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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cpu-reset.c (2181B)

      1/*
      2 * Copyright (C) 2014 Marvell
      3 *
      4 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
      5 *
      6 * This file is licensed under the terms of the GNU General Public
      7 * License version 2.  This program is licensed "as is" without any
      8 * warranty of any kind, whether express or implied.
      9 */
     10
     11#define pr_fmt(fmt) "mvebu-cpureset: " fmt
     12
     13#include <linux/kernel.h>
     14#include <linux/init.h>
     15#include <linux/of_address.h>
     16#include <linux/io.h>
     17#include <linux/resource.h>
     18
     19#include "common.h"
     20
     21static void __iomem *cpu_reset_base;
     22static size_t cpu_reset_size;
     23
     24#define CPU_RESET_OFFSET(cpu) (cpu * 0x8)
     25#define CPU_RESET_ASSERT      BIT(0)
     26
     27int mvebu_cpu_reset_deassert(int cpu)
     28{
     29	u32 reg;
     30
     31	if (!cpu_reset_base)
     32		return -ENODEV;
     33
     34	if (CPU_RESET_OFFSET(cpu) >= cpu_reset_size)
     35		return -EINVAL;
     36
     37	reg = readl(cpu_reset_base + CPU_RESET_OFFSET(cpu));
     38	reg &= ~CPU_RESET_ASSERT;
     39	writel(reg, cpu_reset_base + CPU_RESET_OFFSET(cpu));
     40
     41	return 0;
     42}
     43
     44static int mvebu_cpu_reset_map(struct device_node *np, int res_idx)
     45{
     46	struct resource res;
     47
     48	if (of_address_to_resource(np, res_idx, &res)) {
     49		pr_err("unable to get resource\n");
     50		return -ENOENT;
     51	}
     52
     53	if (!request_mem_region(res.start, resource_size(&res),
     54				np->full_name)) {
     55		pr_err("unable to request region\n");
     56		return -EBUSY;
     57	}
     58
     59	cpu_reset_base = ioremap(res.start, resource_size(&res));
     60	if (!cpu_reset_base) {
     61		pr_err("unable to map registers\n");
     62		release_mem_region(res.start, resource_size(&res));
     63		return -ENOMEM;
     64	}
     65
     66	cpu_reset_size = resource_size(&res);
     67
     68	return 0;
     69}
     70
     71static int __init mvebu_cpu_reset_init(void)
     72{
     73	struct device_node *np;
     74	int res_idx;
     75	int ret;
     76
     77	np = of_find_compatible_node(NULL, NULL,
     78				     "marvell,armada-370-cpu-reset");
     79	if (np) {
     80		res_idx = 0;
     81	} else {
     82		/*
     83		 * This code is kept for backward compatibility with
     84		 * old Device Trees.
     85		 */
     86		np = of_find_compatible_node(NULL, NULL,
     87					     "marvell,armada-370-xp-pmsu");
     88		if (np) {
     89			pr_warn(FW_WARN "deprecated pmsu binding\n");
     90			res_idx = 1;
     91		}
     92	}
     93
     94	/* No reset node found */
     95	if (!np)
     96		return -ENODEV;
     97
     98	ret = mvebu_cpu_reset_map(np, res_idx);
     99	of_node_put(np);
    100
    101	return ret;
    102}
    103
    104early_initcall(mvebu_cpu_reset_init);