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/*
* Jz4740 UART support
* Copyright (c) 2011
* Qi Hardware, Xiangfu Liu <xiangfu@sharism.cc>
*
* 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 <config.h>
#include <common.h>
#include <asm/io.h>
#include <asm/jz4740.h>
#include <serial.h>
#include <linux/compiler.h>
/*
* serial_init - initialize a channel
*
* This routine initializes the number of data bits, parity
* and set the selected baud rate. Interrupts are disabled.
* Set the modem control signals if the option is selected.
*
* RETURNS: N/A
*/
struct jz4740_uart *uart = (struct jz4740_uart *)CONFIG_SYS_UART_BASE;
static int jz_serial_init(void)
{
/* Disable port interrupts while changing hardware */
writeb(0, &uart->dlhr_ier);
/* Disable UART unit function */
writeb(~UART_FCR_UUE, &uart->iir_fcr);
/* Set both receiver and transmitter in UART mode (not SIR) */
writeb(~(SIRCR_RSIRE | SIRCR_TSIRE), &uart->isr);
/*
* Set databits, stopbits and parity.
* (8-bit data, 1 stopbit, no parity)
*/
writeb(UART_LCR_WLEN_8 | UART_LCR_STOP_1, &uart->lcr);
/* Set baud rate */
serial_setbrg();
/* Enable UART unit, enable and clear FIFO */
writeb(UART_FCR_UUE | UART_FCR_FE | UART_FCR_TFLS | UART_FCR_RFLS,
&uart->iir_fcr);
return 0;
}
static void jz_serial_setbrg(void)
{
u32 baud_div, tmp;
baud_div = CONFIG_SYS_EXTAL / 16 / CONFIG_BAUDRATE;
tmp = readb(&uart->lcr);
tmp |= UART_LCR_DLAB;
writeb(tmp, &uart->lcr);
writeb((baud_div >> 8) & 0xff, &uart->dlhr_ier);
writeb(baud_div & 0xff, &uart->rbr_thr_dllr);
tmp &= ~UART_LCR_DLAB;
writeb(tmp, &uart->lcr);
}
static int jz_serial_tstc(void)
{
if (readb(&uart->lsr) & UART_LSR_DR)
return 1;
return 0;
}
static void jz_serial_putc(const char c)
{
if (c == '\n')
serial_putc('\r');
/* Wait for fifo to shift out some bytes */
while (!((readb(&uart->lsr) & (UART_LSR_TDRQ | UART_LSR_TEMT)) == 0x60))
;
writeb((u8)c, &uart->rbr_thr_dllr);
}
static int jz_serial_getc(void)
{
while (!serial_tstc())
;
return readb(&uart->rbr_thr_dllr);
}
static struct serial_device jz_serial_drv = {
.name = "jz_serial",
.start = jz_serial_init,
.stop = NULL,
.setbrg = jz_serial_setbrg,
.putc = jz_serial_putc,
.puts = default_serial_puts,
.getc = jz_serial_getc,
.tstc = jz_serial_tstc,
};
void jz_serial_initialize(void)
{
serial_register(&jz_serial_drv);
}
__weak struct serial_device *default_serial_console(void)
{
return &jz_serial_drv;
}
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