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/clk.h>
  18 #include <asm/mach_desc.h>
  19
  20 static const void * __init arch_get_next_mach(const char *const **match)
  21 {
  22         static const struct machine_desc *mdesc = __arch_info_begin;
  23         const struct machine_desc *m = mdesc;
  24
  25         if (m >= __arch_info_end)
  26                 return NULL;
  27
  28         mdesc++;
  29         *match = m->dt_compat;
  30         return m;
  31 }
  32
  33 /**
  34  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
  35  * @dt:         virtual address pointer to dt blob
  36  *
  37  * If a dtb was passed to the kernel, then use it to choose the correct
  38  * machine_desc and to setup the system.
  39  */
  40 const struct machine_desc * __init setup_machine_fdt(void *dt)
  41 {
  42         const struct machine_desc *mdesc;
  43         unsigned long dt_root;
  44         const void *clk;
  45         int len;
  46
  47         if (!early_init_dt_scan(dt))
  48                 return NULL;
  49
  50         mdesc = of_flat_dt_match_machine(NULL, arch_get_next_mach);
  51         if (!mdesc)
  52                 machine_halt();
  53
  54         dt_root = of_get_flat_dt_root();
  55         clk = of_get_flat_dt_prop(dt_root, "clock-frequency", &len);
  56         if (clk)
  57                 arc_set_core_freq(of_read_ulong(clk, len/4));
  58
  59         return mdesc;
  60 }