arch/arc/kernel/devtree.c

   1 /*
   2  * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
   3  *
   4  * Based on reduced version of METAG
   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
  12 #include <linux/init.h>
  13 #include <linux/reboot.h>
  14 #include <linux/memblock.h>
  15 #include <linux/of.h>
  16 #include <linux/of_fdt.h>
  17 #include <asm/prom.h>
  18 #include <asm/clk.h>
  19 #include <asm/mach_desc.h>
  20
  21 /* called from unflatten_device_tree() to bootstrap devicetree itself */
  22 void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
  23 {
  24         return __va(memblock_alloc(size, align));
  25 }
  26
  27 /**
  28  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
  29  * @dt:         virtual address pointer to dt blob
  30  *
  31  * If a dtb was passed to the kernel, then use it to choose the correct
  32  * machine_desc and to setup the system.
  33  */
  34 struct machine_desc * __init setup_machine_fdt(void *dt)
  35 {
  36         struct boot_param_header *devtree = dt;
  37         struct machine_desc *mdesc = NULL, *mdesc_best = NULL;
  38         unsigned int score, mdesc_score = ~1;
  39         unsigned long dt_root;
  40         const char *model, *compat;
  41         void *clk;
  42         char manufacturer[16];
  43         unsigned long len;
  44
  45         /* check device tree validity */
  46         if (be32_to_cpu(devtree->magic) != OF_DT_HEADER)
  47                 return NULL;
  48
  49         initial_boot_params = devtree;
  50         dt_root = of_get_flat_dt_root();
  51
  52         /*
  53          * The kernel could be multi-platform enabled, thus could have many
  54          * "baked-in" machine descriptors. Search thru all for the best
  55          * "compatible" string match.
  56          */
  57         for_each_machine_desc(mdesc) {
  58                 score = of_flat_dt_match(dt_root, mdesc->dt_compat);
  59                 if (score > 0 && score < mdesc_score) {
  60                         mdesc_best = mdesc;
  61                         mdesc_score = score;
  62                 }
  63         }
  64         if (!mdesc_best) {
  65                 const char *prop;
  66                 long size;
  67
  68                 pr_err("\n unrecognized device tree list:\n[ ");
  69
  70                 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
  71                 if (prop) {
  72                         while (size > 0) {
  73                                 printk("'%s' ", prop);
  74                                 size -= strlen(prop) + 1;
  75                                 prop += strlen(prop) + 1;
  76                         }
  77                 }
  78                 printk("]\n\n");
  79
  80                 machine_halt();
  81         }
  82
  83         /* compat = "<manufacturer>,<model>" */
  84         compat =  mdesc_best->dt_compat[0];
  85
  86         model = strchr(compat, ',');
  87         if (model)
  88                 model++;
  89
  90         strlcpy(manufacturer, compat, model ? model - compat : strlen(compat));
  91
  92         pr_info("Board \"%s\" from %s (Manufacturer)\n", model, manufacturer);
  93
  94         /* Retrieve various information from the /chosen node */
  95         of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
  96
  97         /* Initialize {size,address}-cells info */
  98         of_scan_flat_dt(early_init_dt_scan_root, NULL);
  99
 100         /* Setup memory, calling early_init_dt_add_memory_arch */
 101         of_scan_flat_dt(early_init_dt_scan_memory, NULL);
 102
 103         clk = of_get_flat_dt_prop(dt_root, "clock-frequency", &len);
 104         if (clk)
 105                 arc_set_core_freq(of_read_ulong(clk, len/4));
 106
 107         return mdesc_best;
 108 }
 109
 110 /*
 111  * Copy the flattened DT out of .init since unflattening doesn't copy strings
 112  * and the normal DT APIs refs them from orig flat DT
 113  */
 114 void __init copy_devtree(void)
 115 {
 116         void *alloc = early_init_dt_alloc_memory_arch(
 117                         be32_to_cpu(initial_boot_params->totalsize), 64);
 118         if (alloc) {
 119                 memcpy(alloc, initial_boot_params,
 120                                 be32_to_cpu(initial_boot_params->totalsize));
 121                 initial_boot_params = alloc;
 122         }
 123 }