• Andre Przywara's avatar
    rpi3: Do prescaler and control setup in C · dcf6d4f8
    Andre Przywara authored
    
    To initialise the arch timer configuration and some clock prescaler, we
    need to do two MMIO access *once*, early during boot.
    
    As tempting as it may sound, plat_reset_handler() is not the right place
    to do this, as it will be called on every CPU coming up, both for
    secondary cores as well as during warmboots. So this access will be done
    multiple times, and even during a rich OS' runtime. Whether doing so anyway
    is actually harmful is hard to say, but we should definitely avoid this if
    possible.
    
    Move the initialisation of these registers to C code in
    bl1_early_platform_setup(), where it will still be executed early enough
    (before enabling the console), but only once during the whole boot
    process.
    
    Change-Id: I081c41a5476d424411411488ff8f633e87d3bcc5
    Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
    dcf6d4f8
plat_helpers.S 4.57 KB
/*
 * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch.h>
#include <asm_macros.S>
#include <assert_macros.S>
#include <platform_def.h>

#include "../include/rpi_hw.h"

	.globl	plat_crash_console_flush
	.globl	plat_crash_console_init
	.globl	plat_crash_console_putc
	.globl	platform_mem_init
	.globl	plat_get_my_entrypoint
	.globl	plat_is_my_cpu_primary
	.globl	plat_my_core_pos
	.globl	plat_rpi3_calc_core_pos
	.globl	plat_secondary_cold_boot_setup

	/* -----------------------------------------------------
	 *  unsigned int plat_my_core_pos(void)
	 *
	 *  This function uses the plat_rpi3_calc_core_pos()
	 *  definition to get the index of the calling CPU.
	 * -----------------------------------------------------
	 */
func plat_my_core_pos
	mrs	x0, mpidr_el1
	b	plat_rpi3_calc_core_pos
endfunc plat_my_core_pos

	/* -----------------------------------------------------
	 *  unsigned int plat_rpi3_calc_core_pos(u_register_t mpidr);
	 *
	 *  CorePos = (ClusterId * 4) + CoreId
	 * -----------------------------------------------------
	 */
func plat_rpi3_calc_core_pos
	and	x1, x0, #MPIDR_CPU_MASK
	and	x0, x0, #MPIDR_CLUSTER_MASK
	add	x0, x1, x0, LSR #6
	ret
endfunc plat_rpi3_calc_core_pos

	/* -----------------------------------------------------
	 * unsigned int plat_is_my_cpu_primary (void);
	 *
	 * Find out whether the current cpu is the primary
	 * cpu.
	 * -----------------------------------------------------
	 */
func plat_is_my_cpu_primary
	mrs	x0, mpidr_el1
	and	x0, x0, #(MPIDR_CLUSTER_MASK | MPIDR_CPU_MASK)
	cmp	x0, #RPI3_PRIMARY_CPU
	cset	w0, eq
	ret
endfunc plat_is_my_cpu_primary

	/* -----------------------------------------------------
	 * void plat_secondary_cold_boot_setup (void);
	 *
	 * This function performs any platform specific actions
	 * needed for a secondary cpu after a cold reset e.g
	 * mark the cpu's presence, mechanism to place it in a
	 * holding pen etc.
	 * -----------------------------------------------------
	 */
func plat_secondary_cold_boot_setup
	/* Calculate address of our hold entry */
	bl	plat_my_core_pos
	lsl	x0, x0, #3
	mov_imm	x2, PLAT_RPI3_TM_HOLD_BASE
	add	x0, x0, x2

	/*
	 * This code runs way before requesting the warmboot of this core,
	 * so it is possible to clear the mailbox before getting a request
	 * to boot.
	 */
	mov	x1, PLAT_RPI3_TM_HOLD_STATE_WAIT
	str	x1,[x0]

	/* Wait until we have a go */
poll_mailbox:
	wfe
	ldr	x1, [x0]
	cmp	x1, PLAT_RPI3_TM_HOLD_STATE_GO
	bne	poll_mailbox

	/* Jump to the provided entrypoint */
	mov_imm	x0, PLAT_RPI3_TM_ENTRYPOINT
	ldr	x1, [x0]
	br	x1
endfunc plat_secondary_cold_boot_setup

	/* ---------------------------------------------------------------------
	 * uintptr_t plat_get_my_entrypoint (void);
	 *
	 * Main job of this routine is to distinguish between a cold and a warm
	 * boot.
	 *
	 * This functions returns:
	 *  - 0 for a cold boot.
	 *  - Any other value for a warm boot.
	 * ---------------------------------------------------------------------
	 */
func plat_get_my_entrypoint
	/* TODO: support warm boot */
	mov	x0, #0
	ret
endfunc plat_get_my_entrypoint

	/* ---------------------------------------------
	 * void platform_mem_init (void);
	 *
	 * No need to carry out any memory initialization.
	 * ---------------------------------------------
	 */
func platform_mem_init
	ret
endfunc platform_mem_init

	/* ---------------------------------------------
	 * int plat_crash_console_init(void)
	 * Function to initialize the crash console
	 * without a C Runtime to print crash report.
	 * Clobber list : x0 - x3
	 * ---------------------------------------------
	 */
func plat_crash_console_init
	mov_imm	x0, PLAT_RPI3_UART_BASE
	mov_imm	x1, PLAT_RPI3_UART_CLK_IN_HZ
	mov_imm	x2, PLAT_RPI3_UART_BAUDRATE
	b	console_16550_core_init
endfunc plat_crash_console_init

	/* ---------------------------------------------
	 * int plat_crash_console_putc(int c)
	 * Function to print a character on the crash
	 * console without a C Runtime.
	 * Clobber list : x1, x2
	 * ---------------------------------------------
	 */
func plat_crash_console_putc
	mov_imm	x1, PLAT_RPI3_UART_BASE
	b	console_16550_core_putc
endfunc plat_crash_console_putc

	/* ---------------------------------------------
	 * int plat_crash_console_flush()
	 * Function to force a write of all buffered
	 * data that hasn't been output.
	 * Out : return -1 on error else return 0.
	 * Clobber list : x0, x1
	 * ---------------------------------------------
	 */
func plat_crash_console_flush
	mov_imm	x0, PLAT_RPI3_UART_BASE
	b	console_16550_core_flush
endfunc plat_crash_console_flush