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/*
* (C) Copyright 2002
* Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
*
* (C) Copyright 2008
* Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
*
* 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 <s3c6400.h>
#ifdef CONFIG_SERIAL1
#define UART_NR S3C64XX_UART0
#elif defined(CONFIG_SERIAL2)
#define UART_NR S3C64XX_UART1
#elif defined(CONFIG_SERIAL3)
#define UART_NR S3C64XX_UART2
#else
#error "Bad: you didn't configure serial ..."
#endif
#define barrier() asm volatile("" ::: "memory")
/*
* The coefficient, used to calculate the baudrate on S3C6400 UARTs is
* calculated as
* C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT
* however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1,
* 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants:
*/
static const int udivslot[] = {
0,
0x0080,
0x0808,
0x0888,
0x2222,
0x4924,
0x4a52,
0x54aa,
0x5555,
0xd555,
0xd5d5,
0xddd5,
0xdddd,
0xdfdd,
0xdfdf,
0xffdf,
};
void serial_setbrg(void)
{
DECLARE_GLOBAL_DATA_PTR;
s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
u32 pclk = get_PCLK();
u32 baudrate = gd->baudrate;
int i;
i = (pclk / baudrate) % 16;
uart->UBRDIV = pclk / baudrate / 16 - 1;
uart->UDIVSLOT = udivslot[i];
for (i = 0; i < 100; i++)
barrier();
}
/*
* Initialise the serial port with the given baudrate. The settings
* are always 8 data bits, no parity, 1 stop bit, no start bits.
*/
int serial_init(void)
{
s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
/* reset and enable FIFOs, set triggers to the maximum */
uart->UFCON = 0xff;
uart->UMCON = 0;
/* 8N1 */
uart->ULCON = 3;
/* No interrupts, no DMA, pure polling */
uart->UCON = 5;
serial_setbrg();
return 0;
}
/*
* Read a single byte from the serial port. Returns 1 on success, 0
* otherwise. When the function is succesfull, the character read is
* written into its argument c.
*/
int serial_getc(void)
{
s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
/* wait for character to arrive */
while (!(uart->UTRSTAT & 0x1));
return uart->URXH & 0xff;
}
#ifdef CONFIG_HWFLOW
static int hwflow; /* turned off by default */
int hwflow_onoff(int on)
{
switch (on) {
case 1:
hwflow = 1; /* turn on */
break;
case -1:
hwflow = 0; /* turn off */
break;
}
return hwflow;
}
#endif
#ifdef CONFIG_MODEM_SUPPORT
static int be_quiet;
void disable_putc(void)
{
be_quiet = 1;
}
void enable_putc(void)
{
be_quiet = 0;
}
#endif
/*
* Output a single byte to the serial port.
*/
void serial_putc(const char c)
{
s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
#ifdef CONFIG_MODEM_SUPPORT
if (be_quiet)
return;
#endif
/* wait for room in the tx FIFO */
while (!(uart->UTRSTAT & 0x2));
#ifdef CONFIG_HWFLOW
/* Wait for CTS up */
while (hwflow && !(uart->UMSTAT & 0x1));
#endif
uart->UTXH = c;
/* If \n, also do \r */
if (c == '\n')
serial_putc('\r');
}
/*
* Test whether a character is in the RX buffer
*/
int serial_tstc(void)
{
s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
return uart->UTRSTAT & 0x1;
}
void serial_puts(const char *s)
{
while (*s)
serial_putc(*s++);
}
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