arch/mips/boot/compressed/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 #ifndef IOTYPE
  24 #define IOTYPE char
  25 #endif
  26
  27 #ifndef PORT
  28 #error please define the serial port address for your own machine
  29 #endif
  30
  31 static inline unsigned int serial_in(int offset)
  32 {
  33         return *((volatile IOTYPE *)PORT(offset)) & 0xFF;
  34 }
  35
  36 static inline void serial_out(int offset, int value)
  37 {
  38         *((volatile IOTYPE *)PORT(offset)) = value & 0xFF;
  39 }
  40
  41 void putc(char c)
  42 {
  43         int timeout = 1000000;
  44
  45         while (((serial_in(UART_LSR) & UART_LSR_THRE) == 0) && (timeout-- > 0))
  46                 ;
  47
  48         serial_out(UART_TX, c);
  49 }