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kernel/linux-rt-4.4.41/arch/mips/ath25/early_printk.c 1.02 KB
5113f6f70   김현기   kernel add
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  /*
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
   */
  
  #include <linux/mm.h>
  #include <linux/io.h>
  #include <linux/serial_reg.h>
  
  #include "devices.h"
  #include "ar2315_regs.h"
  #include "ar5312_regs.h"
  
  static inline void prom_uart_wr(void __iomem *base, unsigned reg,
  				unsigned char ch)
  {
  	__raw_writel(ch, base + 4 * reg);
  }
  
  static inline unsigned char prom_uart_rr(void __iomem *base, unsigned reg)
  {
  	return __raw_readl(base + 4 * reg);
  }
  
  void prom_putchar(unsigned char ch)
  {
  	static void __iomem *base;
  
  	if (unlikely(base == NULL)) {
  		if (is_ar2315())
  			base = (void __iomem *)(KSEG1ADDR(AR2315_UART0_BASE));
  		else
  			base = (void __iomem *)(KSEG1ADDR(AR5312_UART0_BASE));
  	}
  
  	while ((prom_uart_rr(base, UART_LSR) & UART_LSR_THRE) == 0)
  		;
  	prom_uart_wr(base, UART_TX, ch);
  	while ((prom_uart_rr(base, UART_LSR) & UART_LSR_THRE) == 0)
  		;
  }