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); 105