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https://github.com/AsahiLinux/u-boot
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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>
70 lines
1.8 KiB
C
70 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (c) 2023 Nuvoton Technology Corp.
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*/
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#include <clk.h>
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#include <dm.h>
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#include <env.h>
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#include <serial.h>
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#include <linux/delay.h>
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#define UART_DLL 0x0
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#define UART_DLM 0x4
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#define UART_LCR 0xc
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#define LCR_DLAB BIT(7)
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void board_set_console(void)
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{
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const unsigned long baudrate_table[] = CFG_SYS_BAUDRATE_TABLE;
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struct udevice *dev = gd->cur_serial_dev;
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unsigned int baudrate, max_delta;
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void __iomem *uart_reg;
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struct clk clk;
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char string[32];
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u32 uart_clk;
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u8 dll, dlm;
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u16 divisor;
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int ret, i;
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if (!dev)
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return;
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uart_reg = dev_read_addr_ptr(dev);
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ret = clk_get_by_index(dev, 0, &clk);
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if (ret)
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return;
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uart_clk = clk_get_rate(&clk);
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setbits_8(uart_reg + UART_LCR, LCR_DLAB);
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dll = readb(uart_reg + UART_DLL);
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dlm = readb(uart_reg + UART_DLM);
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clrbits_8(uart_reg + UART_LCR, LCR_DLAB);
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divisor = dll | (dlm << 8);
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baudrate = uart_clk / ((16 * (divisor + 2)));
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for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
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max_delta = baudrate_table[i] / 20;
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if (abs(baudrate - baudrate_table[i]) < max_delta) {
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/* The baudrate is supported */
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gd->baudrate = baudrate_table[i];
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break;
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}
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}
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if (i == ARRAY_SIZE(baudrate_table)) {
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/* current baudrate is not suitable, set to default */
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divisor = DIV_ROUND_CLOSEST(uart_clk, 16 * gd->baudrate) - 2;
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setbits_8(uart_reg + UART_LCR, LCR_DLAB);
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writeb(divisor & 0xff, uart_reg + UART_DLL);
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writeb(divisor >> 8, uart_reg + UART_DLM);
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clrbits_8(uart_reg + UART_LCR, LCR_DLAB);
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udelay(100);
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printf("\r\nUART(source %u): change baudrate from %u to %u\n",
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uart_clk, baudrate, uart_clk / ((16 * (divisor + 2))));
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}
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debug("Set env baudrate=%u\n", gd->baudrate);
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snprintf(string, sizeof(string), "ttyS0,%un8", gd->baudrate);
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env_set("console", string);
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}
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