LXR linux/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/mach_desc.h>
  18
  19#ifdef CONFIG_SERIAL_EARLYCON
  20
  21static unsigned int __initdata arc_base_baud;
  22
  23unsigned int __init arc_early_base_baud(void)
  24{
  25        return arc_base_baud/16;
  26}
  27
  28static void __init arc_set_early_base_baud(unsigned long dt_root)
  29{
  30        if (of_flat_dt_is_compatible(dt_root, "abilis,arc-tb10x"))
  31                arc_base_baud = 166666666;      /* Fixed 166.6MHz clk (TB10x) */
  32        else if (of_flat_dt_is_compatible(dt_root, "snps,arc-sdp"))
  33                arc_base_baud = 33333333;       /* Fixed 33MHz clk (AXS10x) */
  34        else
  35                arc_base_baud = 50000000;       /* Fixed default 50MHz */
  36}
  37#else
  38#define arc_set_early_base_baud(dt_root)
  39#endif
  40
  41static const void * __init arch_get_next_mach(const char *const **match)
  42{
  43        static const struct machine_desc *mdesc = __arch_info_begin;
  44        const struct machine_desc *m = mdesc;
  45
  46        if (m >= __arch_info_end)
  47                return NULL;
  48
  49        mdesc++;
  50        *match = m->dt_compat;
  51        return m;
  52}
  53
  54/**
  55 * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
  56 * @dt:         virtual address pointer to dt blob
  57 *
  58 * If a dtb was passed to the kernel, then use it to choose the correct
  59 * machine_desc and to setup the system.
  60 */
  61const struct machine_desc * __init setup_machine_fdt(void *dt)
  62{
  63        const struct machine_desc *mdesc;
  64        unsigned long dt_root;
  65
  66        if (!early_init_dt_scan(dt))
  67                return NULL;
  68
  69        mdesc = of_flat_dt_match_machine(NULL, arch_get_next_mach);
  70        if (!mdesc)
  71                machine_halt();
  72
  73        dt_root = of_get_flat_dt_root();
  74        arc_set_early_base_baud(dt_root);
  75
  76        return mdesc;
  77}
  78