u-boot/arch/arc/lib/start.S

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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Copyright (C) 2013-2014 Synopsys, Inc. All rights reserved.
*/
#include <asm-offsets.h>
#include <config.h>
#include <linux/linkage.h>
#include <asm/arcregs.h>
#include <system-constants.h>
ENTRY(_start)
/* Setup interrupt vector base that matches "__text_start" */
sr __ivt_start, [ARC_AUX_INTR_VEC_BASE]
; Disable/enable I-cache according to configuration
lr r5, [ARC_BCR_IC_BUILD]
breq r5, 0, 1f ; I$ doesn't exist
lr r5, [ARC_AUX_IC_CTRL]
#if !CONFIG_IS_ENABLED(SYS_ICACHE_OFF)
bclr r5, r5, 0 ; 0 - Enable, 1 is Disable
#else
bset r5, r5, 0 ; I$ exists, but is not used
#endif
sr r5, [ARC_AUX_IC_CTRL]
mov r5, 1
sr r5, [ARC_AUX_IC_IVIC]
; As per ARC HS databook (see chapter 5.3.3.2)
; it is required to add 3 NOPs after each write to IC_IVIC.
nop
nop
nop
1:
; Disable/enable D-cache according to configuration
lr r5, [ARC_BCR_DC_BUILD]
breq r5, 0, 1f ; D$ doesn't exist
lr r5, [ARC_AUX_DC_CTRL]
bclr r5, r5, 6 ; Invalidate (discard w/o wback)
#if !CONFIG_IS_ENABLED(SYS_DCACHE_OFF)
bclr r5, r5, 0 ; Enable (+Inv)
#else
bset r5, r5, 0 ; Disable (+Inv)
#endif
sr r5, [ARC_AUX_DC_CTRL]
mov r5, 1
sr r5, [ARC_AUX_DC_IVDC]
1:
#ifdef CONFIG_ISA_ARCV2
; Disable System-Level Cache (SLC)
lr r5, [ARC_BCR_SLC]
breq r5, 0, 1f ; SLC doesn't exist
lr r5, [ARC_AUX_SLC_CTRL]
bclr r5, r5, 6 ; Invalidate (discard w/o wback)
bclr r5, r5, 0 ; Enable (+Inv)
sr r5, [ARC_AUX_SLC_CTRL]
1:
#endif
#ifdef CONFIG_ISA_ARCV2
; In case of DSP extension presence in HW some instructions
; (related to integer multiply, multiply-accumulate, and divide
; operation) executes on this DSP execution unit. So their
; execution will depend on dsp configuration register (DSP_CTRL)
; As we want these instructions to execute the same way regardless
; of DSP presence we need to set DSP_CTRL properly.
lr r5, [ARC_AUX_DSP_BUILD]
bmsk r5, r5, 7
breq r5, 0, 1f
mov r5, 0
sr r5, [ARC_AUX_DSP_CTRL]
1:
#endif
#ifdef __ARC_UNALIGNED__
/*
* Enable handling of unaligned access in the CPU as by default
* this HW feature is disabled while GCC starting from 8.1.0
* unconditionally uses it for ARC HS cores.
*/
flag 1 << STATUS_AD_BIT
#endif
/* Establish C runtime stack and frame */
mov %sp, SYS_INIT_SP_ADDR
mov %fp, %sp
/* Allocate reserved area from current top of stack */
mov %r0, %sp
bl board_init_f_alloc_reserve
/* Set stack below reserved area, adjust frame pointer accordingly */
mov %sp, %r0
mov %fp, %sp
/* Initialize reserved area - note: r0 already contains address */
bl board_init_f_init_reserve
#ifdef CONFIG_DEBUG_UART
/* Earliest point to set up early debug uart */
bl debug_uart_init
#endif
/* Zero the one and only argument of "board_init_f" */
mov_s %r0, 0
bl board_init_f
/* We only get here if relocation is disabled by GD_FLG_SKIP_RELOC */
/* Make sure we don't lose GD overwritten by zero new GD */
mov %r0, %r25
mov %r1, 0
bl board_init_r
ENDPROC(_start)
/*
* void board_init_f_r_trampoline(stack-pointer address)
*
* This "function" does not return, instead it continues in RAM
* after relocating the monitor code.
*
* r0 = new stack-pointer
*/
ENTRY(board_init_f_r_trampoline)
/* Set up the stack- and frame-pointers */
mov %sp, %r0
mov %fp, %sp
/* Update position of intterupt vector table */
lr %r0, [ARC_AUX_INTR_VEC_BASE]
ld %r1, [%r25, GD_RELOC_OFF]
add %r0, %r0, %r1
sr %r0, [ARC_AUX_INTR_VEC_BASE]
/* Re-enter U-Boot by calling board_init_f_r */
j board_init_f_r
ENDPROC(board_init_f_r_trampoline)