xref: /openbmc/linux/arch/mips/ath25/early_printk.c (revision a44e4f3a)
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 }
46