[people/ms/u-boot.git] / drivers / serial / serial_arc.c

/*
 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
 *
 * 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.
 *
 */

#include <common.h>
#include <serial.h>

DECLARE_GLOBAL_DATA_PTR;

struct arc_serial_regs {
	unsigned int id0;
	unsigned int id1;
	unsigned int id2;
	unsigned int id3;
	unsigned int data;
	unsigned int status;
	unsigned int baudl;
	unsigned int baudh;
};

/* Bit definitions of STATUS register */
#define UART_RXEMPTY		(1 << 5)
#define UART_OVERFLOW_ERR	(1 << 1)
#define UART_TXEMPTY		(1 << 7)

struct arc_serial_regs *regs = (struct arc_serial_regs *)CONFIG_ARC_UART_BASE;

static void arc_serial_setbrg(void)
{
	int arc_console_baud;

	if (!gd->baudrate)
		gd->baudrate = CONFIG_BAUDRATE;

	arc_console_baud = gd->cpu_clk / (gd->baudrate * 4) - 1;
	writeb(arc_console_baud & 0xff, &regs->baudl);

#ifdef CONFIG_ARC
	/*
	 * UART ISS(Instruction Set simulator) emulation has a subtle bug:
	 * A existing value of Baudh = 0 is used as a indication to startup
	 * it's internal state machine.
	 * Thus if baudh is set to 0, 2 times, it chokes.
	 * This happens with BAUD=115200 and the formaula above
	 * Until that is fixed, when running on ISS, we will set baudh to !0
	 */
	if (gd->arch.running_on_hw)
		writeb((arc_console_baud & 0xff00) >> 8, &regs->baudh);
	else
		writeb(1, &regs->baudh);
#else
	writeb((arc_console_baud & 0xff00) >> 8, &regs->baudh);
#endif
}

static int arc_serial_init(void)
{
	serial_setbrg();
	return 0;
}

static void arc_serial_putc(const char c)
{
	if (c == '\n')
		arc_serial_putc('\r');

	while (!(readb(&regs->status) & UART_TXEMPTY))
		;

	writeb(c, &regs->data);
}

static int arc_serial_tstc(void)
{
	return !(readb(&regs->status) & UART_RXEMPTY);
}

static int arc_serial_getc(void)
{
	while (!arc_serial_tstc())
		;

	/* Check for overflow errors */
	if (readb(&regs->status) & UART_OVERFLOW_ERR)
		return 0;

	return readb(&regs->data) & 0xFF;
}

static struct serial_device arc_serial_drv = {
	.name	= "arc_serial",
	.start	= arc_serial_init,
	.stop	= NULL,
	.setbrg	= arc_serial_setbrg,
	.putc	= arc_serial_putc,
	.puts	= default_serial_puts,
	.getc	= arc_serial_getc,
	.tstc	= arc_serial_tstc,
};

void arc_serial_initialize(void)
{
	serial_register(&arc_serial_drv);
}

__weak struct serial_device *default_serial_console(void)
{
	return &arc_serial_drv;
}
Commit	Line	Data
22a240c3 AB	1	/*
	2	* Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	*/
	9
	10	#include <common.h>
	11	#include <serial.h>
	12
	13	DECLARE_GLOBAL_DATA_PTR;
	14
	15	struct arc_serial_regs {
	16	unsigned int id0;
	17	unsigned int id1;
	18	unsigned int id2;
	19	unsigned int id3;
	20	unsigned int data;
	21	unsigned int status;
	22	unsigned int baudl;
	23	unsigned int baudh;
	24	};
	25
	26	/* Bit definitions of STATUS register */
	27	#define UART_RXEMPTY (1 << 5)
	28	#define UART_OVERFLOW_ERR (1 << 1)
	29	#define UART_TXEMPTY (1 << 7)
	30
36d68668	31	struct arc_serial_regs regs = (struct arc_serial_regs )CONFIG_ARC_UART_BASE;
22a240c3 AB	32
	33	static void arc_serial_setbrg(void)
	34	{
	35	int arc_console_baud;
	36
	37	if (!gd->baudrate)
	38	gd->baudrate = CONFIG_BAUDRATE;
	39
	40	arc_console_baud = gd->cpu_clk / (gd->baudrate * 4) - 1;
94b5400e	41	writeb(arc_console_baud & 0xff, &regs->baudl);
1d568c76 AB	42
	43	#ifdef CONFIG_ARC
	44	/*
	45	* UART ISS(Instruction Set simulator) emulation has a subtle bug:
	46	* A existing value of Baudh = 0 is used as a indication to startup
	47	* it's internal state machine.
	48	* Thus if baudh is set to 0, 2 times, it chokes.
	49	* This happens with BAUD=115200 and the formaula above
	50	* Until that is fixed, when running on ISS, we will set baudh to !0
	51	*/
	52	if (gd->arch.running_on_hw)
94b5400e	53	writeb((arc_console_baud & 0xff00) >> 8, &regs->baudh);
1d568c76	54	else
94b5400e	55	writeb(1, &regs->baudh);
1d568c76	56	#else
94b5400e	57	writeb((arc_console_baud & 0xff00) >> 8, &regs->baudh);
1d568c76	58	#endif
22a240c3 AB	59	}
	60
	61	static int arc_serial_init(void)
	62	{
22a240c3 AB	63	serial_setbrg();
	64	return 0;
	65	}
	66
	67	static void arc_serial_putc(const char c)
	68	{
	69	if (c == '\n')
	70	arc_serial_putc('\r');
	71
94b5400e	72	while (!(readb(&regs->status) & UART_TXEMPTY))
22a240c3 AB	73	;
22a240c3 AB	74
94b5400e	75	writeb(c, &regs->data);
22a240c3 AB	76	}
	77
	78	static int arc_serial_tstc(void)
	79	{
94b5400e	80	return !(readb(&regs->status) & UART_RXEMPTY);
22a240c3 AB	81	}
	82
	83	static int arc_serial_getc(void)
	84	{
	85	while (!arc_serial_tstc())
	86	;
	87
	88	/* Check for overflow errors */
94b5400e	89	if (readb(&regs->status) & UART_OVERFLOW_ERR)
22a240c3 AB	90	return 0;
22a240c3 AB	91
94b5400e	92	return readb(&regs->data) & 0xFF;
22a240c3 AB	93	}
22a240c3 AB	94
22a240c3 AB	95	static struct serial_device arc_serial_drv = {
	96	.name = "arc_serial",
	97	.start = arc_serial_init,
	98	.stop = NULL,
	99	.setbrg = arc_serial_setbrg,
	100	.putc = arc_serial_putc,
1cb8393a	101	.puts = default_serial_puts,
22a240c3 AB	102	.getc = arc_serial_getc,
	103	.tstc = arc_serial_tstc,
	104	};
	105
	106	void arc_serial_initialize(void)
	107	{
	108	serial_register(&arc_serial_drv);
	109	}
	110
	111	__weak struct serial_device *default_serial_console(void)
	112	{
	113	return &arc_serial_drv;
	114	}