target/linux/ramips/files/arch/mips/ralink/rt288x/early_printk.c

   1 /*
   2  *  Ralink RT288x SoC early printk support
   3  *
   4  *  Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
   5  *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify it
   8  *  under the terms of the GNU General Public License version 2 as published
   9  *  by the Free Software Foundation.
  10  */
  11
  12 #include <linux/io.h>
  13 #include <linux/serial_reg.h>
  14
  15 #include <asm/addrspace.h>
  16
  17 #include <asm/mach-ralink/rt288x_regs.h>
  18
  19 #define UART_READ(r) \
  20         __raw_readl((void __iomem *)(KSEG1ADDR(RT2880_UART1_BASE) + 4 * (r)))
  21
  22 #define UART_WRITE(r, v) \
  23         __raw_writel((v), (void __iomem *)(KSEG1ADDR(RT2880_UART1_BASE) + 4 * (r)))
  24
  25 void prom_putchar(unsigned char ch)
  26 {
  27         while (((UART_READ(UART_REG_LSR)) & UART_LSR_THRE) == 0);
  28         UART_WRITE(UART_REG_TX, ch);
  29         while (((UART_READ(UART_REG_LSR)) & UART_LSR_THRE) == 0);
  30 }