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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2003 Eric Biederman
* Copyright (C) 2006-2010 coresystems GmbH
* Copyright (C) 2014 Imagination Technologies
*
* 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 <arch/io.h>
#include <console/console.h>
#include <device/device.h>
#include <delay.h>
#include <uart.h>
#include <uart8250.h>
/* Should support 8250, 16450, 16550, 16550A type UARTs */
/* Expected character delay at 1200bps is 9ms for a working UART
* and no flow-control. Assume UART as stuck if shift register
* or FIFO takes more than 50ms per character to appear empty.
*/
#define SINGLE_CHAR_TIMEOUT (50 * 1000)
#define FIFO_TIMEOUT (16 * SINGLE_CHAR_TIMEOUT)
#define UART_SHIFT 2
#define GEN_ACCESSOR(name, idx) \
static inline uint8_t read_##name(unsigned base_port) \
{ \
return read8(base_port + (idx << UART_SHIFT)); \
} \
\
static inline void write_##name(unsigned base_port, uint8_t val) \
{ \
write8(base_port + (idx << UART_SHIFT), val); \
}
GEN_ACCESSOR(rbr, UART8250_RBR)
GEN_ACCESSOR(tbr, UART8250_TBR)
GEN_ACCESSOR(ier, UART8250_IER)
GEN_ACCESSOR(fcr, UART8250_FCR)
GEN_ACCESSOR(lcr, UART8250_LCR)
GEN_ACCESSOR(mcr, UART8250_MCR)
GEN_ACCESSOR(lsr, UART8250_LSR)
GEN_ACCESSOR(dll, UART8250_DLL)
GEN_ACCESSOR(dlm, UART8250_DLM)
static int uart8250_mem_can_tx_byte(unsigned base_port)
{
return read_lsr(base_port) & UART8250_LSR_THRE;
}
static void uart8250_mem_tx_byte(unsigned base_port, unsigned char data)
{
unsigned long int i = SINGLE_CHAR_TIMEOUT;
while (i-- && !uart8250_mem_can_tx_byte(base_port))
udelay(1);
write_tbr(base_port, data);
}
static void uart8250_mem_tx_flush(unsigned base_port)
{
unsigned long int i = FIFO_TIMEOUT;
while (i-- && !(read_lsr(base_port) & UART8250_LSR_TEMT))
udelay(1);
}
static int uart8250_mem_can_rx_byte(unsigned base_port)
{
return read_lsr(base_port) & UART8250_LSR_DR;
}
static unsigned char uart8250_mem_rx_byte(unsigned base_port)
{
unsigned long int i = SINGLE_CHAR_TIMEOUT;
while (i-- && !uart8250_mem_can_rx_byte(base_port))
udelay(1);
if (i)
return read_rbr(base_port);
else
return 0x0;
}
static void uart8250_mem_init(unsigned base_port, unsigned divisor)
{
/* Disable interrupts */
write_ier(base_port, 0x0);
/* Enable FIFOs */
write_fcr(base_port, UART8250_FCR_FIFO_EN);
/* Assert DTR and RTS so the other end is happy */
write_mcr(base_port, UART8250_MCR_DTR | UART8250_MCR_RTS);
/* DLAB on */
write_lcr(base_port, UART8250_LCR_DLAB | CONFIG_TTYS0_LCS);
write_dll(base_port, divisor & 0xFF);
write_dlm(base_port, (divisor >> 8) & 0xFF);
/* Set to 3 for 8N1 */
write_lcr(base_port, CONFIG_TTYS0_LCS);
}
static unsigned int uart_platform_refclk(void)
{
/* TODO: this is entirely arbitrary */
return 1000000;
}
static unsigned int uart_platform_base(int idx)
{
switch (idx) {
case 0:
return 0xb8101400;
case 1:
return 0xb8101500;
default:
return 0x0;
}
}
/* Calculate divisor. Do not floor but round to nearest integer. */
static unsigned int uart_baudrate_divisor(unsigned int baudrate,
unsigned int refclk, unsigned int oversample)
{
return (1 + (2 * refclk) / (baudrate * oversample)) / 2;
}
static void danube_uart_init(void)
{
u32 base = uart_platform_base(0);
if (!base)
return;
unsigned int div;
div = uart_baudrate_divisor(CONFIG_TTYS0_BAUD,
uart_platform_refclk(), 16);
uart8250_mem_init(base, div);
}
static void danube_uart_tx_byte(unsigned char data)
{
u32 base = uart_platform_base(0);
if (!base)
return;
uart8250_mem_tx_byte(base, data);
}
static unsigned char danube_uart_rx_byte(void)
{
u32 base = uart_platform_base(0);
if (!base)
return 0xff;
return uart8250_mem_rx_byte(base);
}
static void danube_uart_tx_flush(void)
{
u32 base = uart_platform_base(0);
if (!base)
return;
uart8250_mem_tx_flush(base);
}
#if !defined(__PRE_RAM__)
static const struct console_driver danube_uart_console __console = {
.init = danube_uart_init,
.tx_byte = danube_uart_tx_byte,
.tx_flush = danube_uart_tx_flush,
.rx_byte = danube_uart_rx_byte,
};
uint32_t uartmem_getbaseaddr(void)
{
return uart_platform_base(0);
}
#else /* __PRE_RAM__ */
void uart_init(void)
{
danube_uart_init();
}
void uart_tx_byte(unsigned char data)
{
danube_uart_tx_byte(data);
}
unsigned char uart_rx_byte(void)
{
return danube_uart_rx_byte();
}
void uart_tx_flush(void)
{
danube_uart_tx_flush();
}
#endif /* __PRE_RAM__ */
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