| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* early printk support |
| * |
| * Copyright (c) 2009 Philippe Vachon <philippe@cowpig.ca> |
| * Copyright (c) 2009 Lemote Inc. |
| * Author: Wu Zhangjin, wuzhangjin@gmail.com |
| */ |
| #include <linux/serial_reg.h> |
| #include <asm/setup.h> |
| |
| #include <loongson.h> |
| |
| #define PORT(base, offset) (u8 *)(base + offset) |
| |
| static inline unsigned int serial_in(unsigned char *base, int offset) |
| { |
| return readb(PORT(base, offset)); |
| } |
| |
| static inline void serial_out(unsigned char *base, int offset, int value) |
| { |
| writeb(value, PORT(base, offset)); |
| } |
| |
| void prom_putchar(char c) |
| { |
| int timeout; |
| unsigned char *uart_base; |
| |
| uart_base = (unsigned char *)_loongson_uart_base[0]; |
| timeout = 1024; |
| |
| while (((serial_in(uart_base, UART_LSR) & UART_LSR_THRE) == 0) && |
| (timeout-- > 0)) |
| ; |
| |
| serial_out(uart_base, UART_TX, c); |
| } |
