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 extern char default_command_line[COMMAND_LINE_SIZE];
  30
  31 void __init early_init_dt_add_memory_arch(u64 base, u64 size)
  32 {
  33         arm_add_memory(base, size);
  34 }
  35
  36 void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
  37 {
  38         return alloc_bootmem_align(size, align);
  39 }
  40
  41 void __init arm_dt_memblock_reserve(void)
  42 {
  43         u64 *reserve_map, base, size;
  44
  45         if (!initial_boot_params)
  46                 return;
  47
  48         /* Reserve the dtb region */
  49         memblock_reserve(virt_to_phys(initial_boot_params),
  50                          be32_to_cpu(initial_boot_params->totalsize));
  51
  52         /*
  53          * Process the reserve map.  This will probably overlap the initrd
  54          * and dtb locations which are already reserved, but overlaping
  55          * doesn't hurt anything
  56          */
  57         reserve_map = ((void*)initial_boot_params) +
  58                         be32_to_cpu(initial_boot_params->off_mem_rsvmap);
  59         while (1) {
  60                 base = be64_to_cpup(reserve_map++);
  61                 size = be64_to_cpup(reserve_map++);
  62                 if (!size)
  63                         break;
  64                 memblock_reserve(base, size);
  65         }
  66 }
  67
  68 /*
  69  * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
  70  * and builds the cpu logical map array containing MPIDR values related to
  71  * logical cpus
  72  *
  73  * Updates the cpu possible mask with the number of parsed cpu nodes
  74  */
  75 void __init arm_dt_init_cpu_maps(void)
  76 {
  77         /*
  78          * Temp logical map is initialized with UINT_MAX values that are
  79          * considered invalid logical map entries since the logical map must
  80          * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
  81          * read as 0.
  82          */
  83         struct device_node *cpu, *cpus;
  84         u32 i, j, cpuidx = 1;
  85         u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
  86
  87         u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
  88         bool bootcpu_valid = false;
  89         cpus = of_find_node_by_path("/cpus");
  90
  91         if (!cpus)
  92                 return;
  93
  94         for_each_child_of_node(cpus, cpu) {
  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                 if (of_property_read_u32(cpu, "reg", &hwid)) {
 107                         pr_debug(" * %s missing reg property\n",
 108                                      cpu->full_name);
 109                         return;
 110                 }
 111
 112                 /*
 113                  * 8 MSBs must be set to 0 in the DT since the reg property
 114                  * defines the MPIDR[23:0].
 115                  */
 116                 if (hwid & ~MPIDR_HWID_BITMASK)
 117                         return;
 118
 119                 /*
 120                  * Duplicate MPIDRs are a recipe for disaster.
 121                  * Scan all initialized entries and check for
 122                  * duplicates. If any is found just bail out.
 123                  * temp values were initialized to UINT_MAX
 124                  * to avoid matching valid MPIDR[23:0] values.
 125                  */
 126                 for (j = 0; j < cpuidx; j++)
 127                         if (WARN(tmp_map[j] == hwid, "Duplicate /cpu reg "
 128                                                      "properties in the DT\n"))
 129                                 return;
 130
 131                 /*
 132                  * Build a stashed array of MPIDR values. Numbering scheme
 133                  * requires that if detected the boot CPU must be assigned
 134                  * logical id 0. Other CPUs get sequential indexes starting
 135                  * from 1. If a CPU node with a reg property matching the
 136                  * boot CPU MPIDR is detected, this is recorded so that the
 137                  * logical map built from DT is validated and can be used
 138                  * to override the map created in smp_setup_processor_id().
 139                  */
 140                 if (hwid == mpidr) {
 141                         i = 0;
 142                         bootcpu_valid = true;
 143                 } else {
 144                         i = cpuidx++;
 145                 }
 146
 147                 if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
 148                                                "max cores %u, capping them\n",
 149                                                cpuidx, nr_cpu_ids)) {
 150                         cpuidx = nr_cpu_ids;
 151                         break;
 152                 }
 153
 154                 tmp_map[i] = hwid;
 155         }
 156
 157         if (!bootcpu_valid) {
 158                 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
 159                 return;
 160         }
 161
 162         /*
 163          * Since the boot CPU node contains proper data, and all nodes have
 164          * a reg property, the DT CPU list can be considered valid and the
 165          * logical map created in smp_setup_processor_id() can be overridden
 166          */
 167         for (i = 0; i < cpuidx; i++) {
 168                 set_cpu_possible(i, true);
 169                 cpu_logical_map(i) = tmp_map[i];
 170                 pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
 171         }
 172 }
 173
 174 /**
 175  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
 176  * @dt_phys: physical address of dt blob
 177  *
 178  * If a dtb was passed to the kernel in r2, then use it to choose the
 179  * correct machine_desc and to setup the system.
 180  */
 181 struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
 182 {
 183         struct boot_param_header *devtree;
 184         struct machine_desc *mdesc, *mdesc_best = NULL;
 185         unsigned int score, mdesc_score = ~1;
 186         unsigned long dt_root;
 187         const char *model;
 188         char *from = default_command_line;
 189
 190 #ifdef CONFIG_ARCH_MULTIPLATFORM
 191         DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
 192         MACHINE_END
 193
 194         mdesc_best = (struct machine_desc *)&__mach_desc_GENERIC_DT;
 195 #endif
 196
 197         if (!dt_phys)
 198                 return NULL;
 199
 200         devtree = phys_to_virt(dt_phys);
 201
 202         /* check device tree validity */
 203         if (be32_to_cpu(devtree->magic) != OF_DT_HEADER)
 204                 return NULL;
 205
 206         /* Search the mdescs for the 'best' compatible value match */
 207         initial_boot_params = devtree;
 208         dt_root = of_get_flat_dt_root();
 209         for_each_machine_desc(mdesc) {
 210                 score = of_flat_dt_match(dt_root, mdesc->dt_compat);
 211                 if (score > 0 && score < mdesc_score) {
 212                         mdesc_best = mdesc;
 213                         mdesc_score = score;
 214                 }
 215         }
 216         if (!mdesc_best) {
 217                 const char *prop;
 218                 long size;
 219
 220                 early_print("\nError: unrecognized/unsupported "
 221                             "device tree compatible list:\n[ ");
 222
 223                 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
 224                 while (size > 0) {
 225                         early_print("'%s' ", prop);
 226                         size -= strlen(prop) + 1;
 227                         prop += strlen(prop) + 1;
 228                 }
 229                 early_print("]\n\n");
 230
 231                 dump_machine_table(); /* does not return */
 232         }
 233
 234         model = of_get_flat_dt_prop(dt_root, "model", NULL);
 235         if (!model)
 236                 model = of_get_flat_dt_prop(dt_root, "compatible", NULL);
 237         if (!model)
 238                 model = "<unknown>";
 239         pr_info("Machine: %s, model: %s\n", mdesc_best->name, model);
 240
 241         /* Retrieve various information from the /chosen node */
 242         of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
 243         /* Initialize {size,address}-cells info */
 244         of_scan_flat_dt(early_init_dt_scan_root, NULL);
 245         /* Setup memory, calling early_init_dt_add_memory_arch */
 246         of_scan_flat_dt(early_init_dt_scan_memory, NULL);
 247
 248         /* Change machine number to match the mdesc we're using */
 249         __machine_arch_type = mdesc_best->nr;
 250
 251         if (mdesc_best->fixup) {
 252         mdesc_best->fixup((void *)dt_root, &from, &meminfo);
 253         strlcpy(boot_command_line, from, COMMAND_LINE_SIZE);
 254     }
 255
 256         return mdesc_best;
 257 }