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