pd-buddy-firmware/src/hard_reset.c

/*
 * PD Buddy - USB Power Delivery for everyone
 * Copyright (C) 2017 Clayton G. Hobbs <clay@lakeserv.net>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "hard_reset.h"

#include "priorities.h"
#include "policy_engine.h"
#include "protocol_rx.h"
#include "protocol_tx.h"
#include "fusb302b.h"
#include "pd.h"


thread_t *pdb_hardrst_thread;

/*
 * Hard Reset machine states
 */
enum hardrst_state {
    PRLHRResetLayer,
    PRLHRIndicateHardReset,
    PRLHRRequestHardReset,
    PRLHRWaitPHY,
    PRLHRHardResetRequested,
    PRLHRWaitPE,
    PRLHRComplete
};

/*
 * PRL_HR_Reset_Layer state
 */
static enum hardrst_state hardrst_reset_layer(void)
{
    /* First, wait for the signal to run a hard reset. */
    eventmask_t evt = chEvtWaitAny(PDB_EVT_HARDRST_RESET
            | PDB_EVT_HARDRST_I_HARDRST);

    /* Reset the stored message IDs */
    pdb_prlrx_messageid = 0;
    pdb_prltx_messageidcounter = 0;

    /* Reset the Protocol RX machine */
    chEvtSignal(pdb_prlrx_thread, PDB_EVT_PRLRX_RESET);
    chThdYield();

    /* Reset the Protocol TX machine */
    chEvtSignal(pdb_prltx_thread, PDB_EVT_PRLTX_RESET);
    chThdYield();

    /* Continue the process based on what event started the reset. */
    if (evt & PDB_EVT_HARDRST_RESET) {
        /* Policy Engine started the reset. */
        return PRLHRRequestHardReset;
    } else {
        /* PHY started the reset */
        return PRLHRIndicateHardReset;
    }
}

static enum hardrst_state hardrst_indicate_hard_reset(void)
{
    /* Tell the PE that we're doing a hard reset */
    chEvtSignal(pdb_pe_thread, PDB_EVT_PE_RESET);

    return PRLHRWaitPE;
}

static enum hardrst_state hardrst_request_hard_reset(void)
{
    /* Tell the PHY to send a hard reset */
    fusb_send_hardrst();

    return PRLHRWaitPHY;
}

static enum hardrst_state hardrst_wait_phy(void)
{
    /* Wait for the PHY to tell us that it's done sending the hard reset */
    chEvtWaitAnyTimeout(PDB_EVT_HARDRST_I_HARDSENT, PD_T_HARD_RESET_COMPLETE);

    /* Move on no matter what made us stop waiting. */
    return PRLHRHardResetRequested;
}

static enum hardrst_state hardrst_hard_reset_requested(void)
{
    /* Tell the PE that the hard reset was sent */
    chEvtSignal(pdb_pe_thread, PDB_EVT_PE_HARD_SENT);

    return PRLHRWaitPE;
}

static enum hardrst_state hardrst_wait_pe(void)
{
    /* Wait for the PE to tell us that it's done */
    chEvtWaitAny(PDB_EVT_HARDRST_DONE);

    return PRLHRComplete;
}

static enum hardrst_state hardrst_complete(void)
{
    /* I'm not aware of anything we have to tell the FUSB302B, so just finish
     * the reset routine. */
    return PRLHRResetLayer;
}

/*
 * Hard Reset state machine thread
 */
static THD_WORKING_AREA(waHardReset, 128);
static THD_FUNCTION(HardReset, arg) {
    (void) arg;
    enum hardrst_state state = PRLHRResetLayer;

    while (true) {
        switch (state) {
            case PRLHRResetLayer:
                state = hardrst_reset_layer();
                break;
            case PRLHRIndicateHardReset:
                state = hardrst_indicate_hard_reset();
                break;
            case PRLHRRequestHardReset:
                state = hardrst_request_hard_reset();
                break;
            case PRLHRWaitPHY:
                state = hardrst_wait_phy();
                break;
            case PRLHRHardResetRequested:
                state = hardrst_hard_reset_requested();
                break;
            case PRLHRWaitPE:
                state = hardrst_wait_pe();
                break;
            case PRLHRComplete:
                state = hardrst_complete();
                break;
            default:
                /* This is an error.  It really shouldn't happen.  We might
                 * want to handle it anyway, though. */
                break;
        }
    }
}

void pdb_hardrst_run(void)
{
    pdb_hardrst_thread = chThdCreateStatic(waHardReset, sizeof(waHardReset),
            PDB_PRIO_PRL, HardReset, NULL);
}