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 static void __iomem *cpu_reset_base;
  20 static size_t cpu_reset_size;
  21
  22 #define CPU_RESET_OFFSET(cpu) (cpu * 0x8)
  23 #define CPU_RESET_ASSERT      BIT(0)
  24
  25 int 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
  42 static 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
  69 static 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
 102 early_initcall(mvebu_cpu_reset_init);