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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txx9wdt.c (4458B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
      4 *
      5 * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
      6 */
      7
      8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
      9
     10#include <linux/module.h>
     11#include <linux/moduleparam.h>
     12#include <linux/types.h>
     13#include <linux/watchdog.h>
     14#include <linux/init.h>
     15#include <linux/platform_device.h>
     16#include <linux/clk.h>
     17#include <linux/err.h>
     18#include <linux/io.h>
     19#include <asm/txx9tmr.h>
     20
     21#define WD_TIMER_CCD	7		/* 1/256 */
     22#define WD_TIMER_CLK	(clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
     23#define WD_MAX_TIMEOUT	((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
     24#define TIMER_MARGIN	60		/* Default is 60 seconds */
     25
     26static unsigned int timeout = TIMER_MARGIN;	/* in seconds */
     27module_param(timeout, uint, 0);
     28MODULE_PARM_DESC(timeout,
     29	"Watchdog timeout in seconds. "
     30	"(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
     31	"default=" __MODULE_STRING(TIMER_MARGIN) ")");
     32
     33static bool nowayout = WATCHDOG_NOWAYOUT;
     34module_param(nowayout, bool, 0);
     35MODULE_PARM_DESC(nowayout,
     36	"Watchdog cannot be stopped once started "
     37	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
     38
     39static struct txx9_tmr_reg __iomem *txx9wdt_reg;
     40static struct clk *txx9_imclk;
     41static DEFINE_SPINLOCK(txx9_lock);
     42
     43static int txx9wdt_ping(struct watchdog_device *wdt_dev)
     44{
     45	spin_lock(&txx9_lock);
     46	__raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
     47	spin_unlock(&txx9_lock);
     48	return 0;
     49}
     50
     51static int txx9wdt_start(struct watchdog_device *wdt_dev)
     52{
     53	spin_lock(&txx9_lock);
     54	__raw_writel(WD_TIMER_CLK * wdt_dev->timeout, &txx9wdt_reg->cpra);
     55	__raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
     56	__raw_writel(0, &txx9wdt_reg->tisr);	/* clear pending interrupt */
     57	__raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
     58		     &txx9wdt_reg->tcr);
     59	__raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
     60	spin_unlock(&txx9_lock);
     61	return 0;
     62}
     63
     64static int txx9wdt_stop(struct watchdog_device *wdt_dev)
     65{
     66	spin_lock(&txx9_lock);
     67	__raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
     68	__raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
     69		     &txx9wdt_reg->tcr);
     70	spin_unlock(&txx9_lock);
     71	return 0;
     72}
     73
     74static int txx9wdt_set_timeout(struct watchdog_device *wdt_dev,
     75			       unsigned int new_timeout)
     76{
     77	wdt_dev->timeout = new_timeout;
     78	txx9wdt_stop(wdt_dev);
     79	txx9wdt_start(wdt_dev);
     80	return 0;
     81}
     82
     83static const struct watchdog_info txx9wdt_info = {
     84	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
     85	.identity = "Hardware Watchdog for TXx9",
     86};
     87
     88static const struct watchdog_ops txx9wdt_ops = {
     89	.owner = THIS_MODULE,
     90	.start = txx9wdt_start,
     91	.stop = txx9wdt_stop,
     92	.ping = txx9wdt_ping,
     93	.set_timeout = txx9wdt_set_timeout,
     94};
     95
     96static struct watchdog_device txx9wdt = {
     97	.info = &txx9wdt_info,
     98	.ops = &txx9wdt_ops,
     99};
    100
    101static int __init txx9wdt_probe(struct platform_device *dev)
    102{
    103	int ret;
    104
    105	txx9_imclk = clk_get(NULL, "imbus_clk");
    106	if (IS_ERR(txx9_imclk)) {
    107		ret = PTR_ERR(txx9_imclk);
    108		txx9_imclk = NULL;
    109		goto exit;
    110	}
    111	ret = clk_prepare_enable(txx9_imclk);
    112	if (ret) {
    113		clk_put(txx9_imclk);
    114		txx9_imclk = NULL;
    115		goto exit;
    116	}
    117
    118	txx9wdt_reg = devm_platform_ioremap_resource(dev, 0);
    119	if (IS_ERR(txx9wdt_reg)) {
    120		ret = PTR_ERR(txx9wdt_reg);
    121		goto exit;
    122	}
    123
    124	if (timeout < 1 || timeout > WD_MAX_TIMEOUT)
    125		timeout = TIMER_MARGIN;
    126	txx9wdt.timeout = timeout;
    127	txx9wdt.min_timeout = 1;
    128	txx9wdt.max_timeout = WD_MAX_TIMEOUT;
    129	txx9wdt.parent = &dev->dev;
    130	watchdog_set_nowayout(&txx9wdt, nowayout);
    131
    132	ret = watchdog_register_device(&txx9wdt);
    133	if (ret)
    134		goto exit;
    135
    136	pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n",
    137		timeout, WD_MAX_TIMEOUT, nowayout);
    138
    139	return 0;
    140exit:
    141	if (txx9_imclk) {
    142		clk_disable_unprepare(txx9_imclk);
    143		clk_put(txx9_imclk);
    144	}
    145	return ret;
    146}
    147
    148static int __exit txx9wdt_remove(struct platform_device *dev)
    149{
    150	watchdog_unregister_device(&txx9wdt);
    151	clk_disable_unprepare(txx9_imclk);
    152	clk_put(txx9_imclk);
    153	return 0;
    154}
    155
    156static void txx9wdt_shutdown(struct platform_device *dev)
    157{
    158	txx9wdt_stop(&txx9wdt);
    159}
    160
    161static struct platform_driver txx9wdt_driver = {
    162	.remove = __exit_p(txx9wdt_remove),
    163	.shutdown = txx9wdt_shutdown,
    164	.driver = {
    165		.name = "txx9wdt",
    166	},
    167};
    168
    169module_platform_driver_probe(txx9wdt_driver, txx9wdt_probe);
    170
    171MODULE_DESCRIPTION("TXx9 Watchdog Driver");
    172MODULE_LICENSE("GPL");
    173MODULE_ALIAS("platform:txx9wdt");