arch/arm/kernel/devtree.c

   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
  22 #include <asm/cputype.h>
  23 #include <asm/setup.h>
  24 #include <asm/page.h>
  25 #include <asm/smp_plat.h>
  26 #include <asm/mach/arch.h>
  27 #include <asm/mach-types.h>
  28
  29 void __init early_init_dt_add_memory_arch(u64 base, u64 size)
  30 {
  31         arm_add_memory(base, size);
  32 }
  33
  34 void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
  35 {
  36         return alloc_bootmem_align(size, align);
  37 }
  38
  39 void __init arm_dt_memblock_reserve(void)
  40 {
  41         u64 *reserve_map, base, size;
  42
  43         if (!initial_boot_params)
  44                 return;
  45
  46         /* Reserve the dtb region */
  47         memblock_reserve(virt_to_phys(initial_boot_params),
  48                          be32_to_cpu(initial_boot_params->totalsize));
  49
  50         /*
  51          * Process the reserve map.  This will probably overlap the initrd
  52          * and dtb locations which are already reserved, but overlaping
  53          * doesn't hurt anything
  54          */
  55         reserve_map = ((void*)initial_boot_params) +
  56                         be32_to_cpu(initial_boot_params->off_mem_rsvmap);
  57         while (1) {
  58                 base = be64_to_cpup(reserve_map++);
  59                 size = be64_to_cpup(reserve_map++);
  60                 if (!size)
  61                         break;
  62                 memblock_reserve(base, size);
  63         }
  64 }
  65
  66 /*
  67  * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
  68  * and builds the cpu logical map array containing MPIDR values related to
  69  * logical cpus
  70  *
  71  * Updates the cpu possible mask with the number of parsed cpu nodes
  72  */
  73 void __init arm_dt_init_cpu_maps(void)
  74 {
  75         /*
  76          * Temp logical map is initialized with UINT_MAX values that are
  77          * considered invalid logical map entries since the logical map must
  78          * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
  79          * read as 0.
  80          */
  81         struct device_node *cpu, *cpus;
  82         u32 i, j, cpuidx = 1;
  83         u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
  84
  85         u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
  86         bool bootcpu_valid = false;
  87         cpus = of_find_node_by_path("/cpus");
  88
  89         if (!cpus)
  90                 return;
  91
  92         for_each_child_of_node(cpus, cpu) {
  93                 const __be32 *cell;
  94                 int prop_bytes;
  95                 u32 hwid;
  96
  97                 if (of_node_cmp(cpu->type, "cpu"))
  98                         continue;
  99
 100                 pr_debug(" * %s...\n", cpu->full_name);
 101                 /*
 102                  * A device tree containing CPU nodes with missing "reg"
 103                  * properties is considered invalid to build the
 104                  * cpu_logical_map.
 105                  */
 106                 cell = of_get_property(cpu, "reg", &prop_bytes);
 107                 if (!cell || prop_bytes < sizeof(*cell)) {
 108                         pr_debug(" * %s missing reg property\n",
 109                                      cpu->full_name);
 110                         return;
 111                 }
 112
 113                 /*
 114                  * Bits n:24 must be set to 0 in the DT since the reg property
 115                  * defines the MPIDR[23:0].
 116                  */
 117                 do {
 118                         hwid = be32_to_cpu(*cell++);
 119                         prop_bytes -= sizeof(*cell);
 120                 } while (!hwid && prop_bytes > 0);
 121
 122                 if (prop_bytes || (hwid & ~MPIDR_HWID_BITMASK))
 123                         return;
 124
 125                 /*
 126                  * Duplicate MPIDRs are a recipe for disaster.
 127                  * Scan all initialized entries and check for
 128                  * duplicates. If any is found just bail out.
 129                  * temp values were initialized to UINT_MAX
 130                  * to avoid matching valid MPIDR[23:0] values.
