1/*
2 *  Atheros AR7XXX/AR9XXX SoC early printk support
3 *
4 *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
5 *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
6 *
7 *  This program is free software; you can redistribute it and/or modify it
8 *  under the terms of the GNU General Public License version 2 as published
9 *  by the Free Software Foundation.
10 */
11
12#include <linux/io.h>
13#include <linux/errno.h>
14#include <linux/serial_reg.h>
15#include <asm/addrspace.h>
16
17#include <asm/mach-ath79/ath79.h>
18#include <asm/mach-ath79/ar71xx_regs.h>
19#include <asm/mach-ath79/ar933x_uart.h>
20
21static void (*_prom_putchar) (unsigned char);
22
23static inline void prom_putchar_wait(void __iomem *reg, u32 mask, u32 val)
24{
25	u32 t;
26
27	do {
28		t = __raw_readl(reg);
29		if ((t & mask) == val)
30			break;
31	} while (1);
32}
33
34static void prom_putchar_ar71xx(unsigned char ch)
35{
36	void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));
37
38	prom_putchar_wait(base + UART_LSR * 4, UART_LSR_THRE, UART_LSR_THRE);
39	__raw_writel(ch, base + UART_TX * 4);
40	prom_putchar_wait(base + UART_LSR * 4, UART_LSR_THRE, UART_LSR_THRE);
41}
42
43static void prom_putchar_ar933x(unsigned char ch)
44{
45	void __iomem *base = (void __iomem *)(KSEG1ADDR(AR933X_UART_BASE));
46
47	prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR,
48			  AR933X_UART_DATA_TX_CSR);
49	__raw_writel(AR933X_UART_DATA_TX_CSR | ch, base + AR933X_UART_DATA_REG);
50	prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR,
51			  AR933X_UART_DATA_TX_CSR);
52}
53
54static void prom_putchar_dummy(unsigned char ch)
55{
56	/* nothing to do */
57}
58
59static void prom_putchar_init(void)
60{
61	void __iomem *base;
62	u32 id;
63
64	base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE));
65	id = __raw_readl(base + AR71XX_RESET_REG_REV_ID);
66	id &= REV_ID_MAJOR_MASK;
67
68	switch (id) {
69	case REV_ID_MAJOR_AR71XX:
70	case REV_ID_MAJOR_AR7240:
71	case REV_ID_MAJOR_AR7241:
72	case REV_ID_MAJOR_AR7242:
73	case REV_ID_MAJOR_AR913X:
74	case REV_ID_MAJOR_AR9341:
75	case REV_ID_MAJOR_AR9342:
76	case REV_ID_MAJOR_AR9344:
77	case REV_ID_MAJOR_QCA9556:
78	case REV_ID_MAJOR_QCA9558:
79		_prom_putchar = prom_putchar_ar71xx;
80		break;
81
82	case REV_ID_MAJOR_AR9330:
83	case REV_ID_MAJOR_AR9331:
84		_prom_putchar = prom_putchar_ar933x;
85		break;
86
87	default:
88		_prom_putchar = prom_putchar_dummy;
89		break;
90	}
91}
92
93void prom_putchar(unsigned char ch)
94{
95	if (!_prom_putchar)
96		prom_putchar_init();
97
98	_prom_putchar(ch);
99}
100