src/drivers/spi/spiconsole.c

/*
 * This file is part of the coreboot project.
 *
 * Copyright 2015 Google 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; version 2 of the License.
 *
 * 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.
 */

#include <spi-generic.h>
#include <spi_flash.h>
#include <console/spi.h>

void spiconsole_init(void) {
	spi_init();
	return;
}

/*
 * The EM100 'hyper terminal' specification defines a header of 9 characters.
 * Because of this, devices with a spi_crop_chunk of less than 10 characters
 * can't be supported by this standard.
 *
 * To add support in romstage, the static struct here and the ones used by
 * spi_xfer will need to be modified - removed, or mapped into cbmem.
 *
 * Because the Dediprog software expects strings, not single characters, and
 * because of the header overhead, this builds up a buffer to send.
 */
void spiconsole_tx_byte(unsigned char c) {
	static struct em100_msg msg = {
		.header.spi_command = EM100_DEDICATED_CMD,
		.header.em100_command = EM100_UFIFO_CMD,
		.header.msg_signature = EM100_MSG_SIGNATURE,
		.header.msg_type = EM100_MSG_ASCII,
		.header.msg_length = 0
	};

	/* Verify the spi buffer is big enough to send even a single byte */
	if (spi_crop_chunk(0,MAX_MSG_LENGTH) <
			sizeof(struct em100_msg_header) + 1)
		return;

	msg.data[msg.header.msg_length] = c;
	msg.header.msg_length++;

	/* Send the data on newline or when the max spi length is reached */
	if (c == '\n' || (sizeof(struct em100_msg_header) +
			msg.header.msg_length == spi_crop_chunk(0,
			MAX_MSG_LENGTH))) {
		struct spi_slave spi = { };

		spi_xfer(&spi, &msg, sizeof(struct em100_msg_header) +
				msg.header.msg_length, NULL, 0);

		msg.header.msg_length = 0;
	}

	return;
}