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 #include <asm/setup.h>
  13
  14 #include "devices.h"
  15 #include "ar2315_regs.h"
  16 #include "ar5312_regs.h"
  17
  18 static inline void prom_uart_wr(void __iomem *base, unsigned reg,
  19                                 unsigned char ch)
  20 {
  21         __raw_writel(ch, base + 4 * reg);
  22 }
  23
  24 static inline unsigned char prom_uart_rr(void __iomem *base, unsigned reg)
  25 {
  26         return __raw_readl(base + 4 * reg);
  27 }
  28
  29 void prom_putchar(char ch)
  30 {
  31         static void __iomem *base;
  32
  33         if (unlikely(base == NULL)) {
  34                 if (is_ar2315())
  35                         base = (void __iomem *)(KSEG1ADDR(AR2315_UART0_BASE));
  36                 else
  37                         base = (void __iomem *)(KSEG1ADDR(AR5312_UART0_BASE));
  38         }
  39
  40         while ((prom_uart_rr(base, UART_LSR) & UART_LSR_THRE) == 0)
  41                 ;
  42         prom_uart_wr(base, UART_TX, (unsigned char)ch);
  43         while ((prom_uart_rr(base, UART_LSR) & UART_LSR_THRE) == 0)
  44                 ;
  45 }