src/drivers/spi/spiconsole.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <spi-generic.h>
   4 #include <spi_flash.h>
   5 #include <console/spi.h>
   6
   7 static struct spi_slave slave;
   8
   9 void spiconsole_init(void) {
  10         spi_init();
  11         spi_setup_slave(0, 0, &slave);
  12 }
  13
  14 /*
  15  * The EM100 'hyper terminal' specification defines a header of 9 characters.
  16  * Because of this, devices with a spi_crop_chunk of less than 10 characters
  17  * can't be supported by this standard.
  18  *
  19  * To add support in romstage, the static struct here and the ones used by
  20  * spi_xfer will need to be modified - removed, or mapped into cbmem.
  21  *
  22  * Because the Dediprog software expects strings, not single characters, and
  23  * because of the header overhead, this builds up a buffer to send.
  24  */
  25 void spiconsole_tx_byte(unsigned char c) {
  26         static struct em100_msg msg = {
  27                 .header.spi_command = EM100_DEDICATED_CMD,
  28                 .header.em100_command = EM100_UFIFO_CMD,
  29                 .header.msg_signature = EM100_MSG_SIGNATURE,
  30                 .header.msg_type = EM100_MSG_ASCII,
  31                 .header.msg_length = 0
  32         };
  33
  34         /* Verify the spi buffer is big enough to send even a single byte */
  35         if (spi_crop_chunk(&slave, 0, MAX_MSG_LENGTH) <
  36                         sizeof(struct em100_msg_header) + 1)
  37                 return;
  38
  39         msg.data[msg.header.msg_length] = c;
  40         msg.header.msg_length++;
  41
  42         /* Send the data on newline or when the max spi length is reached */
  43         if (c == '\n' || (sizeof(struct em100_msg_header) +
  44                         msg.header.msg_length == spi_crop_chunk(&slave, 0,
  45                         MAX_MSG_LENGTH))) {
  46                 spi_xfer(&slave, &msg, sizeof(struct em100_msg_header) +
  47                                 msg.header.msg_length, NULL, 0);
  48
  49                 msg.header.msg_length = 0;
  50         }
  51 }