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] = UINT_MAX };
  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                 u32 hwid;
  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                         return;
 105                 }
 106
 107                 /*
 108                  * 8 MSBs must be set to 0 in the DT since the reg property
 109                  * defines the MPIDR[23:0].
 110                  */
 111                 if (hwid & ~MPIDR_HWID_BITMASK)
 112                         return;
 113
 114                 /*
 115                  * Duplicate MPIDRs are a recipe for disaster.
 116                  * Scan all initialized entries and check for
 117                  * duplicates. If any is found just bail out.
 118                  * temp values were initialized to UINT_MAX
 119                  * to avoid matching valid MPIDR[23:0] values.
 120                  */
 121                 for (j = 0; j < cpuidx; j++)
 122                         if (WARN(tmp_map[j] == hwid, "Duplicate /cpu reg "
 123                                                      "properties in the DT\n"))
 124                                 return;
 125
 126                 /*
 127                  * Build a stashed array of MPIDR values. Numbering scheme
 128                  * requires that if detected the boot CPU must be assigned
 129                  * logical id 0. Other CPUs get sequential indexes starting
 130                  * from 1. If a CPU node with a reg property matching the
 131                  * boot CPU MPIDR is detected, this is recorded so that the
 132                  * logical map built from DT is validated and can be used
 133                  * to override the map created in smp_setup_processor_id().
 134                  */
 135                 if (hwid == mpidr) {
 136                         i = 0;
 137                         bootcpu_valid = true;
 138                 } else {
 139                         i = cpuidx++;
 140                 }
 141
 142                 if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
 143                                                "max cores %u, capping them\n",
 144                                                cpuidx, nr_cpu_ids)) {
 145                         cpuidx = nr_cpu_ids;
 146                         break;
 147                 }
 148
 149                 tmp_map[i] = hwid;
 150         }
 151
 152         if (WARN(!bootcpu_valid, "DT missing boot CPU MPIDR[23:0], "
 153                                  "fall back to default cpu_logical_map\n"))
 154                 return;
 155
 156         /*
 157          * Since the boot CPU node contains proper data, and all nodes have
 158          * a reg property, the DT CPU list can be considered valid and the
 159          * logical map created in smp_setup_processor_id() can be overridden
 160          */
 161         for (i = 0; i < cpuidx; i++) {
 162                 set_cpu_possible(i, true);
 163                 cpu_logical_map(i) = tmp_map[i];
 164                 pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
 165         }
 166 }
 167
 168 /**
 169  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
 170  * @dt_phys: physical address of dt blob
 171  *
 172  * If a dtb was passed to the kernel in r2, then use it to choose the
 173  * correct machine_desc and to setup the system.
 174  */
 175 struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
 176 {
 177         struct boot_param_header *devtree;
 178         struct machine_desc *mdesc, *mdesc_best = NULL;
 179         unsigned int score, mdesc_score = ~1;
 180         unsigned long dt_root;
 181         const char *model;
 182
 183 #ifdef CONFIG_ARCH_MULTIPLATFORM
 184         DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
 185         MACHINE_END
 186
 187         mdesc_best = (struct machine_desc *)&__mach_desc_GENERIC_DT;
 188 #endif
 189
 190         if (!dt_phys)
 191                 return NULL;
 192
 193         devtree = phys_to_virt(dt_phys);
 194
 195         /* check device tree validity */
 196         if (be32_to_cpu(devtree->magic) != OF_DT_HEADER)
 197                 return NULL;
 198
 199         /* Search the mdescs for the 'best' compatible value match */
 200         initial_boot_params = devtree;
 201         dt_root = of_get_flat_dt_root();
 202         for_each_machine_desc(mdesc) {
 203                 score = of_flat_dt_match(dt_root, mdesc->dt_compat);
 204                 if (score > 0 && score < mdesc_score) {
 205                         mdesc_best = mdesc;
 206                         mdesc_score = score;
 207                 }
 208         }
 209         if (!mdesc_best) {
 210                 const char *prop;
 211                 long size;
 212
 213                 early_print("\nError: unrecognized/unsupported "
 214                             "device tree compatible list:\n[ ");
 215
 216                 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
 217                 while (size > 0) {
 218                         early_print("'%s' ", prop);
 219                         size -= strlen(prop) + 1;
 220                         prop += strlen(prop) + 1;
 221                 }
 222                 early_print("]\n\n");
 223
 224                 dump_machine_table(); /* does not return */
 225         }
 226
 227         model = of_get_flat_dt_prop(dt_root, "model", NULL);
 228         if (!model)
 229                 model = of_get_flat_dt_prop(dt_root, "compatible", NULL);
 230         if (!model)
 231                 model = "<unknown>";
 232         pr_info("Machine: %s, model: %s\n", mdesc_best->name, model);
 233
 234         /* Retrieve various information from the /chosen node */
 235         of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
 236         /* Initialize {size,address}-cells info */
 237         of_scan_flat_dt(early_init_dt_scan_root, NULL);
 238         /* Setup memory, calling early_init_dt_add_memory_arch */
 239         of_scan_flat_dt(early_init_dt_scan_memory, NULL);
 240
 241         /* Change machine number to match the mdesc we're using */
 242         __machine_arch_type = mdesc_best->nr;
 243
 244         return mdesc_best;
 245 }