/*
 * Copyright (C) 2012, 2013 Antony Pavlov <antonynpavlov@gmail.com>
 *
 * This file is part of barebox.
 * See file CREDITS for list of people who contributed to this project.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * 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.
 *
 */

/** @file
 *  This file contains declaration for early output support
 */
#ifndef __INCLUDE_MIPS_ASM_DEBUG_LL_NS16550_H__
#define __INCLUDE_MIPS_ASM_DEBUG_LL_NS16550_H__

#ifdef CONFIG_DEBUG_LL

#ifndef DEBUG_LL_UART_ADDR
#error DEBUG_LL_UART_ADDR is undefined!
#endif

#ifndef DEBUG_LL_UART_SHIFT
#error DEBUG_LL_UART_SHIFT is undefined!
#endif

#ifndef DEBUG_LL_UART_DIVISOR
#error DEBUG_LL_UART_DIVISOR is undefined!
#endif

#endif /* CONFIG_DEBUG_LL */

#define UART_THR	(0x0 << DEBUG_LL_UART_SHIFT)
#define UART_DLL	(0x0 << DEBUG_LL_UART_SHIFT)
#define UART_DLM	(0x1 << DEBUG_LL_UART_SHIFT)
#define UART_LCR	(0x3 << DEBUG_LL_UART_SHIFT)
#define UART_LSR	(0x5 << DEBUG_LL_UART_SHIFT)

#define UART_LCR_W	0x07		/* Set UART to 8,N,2 & DLAB = 0 */
#define UART_LCR_DLAB	0x87	/* Set UART to 8,N,2 & DLAB = 1 */

#define UART_LSR_THRE	0x20	/* Xmit holding register empty */

#ifndef __ASSEMBLY__
/*
 * C macros
 */

#include <asm/io.h>

static __inline__ void PUTC_LL(char ch)
{
	while (!(__raw_readb((u8 *)DEBUG_LL_UART_ADDR + UART_LSR) & UART_LSR_THRE))
		;
	__raw_writeb(ch, (u8 *)DEBUG_LL_UART_ADDR + UART_THR);
}
#else /* __ASSEMBLY__ */
/*
 * Macros for use in assembly language code
 */

.macro	debug_ll_ns16550_init
#ifdef CONFIG_DEBUG_LL
	la	t0, DEBUG_LL_UART_ADDR

	li	t1, UART_LCR_DLAB		/* DLAB on */
	sb	t1, UART_LCR(t0)		/* Write it out */

	li	t1, DEBUG_LL_UART_DIVISOR
	sb	t1, UART_DLL(t0)		/* write low order byte */
	srl	t1, t1, 8
	sb	t1, UART_DLM(t0)		/* write high order byte */

	li	t1, UART_LCR_W			/* DLAB off */
	sb	t1, UART_LCR(t0)		/* Write it out */
#endif /* CONFIG_DEBUG_LL */
.endm

/*
 * output a character in a0
 */
.macro	debug_ll_ns16550_outc chr
#ifdef CONFIG_DEBUG_LL
	li	a0, \chr
	la	t0, DEBUG_LL_UART_ADDR

1:	lbu	t1, UART_LSR(t0)	/* get line status */
	nop
	andi	t1, t1, UART_LSR_THRE	/* check for transmitter empty */
	beqz	t1, 1b			/* try again */
	 nop

	sb	a0, UART_THR(t0)	/* write the character */
#endif /* CONFIG_DEBUG_LL */
.endm

/*
 * output CR + NL
 */
.macro	debug_ll_ns16550_outnl
#ifdef CONFIG_DEBUG_LL
	debug_ll_ns16550_outc '\r'
	debug_ll_ns16550_outc '\n'
#endif /* CONFIG_DEBUG_LL */
.endm
#endif /* __ASSEMBLY__ */

#endif /* __INCLUDE_MIPS_ASM_DEBUG_LL_NS16550_H__ */