arch/arm/mach-mvebu/cpu-reset.c

   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
  21 static void __iomem *cpu_reset_base;
  22 static size_t cpu_reset_size;
  23
  24 #define CPU_RESET_OFFSET(cpu) (cpu * 0x8)
  25 #define CPU_RESET_ASSERT      BIT(0)
  26
  27 int 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
  44 static 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
  71 static 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
 104 early_initcall(mvebu_cpu_reset_init);