Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
uart-16550.c
Go to the documentation of this file.
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 #ifdef CONFIG_MACH_JZ4740
22 #define UART0_BASE 0xB0030000
23 #define PORT(offset) (UART0_BASE + (4 * offset))
24 #endif
25 
26 #ifndef PORT
27 #error please define the serial port address for your own machine
28 #endif
29 
30 static inline unsigned int serial_in(int offset)
31 {
32  return *((char *)PORT(offset));
33 }
34 
35 static inline void serial_out(int offset, int value)
36 {
37  *((char *)PORT(offset)) = value;
38 }
39 
40 void putc(char c)
41 {
42  int timeout = 1024;
43 
44  while (((serial_in(UART_LSR) & UART_LSR_THRE) == 0) && (timeout-- > 0))
45  ;
46 
47  serial_out(UART_TX, c);
48 }