1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *  Atheros AR7XXX/AR9XXX SoC early printk support
4 *
5 *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
6 *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
7 */
8
9#include <linux/io.h>
10#include <linux/errno.h>
11#include <linux/serial.h>
12#include <linux/serial_reg.h>
13#include <asm/addrspace.h>
14#include <asm/setup.h>
15
16#include <asm/mach-ath79/ath79.h>
17#include <asm/mach-ath79/ar71xx_regs.h>
18#include <asm/mach-ath79/ar933x_uart.h>
19
20static void (*_prom_putchar)(char);
21
22static inline void prom_putchar_wait(void __iomem *reg, u32 val)
23{
24	u32 t;
25
26	do {
27		t = __raw_readl(reg);
28		if ((t & val) == val)
29			break;
30	} while (1);
31}
32
33static void prom_putchar_ar71xx(char ch)
34{
35	void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));
36
37	prom_putchar_wait(base + UART_LSR * 4, UART_LSR_BOTH_EMPTY);
38	__raw_writel((unsigned char)ch, base + UART_TX * 4);
39	prom_putchar_wait(base + UART_LSR * 4, UART_LSR_BOTH_EMPTY);
40}
41
42static void prom_putchar_ar933x(char ch)
43{
44	void __iomem *base = (void __iomem *)(KSEG1ADDR(AR933X_UART_BASE));
45
46	prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR);
47	__raw_writel(AR933X_UART_DATA_TX_CSR | (unsigned char)ch,
48		     base + AR933X_UART_DATA_REG);
49	prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR);
50}
51
52static void prom_putchar_dummy(char ch)
53{
54	/* nothing to do */
55}
56
57static void prom_enable_uart(u32 id)
58{
59	void __iomem *gpio_base;
60	u32 uart_en;
61	u32 t;
62
63	switch (id) {
64	case REV_ID_MAJOR_AR71XX:
65		uart_en = AR71XX_GPIO_FUNC_UART_EN;
66		break;
67
68	case REV_ID_MAJOR_AR7240:
69	case REV_ID_MAJOR_AR7241:
70	case REV_ID_MAJOR_AR7242:
71		uart_en = AR724X_GPIO_FUNC_UART_EN;
72		break;
73
74	case REV_ID_MAJOR_AR913X:
75		uart_en = AR913X_GPIO_FUNC_UART_EN;
76		break;
77
78	case REV_ID_MAJOR_AR9330:
79	case REV_ID_MAJOR_AR9331:
80		uart_en = AR933X_GPIO_FUNC_UART_EN;
81		break;
82
83	case REV_ID_MAJOR_AR9341:
84	case REV_ID_MAJOR_AR9342:
85	case REV_ID_MAJOR_AR9344:
86		/* TODO */
87	default:
88		return;
89	}
90
91	gpio_base = (void __iomem *)KSEG1ADDR(AR71XX_GPIO_BASE);
92	t = __raw_readl(gpio_base + AR71XX_GPIO_REG_FUNC);
93	t |= uart_en;
94	__raw_writel(t, gpio_base + AR71XX_GPIO_REG_FUNC);
95}
96
97static void prom_putchar_init(void)
98{
99	void __iomem *base;
100	u32 id;
101
102	base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE));
103	id = __raw_readl(base + AR71XX_RESET_REG_REV_ID);
104	id &= REV_ID_MAJOR_MASK;
105
106	switch (id) {
107	case REV_ID_MAJOR_AR71XX:
108	case REV_ID_MAJOR_AR7240:
109	case REV_ID_MAJOR_AR7241:
110	case REV_ID_MAJOR_AR7242:
111	case REV_ID_MAJOR_AR913X:
112	case REV_ID_MAJOR_AR9341:
113	case REV_ID_MAJOR_AR9342:
114	case REV_ID_MAJOR_AR9344:
115	case REV_ID_MAJOR_QCA9533:
116	case REV_ID_MAJOR_QCA9533_V2:
117	case REV_ID_MAJOR_QCA9556:
118	case REV_ID_MAJOR_QCA9558:
119	case REV_ID_MAJOR_TP9343:
120	case REV_ID_MAJOR_QCA956X:
121	case REV_ID_MAJOR_QCN550X:
122		_prom_putchar = prom_putchar_ar71xx;
123		break;
124
125	case REV_ID_MAJOR_AR9330:
126	case REV_ID_MAJOR_AR9331:
127		_prom_putchar = prom_putchar_ar933x;
128		break;
129
130	default:
131		_prom_putchar = prom_putchar_dummy;
132		return;
133	}
134
135	prom_enable_uart(id);
136}
137
138void prom_putchar(char ch)
139{
140	if (!_prom_putchar)
141		prom_putchar_init();
142
143	_prom_putchar(ch);
144}
145