target/linux/ramips/files/arch/mips/ralink/rt3883/early_printk.c

   1 /*
   2  *  Ralink RT3662/RT3883 SoC early printk support
   3  *
   4  *  Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify it
   7  *  under the terms of the GNU General Public License version 2 as published
   8  *  by the Free Software Foundation.
   9  */
  10
  11 #include <linux/io.h>
  12 #include <linux/serial_reg.h>
  13
  14 #include <asm/addrspace.h>
  15
  16 #include <asm/mach-ralink/rt3883_regs.h>
  17
  18 #define UART_READ(r) \
  19         __raw_readl((void __iomem *)(KSEG1ADDR(RT3883_UART1_BASE) + 4 * (r)))
  20
  21 #define UART_WRITE(r, v) \
  22         __raw_writel((v), (void __iomem *)(KSEG1ADDR(RT3883_UART1_BASE) + 4 * (r)))
  23
  24 void prom_putchar(unsigned char ch)
  25 {
  26         while (((UART_READ(RT3883_UART_REG_LSR)) & UART_LSR_THRE) == 0);
  27         UART_WRITE(RT3883_UART_REG_TX, ch);
  28         while (((UART_READ(RT3883_UART_REG_LSR)) & UART_LSR_THRE) == 0);
  29 }