plat/arm/board/fvp/aarch32/fvp_helpers.S

/*
 * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch.h>
#include <asm_macros.S>
#include <platform_def.h>
#include "../drivers/pwrc/fvp_pwrc.h"
#include "../fvp_def.h"

	.globl	plat_secondary_cold_boot_setup
	.globl	plat_get_my_entrypoint
	.globl	plat_is_my_cpu_primary

	/* --------------------------------------------------------------------
	 * void plat_secondary_cold_boot_setup (void);
	 *
	 * For AArch32, cold-booting secondary CPUs is not yet
	 * implemented and they panic.
	 * --------------------------------------------------------------------
	 */
func plat_secondary_cold_boot_setup
cb_panic:
	b	cb_panic
endfunc plat_secondary_cold_boot_setup

	/* ---------------------------------------------------------------------
	 * unsigned long plat_get_my_entrypoint (void);
	 *
	 * Main job of this routine is to distinguish between a cold and warm
	 * boot. On FVP, this information can be queried from the power
	 * controller. The Power Control SYS Status Register (PSYSR) indicates
	 * the wake-up reason for the CPU.
	 *
	 * For a cold boot, return 0.
	 * For a warm boot, read the mailbox and return the address it contains.
	 *
	 * TODO: PSYSR is a common register and should be
	 * 	accessed using locks. Since it is not possible
	 * 	to use locks immediately after a cold reset
	 * 	we are relying on the fact that after a cold
	 * 	reset all cpus will read the same WK field
	 * ---------------------------------------------------------------------
	 */
func plat_get_my_entrypoint
	/* ---------------------------------------------------------------------
	 * When bit PSYSR.WK indicates either "Wake by PPONR" or "Wake by GIC
	 * WakeRequest signal" then it is a warm boot.
	 * ---------------------------------------------------------------------
	 */
	ldcopr	r2, MPIDR
	ldr	r1, =PWRC_BASE
	str	r2, [r1, #PSYSR_OFF]
	ldr	r2, [r1, #PSYSR_OFF]
	ubfx	r2, r2, #PSYSR_WK_SHIFT, #PSYSR_WK_WIDTH
	cmp	r2, #WKUP_PPONR
	beq	warm_reset
	cmp	r2, #WKUP_GICREQ
	beq	warm_reset

	/* Cold reset */
	mov	r0, #0
	bx	lr

warm_reset:
	/* ---------------------------------------------------------------------
	 * A mailbox is maintained in the trusted SRAM. It is flushed out of the
	 * caches after every update using normal memory so it is safe to read
	 * it here with SO attributes.
	 * ---------------------------------------------------------------------
	 */
	ldr	r0, =PLAT_ARM_TRUSTED_MAILBOX_BASE
	ldr	r0, [r0]
	cmp	r0, #0
	beq	_panic
	bx	lr

	/* ---------------------------------------------------------------------
	 * The power controller indicates this is a warm reset but the mailbox
	 * is empty. This should never happen!
	 * ---------------------------------------------------------------------
	 */
_panic:
	b	_panic
endfunc plat_get_my_entrypoint

	/* -----------------------------------------------------
	 * unsigned int plat_is_my_cpu_primary (void);
	 *
	 * Find out whether the current cpu is the primary
	 * cpu.
	 * -----------------------------------------------------
	 */
func plat_is_my_cpu_primary
	ldcopr	r0, MPIDR
	ldr	r1, =(MPIDR_CLUSTER_MASK | MPIDR_CPU_MASK)
	and	r0, r1
	cmp	r0, #FVP_PRIMARY_CPU
	moveq	r0, #1
	movne	r0, #0
	bx	lr
endfunc plat_is_my_cpu_primary