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/setup.h>
  23 #include <asm/page.h>
  24 #include <asm/mach/arch.h>
  25 #include <asm/mach-types.h>
  26
  27 void __init early_init_dt_add_memory_arch(u64 base, u64 size)
  28 {
  29         arm_add_memory(base, size);
  30 }
  31
  32 void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
  33 {
  34         return alloc_bootmem_align(size, align);
  35 }
  36
  37 void __init arm_dt_memblock_reserve(void)
  38 {
  39         u64 *reserve_map, base, size;
  40
  41         if (!initial_boot_params)
  42                 return;
  43
  44         /* Reserve the dtb region */
  45         memblock_reserve(virt_to_phys(initial_boot_params),
  46                          be32_to_cpu(initial_boot_params->totalsize));
  47
  48         /*
  49          * Process the reserve map.  This will probably overlap the initrd
  50          * and dtb locations which are already reserved, but overlaping
  51          * doesn't hurt anything
  52          */
  53         reserve_map = ((void*)initial_boot_params) +
  54                         be32_to_cpu(initial_boot_params->off_mem_rsvmap);
  55         while (1) {
  56                 base = be64_to_cpup(reserve_map++);
  57                 size = be64_to_cpup(reserve_map++);
  58                 if (!size)
  59                         break;
  60                 memblock_reserve(base, size);
  61         }
  62 }
  63
  64 /**
  65  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
  66  * @dt_phys: physical address of dt blob
  67  *
  68  * If a dtb was passed to the kernel in r2, then use it to choose the
  69  * correct machine_desc and to setup the system.
  70  */
  71 struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
  72 {
  73         struct boot_param_header *devtree;
  74         struct machine_desc *mdesc, *mdesc_best = NULL;
  75         unsigned int score, mdesc_score = ~1;
  76         unsigned long dt_root;
  77         const char *model;
  78
  79         if (!dt_phys)
  80                 return NULL;
  81
  82         devtree = phys_to_virt(dt_phys);
  83
  84         /* check device tree validity */
  85         if (be32_to_cpu(devtree->magic) != OF_DT_HEADER)
  86                 return NULL;
  87
  88         /* Search the mdescs for the 'best' compatible value match */
  89         initial_boot_params = devtree;
  90         dt_root = of_get_flat_dt_root();
  91         for_each_machine_desc(mdesc) {
  92                 score = of_flat_dt_match(dt_root, mdesc->dt_compat);
  93                 if (score > 0 && score < mdesc_score) {
  94                         mdesc_best = mdesc;
  95                         mdesc_score = score;
  96                 }
  97         }
  98         if (!mdesc_best) {
  99                 const char *prop;
 100                 long size;
 101
 102                 early_print("\nError: unrecognized/unsupported "
 103                             "device tree compatible list:\n[ ");
 104
 105                 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
 106                 while (size > 0) {
 107                         early_print("'%s' ", prop);
 108                         size -= strlen(prop) + 1;
 109                         prop += strlen(prop) + 1;
 110                 }
 111                 early_print("]\n\n");
 112
 113                 dump_machine_table(); /* does not return */
 114         }
 115
 116         model = of_get_flat_dt_prop(dt_root, "model", NULL);
 117         if (!model)
 118                 model = of_get_flat_dt_prop(dt_root, "compatible", NULL);
 119         if (!model)
 120                 model = "<unknown>";
 121         pr_info("Machine: %s, model: %s\n", mdesc_best->name, model);
 122
 123         /* Retrieve various information from the /chosen node */
 124         of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
 125         /* Initialize {size,address}-cells info */
 126         of_scan_flat_dt(early_init_dt_scan_root, NULL);
 127         /* Setup memory, calling early_init_dt_add_memory_arch */
 128         of_scan_flat_dt(early_init_dt_scan_memory, NULL);
 129
 130         /* Change machine number to match the mdesc we're using */
 131         __machine_arch_type = mdesc_best->nr;
 132
 133         return mdesc_best;
 134 }