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/* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright 2020 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.
*
* Implement a state machine for powering on, booting, and powering off the
* FPGA System-on-Module (SOM) that is the heart of Chameleon v3.
* See doc/fpga_sm.md for design details.
*/
#ifndef __FPGABOOT_SM_H
#define __FPGABOOT_SM_H
#include <stdbool.h>
#include <zephyr.h>
enum fpga_state {
FPGABOOT_INIT,
FPGABOOT_OFF,
FPGABOOT_PWR_GOOD,
FPGABOOT_LOAD,
FPGABOOT_RUNNING,
};
enum fpga_event {
FPGABOOT_EVENT_NONE,
FPGABOOT_POWER_ON_REQ,
FPGABOOT_POWER_OFF_REQ,
FPGABOOT_SOM_PWR_GOOD_ASSERTED,
FPGABOOT_SOM_PWR_GOOD_DEASSERTED,
FPGABOOT_SOM_FPGA_DONE_ASSERTED,
FPGABOOT_SOM_FPGA_DONE_DEASSERTED,
FPGABOOT_TIMER_EXPIRED,
};
#define FPGABOOT_ACTION_NONE 0x00
#define FPGABOOT_ASSERT_SOM_PWR_EN 0x01
#define FPGABOOT_DEASSERT_SOM_PWR_EN 0x02
/* NB: SOM_POR_L_LOAD_L is active low, so "assert" == "set to 0V" */
#define FPGABOOT_ASSERT_SOM_POR_L_LOAD_L 0x04
#define FPGABOOT_DEASSERT_SOM_POR_L_LOAD_L 0x08
#define FPGABOOT_START_SHORT_TIMER 0x10
#define FPGABOOT_START_LONG_TIMER 0x20
#define FPGABOOT_STOP_TIMER 0x40
/**
* @brief Initialize the state machine data
*
* @param p_state pointer to an `fpga_state` variable
* @param[out] p_actions pointer to variable to set bit flags for actions.
*/
void fpgaboot_init_state_machine(enum fpga_state *p_state, uint32_t *p_actions);
/**
* @brief Run the state machine
*
* The caller should set `event` to indicate the event being processed.
* The state machine may change `*p_state` and set one or more bits in
* `*p_actions` to indicate what the caller should do next.
*
* @param event the event being processed
* @param[inout] p_state pointer to an `fpga_state` variable
* @param[out] p_actions pointer to variable to set bit flags for actions.
*/
void fpgaboot_run_state_machine(enum fpga_event event, enum fpga_state *p_state,
uint32_t *p_actions);
/**
* @brief Determine if the FPGA is in a steady state, on or off
*
* @param state an `fpga_state` variable
* @retval true
* if the FPGA is either on or off
* @retval false
* if the FPGA is in a different state moving towards either on or off
*/
bool fpgaboot_is_steady_state(enum fpga_state state);
#endif