arch/arm/kernel/devtree.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/arch/arm/kernel/devtree.c
   4  *
   5  *  Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com>
   6  */
   7
   8 #include <linux/init.h>
   9 #include <linux/export.h>
  10 #include <linux/errno.h>
  11 #include <linux/types.h>
  12 #include <linux/memblock.h>
  13 #include <linux/of.h>
  14 #include <linux/of_fdt.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/smp.h>
  17
  18 #include <asm/cputype.h>
  19 #include <asm/setup.h>
  20 #include <asm/page.h>
  21 #include <asm/prom.h>
  22 #include <asm/smp_plat.h>
  23 #include <asm/mach/arch.h>
  24 #include <asm/mach-types.h>
  25
  26
  27 #ifdef CONFIG_SMP
  28 extern struct of_cpu_method __cpu_method_of_table[];
  29
  30 static const struct of_cpu_method __cpu_method_of_table_sentinel
  31         __used __section("__cpu_method_of_table_end");
  32
  33
  34 static int __init set_smp_ops_by_method(struct device_node *node)
  35 {
  36         const char *method;
  37         struct of_cpu_method *m = __cpu_method_of_table;
  38
  39         if (of_property_read_string(node, "enable-method", &method))
  40                 return 0;
  41
  42         for (; m->method; m++)
  43                 if (!strcmp(m->method, method)) {
  44                         smp_set_ops(m->ops);
  45                         return 1;
  46                 }
  47
  48         return 0;
  49 }
  50 #else
  51 static inline int set_smp_ops_by_method(struct device_node *node)
  52 {
  53         return 1;
  54 }
  55 #endif
  56
  57
  58 /*
  59  * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
  60  * and builds the cpu logical map array containing MPIDR values related to
  61  * logical cpus
  62  *
  63  * Updates the cpu possible mask with the number of parsed cpu nodes
  64  */
  65 void __init arm_dt_init_cpu_maps(void)
  66 {
  67         /*
  68          * Temp logical map is initialized with UINT_MAX values that are
  69          * considered invalid logical map entries since the logical map must
  70          * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
  71          * read as 0.
  72          */
  73         struct device_node *cpu, *cpus;
  74         int found_method = 0;
  75         u32 i, j, cpuidx = 1;
  76         u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
  77
  78         u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
  79         bool bootcpu_valid = false;
  80         cpus = of_find_node_by_path("/cpus");
  81
  82         if (!cpus)
  83                 return;
  84
  85         for_each_of_cpu_node(cpu) {
  86                 u32 hwid = of_get_cpu_hwid(cpu, 0);
  87
  88                 pr_debug(" * %pOF...\n", cpu);
  89
  90                 /*
  91                  * Bits n:24 must be set to 0 in the DT since the reg property
  92                  * defines the MPIDR[23:0].
  93                  */
  94                 if (hwid & ~MPIDR_HWID_BITMASK) {
  95                         of_node_put(cpu);
  96                         return;
  97                 }
  98
  99                 /*
 100                  * Duplicate MPIDRs are a recipe for disaster.
 101                  * Scan all initialized entries and check for
 102                  * duplicates. If any is found just bail out.
 103                  * temp values were initialized to UINT_MAX
 104                  * to avoid matching valid MPIDR[23:0] values.
 105                  */
 106                 for (j = 0; j < cpuidx; j++)
 107                         if (WARN(tmp_map[j] == hwid,
 108                                  "Duplicate /cpu reg properties in the DT\n")) {
 109                                 of_node_put(cpu);
 110                                 return;
 111                         }
 112
 113                 /*
 114                  * Build a stashed array of MPIDR values. Numbering scheme
 115                  * requires that if detected the boot CPU must be assigned
 116                  * logical id 0. Other CPUs get sequential indexes starting
 117                  * from 1. If a CPU node with a reg property matching the
 118                  * boot CPU MPIDR is detected, this is recorded so that the
 119                  * logical map built from DT is validated and can be used
 120                  * to override the map created in smp_setup_processor_id().
 121                  */
 122                 if (hwid == mpidr) {
 123                         i = 0;
 124                         bootcpu_valid = true;
 125                 } else {
 126                         i = cpuidx++;
 127                 }
 128
 129                 if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
 130                                                "max cores %u, capping them\n",
 131                                                cpuidx, nr_cpu_ids)) {
 132                         cpuidx = nr_cpu_ids;
 133                         of_node_put(cpu);
 134                         break;
 135                 }
 136
 137                 tmp_map[i] = hwid;
 138
 139                 if (!found_method)
 140                         found_method = set_smp_ops_by_method(cpu);
 141         }
 142
 143         /*
 144          * Fallback to an enable-method in the cpus node if nothing found in
 145          * a cpu node.
 146          */
 147         if (!found_method)
 148                 set_smp_ops_by_method(cpus);
 149
 150         if (!bootcpu_valid) {
 151                 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
 152                 return;
 153         }
 154
 155         /*
 156          * Since the boot CPU node contains proper data, and all nodes have
 157          * a reg property, the DT CPU list can be considered valid and the
 158          * logical map created in smp_setup_processor_id() can be overridden
 159          */
 160         for (i = 0; i < cpuidx; i++) {
 161                 set_cpu_possible(i, true);
 162                 cpu_logical_map(i) = tmp_map[i];
 163                 pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
 164         }
 165 }
 166
 167 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 168 {
 169         return phys_id == cpu_logical_map(cpu);
 170 }
 171
 172 static const void * __init arch_get_next_mach(const char *const **match)
 173 {
 174         static const struct machine_desc *mdesc = __arch_info_begin;
 175         const struct machine_desc *m = mdesc;
 176
 177         if (m >= __arch_info_end)
 178                 return NULL;
 179
 180         mdesc++;
 181         *match = m->dt_compat;
 182         return m;
 183 }
 184
 185 /**
 186  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
 187  * @dt_virt: virtual address of dt blob
 188  *
 189  * If a dtb was passed to the kernel in r2, then use it to choose the
 190  * correct machine_desc and to setup the system.
 191  */
 192 const struct machine_desc * __init setup_machine_fdt(void *dt_virt)
 193 {
 194         const struct machine_desc *mdesc, *mdesc_best = NULL;
 195
 196         DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
 197                 .l2c_aux_val = 0x0,
 198                 .l2c_aux_mask = ~0x0,
 199         MACHINE_END
 200
 201         mdesc_best = &__mach_desc_GENERIC_DT;
 202
 203         if (!dt_virt || !early_init_dt_verify(dt_virt, __pa(dt_virt)))
 204                 return NULL;
 205
 206         mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);
 207
 208         if (!mdesc) {
 209                 const char *prop;
 210                 int size;
 211                 unsigned long dt_root;
 212
 213                 early_print("\nError: unrecognized/unsupported "
 214                             "device tree compatible list:\n[ ");
 215
 216                 dt_root = of_get_flat_dt_root();
 217                 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
 218                 while (size > 0) {
 219                         early_print("'%s' ", prop);
 220                         size -= strlen(prop) + 1;
 221                         prop += strlen(prop) + 1;
 222                 }
 223                 early_print("]\n\n");
 224
 225                 dump_machine_table(); /* does not return */
 226         }
 227
 228         /* We really don't want to do this, but sometimes firmware provides buggy data */
 229         if (mdesc->dt_fixup)
 230                 mdesc->dt_fixup();
 231
 232         early_init_dt_scan_nodes();
 233
 234         /* Change machine number to match the mdesc we're using */
 235         __machine_arch_type = mdesc->nr;
 236
 237         return mdesc;
 238 }