lib/mpmm/mpmm.c

/*
 * Copyright (c) 2021-2022, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <stdbool.h>

#include <common/debug.h>
#include <lib/mpmm/mpmm.h>

#include <plat/common/platform.h>

#if ENABLE_MPMM_FCONF
#	include <lib/fconf/fconf.h>
#	include <lib/fconf/fconf_mpmm_getter.h>
#endif

static uint64_t read_cpuppmcr_el3_mpmmpinctl(void)
{
	return (read_cpuppmcr_el3() >> CPUPPMCR_EL3_MPMMPINCTL_SHIFT) &
		CPUPPMCR_EL3_MPMMPINCTL_MASK;
}

static void write_cpumpmmcr_el3_mpmm_en(uint64_t mpmm_en)
{
	uint64_t value = read_cpumpmmcr_el3();

	value &= ~(CPUMPMMCR_EL3_MPMM_EN_MASK << CPUMPMMCR_EL3_MPMM_EN_SHIFT);
	value |= (mpmm_en & CPUMPMMCR_EL3_MPMM_EN_MASK) <<
		CPUMPMMCR_EL3_MPMM_EN_SHIFT;

	write_cpumpmmcr_el3(value);
}

static bool mpmm_supported(void)
{
	bool supported = false;
	const struct mpmm_topology *topology;

#if ENABLE_MPMM_FCONF
	topology = FCONF_GET_PROPERTY(mpmm, config, topology);
#else
	topology = plat_mpmm_topology();
#endif /* ENABLE_MPMM_FCONF */

	/*
	 * For the current core firstly try to find out if the platform
	 * configuration has claimed support for MPMM, then make sure that MPMM
	 * is controllable through the system registers.
	 */

	if (topology != NULL) {
		unsigned int core_pos = plat_my_core_pos();

		supported = topology->cores[core_pos].supported &&
			(read_cpuppmcr_el3_mpmmpinctl() == 0U);
	} else {
		ERROR("MPMM: failed to generate MPMM topology\n");
	}

	return supported;
}

/* Defaults to false */
static bool mpmm_disable_for_errata;

void mpmm_enable(void)
{
	if (mpmm_supported()) {
		if (mpmm_disable_for_errata) {
			WARN("MPMM: disabled by errata workaround\n");
			return;
		}
		write_cpumpmmcr_el3_mpmm_en(1U);
	}
}

/*
 * This function is called from assembly code very early in BL31 so it must be
 * small and simple.
 */
void mpmm_errata_disable(void)
{
	mpmm_disable_for_errata = true;
}