u-boot/drivers/serial/arm_dcc.c

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/*
* Copyright (C) 2004-2007 ARM Limited.
* Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.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.
*
* 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.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* As a special exception, if other files instantiate templates or use macros
* or inline functions from this file, or you compile this file and link it
* with other works to produce a work based on this file, this file does not
* by itself cause the resulting work to be covered by the GNU General Public
* License. However the source code for this file must still be made available
* in accordance with section (3) of the GNU General Public License.
* This exception does not invalidate any other reasons why a work based on
* this file might be covered by the GNU General Public License.
*/
#include <common.h>
#include <stdio_dev.h>
#if defined(CONFIG_CPU_V6)
/*
* ARMV6
*/
#define DCC_RBIT (1 << 30)
#define DCC_WBIT (1 << 29)
#define write_dcc(x) \
__asm__ volatile ("mcr p14, 0, %0, c0, c5, 0\n" : : "r" (x))
#define read_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c0, c5, 0\n" : "=r" (x))
#define status_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c0, c1, 0\n" : "=r" (x))
#elif defined(CONFIG_CPU_XSCALE)
/*
* XSCALE
*/
#define DCC_RBIT (1 << 31)
#define DCC_WBIT (1 << 28)
#define write_dcc(x) \
__asm__ volatile ("mcr p14, 0, %0, c8, c0, 0\n" : : "r" (x))
#define read_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c9, c0, 0\n" : "=r" (x))
#define status_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c14, c0, 0\n" : "=r" (x))
#else
#define DCC_RBIT (1 << 0)
#define DCC_WBIT (1 << 1)
#define write_dcc(x) \
__asm__ volatile ("mcr p14, 0, %0, c1, c0, 0\n" : : "r" (x))
#define read_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c1, c0, 0\n" : "=r" (x))
#define status_dcc(x) \
__asm__ volatile ("mrc p14, 0, %0, c0, c0, 0\n" : "=r" (x))
#endif
#define can_read_dcc(x) do { \
status_dcc(x); \
x &= DCC_RBIT; \
} while (0);
#define can_write_dcc(x) do { \
status_dcc(x); \
x &= DCC_WBIT; \
x = (x == 0); \
} while (0);
#define TIMEOUT_COUNT 0x4000000
int arm_dcc_init(void)
{
return 0;
}
int arm_dcc_getc(void)
{
int ch;
register unsigned int reg;
do {
can_read_dcc(reg);
} while (!reg);
read_dcc(ch);
return ch;
}
void arm_dcc_putc(char ch)
{
register unsigned int reg;
unsigned int timeout_count = TIMEOUT_COUNT;
while (--timeout_count) {
can_write_dcc(reg);
if (reg)
break;
}
if (timeout_count == 0)
return;
else
write_dcc(ch);
}
void arm_dcc_puts(const char *s)
{
while (*s)
arm_dcc_putc(*s++);
}
int arm_dcc_tstc(void)
{
register unsigned int reg;
can_read_dcc(reg);
return reg;
}
static struct stdio_dev arm_dcc_dev;
int drv_arm_dcc_init(void)
{
strcpy(arm_dcc_dev.name, "dcc");
arm_dcc_dev.ext = 0; /* No extensions */
arm_dcc_dev.flags = DEV_FLAGS_INPUT | DEV_FLAGS_OUTPUT;
arm_dcc_dev.tstc = arm_dcc_tstc; /* 'tstc' function */
arm_dcc_dev.getc = arm_dcc_getc; /* 'getc' function */
arm_dcc_dev.putc = arm_dcc_putc; /* 'putc' function */
arm_dcc_dev.puts = arm_dcc_puts; /* 'puts' function */
return stdio_register(&arm_dcc_dev);
}
__weak struct serial_device *default_serial_console(void)
{
return NULL;
}