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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2009 Samsung Electronics
*
* 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; version 2 of the License.
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <console/console.h> /* for __console definition */
#include <uart.h>
#include <arch/io.h>
#include "uart.h"
#include "clk.h"
#include "cpu.h"
#include "periph.h"
#define RX_FIFO_COUNT_MASK 0xff
#define RX_FIFO_FULL_MASK (1 << 8)
#define TX_FIFO_FULL_MASK (1 << 24)
/* FIXME(dhendrix): exynos5 has 4 UARTs and its functions in u-boot take a
base_port argument. However console_driver functions do not. */
static uint32_t base_port = CONFIG_CONSOLE_SERIAL_UART_ADDRESS;
/*
* The coefficient, used to calculate the baudrate on S5P 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 serial_setbrg_dev(void)
{
struct s5p_uart *uart = (struct s5p_uart *)base_port;
u32 uclk;
u32 baudrate = CONFIG_TTYS0_BAUD;
u32 val;
// All UARTs share the same clock.
uclk = clock_get_periph_rate(PERIPH_ID_UART3);
val = uclk / baudrate;
writel(val / 16 - 1, &uart->ubrdiv);
/*
* FIXME(dhendrix): the original uart.h had a "br_rest" value which
* does not seem relevant to the exynos5420... not entirely sure
* where/if we need to worry about it here
*/
#if 0
if (s5p_uart_divslot())
writel(udivslot[val % 16], &uart->rest.slot);
else
writeb(val % 16, &uart->rest.value);
#endif
}
/*
* Initialise the serial port with the given baudrate. The settings
* are always 8 data bits, no parity, 1 stop bit, no start bits.
*/
static void exynos5_init_dev(void)
{
struct s5p_uart *uart = (struct s5p_uart *)base_port;
/* enable FIFOs */
writel(0x1, &uart->ufcon);
writel(0, &uart->umcon);
/* 8N1 */
writel(0x3, &uart->ulcon);
/* No interrupts, no DMA, pure polling */
writel(0x245, &uart->ucon);
serial_setbrg_dev();
}
static int exynos5_uart_err_check(int op)
{
struct s5p_uart *uart = (struct s5p_uart *)base_port;
unsigned int mask;
/*
* UERSTAT
* Break Detect [3]
* Frame Err [2] : receive operation
* Parity Err [1] : receive operation
* Overrun Err [0] : receive operation
*/
if (op)
mask = 0x8;
else
mask = 0xf;
return readl(&uart->uerstat) & mask;
}
/*
* 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 unsigned char exynos5_uart_rx_byte(void)
{
struct s5p_uart *uart = (struct s5p_uart *)base_port;
/* wait for character to arrive */
while (!(readl(&uart->ufstat) & (RX_FIFO_COUNT_MASK |
RX_FIFO_FULL_MASK))) {
if (exynos5_uart_err_check(0))
return 0;
}
return readb(&uart->urxh) & 0xff;
}
/*
* Output a single byte to the serial port.
*/
static void exynos5_uart_tx_byte(unsigned char data)
{
struct s5p_uart *uart = (struct s5p_uart *)base_port;
/* wait for room in the tx FIFO */
while ((readl(&uart->ufstat) & TX_FIFO_FULL_MASK)) {
if (exynos5_uart_err_check(1))
return;
}
writeb(data, &uart->utxh);
}
#if !defined(__PRE_RAM__)
static const struct console_driver exynos5_uart_console __console = {
.init = exynos5_init_dev,
.tx_byte = exynos5_uart_tx_byte,
// .tx_flush = exynos5_uart_tx_flush,
.rx_byte = exynos5_uart_rx_byte,
// .tst_byte = exynos5_uart_tst_byte,
};
uint32_t uartmem_getbaseaddr(void)
{
return base_port;
}
#else
void uart_init(void)
{
exynos5_init_dev();
}
unsigned char uart_rx_byte(void)
{
return exynos5_uart_rx_byte();
}
void uart_tx_byte(unsigned char data)
{
exynos5_uart_tx_byte(data);
}
void uart_tx_flush(void)
{
}
#endif
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