/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * ipmi_si_sm.h
 *
 * State machine interface for low-level IPMI system management
 * interface state machines.  This code is the interface between
 * the ipmi_smi code (that handles the policy of a KCS, SMIC, or
 * BT interface) and the actual low-level state machine.
 *
 * Author: MontaVista Software, Inc.
 *         Corey Minyard <minyard@mvista.com>
 *         source@mvista.com
 *
 * Copyright 2002 MontaVista Software Inc.
 */

#ifndef __IPMI_SI_SM_H__
#define __IPMI_SI_SM_H__

#include "ipmi_si.h"

/*
 * This is defined by the state machines themselves, it is an opaque
 * data type for them to use.
 */
struct si_sm_data;

/* Results of SMI events. */
enum si_sm_result {
        SI_SM_CALL_WITHOUT_DELAY, /* Call the driver again immediately */
        SI_SM_CALL_WITH_DELAY,  /* Delay some before calling again. */
        SI_SM_CALL_WITH_TICK_DELAY,/* Delay >=1 tick before calling again. */
        SI_SM_TRANSACTION_COMPLETE, /* A transaction is finished. */
        SI_SM_IDLE,             /* The SM is in idle state. */
        SI_SM_HOSED,            /* The hardware violated the state machine. */

        /*
         * The hardware is asserting attn and the state machine is
         * idle.
         */
        SI_SM_ATTN
};

/* Handlers for the SMI state machine. */
struct si_sm_handlers {
        /*
         * Put the version number of the state machine here so the
         * upper layer can print it.
         */
        char *version;

        /*
         * Initialize the data and return the amount of I/O space to
         * reserve for the space.
         */
        unsigned int (*init_data)(struct si_sm_data *smi,
                                  struct si_sm_io   *io);

        /*
         * Start a new transaction in the state machine.  This will
         * return -2 if the state machine is not idle, -1 if the size
         * is invalid (to large or too small), or 0 if the transaction
         * is successfully completed.
         */
        int (*start_transaction)(struct si_sm_data *smi,
                                 unsigned char *data, unsigned int size);

        /*
         * Return the results after the transaction.  This will return
         * -1 if the buffer is too small, zero if no transaction is
         * present, or the actual length of the result data.
         */
        int (*get_result)(struct si_sm_data *smi,
                          unsigned char *data, unsigned int length);

        /*
         * Call this periodically (for a polled interface) or upon
         * receiving an interrupt (for a interrupt-driven interface).
         * If interrupt driven, you should probably poll this
         * periodically when not in idle state.  This should be called
         * with the time that passed since the last call, if it is
         * significant.  Time is in microseconds.
         */
        enum si_sm_result (*event)(struct si_sm_data *smi, long time);

        /*
         * Attempt to detect an SMI.  Returns 0 on success or nonzero
         * on failure.
         */
        int (*detect)(struct si_sm_data *smi);

        /* The interface is shutting down, so clean it up. */
        void (*cleanup)(struct si_sm_data *smi);

        /* Return the size of the SMI structure in bytes. */
        int (*size)(void);
};

/* Current state machines that we can use. */
extern const struct si_sm_handlers kcs_smi_handlers;
extern const struct si_sm_handlers smic_smi_handlers;
extern const struct si_sm_handlers bt_smi_handlers;

#endif /* __IPMI_SI_SM_H__ */