arch/riscv/kernel/soc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2020 Western Digital Corporation or its affiliates.
   4  */
   5 #include <linux/init.h>
   6 #include <linux/libfdt.h>
   7 #include <linux/pgtable.h>
   8 #include <asm/soc.h>
   9
  10 /*
  11  * This is called extremly early, before parse_dtb(), to allow initializing
  12  * SoC hardware before memory or any device driver initialization.
  13  */
  14 void __init soc_early_init(void)
  15 {
  16         void (*early_fn)(const void *fdt);
  17         const struct of_device_id *s;
  18         const void *fdt = dtb_early_va;
  19
  20         for (s = (void *)&__soc_early_init_table_start;
  21              (void *)s < (void *)&__soc_early_init_table_end; s++) {
  22                 if (!fdt_node_check_compatible(fdt, 0, s->compatible)) {
  23                         early_fn = s->data;
  24                         early_fn(fdt);
  25                         return;
  26                 }
  27         }
  28 }
  29
  30 static bool soc_builtin_dtb_match(unsigned long vendor_id,
  31                                 unsigned long arch_id, unsigned long imp_id,
  32                                 const struct soc_builtin_dtb *entry)
  33 {
  34         return entry->vendor_id == vendor_id &&
  35                entry->arch_id == arch_id &&
  36                entry->imp_id == imp_id;
  37 }
  38
  39 void * __init soc_lookup_builtin_dtb(void)
  40 {
  41         unsigned long vendor_id, arch_id, imp_id;
  42         const struct soc_builtin_dtb *s;
  43
  44         __asm__ ("csrr %0, mvendorid" : "=r"(vendor_id));
  45         __asm__ ("csrr %0, marchid" : "=r"(arch_id));
  46         __asm__ ("csrr %0, mimpid" : "=r"(imp_id));
  47
  48         for (s = (void *)&__soc_builtin_dtb_table_start;
  49              (void *)s < (void *)&__soc_builtin_dtb_table_end; s++) {
  50                 if (soc_builtin_dtb_match(vendor_id, arch_id, imp_id, s))
  51                         return s->dtb_func();
  52         }
  53
  54         return NULL;
  55 }