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/*
* 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;
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, ®s->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, ®s->baudh);
else
writeb(1, ®s->baudh);
#else
writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh);
#endif
}
static int arc_serial_init(void)
{
regs = (struct arc_serial_regs *)CONFIG_ARC_UART_BASE;
serial_setbrg();
return 0;
}
static void arc_serial_putc(const char c)
{
if (c == '\n')
arc_serial_putc('\r');
while (!(readb(®s->status) & UART_TXEMPTY))
;
writeb(c, ®s->data);
}
static int arc_serial_tstc(void)
{
return !(readb(®s->status) & UART_RXEMPTY);
}
static int arc_serial_getc(void)
{
while (!arc_serial_tstc())
;
/* Check for overflow errors */
if (readb(®s->status) & UART_OVERFLOW_ERR)
return 0;
return readb(®s->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;
}
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