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); 103