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path: root/zephyr/subsys/ap_pwrseq/signal_vw.c
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/* Copyright 2022 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include <atomic.h>
#include <zephyr/drivers/espi.h>
#include <x86_non_dsx_common_pwrseq_sm_handler.h>

#include "signal_vw.h"

#define MY_COMPAT	intel_ap_pwrseq_vw

#if HAS_VW_SIGNALS

LOG_MODULE_DECLARE(ap_pwrseq, CONFIG_AP_PWRSEQ_LOG_LEVEL);

#define INIT_ESPI_SIGNAL(id)					\
{								\
	.espi_signal = DT_STRING_UPPER_TOKEN(id, virtual_wire),	\
	.signal = PWR_SIGNAL_ENUM(id),				\
	.invert = DT_PROP(id, vw_invert),			\
},

/*
 * Struct containing the eSPI virtual wire config.
 */
struct vw_config {
	uint8_t espi_signal;	/* associated VW signal */
	uint8_t signal;		/* power signal */
	bool invert;		/* Invert the signal value */
};

const static struct vw_config vw_config[] = {
DT_FOREACH_STATUS_OKAY(MY_COMPAT, INIT_ESPI_SIGNAL)
};

/*
 * Current signal value.
 */
static atomic_t signal_data;
/*
 * Mask of valid signals. If the bus is reset, this is cleared,
 * and when a signal is updated the associated bit is set to indicate
 * the signal is valid.
 */
static atomic_t signal_valid;

#define espi_dev DEVICE_DT_GET(DT_CHOSEN(intel_ap_pwrseq_espi))

BUILD_ASSERT(ARRAY_SIZE(vw_config) <= (sizeof(atomic_t) * 8));

static void espi_handler(const struct device *dev,
			 struct espi_callback *cb,
			 struct espi_event event)
{
	LOG_DBG("ESPI event type 0x%x %d:%d", event.evt_type,
		event.evt_details, event.evt_data);
	switch (event.evt_type) {
	default:
		__ASSERT(0, "ESPI unknown event type: %d",
			 event.evt_type);
		break;

	case ESPI_BUS_RESET:
		/*
		 * Clear the signal valid mask.
		 */
		atomic_clear(&signal_valid);
		break;

	case ESPI_BUS_EVENT_VWIRE_RECEIVED:
		for (int i = 0; i < ARRAY_SIZE(vw_config); i++) {
			if (event.evt_details == vw_config[i].espi_signal) {
				bool value = vw_config[i].invert
						? !event.evt_data
						: !!event.evt_data;

				atomic_set_bit_to(&signal_data, i, value);
				atomic_set_bit(&signal_valid, i);
				power_signal_interrupt(vw_config[i].signal,
						       value);
			}
		}
		break;
	}
}

int power_signal_vw_get(enum pwr_sig_vw vw)
{
	if (vw < 0 || vw >= ARRAY_SIZE(vw_config) ||
	    !atomic_test_bit(&signal_valid, vw)) {
		return -EINVAL;
	}
	return atomic_test_bit(&signal_data, vw);
}

void power_signal_vw_init(void)
{
	static struct espi_callback espi_cb;

	/* Assumes ESPI device is already configured. */

	/* Configure handler for eSPI events */
	espi_init_callback(&espi_cb, espi_handler,
			   ESPI_BUS_RESET |
			   ESPI_BUS_EVENT_VWIRE_RECEIVED);
	espi_add_callback(espi_dev, &espi_cb);
	/*
	 * Check whether the bus is ready, and if so,
	 * initialise the current values of the signals.
	 */
	if (espi_get_channel_status(espi_dev, ESPI_CHANNEL_VWIRE)) {
		for (int i = 0; i < ARRAY_SIZE(vw_config); i++) {
			uint8_t vw_value;

			if (espi_receive_vwire(espi_dev,
					   vw_config[i].espi_signal,
					   &vw_value) == 0) {
				atomic_set_bit_to(&signal_data, i,
					vw_config[i].invert
						? !vw_value
						: !!vw_value);
				atomic_set_bit(&signal_valid, i);

			}
		}
	}
}

#endif /* HAS_VW_SIGNALS */