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_reg.h> 12 #include <asm/addrspace.h> 13 #include <asm/setup.h> 14 15 #include <asm/mach-ath79/ath79.h> 16 #include <asm/mach-ath79/ar71xx_regs.h> 17 #include <asm/mach-ath79/ar933x_uart.h> 18 19 static void (*_prom_putchar)(char); 20 21 static inline void prom_putchar_wait(void __iomem *reg, u32 mask, u32 val) 22 { 23 u32 t; 24 25 do { 26 t = __raw_readl(reg); 27 if ((t & mask) == val) 28 break; 29 } while (1); 30 } 31 32 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) 33 34 static void prom_putchar_ar71xx(char ch) 35 { 36 void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE)); 37 38 prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY); 39 __raw_writel((unsigned char)ch, base + UART_TX * 4); 40 prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY); 41 } 42 43 static void prom_putchar_ar933x(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 | (unsigned char)ch, 50 base + AR933X_UART_DATA_REG); 51 prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR, 52 AR933X_UART_DATA_TX_CSR); 53 } 54 55 static void prom_putchar_dummy(char ch) 56 { 57 /* nothing to do */ 58 } 59 60 static void prom_enable_uart(u32 id) 61 { 62 void __iomem *gpio_base; 63 u32 uart_en; 64 u32 t; 65 66 switch (id) { 67 case REV_ID_MAJOR_AR71XX: 68 uart_en = AR71XX_GPIO_FUNC_UART_EN; 69 break; 70 71 case REV_ID_MAJOR_AR7240: 72 case REV_ID_MAJOR_AR7241: 73 case REV_ID_MAJOR_AR7242: 74 uart_en = AR724X_GPIO_FUNC_UART_EN; 75 break; 76 77 case REV_ID_MAJOR_AR913X: 78 uart_en = AR913X_GPIO_FUNC_UART_EN; 79 break; 80 81 case REV_ID_MAJOR_AR9330: 82 case REV_ID_MAJOR_AR9331: 83 uart_en = AR933X_GPIO_FUNC_UART_EN; 84 break; 85 86 case REV_ID_MAJOR_AR9341: 87 case REV_ID_MAJOR_AR9342: 88 case REV_ID_MAJOR_AR9344: 89 /* TODO */ 90 default: 91 return; 92 } 93 94 gpio_base = (void __iomem *)KSEG1ADDR(AR71XX_GPIO_BASE); 95 t = __raw_readl(gpio_base + AR71XX_GPIO_REG_FUNC); 96 t |= uart_en; 97 __raw_writel(t, gpio_base + AR71XX_GPIO_REG_FUNC); 98 } 99 100 static void prom_putchar_init(void) 101 { 102 void __iomem *base; 103 u32 id; 104 105 base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE)); 106 id = __raw_readl(base + AR71XX_RESET_REG_REV_ID); 107 id &= REV_ID_MAJOR_MASK; 108 109 switch (id) { 110 case REV_ID_MAJOR_AR71XX: 111 case REV_ID_MAJOR_AR7240: 112 case REV_ID_MAJOR_AR7241: 113 case REV_ID_MAJOR_AR7242: 114 case REV_ID_MAJOR_AR913X: 115 case REV_ID_MAJOR_AR9341: 116 case REV_ID_MAJOR_AR9342: 117 case REV_ID_MAJOR_AR9344: 118 case REV_ID_MAJOR_QCA9533: 119 case REV_ID_MAJOR_QCA9533_V2: 120 case REV_ID_MAJOR_QCA9556: 121 case REV_ID_MAJOR_QCA9558: 122 case REV_ID_MAJOR_TP9343: 123 case REV_ID_MAJOR_QCA956X: 124 case REV_ID_MAJOR_QCN550X: 125 _prom_putchar = prom_putchar_ar71xx; 126 break; 127 128 case REV_ID_MAJOR_AR9330: 129 case REV_ID_MAJOR_AR9331: 130 _prom_putchar = prom_putchar_ar933x; 131 break; 132 133 default: 134 _prom_putchar = prom_putchar_dummy; 135 return; 136 } 137 138 prom_enable_uart(id); 139 } 140 141 void prom_putchar(char ch) 142 { 143 if (!_prom_putchar) 144 prom_putchar_init(); 145 146 _prom_putchar(ch); 147 } 148