/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/* Port 80 module for Chrome EC */

#include "board.h"
#include "console.h"
#include "port80.h"
#include "uart.h"
#include "util.h"

#define HISTORY_LEN 16

static uint8_t history[HISTORY_LEN];
static int head;  /* Next index to use / oldest previous entry */
static int scroll;


void port_80_write(int data)
{
	/* Note that this currently prints from inside the LPC interrupt
	 * itself.  Probably not worth the system overhead to buffer the data
	 * and print it from a task, because we're printing a small amount of
	 * data and uart_printf() doesn't block. */
	uart_printf("%c[%T Port 80: 0x%02x]", scroll ? '\n' : '\r', data);

	history[head] = data;
	head = (head + 1) & (HISTORY_LEN - 1);
}

/*****************************************************************************/
/* Console commands */

static int command_port80(int argc, char **argv)
{
	int h = head;
	int i;

	/* 'port80 scroll' toggles whether port 80 output begins with a newline
	 * (scrolling) or CR (non-scrolling). */
	if (argc > 1 && !strcasecmp(argv[1], "scroll")) {
		scroll = !scroll;
		uart_printf("port80 scrolling %sabled\n",
			    scroll ? "en" : "dis");
		return EC_SUCCESS;
	}

	/* Technically, if a port 80 write comes in while we're
	 * printing this, we could print an incorrect history.
	 * Probably not worth the complexity to work around that. */
	uart_puts("Last port 80 writes:");
	for (i = 0; i < HISTORY_LEN; i++)
		uart_printf(" %02x", history[(h + i) & (HISTORY_LEN - 1)]);
	uart_puts(" <--newest\n");
	return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(port80, command_port80);