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