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         ; Disable/enable I-cache according to configuration
  17         lr      r5, [ARC_BCR_IC_BUILD]
  18         breq    r5, 0, 1f               ; I$ doesn't exist
  19         lr      r5, [ARC_AUX_IC_CTRL]
  20 #ifndef CONFIG_SYS_ICACHE_OFF
  21         bclr    r5, r5, 0               ; 0 - Enable, 1 is Disable
  22 #else
  23         bset    r5, r5, 0               ; I$ exists, but is not used
  24 #endif
  25         sr      r5, [ARC_AUX_IC_CTRL]
  26
  27 1:
  28         ; Disable/enable D-cache according to configuration
  29         lr      r5, [ARC_BCR_DC_BUILD]
  30         breq    r5, 0, 1f               ; D$ doesn't exist
  31         lr      r5, [ARC_AUX_DC_CTRL]
  32         bclr    r5, r5, 6               ; Invalidate (discard w/o wback)
  33 #ifndef CONFIG_SYS_DCACHE_OFF
  34         bclr    r5, r5, 0               ; Enable (+Inv)
  35 #else
  36         bset    r5, r5, 0               ; Disable (+Inv)
  37 #endif
  38         sr      r5, [ARC_AUX_DC_CTRL]
  39
  40 1:
  41 #ifdef CONFIG_ISA_ARCV2
  42         ; Disable System-Level Cache (SLC)
  43         lr      r5, [ARC_BCR_SLC]
  44         breq    r5, 0, 1f               ; SLC doesn't exist
  45         lr      r5, [ARC_AUX_SLC_CTRL]
  46         bclr    r5, r5, 6               ; Invalidate (discard w/o wback)
  47         bclr    r5, r5, 0               ; Enable (+Inv)
  48         sr      r5, [ARC_AUX_SLC_CTRL]
  49
  50 1:
  51 #endif
  52
  53         /* Establish C runtime stack and frame */
  54         mov     %sp, CONFIG_SYS_INIT_SP_ADDR
  55         mov     %fp, %sp
  56
  57         /* Allocate reserved area from current top of stack */
  58         mov     %r0, %sp
  59         bl      board_init_f_alloc_reserve
  60         /* Set stack below reserved area, adjust frame pointer accordingly */
  61         mov     %sp, %r0
  62         mov     %fp, %sp
  63
  64         /* Initialize reserved area - note: r0 already contains address */
  65         bl      board_init_f_init_reserve
  66
  67         /* Zero the one and only argument of "board_init_f" */
  68         mov_s   %r0, 0
  69         j       board_init_f
  70 ENDPROC(_start)
  71
  72 /*
  73  * void board_init_f_r_trampoline(stack-pointer address)
  74  *
  75  * This "function" does not return, instead it continues in RAM
  76  * after relocating the monitor code.
  77  *
  78  * r0 = new stack-pointer
  79  */
  80 ENTRY(board_init_f_r_trampoline)
  81         /* Set up the stack- and frame-pointers */
  82         mov     %sp, %r0
  83         mov     %fp, %sp
  84
  85         /* Update position of intterupt vector table */
  86         lr      %r0, [ARC_AUX_INTR_VEC_BASE]
  87         ld      %r1, [%r25, GD_RELOC_OFF]
  88         add     %r0, %r0, %r1
  89         sr      %r0, [ARC_AUX_INTR_VEC_BASE]
  90
  91         /* Re-enter U-Boot by calling board_init_f_r */
  92         j       board_init_f_r
  93 ENDPROC(board_init_f_r_trampoline)