h>
      7#include <linux/dmi.h>
      8#include <linux/errno.h>
      9#include <linux/io.h>
     10#include <linux/ioport.h>
     11#include <linux/isa.h>
     12#include <linux/kernel.h>
     13#include <linux/module.h>
     14#include <linux/moduleparam.h>
     15#include <linux/types.h>
     16#include <linux/watchdog.h>
     17
     18#define MODULE_NAME		"ebc-c384_wdt"
     19#define WATCHDOG_TIMEOUT	60
     20/*
     21 * The timeout value in minutes must fit in a single byte when sent to the
     22 * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds.
     23 */
     24#define WATCHDOG_MAX_TIMEOUT	15300
     25#define BASE_ADDR		0x564
     26#define ADDR_EXTENT		5
     27#define CFG_ADDR		(BASE_ADDR + 1)
     28#define PET_ADDR		(BASE_ADDR + 2)
     29
     30static bool nowayout = WATCHDOG_NOWAYOUT;
     31module_param(nowayout, bool, 0);
     32MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
     33	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
     34
     35static unsigned timeout;
     36module_param(timeout, uint, 0);
     37MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
     38	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
     39
     40static int ebc_c384_wdt_start(struct watchdog_device *wdev)
     41{
     42	unsigned t = wdev->timeout;
     43
     44	/* resolution is in minutes for timeouts greater than 255 seconds */
     45	if (t > 255)
     46		t = DIV_ROUND_UP(t, 60);
     47
     48	outb(t, PET_ADDR);
     49
     50	return 0;
     51}
     52
     53static int ebc_c384_wdt_stop(struct watchdog_device *wdev)
     54{
     55	outb(0x00, PET_ADDR);
     56
     57	return 0;
     58}
     59
     60static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t)
     61{
     62	/* resolution is in minutes for timeouts greater than 255 seconds */
     63	if (t > 255) {
     64		/* round second resolution up to minute granularity */
     65		wdev->timeout = roundup(t, 60);
     66
     67		/* set watchdog timer for minutes */
     68		outb(0x00, CFG_ADDR);
     69	} else {
     70		wdev->timeout = t;
     71
     72		/* set watchdog timer for seconds */
     73		outb(0x80, CFG_ADDR);
     74	}
     75
     76	return 0;
     77}
     78
     79static const struct watchdog_ops ebc_c384_wdt_ops = {
     80	.start = ebc_c384_wdt_start,
     81	.stop = ebc_c384_wdt_stop,
     82	.set_timeout = ebc_c384_wdt_set_timeout
     83};
     84
     85static const struct watchdog_info ebc_c384_wdt_info = {
     86	.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT,
     87	.identity = MODULE_NAME
     88};
     89
     90static int ebc_c384_wdt_probe(struct device *dev, unsigned int id)
     91{
     92	struct watchdog_device *wdd;
     93
     94	if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) {
     95		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
     96			BASE_ADDR, BASE_ADDR + ADDR_EXTENT);
     97		return -EBUSY;
     98	}
     99
    100	wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
    101	if (!wdd)
    102		return -ENOMEM;
    103
    104	wdd->info = &ebc_c384_wdt_info;
    105	wdd->ops = &ebc_c384_wdt_ops;
    106	wdd->timeout = WATCHDOG_TIMEOUT;
    107	wdd->min_timeout = 1;
    108	wdd->max_timeout = WATCHDOG_MAX_TIMEOUT;
    109
    110	watchdog_set_nowayout(wdd, nowayout);
    111	watchdog_init_timeout(wdd, timeout, dev);
    112
    113	return devm_watchdog_register_device(dev, wdd);
    114}
    115
    116static struct isa_driver ebc_c384_wdt_driver = {
    117	.probe = ebc_c384_wdt_probe,
    118	.driver = {
    119		.name = MODULE_NAME
    120	},
    121};
    122
    123static int __init ebc_c384_wdt_init(void)
    124{
    125	if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC"))
    126		return -ENODEV;
    127
    128	return isa_register_driver(&ebc_c384_wdt_driver, 1);
    129}
    130
    131static void __exit ebc_c384_wdt_exit(void)
    132{
    133	isa_unregister_driver(&ebc_c384_wdt_driver);
    134}
    135
    136module_init(ebc_c384_wdt_init);
    137module_exit(ebc_c384_wdt_exit);
    138
    139MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
    140MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver");
    141MODULE_LICENSE("GPL v2");
    142MODULE_ALIAS("isa:" MODULE_NAME);