u-boot/drivers/serial/s3c64xx.c
Marek Vasut cc61c31df2 serial: arm: Implement CONFIG_SERIAL_MULTI into s3c64xx serial driver
Implement support for CONFIG_SERIAL_MULTI into s3c64xx serial driver.
This driver was so far only usable directly, but this patch also adds
support for the multi method. This allows using more than one serial
driver alongside the s3c64xx driver. Also, add a weak implementation
of default_serial_console() returning this driver.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Tom Rini <trini@ti.com>
Cc: John Rigby <john.rigby@linaro.org>
Cc: Minkyu Kang <mk7.kang@samsung.com>
2012-10-15 11:53:55 -07:00

226 lines
4.4 KiB
C

/*
* (C) Copyright 2002
* Gary Jennejohn, DENX Software Engineering, <garyj@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 <asm/arch/s3c6400.h>
DECLARE_GLOBAL_DATA_PTR;
#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,
};
static void s3c64xx_serial_setbrg(void)
{
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.
*/
static int s3c64xx_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.
*/
static int s3c64xx_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_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.
*/
static void s3c64xx_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));
uart->UTXH = c;
/* If \n, also do \r */
if (c == '\n')
serial_putc('\r');
}
/*
* Test whether a character is in the RX buffer
*/
static int s3c64xx_serial_tstc(void)
{
s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
return uart->UTRSTAT & 0x1;
}
static void s3c64xx_serial_puts(const char *s)
{
while (*s)
serial_putc(*s++);
}
#ifdef CONFIG_SERIAL_MULTI
static struct serial_device s3c64xx_serial_drv = {
.name = "s3c64xx_serial",
.start = s3c64xx_serial_init,
.stop = NULL,
.setbrg = s3c64xx_serial_setbrg,
.putc = s3c64xx_serial_putc,
.puts = s3c64xx_serial_puts,
.getc = s3c64xx_serial_getc,
.tstc = s3c64xx_serial_tstc,
};
void s3c64xx_serial_initialize(void)
{
serial_register(&s3c64xx_serial_drv);
}
__weak struct serial_device *default_serial_console(void)
{
return &s3c64xx_serial_drv;
}
#else
int serial_init(void)
{
return s3c64xx_serial_init();
}
void serial_setbrg(void)
{
s3c64xx_serial_setbrg();
}
void serial_putc(const char c)
{
s3c64xx_serial_putc(c);
}
void serial_puts(const char *s)
{
s3c64xx_serial_puts(s);
}
int serial_getc(void)
{
return s3c64xx_serial_getc();
}
int serial_tstc(void)
{
return s3c64xx_serial_tstc();
}
#endif