 131                  */
 132                 for (j = 0; j < cpuidx; j++)
 133                         if (WARN(tmp_map[j] == hwid, "Duplicate /cpu reg "
 134                                                      "properties in the DT\n"))
 135                                 return;
 136
 137                 /*
 138                  * Build a stashed array of MPIDR values. Numbering scheme
 139                  * requires that if detected the boot CPU must be assigned
 140                  * logical id 0. Other CPUs get sequential indexes starting
 141                  * from 1. If a CPU node with a reg property matching the
 142                  * boot CPU MPIDR is detected, this is recorded so that the
 143                  * logical map built from DT is validated and can be used
 144                  * to override the map created in smp_setup_processor_id().
 145                  */
 146                 if (hwid == mpidr) {
 147                         i = 0;
 148                         bootcpu_valid = true;
 149                 } else {
 150                         i = cpuidx++;
 151                 }
 152
 153                 if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
 154                                                "max cores %u, capping them\n",
 155                                                cpuidx, nr_cpu_ids)) {
 156                         cpuidx = nr_cpu_ids;
 157                         break;
 158                 }
 159
 160                 tmp_map[i] = hwid;
 161         }
 162
 163         if (!bootcpu_valid) {
 164                 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
 165                 return;
 166         }
 167
 168         /*
 169          * Since the boot CPU node contains proper data, and all nodes have
 170          * a reg property, the DT CPU list can be considered valid and the
 171          * logical map created in smp_setup_processor_id() can be overridden
 172          */
 173         for (i = 0; i < cpuidx; i++) {
 174                 set_cpu_possible(i, true);
 175                 cpu_logical_map(i) = tmp_map[i];
 176                 pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
 177         }
 178 }
 179
 180 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 181 {
 182         return phys_id == cpu_logical_map(cpu);
 183 }
 184
 185 /**
 186  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
 187  * @dt_phys: physical 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(unsigned int dt_phys)
 193 {
 194         struct boot_param_header *devtree;
 195         const struct machine_desc *mdesc, *mdesc_best = NULL;
 196         unsigned int score, mdesc_score = ~1;
 197         unsigned long dt_root;
 198         const char *model;
 199
 200 #ifdef CONFIG_ARCH_MULTIPLATFORM
 201         DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
 202         MACHINE_END
 203
 204         mdesc_best = &__mach_desc_GENERIC_DT;
 205 #endif
 206
 207         if (!dt_phys)
 208                 return NULL;
 209
 210         devtree = phys_to_virt(dt_phys);
 211
 212         /* check device tree validity */
 213         if (be32_to_cpu(devtree->magic) != OF_DT_HEADER)
 214                 return NULL;
 215
 216         /* Search the mdescs for the 'best' compatible value match */
 217         initial_boot_params = devtree;
 218         dt_root = of_get_flat_dt_root();
 219         for_each_machine_desc(mdesc) {
 220                 score = of_flat_dt_match(dt_root, mdesc->dt_compat);
 221                 if (score > 0 && score < mdesc_score) {
 222                         mdesc_best = mdesc;
 223                         mdesc_score = score;
 224                 }
 225         }
 226         if (!mdesc_best) {
 227                 const char *prop;
 228                 long size;
 229
 230                 early_print("\nError: unrecognized/unsupported "
 231                             "device tree compatible list:\n[ ");
 232
 233                 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
 234                 while (size > 0) {
 235                         early_print("'%s' ", prop);
 236                         size -= strlen(prop) + 1;
 237                         prop += strlen(prop) + 1;
 238                 }
 239                 early_print("]\n\n");
 240
 241                 dump_machine_table(); /* does not return */
 242         }
 243
 244         model = of_get_flat_dt_prop(dt_root, "model", NULL);
 245         if (!model)
 246                 model = of_get_flat_dt_prop(dt_root, "compatible", NULL);
 247         if (!model)
 248                 model = "<unknown>";
 249         pr_info("Machine: %s, model: %s\n", mdesc_best->name, model);
 250
 251         /* Retrieve various information from the /chosen node */
 252         of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
 253         /* Initialize {size,address}-cells info */
 254         of_scan_flat_dt(early_init_dt_scan_root, NULL);
 255         /* Setup memory, calling early_init_dt_add_memory_arch */
 256         of_scan_flat_dt(early_init_dt_scan_memory, NULL);
 257
 258         /* Change machine number to match the mdesc we're using */
 259         __machine_arch_type = mdesc_best->nr;
 260
 261         return mdesc_best;
 262 }