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
  18 static unsigned int __initdata arc_base_baud;
  19
  20 unsigned int __init arc_early_base_baud(void)
  21 {
  22         return arc_base_baud/16;
  23 }
  24
  25 static 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 if (of_flat_dt_is_compatible(dt_root, "ezchip,arc-nps"))
  33                 arc_base_baud = 800000000;      /* Fixed 800MHz clk (NPS) */
  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
  41 static 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  */
  61 const 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 }