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/* -*- c++ -*- */
/*
* Copyright 2007 Free Software Foundation, Inc.
*
* 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/>.
*/
#ifndef INCLUDED_DBSM_H
#define INCLUDED_DBSM_H
/*
* Double Buffering State Machine
*/
#include <stdint.h>
#include "bool.h"
struct _dbsm;
typedef struct _dbsm dbsm_t;
/*
* pointer to function that does packet inspection.
*
* If one of these returns true, it means that the s/w
* handled that packet, and that it should NOT be passed
* on to the normal destination port.
*/
typedef bool (*inspector_t)(dbsm_t *sm, int buf_this);
bool dbsm_nop_inspector(dbsm_t *sm, int buf_this); // returns false
typedef struct
{
uint16_t port;
uint16_t first_line;
uint16_t last_line;
} buf_cmd_args_t;
/*!
* double buffer state machine
*/
struct _dbsm
{
uint8_t buf0; // Must be even. This machine uses buf0 and buf0+1
uint8_t running;
uint8_t rx_idle;
uint8_t tx_idle;
buf_cmd_args_t recv_args;
buf_cmd_args_t send_args;
inspector_t inspect;
uint32_t precomputed_receive_to_buf_ctrl_word[2];
uint32_t precomputed_send_from_buf_ctrl_word[2];
int last_line_adj;
};
void dbsm_init(dbsm_t *sm, int buf0,
const buf_cmd_args_t *recv, const buf_cmd_args_t *send,
inspector_t inspect);
void dbsm_start(dbsm_t *sm);
void dbsm_stop(dbsm_t *sm);
void dbsm_process_status(dbsm_t *sm, uint32_t status);
void dbsm_handle_tx_underrun(dbsm_t *sm);
void dbsm_handle_rx_overrun(dbsm_t *sm);
/*
* The cpu calls this when it want to ensure that it can send a buffer
* to the same destination being used by this state machine.
*
* If neither buffer is EMPTYING it returns immediately. If a buffer
* is EMPYTING, it waits for the h/w to transition to the DONE or
* ERROR state.
*
* When this function returns, the caller queues it's buffer and busy
* waits for it to complete.
*/
void dbsm_wait_for_opening(dbsm_t *sm);
#endif /* INCLUDED_DBSM_H */
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