spiconsole.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <spi-generic.h>
#include <spi_flash.h>
#include <console/spi.h>
 
static struct spi_slave slave;
 
void spiconsole_init(void) {
        spi_init();
        spi_setup_slave(0, 0, &slave);
}
 
/*
 * 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(&slave, 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(&slave, 0,
                        MAX_MSG_LENGTH))) {
                spi_xfer(&slave, &msg, sizeof(struct em100_msg_header) +
                                msg.header.msg_length, NULL, 0);
 
                msg.header.msg_length = 0;
        }
}