Colony » Colony Scout » Colony Scout OS

/*-

 * Copyright (c) 2008-2009, Kohsuke Ohtani

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. 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.

 * 3. Neither the name of the author nor the names of any co-contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <sys/param.h>

#include <boot.h>

#define UART_BASE        0x16000000

#define UART_CLK        14745600

#define BAUD_RATE        115200

/* UART Registers */

#define UART_DR                (*(volatile uint32_t *)(UART_BASE + 0x00))

#define UART_RSR        (*(volatile uint32_t *)(UART_BASE + 0x04))

#define UART_ECR        (*(volatile uint32_t *)(UART_BASE + 0x04))

#define UART_FR                (*(volatile uint32_t *)(UART_BASE + 0x18))

#define UART_IBRD        (*(volatile uint32_t *)(UART_BASE + 0x24))

#define UART_FBRD        (*(volatile uint32_t *)(UART_BASE + 0x28))

#define UART_LCRH        (*(volatile uint32_t *)(UART_BASE + 0x2c))

#define UART_CR                (*(volatile uint32_t *)(UART_BASE + 0x30))

#define UART_IMSC        (*(volatile uint32_t *)(UART_BASE + 0x38))

#define UART_MIS        (*(volatile uint32_t *)(UART_BASE + 0x40))

#define UART_ICR        (*(volatile uint32_t *)(UART_BASE + 0x44))

/* Flag register */

#define FR_RXFE                0x10        /* Receive FIFO empty */

#define FR_TXFF                0x20        /* Transmit FIFO full */

/* Masked interrupt status register */

#define MIS_RX                0x10        /* Receive interrupt */

#define MIS_TX                0x20        /* Transmit interrupt */

/* Interrupt clear register */

#define ICR_RX                0x10        /* Clear receive interrupt */

#define ICR_TX                0x20        /* Clear transmit interrupt */

/* Line control register (High) */

#define LCRH_WLEN8        0x60        /* 8 bits */

#define LCRH_FEN        0x10        /* Enable FIFO */

/* Control register */

#define CR_UARTEN        0x0001        /* UART enable */

#define CR_TXE                0x0100        /* Transmit enable */

#define CR_RXE                0x0200        /* Receive enable */

/* Interrupt mask set/clear register */

#define IMSC_RX                0x10        /* Receive interrupt mask */

#define IMSC_TX                0x20        /* Transmit interrupt mask */

/*

 * Print one chracter

 */

void

debug_putc(int c)

{

#if defined(DEBUG) && defined(CONFIG_DIAG_SERIAL)

        while (UART_FR & FR_TXFF)

                ;

        UART_DR = c;

#endif

}

/*

 * Initialize debug port.

 */

void

debug_init(void)

{

#if defined(DEBUG) && defined(CONFIG_DIAG_SERIAL)

        unsigned int divider;

        unsigned int remainder;

        unsigned int fraction;

        UART_CR = 0x0;                /* Disable everything */

        UART_ICR = 0x07ff;        /* Clear all interrupt status */

        /*

         * Set baud rate:

         * IBRD = UART_CLK / (16 * BAUD_RATE)

         * FBRD = ROUND((64 * MOD(UART_CLK,(16 * BAUD_RATE))) / (16 * BAUD_RATE))

         */

        divider = UART_CLK / (16 * BAUD_RATE);

        remainder = UART_CLK % (16 * BAUD_RATE);

        fraction = (8 * remainder / BAUD_RATE) >> 1;

        fraction += (8 * remainder / BAUD_RATE) & 1;

        UART_IBRD = divider;

        UART_FBRD = fraction;

        UART_LCRH = (LCRH_WLEN8 | LCRH_FEN);        /* N, 8, 1, FIFO enable */

        UART_CR = (CR_RXE | CR_TXE | CR_UARTEN);        /* Enable UART */

#endif

}