xref: /openbmc/linux/arch/mips/ath25/early_printk.c (revision bc5aa3a0)
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 }
45