arch/arc/lib/start.S

   1 /*
   2  * Copyright (C) 2013-2014 Synopsys, Inc. All rights reserved.
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <asm-offsets.h>
   8 #include <config.h>
   9 #include <linux/linkage.h>
  10 #include <asm/arcregs.h>
  11
  12 ENTRY(_start)
  13         /* Setup interrupt vector base that matches "__text_start" */
  14         sr      __ivt_start, [ARC_AUX_INTR_VEC_BASE]
  15
  16         /* Setup stack- and frame-pointers */
  17         mov     %sp, CONFIG_SYS_INIT_SP_ADDR
  18         mov     %fp, %sp
  19
  20         /* Unconditionally disable caches */
  21         bl      flush_dcache_all
  22         bl      dcache_disable
  23         bl      icache_disable
  24
  25         /* Allocate and zero GD, update SP */
  26         mov     %r0, %sp
  27         bl      board_init_f_mem
  28
  29         /* Update stack- and frame-pointers */
  30         mov     %sp, %r0
  31         mov     %fp, %sp
  32
  33         /* Zero the one and only argument of "board_init_f" */
  34         mov_s   %r0, 0
  35         j       board_init_f
  36 ENDPROC(_start)
  37
  38 /*
  39  * void board_init_f_r_trampoline(stack-pointer address)
  40  *
  41  * This "function" does not return, instead it continues in RAM
  42  * after relocating the monitor code.
  43  *
  44  * r0 = new stack-pointer
  45  */
  46 ENTRY(board_init_f_r_trampoline)
  47         /* Set up the stack- and frame-pointers */
  48         mov     %sp, %r0
  49         mov     %fp, %sp
  50
  51         /* Update position of intterupt vector table */
  52         lr      %r0, [ARC_AUX_INTR_VEC_BASE]
  53         ld      %r1, [%r25, GD_RELOC_OFF]
  54         add     %r0, %r0, %r1
  55         sr      %r0, [ARC_AUX_INTR_VEC_BASE]
  56
  57         /* Re-enter U-Boot by calling board_init_f_r */
  58         j       board_init_f_r
  59 ENDPROC(board_init_f_r_trampoline)