/* SPDX-License-Identifier: GPL-2.0-or-later */

#include <acpi/acpigen.h>
#include <console/console.h>
#include <intelblocks/acpi.h>
#include <types.h>

#define LPI_S0_HELPER_UUID		"c4eb40a0-6cd2-11e2-bcfd-0800200c9a66"
#define SYSTEM_POWER_MANAGEMENT_HID	"INT33A1"
#define SYSTEM_POWER_MANAGEMENT_CID	"PNP0D80"
#define EC_S0IX_HOOK			"\\_SB.PCI0.LPCB.EC0.S0IX"
#define MAINBOARD_HOOK			"\\_SB.MS0X"
#define ENABLE_PM_BITS_HOOK		"\\_SB.PCI0.EGPM"
#define RESTORE_PM_BITS_HOOK		"\\_SB.PCI0.RGPM"
#define LPI_STATES_ALL			0xff
#define MIN_DEVICE_STATE		ACPI_DEVICE_SLEEP_D0
#define PEPD_SCOPE			"\\_SB.PCI0"

/*
 * For now there is only one disabled non-existent device, because Windows
 * expects at least one device and crashes without it with a bluescreen
 * (`INTERNAL_POWER_ERROR`). Returning an empty package does not work.
 */
static void lpi_get_constraints(void *unused)
{
	/*
	 * Return (Package() {
	 *     Package() { "\NULL", 0,
	 *         Package() { 0,
	 *             Package() { 0xff, 0 }}}})
	 */
	acpigen_emit_byte(RETURN_OP);
	acpigen_write_package(1);
	{
		acpigen_write_package(3);
		{
			acpigen_emit_namestring("\\NULL");
			acpigen_write_integer(0); /* device disabled */
			acpigen_write_package(2);
			{
				acpigen_write_integer(0); /* revision */
				acpigen_write_package(2);
				{
					acpigen_write_integer(LPI_STATES_ALL);
					acpigen_write_integer(MIN_DEVICE_STATE);
				}
				acpigen_write_package_end();
			}
			acpigen_write_package_end();
		}
		acpigen_write_package_end();
	}
	acpigen_write_package_end();
}

static void lpi_s0ix_entry(void *unused)
{
	/* Inform the EC */
	acpigen_write_if_cond_ref_of(EC_S0IX_HOOK);
	acpigen_emit_namestring(EC_S0IX_HOOK);
	acpigen_write_integer(1);
	acpigen_write_if_end();

	/* Provide a board level S0ix hook */
	acpigen_write_if_cond_ref_of(MAINBOARD_HOOK);
	acpigen_emit_namestring(MAINBOARD_HOOK);
	acpigen_write_integer(1);
	acpigen_write_if_end();

	/* Save the current PM bits then enable GPIO PM with
	   MISCCFG_GPIO_PM_CONFIG_BITS */
	acpigen_write_if_cond_ref_of(ENABLE_PM_BITS_HOOK);
	acpigen_emit_namestring(ENABLE_PM_BITS_HOOK);
	acpigen_write_if_end();
}

static void lpi_s0ix_exit(void *unused)
{
	/* Inform the EC */
	acpigen_write_if_cond_ref_of(EC_S0IX_HOOK);
	acpigen_emit_namestring(EC_S0IX_HOOK);
	acpigen_write_integer(0);
	acpigen_write_if_end();

	/* Provide a board level S0ix hook */
	acpigen_write_if_cond_ref_of(MAINBOARD_HOOK);
	acpigen_emit_namestring(MAINBOARD_HOOK);
	acpigen_write_integer(0);
	acpigen_write_if_end();

	/* Restore GPIO all Community PM */
	acpigen_write_if_cond_ref_of(RESTORE_PM_BITS_HOOK);
	acpigen_emit_namestring(RESTORE_PM_BITS_HOOK);
	acpigen_write_if_end();
}

static void (*lpi_s0_helpers[])(void *) = {
	NULL,			/* enumerate functions (autogenerated) */
	lpi_get_constraints,	/* get device constraints */
	NULL,			/* get crash dump device */
	NULL,			/* display off notify */
	NULL,			/* display on notify */
	lpi_s0ix_entry,		/* s0ix entry */
	lpi_s0ix_exit,		/* s0ix exit */
};

void generate_acpi_power_engine(void)
{
	acpigen_write_scope(PEPD_SCOPE);
	acpigen_write_device("PEPD");

	acpigen_write_name_string("_HID", SYSTEM_POWER_MANAGEMENT_HID);
	acpigen_write_name("_CID");
	acpigen_emit_eisaid(SYSTEM_POWER_MANAGEMENT_CID);

	acpigen_write_dsm(LPI_S0_HELPER_UUID, lpi_s0_helpers, ARRAY_SIZE(lpi_s0_helpers), NULL);

	acpigen_write_device_end();
	acpigen_write_scope_end();

	printk(BIOS_INFO, PEPD_SCOPE ".PEPD: Intel Power Engine Plug-in\n");
}