arch/mips/ath25/early_printk.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
   7  */
   8
   9 #include <linux/mm.h>
  10 #include <linux/io.h>
  11 #include <linux/serial_reg.h>
  12
  13 #include "devices.h"
  14 #include "ar2315_regs.h"
  15 #include "ar5312_regs.h"
  16
  17 static inline void prom_uart_wr(void __iomem *base, unsigned reg,
  18                                 unsigned char ch)
  19 {
  20         __raw_writel(ch, base + 4 * reg);
  21 }
  22
  23 static inline unsigned char prom_uart_rr(void __iomem *base, unsigned reg)
  24 {
  25         return __raw_readl(base + 4 * reg);
  26 }
  27
  28 void prom_putchar(unsigned char ch)
  29 {
  30         static void __iomem *base;
  31
  32         if (unlikely(base == NULL)) {
  33                 if (is_ar2315())
  34                         base = (void __iomem *)(KSEG1ADDR(AR2315_UART0_BASE));
  35                 else
  36                         base = (void __iomem *)(KSEG1ADDR(AR5312_UART0_BASE));
  37         }
  38
  39         while ((prom_uart_rr(base, UART_LSR) & UART_LSR_THRE) == 0)
  40                 ;
  41         prom_uart_wr(base, UART_TX, ch);
  42         while ((prom_uart_rr(base, UART_LSR) & UART_LSR_THRE) == 0)
  43                 ;
  44 }