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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menz69_wdt.c (4078B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Watchdog driver for the MEN z069 IP-Core
      4 *
      5 * Copyright (C) 2018 Johannes Thumshirn <jth@kernel.org>
      6 */
      7#include <linux/io.h>
      8#include <linux/kernel.h>
      9#include <linux/mcb.h>
     10#include <linux/module.h>
     11#include <linux/watchdog.h>
     12
     13struct men_z069_drv {
     14	struct watchdog_device wdt;
     15	void __iomem *base;
     16	struct resource *mem;
     17};
     18
     19#define MEN_Z069_WTR			0x10
     20#define MEN_Z069_WTR_WDEN		BIT(15)
     21#define MEN_Z069_WTR_WDET_MASK		0x7fff
     22#define MEN_Z069_WVR			0x14
     23
     24#define MEN_Z069_TIMER_FREQ		500 /* 500 Hz */
     25#define MEN_Z069_WDT_COUNTER_MIN	1
     26#define MEN_Z069_WDT_COUNTER_MAX	0x7fff
     27#define MEN_Z069_DEFAULT_TIMEOUT	30
     28
     29static bool nowayout = WATCHDOG_NOWAYOUT;
     30module_param(nowayout, bool, 0);
     31MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
     32			    __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
     33
     34static int men_z069_wdt_start(struct watchdog_device *wdt)
     35{
     36	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
     37	u16 val;
     38
     39	val = readw(drv->base + MEN_Z069_WTR);
     40	val |= MEN_Z069_WTR_WDEN;
     41	writew(val, drv->base + MEN_Z069_WTR);
     42
     43	return 0;
     44}
     45
     46static int men_z069_wdt_stop(struct watchdog_device *wdt)
     47{
     48	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
     49	u16 val;
     50
     51	val = readw(drv->base + MEN_Z069_WTR);
     52	val &= ~MEN_Z069_WTR_WDEN;
     53	writew(val, drv->base + MEN_Z069_WTR);
     54
     55	return 0;
     56}
     57
     58static int men_z069_wdt_ping(struct watchdog_device *wdt)
     59{
     60	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
     61	u16 val;
     62
     63	/* The watchdog trigger value toggles between 0x5555 and 0xaaaa */
     64	val = readw(drv->base + MEN_Z069_WVR);
     65	val ^= 0xffff;
     66	writew(val, drv->base + MEN_Z069_WVR);
     67
     68	return 0;
     69}
     70
     71static int men_z069_wdt_set_timeout(struct watchdog_device *wdt,
     72				    unsigned int timeout)
     73{
     74	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
     75	u16 reg, val, ena;
     76
     77	wdt->timeout = timeout;
     78	val = timeout * MEN_Z069_TIMER_FREQ;
     79
     80	reg = readw(drv->base + MEN_Z069_WVR);
     81	ena = reg & MEN_Z069_WTR_WDEN;
     82	reg = ena | val;
     83	writew(reg, drv->base + MEN_Z069_WTR);
     84
     85	return 0;
     86}
     87
     88static const struct watchdog_info men_z069_info = {
     89	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
     90	.identity = "MEN z069 Watchdog",
     91};
     92
     93static const struct watchdog_ops men_z069_ops = {
     94	.owner = THIS_MODULE,
     95	.start = men_z069_wdt_start,
     96	.stop = men_z069_wdt_stop,
     97	.ping = men_z069_wdt_ping,
     98	.set_timeout = men_z069_wdt_set_timeout,
     99};
    100
    101static struct watchdog_device men_z069_wdt = {
    102	.info = &men_z069_info,
    103	.ops = &men_z069_ops,
    104	.timeout = MEN_Z069_DEFAULT_TIMEOUT,
    105	.min_timeout = 1,
    106	.max_timeout = MEN_Z069_WDT_COUNTER_MAX / MEN_Z069_TIMER_FREQ,
    107};
    108
    109static int men_z069_probe(struct mcb_device *dev,
    110			  const struct mcb_device_id *id)
    111{
    112	struct men_z069_drv *drv;
    113	struct resource *mem;
    114
    115	drv = devm_kzalloc(&dev->dev, sizeof(struct men_z069_drv), GFP_KERNEL);
    116	if (!drv)
    117		return -ENOMEM;
    118
    119	mem = mcb_request_mem(dev, "z069-wdt");
    120	if (IS_ERR(mem))
    121		return PTR_ERR(mem);
    122
    123	drv->base = devm_ioremap(&dev->dev, mem->start, resource_size(mem));
    124	if (drv->base == NULL)
    125		goto release_mem;
    126
    127	drv->mem = mem;
    128
    129	drv->wdt = men_z069_wdt;
    130	watchdog_init_timeout(&drv->wdt, 0, &dev->dev);
    131	watchdog_set_nowayout(&drv->wdt, nowayout);
    132	watchdog_set_drvdata(&drv->wdt, drv);
    133	drv->wdt.parent = &dev->dev;
    134	mcb_set_drvdata(dev, drv);
    135
    136	return watchdog_register_device(&men_z069_wdt);
    137
    138release_mem:
    139	mcb_release_mem(mem);
    140	return -ENOMEM;
    141}
    142
    143static void men_z069_remove(struct mcb_device *dev)
    144{
    145	struct men_z069_drv *drv = mcb_get_drvdata(dev);
    146
    147	watchdog_unregister_device(&drv->wdt);
    148	mcb_release_mem(drv->mem);
    149}
    150
    151static const struct mcb_device_id men_z069_ids[] = {
    152	{ .device = 0x45 },
    153	{ }
    154};
    155MODULE_DEVICE_TABLE(mcb, men_z069_ids);
    156
    157static struct mcb_driver men_z069_driver = {
    158	.driver = {
    159		.name = "z069-wdt",
    160		.owner = THIS_MODULE,
    161	},
    162	.probe = men_z069_probe,
    163	.remove = men_z069_remove,
    164	.id_table = men_z069_ids,
    165};
    166module_mcb_driver(men_z069_driver);
    167
    168MODULE_AUTHOR("Johannes Thumshirn <jth@kernel.org>");
    169MODULE_LICENSE("GPL v2");
    170MODULE_ALIAS("mcb:16z069");
    171MODULE_IMPORT_NS(MCB);