1 /*
2  * 16550 compatible uart based serial debug support for zboot
3  */
4 
5 #include <linux/types.h>
6 #include <linux/serial_reg.h>
7 #include <linux/init.h>
8 
9 #include <asm/addrspace.h>
10 
11 #if defined(CONFIG_MACH_LOONGSON) || defined(CONFIG_MIPS_MALTA)
12 #define UART_BASE 0x1fd003f8
13 #define PORT(offset) (CKSEG1ADDR(UART_BASE) + (offset))
14 #endif
15 
16 #ifdef CONFIG_AR7
17 #include <ar7.h>
18 #define PORT(offset) (CKSEG1ADDR(AR7_REGS_UART0) + (4 * offset))
19 #endif
20 
21 #ifndef PORT
22 #error please define the serial port address for your own machine
23 #endif
24 
serial_in(int offset)25 static inline unsigned int serial_in(int offset)
26 {
27 	return *((char *)PORT(offset));
28 }
29 
serial_out(int offset,int value)30 static inline void serial_out(int offset, int value)
31 {
32 	*((char *)PORT(offset)) = value;
33 }
34 
putc(char c)35 void putc(char c)
36 {
37 	int timeout = 1024;
38 
39 	while (((serial_in(UART_LSR) & UART_LSR_THRE) == 0) && (timeout-- > 0))
40 		;
41 
42 	serial_out(UART_TX, c);
43 }
44