xref: /openbmc/linux/drivers/acpi/acpica/hwsleep.c (revision 8e41e0a5)

// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Name: hwsleep.c - ACPI Hardware Sleep/Wake Support functions for the
 *                   original/legacy sleep/PM registers.
 *
 * Copyright (C) 2000 - 2023, Intel Corp.
 *
 *****************************************************************************/

#include <acpi/acpi.h>
#include "accommon.h"

#define _COMPONENT          ACPI_HARDWARE
ACPI_MODULE_NAME("hwsleep")

#if (!ACPI_REDUCED_HARDWARE)	/* Entire module */
/*******************************************************************************
 *
 * FUNCTION:    acpi_hw_legacy_sleep
 *
 * PARAMETERS:  sleep_state         - Which sleep state to enter
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Enter a system sleep state via the legacy FADT PM registers
 *              THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED
 *
 ******************************************************************************/
acpi_status acpi_hw_legacy_sleep(u8 sleep_state)
{
	struct acpi_bit_register_info *sleep_type_reg_info;
	struct acpi_bit_register_info *sleep_enable_reg_info;
	u32 pm1a_control;
	u32 pm1b_control;
	u32 in_value;
	acpi_status status;

	ACPI_FUNCTION_TRACE(hw_legacy_sleep);

	sleep_type_reg_info =
	    acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_TYPE);
	sleep_enable_reg_info =
	    acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_ENABLE);

	/* Clear wake status */

	status = acpi_write_bit_register(ACPI_BITREG_WAKE_STATUS,
					 ACPI_CLEAR_STATUS);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	/* Disable all GPEs */
	status = acpi_hw_disable_all_gpes();
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}
	status = acpi_hw_clear_acpi_status();
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}
	acpi_gbl_system_awake_and_running = FALSE;

	 /* Enable all wakeup GPEs */
	status = acpi_hw_enable_all_wakeup_gpes();
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	/* Get current value of PM1A control */

	status = acpi_hw_register_read(ACPI_REGISTER_PM1_CONTROL,
				       &pm1a_control);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}
	ACPI_DEBUG_PRINT((ACPI_DB_INIT,
			  "Entering sleep state [S%u]\n", sleep_state));

	/* Clear the SLP_EN and SLP_TYP fields */

	pm1a_control &= ~(sleep_type_reg_info->access_bit_mask |
			  sleep_enable_reg_info->access_bit_mask);
	pm1b_control = pm1a_control;

	/* Insert the SLP_TYP bits */

	pm1a_control |=
	    (acpi_gbl_sleep_type_a << sleep_type_reg_info->bit_position);
	pm1b_control |=
	    (acpi_gbl_sleep_type_b << sleep_type_reg_info->bit_position);

	/*
	 * We split the writes of SLP_TYP and SLP_EN to workaround
	 * poorly implemented hardware.
	 */

	/* Write #1: write the SLP_TYP data to the PM1 Control registers */

	status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	/* Insert the sleep enable (SLP_EN) bit */

	pm1a_control |= sleep_enable_reg_info->access_bit_mask;
	pm1b_control |= sleep_enable_reg_info->access_bit_mask;

	/* Flush caches, as per ACPI specification */

	if (sleep_state < ACPI_STATE_S4) {
		ACPI_FLUSH_CPU_CACHE();
	}

	status = acpi_os_enter_sleep(sleep_state, pm1a_control, pm1b_control);
	if (status == AE_CTRL_TERMINATE) {
		return_ACPI_STATUS(AE_OK);
	}
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	/* Write #2: Write both SLP_TYP + SLP_EN */

	status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	if (sleep_state > ACPI_STATE_S3) {
		/*
		 * We wanted to sleep > S3, but it didn't happen (by virtue of the
		 * fact that we are still executing!)
		 *
		 * Wait ten seconds, then try again. This is to get S4/S5 to work on
		 * all machines.
		 *
		 * We wait so long to allow chipsets that poll this reg very slowly
		 * to still read the right value. Ideally, this block would go
		 * away entirely.
		 */
		acpi_os_stall(10 * ACPI_USEC_PER_SEC);

		status = acpi_hw_register_write(ACPI_REGISTER_PM1_CONTROL,
						sleep_enable_reg_info->
						access_bit_mask);
		if (ACPI_FAILURE(status)) {
			return_ACPI_STATUS(status);
		}
	}

	/* Wait for transition back to Working State */

	do {
		status =
		    acpi_read_bit_register(ACPI_BITREG_WAKE_STATUS, &in_value);
		if (ACPI_FAILURE(status)) {
			return_ACPI_STATUS(status);
		}

