arch/mips/boot/compressed/uart-16550.c

   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 }