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/* Copyright 2019 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.
/* USB State Machine Framework */
#ifndef __CROS_EC_USB_SM_H
#define __CROS_EC_USB_SM_H
/* Function pointer that implements a portion of a usb state */
typedef void (*state_execution)(const int port);
* General usb state that can be used in multiple state machines.
* entry - Optional method that will be run when this state is entered
* run - Optional method that will be run repeatedly during state machine loop
* exit - Optional method that will be run when this state exists
* parent- Optional parent usb_state that contains common entry/run/exit
* implementation between various usb state. All parent entry/run
* functions will before any child entry/run functions. All parent exit
* functions will run after any child exit functions.
struct usb_state {
const state_execution entry;
const state_execution run;
const state_execution exit;
const struct usb_state *parent;
typedef const struct usb_state *usb_state_ptr;
/* Defines the current context of the usb statemachine. */
struct sm_ctx {
usb_state_ptr current;
usb_state_ptr previous;
/* We use intptr_t type to accommodate host tests ptr size variance */
intptr_t internal[2];
/* Local state machine states */
enum sm_local_state {
SM_INIT = 0, /* Ensure static variables initialize to SM_INIT */
* Changes a state machines state. This handles exiting the previous state and
* entering the target state. A common parent state will not exited nor be
* re-entered.
* @param port USB-C port number
* @param ctx State machine context
* @param new_state State to transition to (NULL is valid and exits all states)
void set_state(int port, struct sm_ctx *ctx, usb_state_ptr new_state);
* Runs one iteration of a state machine (including any parent states)
* @param port USB-C port number
* @param ctx State machine context
void run_state(int port, struct sm_ctx *ctx);
* Struct for test builds that allow unit tests to easily iterate through
* state machines
struct test_sm_data {
/* Base pointer of the state machine array */
const usb_state_ptr base;
/* Size fo the state machine array above */
const int size;
/* The array of names for states, can be NULL */
const char * const * const names;
/* The size of the above names array */
const int names_size;
#endif /* __CROS_EC_USB_SM_H */