arch/mips/ralink/early_printk.c

   1 /*
   2  *  This program is free software; you can redistribute it and/or modify it
   3  *  under the terms of the GNU General Public License version 2 as published
   4  *  by the Free Software Foundation.
   5  *
   6  *  Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
   7  */
   8
   9 #include <linux/io.h>
  10 #include <linux/serial_reg.h>
  11
  12 #include <asm/addrspace.h>
  13
  14 #ifdef CONFIG_SOC_RT288X
  15 #define EARLY_UART_BASE         0x300c00
  16 #else
  17 #define EARLY_UART_BASE         0x10000c00
  18 #endif
  19
  20 #define UART_REG_RX             0x00
  21 #define UART_REG_TX             0x04
  22 #define UART_REG_IER            0x08
  23 #define UART_REG_IIR            0x0c
  24 #define UART_REG_FCR            0x10
  25 #define UART_REG_LCR            0x14
  26 #define UART_REG_MCR            0x18
  27 #define UART_REG_LSR            0x1c
  28
  29 static __iomem void *uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE);
  30
  31 static inline void uart_w32(u32 val, unsigned reg)
  32 {
  33         __raw_writel(val, uart_membase + reg);
  34 }
  35
  36 static inline u32 uart_r32(unsigned reg)
  37 {
  38         return __raw_readl(uart_membase + reg);
  39 }
  40
  41 void prom_putchar(unsigned char ch)
  42 {
  43         while ((uart_r32(UART_REG_LSR) & UART_LSR_THRE) == 0)
  44                 ;
  45         uart_w32(ch, UART_REG_TX);
  46         while ((uart_r32(UART_REG_LSR) & UART_LSR_THRE) == 0)
  47                 ;
  48 }