u-boot/arch/sparc/cpu/leon2/serial.c
Daniel Hellstrom ff0b9b77c2 sparc: Serial baud rate register support multiple buses with different frequency
Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
2015-12-03 13:15:48 +02:00

147 lines
3.1 KiB
C

/* GRLIB APBUART Serial controller driver
*
* (C) Copyright 2008, 2015
* Daniel Hellstrom, Cobham Gaisler, daniel@gaisler.com.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/io.h>
#include <serial.h>
#include <watchdog.h>
DECLARE_GLOBAL_DATA_PTR;
static unsigned leon2_serial_calc_scaler(unsigned freq, unsigned baud)
{
return (((freq*10) / (baud*8)) - 5) / 10;
}
static int leon2_serial_init(void)
{
LEON2_regs *leon2 = (LEON2_regs *)LEON2_PREGS;
LEON2_Uart_regs *regs;
unsigned int tmp;
#if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
regs = (LEON2_Uart_regs *)&leon2->UART_Channel_1;
#else
regs = (LEON2_Uart_regs *)&leon2->UART_Channel_2;
#endif
/* Set scaler / baud rate */
tmp = leon2_serial_calc_scaler(CONFIG_SYS_CLK_FREQ, CONFIG_BAUDRATE);
writel(tmp, &regs->UART_Scaler);
/* Let bit 11 be unchanged (debug bit for GRMON) */
tmp = readl(&regs->UART_Control) & LEON2_UART_CTRL_DBG;
tmp |= (LEON2_UART1_LOOPBACK_ENABLE << 7);
tmp |= (LEON2_UART1_FLOWCTRL_ENABLE << 6);
tmp |= (LEON2_UART1_PARITY_ENABLE << 5);
tmp |= (LEON2_UART1_ODDPAR_ENABLE << 4);
/* Receiver & transmitter enable */
tmp |= (LEON2_UART_CTRL_RE | LEON2_UART_CTRL_TE);
writel(tmp, &regs->UART_Control);
gd->arch.uart = regs;
return 0;
}
static inline LEON2_Uart_regs *leon2_get_uart_regs(void)
{
LEON2_Uart_regs *uart = gd->arch.uart;
return uart;
}
static void leon2_serial_putc_raw(const char c)
{
LEON2_Uart_regs *uart = leon2_get_uart_regs();
if (!uart)
return;
/* Wait for last character to go. */
while (!(readl(&uart->UART_Status) & LEON2_UART_STAT_THE))
WATCHDOG_RESET();
/* Send data */
writel(c, &uart->UART_Channel);
#ifdef LEON_DEBUG
/* Wait for data to be sent */
while (!(readl(&uart->UART_Status) & LEON2_UART_STAT_TSE))
WATCHDOG_RESET();
#endif
}
static void leon2_serial_putc(const char c)
{
if (c == '\n')
leon2_serial_putc_raw('\r');
leon2_serial_putc_raw(c);
}
static int leon2_serial_getc(void)
{
LEON2_Uart_regs *uart = leon2_get_uart_regs();
if (!uart)
return 0;
/* Wait for a character to arrive. */
while (!(readl(&uart->UART_Status) & LEON2_UART_STAT_DR))
WATCHDOG_RESET();
/* Read character data */
return readl(&uart->UART_Channel);
}
static int leon2_serial_tstc(void)
{
LEON2_Uart_regs *uart = leon2_get_uart_regs();
if (!uart)
return 0;
return readl(&uart->UART_Status) & LEON2_UART_STAT_DR;
}
static void leon2_serial_setbrg(void)
{
LEON2_Uart_regs *uart = leon2_get_uart_regs();
unsigned int scaler;
if (!uart)
return;
if (!gd->baudrate)
gd->baudrate = CONFIG_BAUDRATE;
scaler = leon2_serial_calc_scaler(CONFIG_SYS_CLK_FREQ, gd->baudrate);
writel(scaler, &uart->UART_Scaler);
}
static struct serial_device leon2_serial_drv = {
.name = "leon2_serial",
.start = leon2_serial_init,
.stop = NULL,
.setbrg = leon2_serial_setbrg,
.putc = leon2_serial_putc,
.puts = default_serial_puts,
.getc = leon2_serial_getc,
.tstc = leon2_serial_tstc,
};
void leon2_serial_initialize(void)
{
serial_register(&leon2_serial_drv);
}
__weak struct serial_device *default_serial_console(void)
{
return &leon2_serial_drv;
}