u-boot/arch/arm/cpu/arm1176/start.S
Cédric Schieli 3e10fcde3f arm: add save_boot_params for ARM1176
Implement a hook to allow boards to save boot-time CPU state for later
use. When U-Boot is chain-loaded by another bootloader, CPU registers may
contain useful information such as system configuration information. This
feature mirrors the equivalent ARMv7 feature.

Signed-off-by: Cédric Schieli <cschieli@gmail.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
2016-11-21 14:07:31 -05:00

122 lines
2.7 KiB
ArmAsm

/*
* armboot - Startup Code for ARM1176 CPU-core
*
* Copyright (c) 2007 Samsung Electronics
*
* Copyright (C) 2008
* Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
*
* SPDX-License-Identifier: GPL-2.0+
*
* 2007-09-21 - Restructured codes by jsgood (jsgood.yang@samsung.com)
* 2007-09-21 - Added MoviNAND and OneNAND boot codes by
* jsgood (jsgood.yang@samsung.com)
* Base codes by scsuh (sc.suh)
*/
#include <asm-offsets.h>
#include <config.h>
#include <linux/linkage.h>
#ifndef CONFIG_SYS_PHY_UBOOT_BASE
#define CONFIG_SYS_PHY_UBOOT_BASE CONFIG_SYS_UBOOT_BASE
#endif
/*
*************************************************************************
*
* Startup Code (reset vector)
*
* do important init only if we don't start from memory!
* setup Memory and board specific bits prior to relocation.
* relocate armboot to ram
* setup stack
*
*************************************************************************
*/
.globl reset
reset:
/* Allow the board to save important registers */
b save_boot_params
.globl save_boot_params_ret
save_boot_params_ret:
/*
* set the cpu to SVC32 mode
*/
mrs r0, cpsr
bic r0, r0, #0x3f
orr r0, r0, #0xd3
msr cpsr, r0
/*
*************************************************************************
*
* CPU_init_critical registers
*
* setup important registers
* setup memory timing
*
*************************************************************************
*/
/*
* we do sys-critical inits only at reboot,
* not when booting from ram!
*/
cpu_init_crit:
/*
* When booting from NAND - it has definitely been a reset, so, no need
* to flush caches and disable the MMU
*/
#ifndef CONFIG_SPL_BUILD
/*
* flush v4 I/D caches
*/
mov r0, #0
mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
/*
* disable MMU stuff and caches
*/
mrc p15, 0, r0, c1, c0, 0
bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
orr r0, r0, #0x00000002 @ set bit 1 (A) Align
orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
/* Prepare to disable the MMU */
adr r2, mmu_disable_phys
sub r2, r2, #(CONFIG_SYS_PHY_UBOOT_BASE - CONFIG_SYS_TEXT_BASE)
b mmu_disable
.align 5
/* Run in a single cache-line */
mmu_disable:
mcr p15, 0, r0, c1, c0, 0
nop
nop
mov pc, r2
mmu_disable_phys:
#endif
/*
* Go setup Memory and board specific bits prior to relocation.
*/
bl lowlevel_init /* go setup pll,mux,memory */
bl _main
/*------------------------------------------------------------------------------*/
.globl c_runtime_cpu_setup
c_runtime_cpu_setup:
mov pc, lr
WEAK(save_boot_params)
b save_boot_params_ret /* back to my caller */
ENDPROC(save_boot_params)