u-boot/cpu/leon3/serial.c

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/* GRLIB APBUART Serial controller driver
*
* (C) Copyright 2007
* Daniel Hellstrom, Gaisler Research, daniel@gaisler.com.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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 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
*
*/
#include <common.h>
#include <asm/processor.h>
#include <asm/leon.h>
#include <ambapp.h>
DECLARE_GLOBAL_DATA_PTR;
/* Force cache miss each time a serial controller reg is read */
#define CACHE_BYPASS 1
#ifdef CACHE_BYPASS
#define READ_BYTE(var) SPARC_NOCACHE_READ_BYTE((unsigned int)&(var))
#define READ_HWORD(var) SPARC_NOCACHE_READ_HWORD((unsigned int)&(var))
#define READ_WORD(var) SPARC_NOCACHE_READ((unsigned int)&(var))
#define READ_DWORD(var) SPARC_NOCACHE_READ_DWORD((unsigned int)&(var))
#endif
ambapp_dev_apbuart *leon3_apbuart = NULL;
int serial_init(void)
{
ambapp_apbdev apbdev;
unsigned int tmp;
/* find UART */
if (ambapp_apb_first(VENDOR_GAISLER, GAISLER_APBUART, &apbdev) == 1) {
leon3_apbuart = (ambapp_dev_apbuart *) apbdev.address;
/* found apbuart, let's init...
*
* Set scaler / baud rate
*
* Receiver & transmitter enable
*/
leon3_apbuart->scaler = CONFIG_SYS_GRLIB_APBUART_SCALER;
/* Let bit 11 be unchanged (debug bit for GRMON) */
tmp = READ_WORD(leon3_apbuart->ctrl);
leon3_apbuart->ctrl = ((tmp & LEON_REG_UART_CTRL_DBG) |
LEON_REG_UART_CTRL_RE |
LEON_REG_UART_CTRL_TE);
return 0;
}
return -1; /* didn't find hardware */
}
void serial_putc(const char c)
{
if (c == '\n')
serial_putc_raw('\r');
serial_putc_raw(c);
}
void serial_putc_raw(const char c)
{
if (!leon3_apbuart)
return;
/* Wait for last character to go. */
while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_THE)) ;
/* Send data */
leon3_apbuart->data = c;
#ifdef LEON_DEBUG
/* Wait for data to be sent */
while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_TSE)) ;
#endif
}
void serial_puts(const char *s)
{
while (*s) {
serial_putc(*s++);
}
}
int serial_getc(void)
{
if (!leon3_apbuart)
return 0;
/* Wait for a character to arrive. */
while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_DR)) ;
/* read data */
return READ_WORD(leon3_apbuart->data);
}
int serial_tstc(void)
{
if (leon3_apbuart)
return (READ_WORD(leon3_apbuart->status) &
LEON_REG_UART_STATUS_DR);
return 0;
}
/* set baud rate for uart */
void serial_setbrg(void)
{
/* update baud rate settings, read it from gd->baudrate */
unsigned int scaler;
if (leon3_apbuart && (gd->baudrate > 0)) {
scaler =
(((CONFIG_SYS_CLK_FREQ * 10) / (gd->baudrate * 8)) -
5) / 10;
leon3_apbuart->scaler = scaler;
}
return;
}