LXR linux/arch/arc/kernel/devtree.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
   4 *
   5 * Based on reduced version of METAG
   6 */
   7
   8
   9#include <linux/init.h>
  10#include <linux/reboot.h>
  11#include <linux/memblock.h>
  12#include <linux/of.h>
  13#include <linux/of_fdt.h>
  14#include <asm/mach_desc.h>
  15
  16#ifdef CONFIG_SERIAL_EARLYCON
  17
  18static unsigned int __initdata arc_base_baud;
  19
  20unsigned int __init arc_early_base_baud(void)
  21{
  22        return arc_base_baud/16;
  23}
  24
  25static void __init arc_set_early_base_baud(unsigned long dt_root)
  26{
  27        if (of_flat_dt_is_compatible(dt_root, "abilis,arc-tb10x"))
  28                arc_base_baud = 166666666;      /* Fixed 166.6MHz clk (TB10x) */
  29        else if (of_flat_dt_is_compatible(dt_root, "snps,arc-sdp") ||
  30                 of_flat_dt_is_compatible(dt_root, "snps,hsdk"))
  31                arc_base_baud = 33333333;       /* Fixed 33MHz clk (AXS10x & HSDK) */
  32        else
  33                arc_base_baud = 50000000;       /* Fixed default 50MHz */
  34}
  35#else
  36#define arc_set_early_base_baud(dt_root)
  37#endif
  38
  39static const void * __init arch_get_next_mach(const char *const **match)
  40{
  41        static const struct machine_desc *mdesc = __arch_info_begin;
  42        const struct machine_desc *m = mdesc;
  43
  44        if (m >= __arch_info_end)
  45                return NULL;
  46
  47        mdesc++;
  48        *match = m->dt_compat;
  49        return m;
  50}
  51
  52/**
  53 * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
  54 * @dt:         virtual address pointer to dt blob
  55 *
  56 * If a dtb was passed to the kernel, then use it to choose the correct
  57 * machine_desc and to setup the system.
  58 */
  59const struct machine_desc * __init setup_machine_fdt(void *dt)
  60{
  61        const struct machine_desc *mdesc;
  62        unsigned long dt_root;
  63
  64        if (!early_init_dt_scan(dt))
  65                return NULL;
  66
  67        mdesc = of_flat_dt_match_machine(NULL, arch_get_next_mach);
  68        if (!mdesc)
  69                machine_halt();
  70
  71        dt_root = of_get_flat_dt_root();
  72        arc_set_early_base_baud(dt_root);
  73
  74        return mdesc;
  75}
  76