1/*
 2 *  This program is free software; you can redistribute it and/or modify it
 3 *  under the terms of the GNU General Public License version 2 as published
 4 *  by the Free Software Foundation.
 5 *
 6 *  Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
 7 */
 8
 9#include <linux/io.h>
10#include <linux/serial_reg.h>
11
12#include <asm/addrspace.h>
13
14#ifdef CONFIG_SOC_RT288X
15#define EARLY_UART_BASE		0x300c00
16#define CHIPID_BASE		0x300004
17#elif defined(CONFIG_SOC_MT7621)
18#define EARLY_UART_BASE		0x1E000c00
19#define CHIPID_BASE		0x1E000004
20#else
21#define EARLY_UART_BASE		0x10000c00
22#define CHIPID_BASE		0x10000004
23#endif
24
25#define MT7628_CHIP_NAME1	0x20203832
26
27#define UART_REG_TX		0x04
28#define UART_REG_LCR		0x0c
29#define UART_REG_LSR		0x14
30#define UART_REG_LSR_RT2880	0x1c
31
32static __iomem void *uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE);
33static __iomem void *chipid_membase = (__iomem void *) KSEG1ADDR(CHIPID_BASE);
34static int init_complete;
35
36static inline void uart_w32(u32 val, unsigned reg)
37{
38	__raw_writel(val, uart_membase + reg);
39}
40
41static inline u32 uart_r32(unsigned reg)
42{
43	return __raw_readl(uart_membase + reg);
44}
45
46static inline int soc_is_mt7628(void)
47{
48	return IS_ENABLED(CONFIG_SOC_MT7620) &&
49		(__raw_readl(chipid_membase) == MT7628_CHIP_NAME1);
50}
51
52static void find_uart_base(void)
53{
54	int i;
55
56	if (!soc_is_mt7628())
57		return;
58
59	for (i = 0; i < 3; i++) {
60		u32 reg = uart_r32(UART_REG_LCR + (0x100 * i));
61
62		if (!reg)
63			continue;
64
65		uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE +
66							  (0x100 * i));
67		break;
68	}
69}
70
71void prom_putchar(unsigned char ch)
72{
73	if (!init_complete) {
74		find_uart_base();
75		init_complete = 1;
76	}
77
78	if (IS_ENABLED(CONFIG_SOC_MT7621) || soc_is_mt7628()) {
79		uart_w32(ch, UART_TX);
80		while ((uart_r32(UART_REG_LSR) & UART_LSR_THRE) == 0)
81			;
82	} else {
83		while ((uart_r32(UART_REG_LSR_RT2880) & UART_LSR_THRE) == 0)
84			;
85		uart_w32(ch, UART_REG_TX);
86		while ((uart_r32(UART_REG_LSR_RT2880) & UART_LSR_THRE) == 0)
87			;
88	}
89}