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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brcm-kona-reset.c (2088B)

      1/*
      2 * Copyright (C) 2016 Broadcom
      3 *
      4 * This program is free software; you can redistribute it and/or
      5 * modify it under the terms of the GNU General Public License as
      6 * published by the Free Software Foundation version 2.
      7 *
      8 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
      9 * kind, whether express or implied; without even the implied warranty
     10 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     11 * GNU General Public License for more details.
     12 */
     13
     14#include <linux/io.h>
     15#include <linux/of_address.h>
     16#include <linux/of_platform.h>
     17#include <linux/reboot.h>
     18
     19#define RSTMGR_REG_WR_ACCESS_OFFSET	0
     20#define RSTMGR_REG_CHIP_SOFT_RST_OFFSET	4
     21
     22#define RSTMGR_WR_PASSWORD		0xa5a5
     23#define RSTMGR_WR_PASSWORD_SHIFT	8
     24#define RSTMGR_WR_ACCESS_ENABLE		1
     25
     26static void __iomem *kona_reset_base;
     27
     28static int kona_reset_handler(struct notifier_block *this,
     29				unsigned long mode, void *cmd)
     30{
     31	/*
     32	 * A soft reset is triggered by writing a 0 to bit 0 of the soft reset
     33	 * register. To write to that register we must first write the password
     34	 * and the enable bit in the write access enable register.
     35	 */
     36	writel((RSTMGR_WR_PASSWORD << RSTMGR_WR_PASSWORD_SHIFT) |
     37		RSTMGR_WR_ACCESS_ENABLE,
     38		kona_reset_base + RSTMGR_REG_WR_ACCESS_OFFSET);
     39	writel(0, kona_reset_base + RSTMGR_REG_CHIP_SOFT_RST_OFFSET);
     40
     41	return NOTIFY_DONE;
     42}
     43
     44static struct notifier_block kona_reset_nb = {
     45	.notifier_call = kona_reset_handler,
     46	.priority = 128,
     47};
     48
     49static int kona_reset_probe(struct platform_device *pdev)
     50{
     51	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
     52
     53	kona_reset_base = devm_ioremap_resource(&pdev->dev, res);
     54	if (IS_ERR(kona_reset_base))
     55		return PTR_ERR(kona_reset_base);
     56
     57	return register_restart_handler(&kona_reset_nb);
     58}
     59
     60static const struct of_device_id of_match[] = {
     61	{ .compatible = "brcm,bcm21664-resetmgr" },
     62	{},
     63};
     64
     65static struct platform_driver bcm_kona_reset_driver = {
     66	.probe = kona_reset_probe,
     67	.driver = {
     68		.name = "brcm-kona-reset",
     69		.of_match_table = of_match,
     70	},
     71};
     72
     73builtin_platform_driver(bcm_kona_reset_driver);