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/prom.h> 27 #include <asm/smp_plat.h> 28 #include <asm/mach/arch.h> 29 #include <asm/mach-types.h> 30 31 32 #ifdef CONFIG_SMP 33 extern struct of_cpu_method __cpu_method_of_table[]; 34 35 static const struct of_cpu_method __cpu_method_of_table_sentinel 36 __used __section(__cpu_method_of_table_end); 37 38 39 static int __init set_smp_ops_by_method(struct device_node *node) 40 { 41 const char *method; 42 struct of_cpu_method *m = __cpu_method_of_table; 43 44 if (of_property_read_string(node, "enable-method", &method)) 45 return 0; 46 47 for (; m->method; m++) 48 if (!strcmp(m->method, method)) { 49 smp_set_ops(m->ops); 50 return 1; 51 } 52 53 return 0; 54 } 55 #else 56 static inline int set_smp_ops_by_method(struct device_node *node) 57 { 58 return 1; 59 } 60 #endif 61 62 63 /* 64 * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree 65 * and builds the cpu logical map array containing MPIDR values related to 66 * logical cpus 67 * 68 * Updates the cpu possible mask with the number of parsed cpu nodes 69 */ 70 void __init arm_dt_init_cpu_maps(void) 71 { 72 /* 73 * Temp logical map is initialized with UINT_MAX values that are 74 * considered invalid logical map entries since the logical map must 75 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must 76 * read as 0. 77 */ 78 struct device_node *cpu, *cpus; 79 int found_method = 0; 80 u32 i, j, cpuidx = 1; 81 u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0; 82 83 u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID }; 84 bool bootcpu_valid = false; 85 cpus = of_find_node_by_path("/cpus"); 86 87 if (!cpus) 88 return; 89 90 for_each_child_of_node(cpus, cpu) { 91 const __be32 *cell; 92 int prop_bytes; 93 u32 hwid; 94 95 if (of_node_cmp(cpu->type, "cpu")) 96 continue; 97 98 pr_debug(" * %s...\n", cpu->full_name); 99 /* 100 * A device tree containing CPU nodes with missing "reg" 101 * properties is considered invalid to build the 102 * cpu_logical_map. 103 */ 104 cell = of_get_property(cpu, "reg", &prop_bytes); 105 if (!cell || prop_bytes < sizeof(*cell)) { 106 pr_debug(" * %s missing reg property\n", 107 cpu->full_name); 108 of_node_put(cpu); 109 return; 110 } 111 112 /* 113 * Bits n:24 must be set to 0 in the DT since the reg property 114 * defines the MPIDR[23:0]. 115 */ 116 do { 117 hwid = be32_to_cpu(*cell++); 118 prop_bytes -= sizeof(*cell); 119 } while (!hwid && prop_bytes > 0); 120 121 if (prop_bytes || (hwid & ~MPIDR_HWID_BITMASK)) { 122 of_node_put(cpu); 123 return; 124 } 125 126 /* 127 * Duplicate MPIDRs are a recipe for disaster. 128 * Scan all initialized entries and check for 129 * duplicates. If any is found just bail out. 130 * temp values were initialized to UINT_MAX 131 * to avoid matching valid MPIDR[23:0] values. 132 */ 133 for (j = 0; j < cpuidx; j++) 134 if (WARN(tmp_map[j] == hwid, 135 "Duplicate /cpu reg properties in the DT\n")) { 136 of_node_put(cpu); 137 return; 138 } 139 140 /* 141 * Build a stashed array of MPIDR values. Numbering scheme 142 * requires that if detected the boot CPU must be assigned 143 * logical id 0. Other CPUs get sequential indexes starting 144 * from 1. If a CPU node with a reg property matching the 145 * boot CPU MPIDR is detected, this is recorded so that the 146 * logical map built from DT is validated and can be used 147 * to override the map created in smp_setup_processor_id(). 148 */ 149 if (hwid == mpidr) { 150 i = 0; 151 bootcpu_valid = true; 152 } else { 153 i = cpuidx++; 154 } 155 156 if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than " 157 "max cores %u, capping them\n", 158 cpuidx, nr_cpu_ids)) { 159 cpuidx = nr_cpu_ids; 160 of_node_put(cpu); 161 break; 162 } 163 164 tmp_map[i] = hwid; 165 166 if (!found_method) 167 found_method = set_smp_ops_by_method(cpu); 168 } 169 170 /* 171 * Fallback to an enable-method in the cpus node if nothing found in 172 * a cpu node. 173 */ 174 if (!found_method) 175 set_smp_ops_by_method(cpus); 176 177 if (!bootcpu_valid) { 178 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n"); 179 return; 180 } 181 182 /* 183 * Since the boot CPU node contains proper data, and all nodes have 184 * a reg property, the DT CPU list can be considered valid and the 185 * logical map created in smp_setup_processor_id() can be overridden 186 */ 187 for (i = 0; i < cpuidx; i++) { 188 set_cpu_possible(i, true); 189 cpu_logical_map(i) = tmp_map[i]; 190 pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i)); 191 } 192 } 193 194 bool arch_match_cpu_phys_id(int cpu, u64 phys_id) 195 { 196 return phys_id == cpu_logical_map(cpu); 197 } 198 199 static const void * __init arch_get_next_mach(const char *const **match) 200 { 201 static const struct machine_desc *mdesc = __arch_info_begin; 202 const struct machine_desc *m = mdesc; 203 204 if (m >= __arch_info_end) 205 return NULL; 206 207 mdesc++; 208 *match = m->dt_compat; 209 return m; 210 } 211 212 /** 213 * setup_machine_fdt - Machine setup when an dtb was passed to the kernel 214 * @dt_phys: physical address of dt blob 215 * 216 * If a dtb was passed to the kernel in r2, then use it to choose the 217 * correct machine_desc and to setup the system. 218 */ 219 const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys) 220 { 221 const struct machine_desc *mdesc, *mdesc_best = NULL; 222 223 #if defined(CONFIG_ARCH_MULTIPLATFORM) || defined(CONFIG_ARM_SINGLE_ARMV7M) 224 DT_MACHINE_START(GENERIC_DT, "Generic DT based system") 225 .l2c_aux_val = 0x0, 226 .l2c_aux_mask = ~0x0, 227 MACHINE_END 228 229 mdesc_best = &__mach_desc_GENERIC_DT; 230 #endif 231 232 if (!dt_phys || !early_init_dt_verify(phys_to_virt(dt_phys))) 233 return NULL; 234 235 mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach); 236 237 if (!mdesc) { 238 const char *prop; 239 int size; 240 unsigned long dt_root; 241 242 early_print("\nError: unrecognized/unsupported " 243 "device tree compatible list:\n[ "); 244 245 dt_root = of_get_flat_dt_root(); 246 prop = of_get_flat_dt_prop(dt_root, "compatible", &size); 247 while (size > 0) { 248 early_print("'%s' ", prop); 249 size -= strlen(prop) + 1; 250 prop += strlen(prop) + 1; 251 } 252 early_print("]\n\n"); 253 254 dump_machine_table(); /* does not return */ 255 } 256 257 /* We really don't want to do this, but sometimes firmware provides buggy data */ 258 if (mdesc->dt_fixup) 259 mdesc->dt_fixup(); 260 261 early_init_dt_scan_nodes(); 262 263 /* Change machine number to match the mdesc we're using */ 264 __machine_arch_type = mdesc->nr; 265 266 return mdesc; 267 } 268