mirror of
https://github.com/smaeul/u-boot.git
synced 2025-11-03 21:48:15 +00:00
5a2070783d
If CONFIG_SYS_SKIP_UART_INIT is enabled, calculate the current baud rate and update the "console" environment variable. Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
71 lines
1.8 KiB
C
71 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
|
|
/*
|
|
* Copyright (c) 2023 Nuvoton Technology Corp.
|
|
*/
|
|
|
|
#include <clk.h>
|
|
#include <dm.h>
|
|
#include <env.h>
|
|
#include <serial.h>
|
|
#include <linux/delay.h>
|
|
|
|
#define UART_DLL 0x0
|
|
#define UART_DLM 0x4
|
|
#define UART_LCR 0xc
|
|
#define LCR_DLAB BIT(7)
|
|
|
|
void board_set_console(void)
|
|
{
|
|
const unsigned long baudrate_table[] = CFG_SYS_BAUDRATE_TABLE;
|
|
struct udevice *dev = gd->cur_serial_dev;
|
|
unsigned int baudrate, max_delta;
|
|
void __iomem *uart_reg;
|
|
struct clk clk;
|
|
char string[32];
|
|
u32 uart_clk;
|
|
u8 dll, dlm;
|
|
u16 divisor;
|
|
int ret, i;
|
|
|
|
if (!dev)
|
|
return;
|
|
|
|
uart_reg = dev_read_addr_ptr(dev);
|
|
ret = clk_get_by_index(dev, 0, &clk);
|
|
if (ret)
|
|
return;
|
|
|
|
uart_clk = clk_get_rate(&clk);
|
|
setbits_8(uart_reg + UART_LCR, LCR_DLAB);
|
|
dll = readb(uart_reg + UART_DLL);
|
|
dlm = readb(uart_reg + UART_DLM);
|
|
clrbits_8(uart_reg + UART_LCR, LCR_DLAB);
|
|
divisor = dll | (dlm << 8);
|
|
baudrate = uart_clk / ((16 * (divisor + 2)));
|
|
for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
|
|
max_delta = baudrate_table[i] / 20;
|
|
if (abs(baudrate - baudrate_table[i]) < max_delta) {
|
|
/* The baudrate is supported */
|
|
gd->baudrate = baudrate_table[i];
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (i == ARRAY_SIZE(baudrate_table)) {
|
|
/* current baudrate is not suitable, set to default */
|
|
divisor = DIV_ROUND_CLOSEST(uart_clk, 16 * gd->baudrate) - 2;
|
|
setbits_8(uart_reg + UART_LCR, LCR_DLAB);
|
|
writeb(divisor & 0xff, uart_reg + UART_DLL);
|
|
writeb(divisor >> 8, uart_reg + UART_DLM);
|
|
clrbits_8(uart_reg + UART_LCR, LCR_DLAB);
|
|
udelay(100);
|
|
printf("\r\nUART(source %u): change baudrate from %u to %u\n",
|
|
uart_clk, baudrate, uart_clk / ((16 * (divisor + 2))));
|
|
}
|
|
|
|
debug("Set env baudrate=%u\n", gd->baudrate);
|
|
snprintf(string, sizeof(string), "ttyS0,%un8", gd->baudrate);
|
|
env_set("console", string);
|
|
|
|
}
|