pl011_console.c

/*
 * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of ARM nor the names of its contributors may be used
 * to endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <assert.h>
#include <console.h>
#include <pl011.h>

static unsigned long uart_base;

void console_init(unsigned long base_addr)
{
	/* TODO: assert() internally calls printf() and will result in
	 * an infinite loop. This needs to be fixed with some kind of
	 * exception  mechanism or early panic support. This also applies
	 * to the other assert() calls below.
	 */
	assert(base_addr);

	/* Initialise internal base address variable */
	uart_base = base_addr;

	/* Baud Rate */
#if defined(PL011_INTEGER) && defined(PL011_FRACTIONAL)
	pl011_write_ibrd(uart_base, PL011_INTEGER);
	pl011_write_fbrd(uart_base, PL011_FRACTIONAL);
#else
	pl011_setbaudrate(uart_base, PL011_BAUDRATE);
#endif

	pl011_write_lcr_h(uart_base, PL011_LINE_CONTROL);

	/* Clear any pending errors */
	pl011_write_ecr(uart_base, 0);

	/* Enable tx, rx, and uart overall */
	pl011_write_cr(uart_base, PL011_UARTCR_RXE | PL011_UARTCR_TXE |
			PL011_UARTCR_UARTEN);

}

#define WAIT_UNTIL_UART_FREE(base)				\
	while ((pl011_read_fr(base) & PL011_UARTFR_TXFF))	\
		continue

int console_putc(int c)
{
	/* If the console has not been initialized then return an error
	 * code. Asserting here would result in recursion and stack
	 * exhaustion
	 */
	if (!uart_base)
		return -1;

	if (c == '\n') {
		WAIT_UNTIL_UART_FREE(uart_base);
		pl011_write_dr(uart_base, '\r');
	}

	WAIT_UNTIL_UART_FREE(uart_base);
	pl011_write_dr(uart_base, c);
	return c;
}

int console_getc(void)
{
	assert(uart_base);

	while ((pl011_read_fr(uart_base) & PL011_UARTFR_RXFE) != 0)
		;
	return pl011_read_dr(uart_base);
}