uart-16550.c

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * 16550 compatible uart based serial debug support for zboot
 4 */
 5
 6#include <linux/types.h>
 7#include <linux/serial_reg.h>
 8
 9#include <asm/addrspace.h>
10
11#include "decompress.h"
12
13#if defined(CONFIG_MACH_LOONGSON64) || defined(CONFIG_MIPS_MALTA)
14#define UART_BASE 0x1fd003f8
15#define PORT(offset) (CKSEG1ADDR(UART_BASE) + (offset))
16#endif
17
18#ifdef CONFIG_MACH_INGENIC
19#define INGENIC_UART_BASE_ADDR	(0x10030000 + 0x1000 * CONFIG_ZBOOT_INGENIC_UART)
20#define PORT(offset) (CKSEG1ADDR(INGENIC_UART_BASE_ADDR) + (4 * offset))
21#endif
22
23#ifdef CONFIG_ECONET
24#define EN75_UART_BASE	0x1fbf0003
25#define PORT(offset)	(CKSEG1ADDR(EN75_UART_BASE) + (4 * (offset)))
26#endif
27
28#ifndef IOTYPE
29#define IOTYPE char
30#endif
31
32#ifndef PORT
33#error please define the serial port address for your own machine
34#endif
35
36static inline unsigned int serial_in(int offset)
37{
38	return *((volatile IOTYPE *)PORT(offset)) & 0xFF;
39}
40
41static inline void serial_out(int offset, int value)
42{
43	*((volatile IOTYPE *)PORT(offset)) = value & 0xFF;
44}
45
46void putc(char c)
47{
48	int timeout = 1000000;
49
50	while (((serial_in(UART_LSR) & UART_LSR_THRE) == 0) && (timeout-- > 0))
51		;
52
53	serial_out(UART_TX, c);
54}