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
20 static void (*_prom_putchar)(char);
21
22 static 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
33 static 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
42 static 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
52 static void prom_putchar_dummy(char ch)
53 {
54 /* nothing to do */
55 }
56
57 static 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
97 static 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
138 void prom_putchar(char ch)
139 {
140 if (!_prom_putchar)
141 prom_putchar_init();
142
143 _prom_putchar(ch);
144 }
145
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