dbg_io.c

linux 内核源代码

/*
 * Copyright 2001 MontaVista Software Inc.
 * Author: Jun Sun, [e-mail] or [e-mail]
 * Copyright (C) 2000, 2001 Ralf Baechle ([e-mail])
 *
 * Copyright (C) 2007 Lemote Inc. & Insititute of Computing Technology
 * Author: Fuxin Zhang, [e-mail]
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *  THIS  SOFTWARE  IS PROVIDED   ``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  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.
 *
 *  You should have received a copy of the  GNU General Public License along
 *  with this program; if not, write  to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/io.h>
#include <linux/init.h>
#include <linux/types.h>

#include <asm/serial.h>

#define         UART16550_BAUD_2400             2400
#define         UART16550_BAUD_4800             4800
#define         UART16550_BAUD_9600             9600
#define         UART16550_BAUD_19200            19200
#define         UART16550_BAUD_38400            38400
#define         UART16550_BAUD_57600            57600
#define         UART16550_BAUD_115200           115200

#define         UART16550_PARITY_NONE           0
#define         UART16550_PARITY_ODD            0x08
#define         UART16550_PARITY_EVEN           0x18
#define         UART16550_PARITY_MARK           0x28
#define         UART16550_PARITY_SPACE          0x38

#define         UART16550_DATA_5BIT             0x0
#define         UART16550_DATA_6BIT             0x1
#define         UART16550_DATA_7BIT             0x2
#define         UART16550_DATA_8BIT             0x3

#define         UART16550_STOP_1BIT             0x0
#define         UART16550_STOP_2BIT             0x4

/* ----------------------------------------------------- */

/* === CONFIG === */
#ifdef CONFIG_64BIT
#define         BASE                    (0xffffffffbfd003f8)
#else
#define         BASE                    (0xbfd003f8)
#endif

#define         MAX_BAUD                BASE_BAUD
/* === END OF CONFIG === */

#define         REG_OFFSET              1

/* register offset */
#define         OFS_RCV_BUFFER          0
#define         OFS_TRANS_HOLD          0
#define         OFS_SEND_BUFFER         0
#define         OFS_INTR_ENABLE         (1*REG_OFFSET)
#define         OFS_INTR_ID             (2*REG_OFFSET)
#define         OFS_DATA_FORMAT         (3*REG_OFFSET)
#define         OFS_LINE_CONTROL        (3*REG_OFFSET)
#define         OFS_MODEM_CONTROL       (4*REG_OFFSET)
#define         OFS_RS232_OUTPUT        (4*REG_OFFSET)
#define         OFS_LINE_STATUS         (5*REG_OFFSET)
#define         OFS_MODEM_STATUS        (6*REG_OFFSET)
#define         OFS_RS232_INPUT         (6*REG_OFFSET)
#define         OFS_SCRATCH_PAD         (7*REG_OFFSET)

#define         OFS_DIVISOR_LSB         (0*REG_OFFSET)
#define         OFS_DIVISOR_MSB         (1*REG_OFFSET)

/* memory-mapped read/write of the port */
#define         UART16550_READ(y)	readb((char *)BASE + (y))
#define         UART16550_WRITE(y, z)	writeb(z, (char *)BASE + (y))

void debugInit(u32 baud, u8 data, u8 parity, u8 stop)
{
	u32 divisor;

	/* disable interrupts */
	UART16550_WRITE(OFS_INTR_ENABLE, 0);

	/* set up buad rate */
	/* set DIAB bit */
	UART16550_WRITE(OFS_LINE_CONTROL, 0x80);

	/* set divisor */
	divisor = MAX_BAUD / baud;
	UART16550_WRITE(OFS_DIVISOR_LSB, divisor & 0xff);
	UART16550_WRITE(OFS_DIVISOR_MSB, (divisor & 0xff00) >> 8);

	/* clear DIAB bit */
	UART16550_WRITE(OFS_LINE_CONTROL, 0x0);

	/* set data format */
	UART16550_WRITE(OFS_DATA_FORMAT, data | parity | stop);
}

static int remoteDebugInitialized;

u8 getDebugChar(void)
{
	if (!remoteDebugInitialized) {
		remoteDebugInitialized = 1;
		debugInit(UART16550_BAUD_115200,
			  UART16550_DATA_8BIT,
			  UART16550_PARITY_NONE, UART16550_STOP_1BIT);
	}

	while ((UART16550_READ(OFS_LINE_STATUS) & 0x1) == 0) ;
	return UART16550_READ(OFS_RCV_BUFFER);
}

int putDebugChar(u8 byte)
{
	if (!remoteDebugInitialized) {
		remoteDebugInitialized = 1;
		/*
		   debugInit(UART16550_BAUD_115200,
		   UART16550_DATA_8BIT,
		   UART16550_PARITY_NONE, UART16550_STOP_1BIT); */
	}

	while ((UART16550_READ(OFS_LINE_STATUS) & 0x20) == 0) ;
	UART16550_WRITE(OFS_SEND_BUFFER, byte);
	return 1;
}