1 /* 2 * linux/arch/arm/kernel/devtree.c 3 * 4 * Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 11 #include <linux/init.h> 12 #include <linux/export.h> 13 #include <linux/errno.h> 14 #include <linux/types.h> 15 #include <linux/bootmem.h> 16 #include <linux/memblock.h> 17 #include <linux/of.h> 18 #include <linux/of_fdt.h> 19 #include <linux/of_irq.h> 20 #include <linux/of_platform.h> 21 #include <linux/smp.h> 22 23 #include <asm/cputype.h> 24 #include <asm/setup.h> 25 #include <asm/page.h> 26 #include <asm/smp_plat.h> 27 #include <asm/mach/arch.h> 28 #include <asm/mach-types.h> 29 30 31 #ifdef CONFIG_SMP 32 extern struct of_cpu_method __cpu_method_of_table[]; 33 34 static const struct of_cpu_method __cpu_method_of_table_sentinel 35 __used __section(__cpu_method_of_table_end); 36 37 38 static int __init set_smp_ops_by_method(struct device_node *node) 39 { 40 const char *method; 41 struct of_cpu_method *m = __cpu_method_of_table; 42 43 if (of_property_read_string(node, "enable-method", &method)) 44 return 0; 45 46 for (; m->method; m++) 47 if (!strcmp(m->method, method)) { 48 smp_set_ops(m->ops); 49 return 1; 50 } 51 52 return 0; 53 } 54 #else 55 static inline int set_smp_ops_by_method(struct device_node *node) 56 { 57 return 1; 58 } 59 #endif 60 61 62 /* 63 * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree 64 * and builds the cpu logical map array containing MPIDR values related to 65 * logical cpus 66 * 67 * Updates the cpu possible mask with the number of parsed cpu nodes 68 */ 69 void __init arm_dt_init_cpu_maps(void) 70 { 71 /* 72 * Temp logical map is initialized with UINT_MAX values that are 73 * considered invalid logical map entries since the logical map must 74 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must 75 * read as 0. 76 */ 77 struct device_node *cpu, *cpus; 78 int found_method = 0; 79 u32 i, j, cpuidx = 1; 80 u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0; 81 82 u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID }; 83 bool bootcpu_valid = false; 84 cpus = of_find_node_by_path("/cpus"); 85 86 if (!cpus) 87 return; 88 89 for_each_child_of_node(cpus, cpu) { 90 u32 hwid; 91 92 if (of_node_cmp(cpu->type, "cpu")) 93 continue; 94 95 pr_debug(" * %s...\n", cpu->full_name); 96 /* 97 * A device tree containing CPU nodes with missing "reg" 98 * properties is considered invalid to build the 99 * cpu_logical_map. 100 */ 101 if (of_property_read_u32(cpu, "reg", &hwid)) { 102 pr_debug(" * %s missing reg property\n", 103 cpu->full_name); 104 of_node_put(cpu); 105 return; 106 } 107 108 /* 109 * 8 MSBs must be set to 0 in the DT since the reg property 110 * defines the MPIDR[23:0]. 111 */ 112 if (hwid & ~MPIDR_HWID_BITMASK) { 113 of_node_put(cpu); 114 return; 115 } 116 117 /* 118 * Duplicate MPIDRs are a recipe for disaster. 119 * Scan all initialized entries and check for 120 * duplicates. If any is found just bail out. 121 * temp values were initialized to UINT_MAX 122 * to avoid matching valid MPIDR[23:0] values. 123 */ 124 for (j = 0; j < cpuidx; j++) 125 if (WARN(tmp_map[j] == hwid, 126 "Duplicate /cpu reg properties in the DT\n")) { 127 of_node_put(cpu); 128 return; 129 } 130 131 /* 132 * Build a stashed array of MPIDR values. Numbering scheme 133 * requires that if detected the boot CPU must be assigned 134 * logical id 0. Other CPUs get sequential indexes starting 135 * from 1. If a CPU node with a reg property matching the 136 * boot CPU MPIDR is detected, this is recorded so that the 137 * logical map built from DT is validated and can be used 138 * to override the map created in smp_setup_processor_id(). 139 */ 140 if (hwid == mpidr) { 141 i = 0; 142 bootcpu_valid = true; 143 } else { 144 i = cpuidx++; 145 } 146 147 if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than " 148 "max cores %u, capping them\n", 149 cpuidx, nr_cpu_ids)) { 150 cpuidx = nr_cpu_ids; 151 of_node_put(cpu); 152 break; 153 } 154 155 tmp_map[i] = hwid; 156 157 if (!found_method) 158 found_method = set_smp_ops_by_method(cpu); 159 } 160 161 /* 162 * Fallback to an enable-method in the cpus node if nothing found in 163 * a cpu node. 164 */ 165 if (!found_method) 166 set_smp_ops_by_method(cpus); 167 168 if (!bootcpu_valid) { 169 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n"); 170 return; 171 } 172 173 /* 174 * Since the boot CPU node contains proper data, and all nodes have 175 * a reg property, the DT CPU list can be considered valid and the 176 * logical map created in smp_setup_processor_id() can be overridden 177 */ 178 for (i = 0; i < cpuidx; i++) { 179 set_cpu_possible(i, true); 180 cpu_logical_map(i) = tmp_map[i]; 181 pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i)); 182 } 183 } 184 185 bool arch_match_cpu_phys_id(int cpu, u64 phys_id) 186 { 187 return phys_id == cpu_logical_map(cpu); 188 } 189 190 static const void * __init arch_get_next_mach(const char *const **match) 191 { 192 static const struct machine_desc *mdesc = __arch_info_begin; 193 const struct machine_desc *m = mdesc; 194 195 if (m >= __arch_info_end) 196 return NULL; 197 198 mdesc++; 199 *match = m->dt_compat; 200 return m; 201 } 202 203 /** 204 * setup_machine_fdt - Machine setup when an dtb was passed to the kernel 205 * @dt_phys: physical address of dt blob 206 * 207 * If a dtb was passed to the kernel in r2, then use it to choose the 208 * correct machine_desc and to setup the system. 209 */ 210 const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys) 211 { 212 const struct machine_desc *mdesc, *mdesc_best = NULL; 213 214 #ifdef CONFIG_ARCH_MULTIPLATFORM 215 DT_MACHINE_START(GENERIC_DT, "Generic DT based system") 216 MACHINE_END 217 218 mdesc_best = &__mach_desc_GENERIC_DT; 219 #endif 220 221 if (!dt_phys || !early_init_dt_verify(phys_to_virt(dt_phys))) 222 return NULL; 223 224 mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach); 225 226 if (!mdesc) { 227 const char *prop; 228 int size; 229 unsigned long dt_root; 230 231 early_print("\nError: unrecognized/unsupported " 232 "device tree compatible list:\n[ "); 233 234 dt_root = of_get_flat_dt_root(); 235 prop = of_get_flat_dt_prop(dt_root, "compatible", &size); 236 while (size > 0) { 237 early_print("'%s' ", prop); 238 size -= strlen(prop) + 1; 239 prop += strlen(prop) + 1; 240 } 241 early_print("]\n\n"); 242 243 dump_machine_table(); /* does not return */ 244 } 245 246 /* We really don't want to do this, but sometimes firmware provides buggy data */ 247 if (mdesc->dt_fixup) 248 mdesc->dt_fixup(); 249 250 early_init_dt_scan_nodes(); 251 252 /* Change machine number to match the mdesc we're using */ 253 __machine_arch_type = mdesc->nr; 254 255 return mdesc; 256 } 257