src/soc/intel/common/block/smm/smm.c

/* SPDX-License-Identifier: GPL-2.0-only */

#include <bootstate.h>
#include <console/console.h>
#include <cpu/x86/smm.h>
#include <cpu/intel/smm_reloc.h>
#include <intelblocks/pmclib.h>
#include <intelblocks/systemagent.h>
#include <soc/pm.h>

void smm_southbridge_clear_state(void)
{
	printk(BIOS_DEBUG, "Clearing SMI status registers\n");

	if (pmc_get_smi_en() & APMC_EN) {
		printk(BIOS_INFO, "SMI# handler already enabled?\n");
		return;
	}

	/* Dump and clear status registers */
	pmc_clear_smi_status();
	pmc_clear_pm1_status();
	pmc_clear_tco_status();
	pmc_clear_all_gpe_status();
}

void smm_southbridge_enable(uint16_t pm1_events)
{
	uint32_t smi_params = ENABLE_SMI_PARAMS;

	printk(BIOS_DEBUG, "Enabling SMIs.\n");
	/* Configure events */
	pmc_enable_pm1(pm1_events);
	pmc_disable_std_gpe(PME_B0_EN);

	/*
	 * GPEs need to be disabled before enabling SMI. Otherwise, it could
	 * lead to SMIs being triggered in coreboot preventing the progress of
	 * normal boot-up. This is done as late as possible so that
	 * pmc_fill_power_state can read the correct state of GPE0_EN* registers
	 * and not lose information about the wake source.
	 */
	pmc_disable_all_gpe();

	/*
	 * Enable SMI generation:
	 *  - on APMC writes (io 0xb2)
	 *  - on writes to SLP_EN (sleep states)
	 *  - on writes to GBL_RLS (bios commands)
	 *  - on eSPI events, unless disabled (does nothing on LPC systems)
	 *  - on TCO events (TIMEOUT, case intrusion, ...), if enabled
	 * No SMIs:
	 *  - on microcontroller writes (io 0x62/0x66)
	 */
	if (CONFIG(SOC_INTEL_COMMON_BLOCK_SMM_ESPI_DISABLE))
		smi_params &= ~ESPI_SMI_EN;

	if (CONFIG(SOC_INTEL_COMMON_BLOCK_SMM_TCO_ENABLE))
		smi_params |= TCO_SMI_EN;

	/* Enable SMI generation: */
	pmc_enable_smi(smi_params);
}

void smm_setup_structures(void *gnvs, void *tcg, void *smi1)
{
	/*
	 * Issue SMI to set the gnvs pointer in SMM.
	 * tcg and smi1 are unused.
	 *
	 * EAX = APM_CNT_GNVS_UPDATE
	 * EBX = gnvs pointer
	 * EDX = APM_CNT
	 */
	asm volatile (
		"outb %%al, %%dx\n\t"
		: /* ignore result */
		: "a" (APM_CNT_GNVS_UPDATE),
		  "b" ((u32)gnvs),
		  "d" (APM_CNT)
	);
}