u-boot/arch/arm/cpu/arm926ejs/cpu.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Marius Groeger <mgroeger@sysgo.de>
 *
 * (C) Copyright 2002
 * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
 */

/*
 * CPU specific code
 */

#include <common.h>
#include <command.h>
#include <cpu_func.h>
#include <irq_func.h>
#include <asm/cache.h>
#include <asm/system.h>

static void cache_flush(void);

/************************************************************
 * sdelay() - simple spin loop.  Will be constant time as
 *  its generally used in bypass conditions only.  This
 *  is necessary until timers are accessible.
 *
 *  not inline to increase chances its in cache when called
 *************************************************************/
void sdelay(unsigned long loops)
{
	__asm__ volatile ("1:\n" "subs %0, %1, #1\n"
			  "bne 1b":"=r" (loops):"0"(loops));
}

int cleanup_before_linux (void)
{
	/*
	 * this function is called just before we call linux
	 * it prepares the processor for linux
	 *
	 * we turn off caches etc ...
	 */

	disable_interrupts();


	/* turn off I/D-cache */
	icache_disable();
	dcache_disable();
	l2_cache_disable();

	/* flush I/D-cache */
	cache_flush();

	return 0;
}

/* flush I/D-cache */
static void cache_flush (void)
{
#if !(CONFIG_IS_ENABLED(SYS_ICACHE_OFF) && CONFIG_IS_ENABLED(SYS_DCACHE_OFF))
	unsigned long i = 0;

	asm ("mcr p15, 0, %0, c7, c7, 0": :"r" (i));
#endif
}