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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axxia-reset.c (2275B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Reset driver for Axxia devices
      4 *
      5 * Copyright (C) 2014 LSI
      6 */
      7#include <linux/init.h>
      8#include <linux/err.h>
      9#include <linux/io.h>
     10#include <linux/kernel.h>
     11#include <linux/mfd/syscon.h>
     12#include <linux/module.h>
     13#include <linux/notifier.h>
     14#include <linux/of.h>
     15#include <linux/platform_device.h>
     16#include <linux/reboot.h>
     17#include <linux/regmap.h>
     18
     19#define SC_CRIT_WRITE_KEY	0x1000
     20#define SC_LATCH_ON_RESET	0x1004
     21#define SC_RESET_CONTROL	0x1008
     22#define   RSTCTL_RST_ZERO	(1<<3)
     23#define   RSTCTL_RST_FAB	(1<<2)
     24#define   RSTCTL_RST_CHIP	(1<<1)
     25#define   RSTCTL_RST_SYS	(1<<0)
     26#define SC_EFUSE_INT_STATUS	0x180c
     27#define   EFUSE_READ_DONE	(1<<31)
     28
     29static struct regmap *syscon;
     30
     31static int axxia_restart_handler(struct notifier_block *this,
     32				 unsigned long mode, void *cmd)
     33{
     34	/* Access Key (0xab) */
     35	regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab);
     36	/* Select internal boot from 0xffff0000 */
     37	regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040);
     38	/* Assert ResetReadDone (to avoid hanging in boot ROM) */
     39	regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE);
     40	/* Assert chip reset */
     41	regmap_update_bits(syscon, SC_RESET_CONTROL,
     42			   RSTCTL_RST_CHIP, RSTCTL_RST_CHIP);
     43
     44	return NOTIFY_DONE;
     45}
     46
     47static struct notifier_block axxia_restart_nb = {
     48	.notifier_call = axxia_restart_handler,
     49	.priority = 128,
     50};
     51
     52static int axxia_reset_probe(struct platform_device *pdev)
     53{
     54	struct device *dev = &pdev->dev;
     55	int err;
     56
     57	syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
     58	if (IS_ERR(syscon)) {
     59		pr_err("%pOFn: syscon lookup failed\n", dev->of_node);
     60		return PTR_ERR(syscon);
     61	}
     62
     63	err = register_restart_handler(&axxia_restart_nb);
     64	if (err)
     65		dev_err(dev, "cannot register restart handler (err=%d)\n", err);
     66
     67	return err;
     68}
     69
     70static const struct of_device_id of_axxia_reset_match[] = {
     71	{ .compatible = "lsi,axm55xx-reset", },
     72	{},
     73};
     74MODULE_DEVICE_TABLE(of, of_axxia_reset_match);
     75
     76static struct platform_driver axxia_reset_driver = {
     77	.probe = axxia_reset_probe,
     78	.driver = {
     79		.name = "axxia-reset",
     80		.of_match_table = of_match_ptr(of_axxia_reset_match),
     81	},
     82};
     83
     84static int __init axxia_reset_init(void)
     85{
     86	return platform_driver_register(&axxia_reset_driver);
     87}
     88device_initcall(axxia_reset_init);