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
 19static void __iomem *cpu_reset_base;
 20static size_t cpu_reset_size;
 21
 22#define CPU_RESET_OFFSET(cpu) (cpu * 0x8)
 23#define CPU_RESET_ASSERT      BIT(0)
 24
 25int mvebu_cpu_reset_deassert(int cpu)
 26{
 27	u32 reg;
 28
 29	if (!cpu_reset_base)
 30		return -ENODEV;
 31
 32	if (CPU_RESET_OFFSET(cpu) >= cpu_reset_size)
 33		return -EINVAL;
 34
 35	reg = readl(cpu_reset_base + CPU_RESET_OFFSET(cpu));
 36	reg &= ~CPU_RESET_ASSERT;
 37	writel(reg, cpu_reset_base + CPU_RESET_OFFSET(cpu));
 38
 39	return 0;
 40}
 41
 42static int mvebu_cpu_reset_map(struct device_node *np, int res_idx)
 43{
 44	struct resource res;
 45
 46	if (of_address_to_resource(np, res_idx, &res)) {
 47		pr_err("unable to get resource\n");
 48		return -ENOENT;
 49	}
 50
 51	if (!request_mem_region(res.start, resource_size(&res),
 52				np->full_name)) {
 53		pr_err("unable to request region\n");
 54		return -EBUSY;
 55	}
 56
 57	cpu_reset_base = ioremap(res.start, resource_size(&res));
 58	if (!cpu_reset_base) {
 59		pr_err("unable to map registers\n");
 60		release_mem_region(res.start, resource_size(&res));
 61		return -ENOMEM;
 62	}
 63
 64	cpu_reset_size = resource_size(&res);
 65
 66	return 0;
 67}
 68
 69static int __init mvebu_cpu_reset_init(void)
 70{
 71	struct device_node *np;
 72	int res_idx;
 73	int ret;
 74
 75	np = of_find_compatible_node(NULL, NULL,
 76				     "marvell,armada-370-cpu-reset");
 77	if (np) {
 78		res_idx = 0;
 79	} else {
 80		/*
 81		 * This code is kept for backward compatibility with
 82		 * old Device Trees.
 83		 */
 84		np = of_find_compatible_node(NULL, NULL,
 85					     "marvell,armada-370-xp-pmsu");
 86		if (np) {
 87			pr_warn(FW_WARN "deprecated pmsu binding\n");
 88			res_idx = 1;
 89		}
 90	}
 91
 92	/* No reset node found */
 93	if (!np)
 94		return -ENODEV;
 95
 96	ret = mvebu_cpu_reset_map(np, res_idx);
 97	of_node_put(np);
 98
 99	return ret;
100}
101
102early_initcall(mvebu_cpu_reset_init);