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/memblock.h> 16 #include <linux/of.h> 17 #include <linux/of_fdt.h> 18 #include <linux/of_irq.h> 19 #include <linux/of_platform.h> 20 #include <linux/smp.h> 21 22 #include <asm/cputype.h> 23 #include <asm/setup.h> 24 #include <asm/page.h> 25 #include <asm/prom.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_of_cpu_node(cpu) { 90 const __be32 *cell; 91 int prop_bytes; 92 u32 hwid; 93 94 pr_debug(" * %pOF...\n", cpu); 95 /* 96 * A device tree containing CPU nodes with missing "reg" 97 * properties is considered invalid to build the 98 * cpu_logical_map. 99 */ 100 cell = of_get_property(cpu, "reg", &prop_bytes); 101 if (!cell || prop_bytes < sizeof(*cell)) { 102 pr_debug(" * %pOF missing reg property\n", cpu); 103 of_node_put(cpu); 104 return; 105 } 106 107 /* 108 * Bits n:24 must be set to 0 in the DT since the reg property 109 * defines the MPIDR[23:0]. 110 */ 111 do { 112 hwid = be32_to_cpu(*cell++); 113 prop_bytes -= sizeof(*cell); 114 } while (!hwid && prop_bytes > 0); 115 116 if (prop_bytes || (hwid & ~MPIDR_HWID_BITMASK)) { 117 of_node_put(cpu); 118 return; 119 } 120 121 /* 122 * Duplicate MPIDRs are a recipe for disaster. 123 * Scan all initialized entries and check for 124 * duplicates. If any is found just bail out. 125 * temp values were initialized to UINT_MAX 126 * to avoid matching valid MPIDR[23:0] values. 127 */ 128 for (j = 0; j < cpuidx; j++) 129 if (WARN(tmp_map[j] == hwid, 130 "Duplicate /cpu reg properties in the DT\n")) { 131 of_node_put(cpu); 132 return; 133 } 134 135 /* 136 * Build a stashed array of MPIDR values. Numbering scheme 137 * requires that if detected the boot CPU must be assigned 138 * logical id 0. Other CPUs get sequential indexes starting 139 * from 1. If a CPU node with a reg property matching the 140 * boot CPU MPIDR is detected, this is recorded so that the 141 * logical map built from DT is validated and can be used 142 * to override the map created in smp_setup_processor_id(). 143 */ 144 if (hwid == mpidr) { 145 i = 0; 146 bootcpu_valid = true; 147 } else { 148 i = cpuidx++; 149 } 150 151 if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than " 152 "max cores %u, capping them\n", 153 cpuidx, nr_cpu_ids)) { 154 cpuidx = nr_cpu_ids; 155 of_node_put(cpu); 156 break; 157 } 158 159 tmp_map[i] = hwid; 160 161 if (!found_method) 162 found_method = set_smp_ops_by_method(cpu); 163 } 164 165 /* 166 * Fallback to an enable-method in the cpus node if nothing found in 167 * a cpu node. 168 */ 169 if (!found_method) 170 set_smp_ops_by_method(cpus); 171 172 if (!bootcpu_valid) { 173 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n"); 174 return; 175 } 176 177 /* 178 * Since the boot CPU node contains proper data, and all nodes have 179 * a reg property, the DT CPU list can be considered valid and the 180 * logical map created in smp_setup_processor_id() can be overridden 181 */ 182 for (i = 0; i < cpuidx; i++) { 183 set_cpu_possible(i, true); 184 cpu_logical_map(i) = tmp_map[i]; 185 pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i)); 186 } 187 } 188 189 bool arch_match_cpu_phys_id(int cpu, u64 phys_id) 190 { 191 return phys_id == cpu_logical_map(cpu); 192 } 193 194 static const void * __init arch_get_next_mach(const char *const **match) 195 { 196 static const struct machine_desc *mdesc = __arch_info_begin; 197 const struct machine_desc *m = mdesc; 198 199 if (m >= __arch_info_end) 200 return NULL; 201 202 mdesc++; 203 *match = m->dt_compat; 204 return m; 205 } 206 207 /** 208 * setup_machine_fdt - Machine setup when an dtb was passed to the kernel 209 * @dt_phys: physical address of dt blob 210 * 211 * If a dtb was passed to the kernel in r2, then use it to choose the 212 * correct machine_desc and to setup the system. 213 */ 214 const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys) 215 { 216 const struct machine_desc *mdesc, *mdesc_best = NULL; 217 218 #if defined(CONFIG_ARCH_MULTIPLATFORM) || defined(CONFIG_ARM_SINGLE_ARMV7M) 219 DT_MACHINE_START(GENERIC_DT, "Generic DT based system") 220 .l2c_aux_val = 0x0, 221 .l2c_aux_mask = ~0x0, 222 MACHINE_END 223 224 mdesc_best = &__mach_desc_GENERIC_DT; 225 #endif 226 227 if (!dt_phys || !early_init_dt_verify(phys_to_virt(dt_phys))) 228 return NULL; 229 230 mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach); 231 232 if (!mdesc) { 233 const char *prop; 234 int size; 235 unsigned long dt_root; 236 237 early_print("\nError: unrecognized/unsupported " 238 "device tree compatible list:\n[ "); 239 240 dt_root = of_get_flat_dt_root(); 241 prop = of_get_flat_dt_prop(dt_root, "compatible", &size); 242 while (size > 0) { 243 early_print("'%s' ", prop); 244 size -= strlen(prop) + 1; 245 prop += strlen(prop) + 1; 246 } 247 early_print("]\n\n"); 248 249 dump_machine_table(); /* does not return */ 250 } 251 252 /* We really don't want to do this, but sometimes firmware provides buggy data */ 253 if (mdesc->dt_fixup) 254 mdesc->dt_fixup(); 255 256 early_init_dt_scan_nodes(); 257 258 /* Change machine number to match the mdesc we're using */ 259 __machine_arch_type = mdesc->nr; 260 261 return mdesc; 262 } 263