u-boot/arch/arm/mach-mediatek/mt7629/lowlevel_init.S

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2018 MediaTek Inc.
*/
#include <linux/linkage.h>
#define WAIT_CODE_SRAM_BASE 0x0010ff00
#define SLAVE_JUMP_REG 0x10202034
#define SLAVE1_MAGIC_REG 0x10202038
#define SLAVE1_MAGIC_NUM 0x534c4131
#define GIC_CPU_BASE 0x10320000
ENTRY(lowlevel_init)
#ifndef CONFIG_SPL_BUILD
/* Return to U-Boot via saved link register */
mov pc, lr
#else
/*
* Arch timer :
* set CNTFRQ = 20Mhz, set CNTVOFF = 0
*/
movw r0, #0x2d00
movt r0, #0x131
mcr p15, 0, r0, c14, c0, 0
/* enable SMP bit */
mrc p15, 0, r0, c1, c0, 1
orr r0, r0, #0x40
mcr p15, 0, r0, c1, c0, 1
/* if MP core, handle secondary cores */
mrc p15, 0, r0, c0, c0, 5
ands r1, r0, #0x40000000
bne go @ Go if UP
/* read slave CPU number */
ands r0, r0, #0x0f
beq go @ Go if core0 on primary core tile
b secondary
go:
/* master CPU */
mov pc, lr
secondary:
/* enable GIC as cores will be waken up by IPI */
ldr r2, =GIC_CPU_BASE
mov r1, #0xf0
str r1, [r2, #4]
mov r1, #1
str r1, [r2, #0]
ldr r1, [r2]
orr r1, #1
str r1, [r2]
/* copy wait code into SRAM */
ldr r0, =slave_cpu_wait
ldm r0, {r1 - r8} @ slave_cpu_wait has eight insns
ldr r0, =WAIT_CODE_SRAM_BASE
stm r0, {r1 - r8}
/* pass args to slave_cpu_wait */
ldr r0, =SLAVE1_MAGIC_REG
ldr r1, =SLAVE1_MAGIC_NUM
/* jump to wait code in SRAM */
ldr pc, =WAIT_CODE_SRAM_BASE
#endif
ENDPROC(lowlevel_init)
/* This function will be copied into SRAM */
ENTRY(slave_cpu_wait)
wfi
ldr r2, [r0]
cmp r2, r1
bne slave_cpu_wait
movw r0, #:lower16:SLAVE_JUMP_REG
movt r0, #:upper16:SLAVE_JUMP_REG
ldr r1, [r0]
mov pc, r1
ENDPROC(slave_cpu_wait)