	} while (!in_value);

	return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_hw_legacy_wake_prep
 *
 * PARAMETERS:  sleep_state         - Which sleep state we just exited
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Perform the first state of OS-independent ACPI cleanup after a
 *              sleep.
 *              Called with interrupts ENABLED.
 *
 ******************************************************************************/

acpi_status acpi_hw_legacy_wake_prep(u8 sleep_state)
{
	acpi_status status = AE_OK;
	struct acpi_bit_register_info *sleep_type_reg_info;
	struct acpi_bit_register_info *sleep_enable_reg_info;
	u32 pm1a_control;
	u32 pm1b_control;

	ACPI_FUNCTION_TRACE(hw_legacy_wake_prep);

	/*
	 * Set SLP_TYPE and SLP_EN to state S0.
	 * This is unclear from the ACPI Spec, but it is required
	 * by some machines.
	 */
	if (acpi_gbl_sleep_type_a_s0 != ACPI_SLEEP_TYPE_INVALID) {
		sleep_type_reg_info =
		    acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_TYPE);
		sleep_enable_reg_info =
		    acpi_hw_get_bit_register_info(ACPI_BITREG_SLEEP_ENABLE);

		/* Get current value of PM1A control */

		status = acpi_hw_register_read(ACPI_REGISTER_PM1_CONTROL,
					       &pm1a_control);
		if (ACPI_SUCCESS(status)) {

			/* Clear the SLP_EN and SLP_TYP fields */

			pm1a_control &= ~(sleep_type_reg_info->access_bit_mask |
					  sleep_enable_reg_info->
					  access_bit_mask);
			pm1b_control = pm1a_control;

			/* Insert the SLP_TYP bits */

			pm1a_control |= (acpi_gbl_sleep_type_a_s0 <<
					 sleep_type_reg_info->bit_position);
			pm1b_control |= (acpi_gbl_sleep_type_b_s0 <<
					 sleep_type_reg_info->bit_position);

			/* Write the control registers and ignore any errors */

			(void)acpi_hw_write_pm1_control(pm1a_control,
							pm1b_control);
		}
	}

	return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_hw_legacy_wake
 *
 * PARAMETERS:  sleep_state         - Which sleep state we just exited
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Perform OS-independent ACPI cleanup after a sleep
 *              Called with interrupts ENABLED.
 *
 ******************************************************************************/

acpi_status acpi_hw_legacy_wake(u8 sleep_state)
{
	acpi_status status;

	ACPI_FUNCTION_TRACE(hw_legacy_wake);

	/* Ensure enter_sleep_state_prep -> enter_sleep_state ordering */

	acpi_gbl_sleep_type_a = ACPI_SLEEP_TYPE_INVALID;
	acpi_hw_execute_sleep_method(METHOD_PATHNAME__SST, ACPI_SST_WAKING);

	/*
	 * GPEs must be enabled before _WAK is called as GPEs
	 * might get fired there
	 *
	 * Restore the GPEs:
	 * 1) Disable all GPEs
	 * 2) Enable all runtime GPEs
	 */
	status = acpi_hw_disable_all_gpes();
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	status = acpi_hw_enable_all_runtime_gpes();
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	/*
	 * Now we can execute _WAK, etc. Some machines require that the GPEs
	 * are enabled before the wake methods are executed.
	 */
	acpi_hw_execute_sleep_method(METHOD_PATHNAME__WAK, sleep_state);

	/*
	 * Some BIOS code assumes that WAK_STS will be cleared on resume
	 * and use it to determine whether the system is rebooting or
	 * resuming. Clear WAK_STS for compatibility.
	 */
	(void)acpi_write_bit_register(ACPI_BITREG_WAKE_STATUS,
				      ACPI_CLEAR_STATUS);
	acpi_gbl_system_awake_and_running = TRUE;

	/* Enable power button */

	(void)
	    acpi_write_bit_register(acpi_gbl_fixed_event_info
				    [ACPI_EVENT_POWER_BUTTON].
				    enable_register_id, ACPI_ENABLE_EVENT);

	(void)
	    acpi_write_bit_register(acpi_gbl_fixed_event_info
				    [ACPI_EVENT_POWER_BUTTON].
				    status_register_id, ACPI_CLEAR_STATUS);

	/* Enable sleep button */

	(void)
	    acpi_write_bit_register(acpi_gbl_fixed_event_info
				    [ACPI_EVENT_SLEEP_BUTTON].
				    enable_register_id, ACPI_ENABLE_EVENT);

	(void)
	    acpi_write_bit_register(acpi_gbl_fixed_event_info
				    [ACPI_EVENT_SLEEP_BUTTON].
				    status_register_id, ACPI_CLEAR_STATUS);

	acpi_hw_execute_sleep_method(METHOD_PATHNAME__SST, ACPI_SST_WORKING);
	return_ACPI_STATUS(status);
}

#endif				/* !ACPI_REDUCED_HARDWARE */