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 #include <asm/setup.h> 14 15 #ifdef CONFIG_SOC_RT288X 16 #define EARLY_UART_BASE 0x300c00 17 #define CHIPID_BASE 0x300004 18 #elif defined(CONFIG_SOC_MT7621) 19 #define EARLY_UART_BASE 0x1E000c00 20 #define CHIPID_BASE 0x1E000004 21 #else 22 #define EARLY_UART_BASE 0x10000c00 23 #define CHIPID_BASE 0x10000004 24 #endif 25 26 #define MT7628_CHIP_NAME1 0x20203832 27 28 #define UART_REG_TX 0x04 29 #define UART_REG_LCR 0x0c 30 #define UART_REG_LSR 0x14 31 #define UART_REG_LSR_RT2880 0x1c 32 33 static __iomem void *uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE); 34 static __iomem void *chipid_membase = (__iomem void *) KSEG1ADDR(CHIPID_BASE); 35 static int init_complete; 36 37 static inline void uart_w32(u32 val, unsigned reg) 38 { 39 __raw_writel(val, uart_membase + reg); 40 } 41 42 static inline u32 uart_r32(unsigned reg) 43 { 44 return __raw_readl(uart_membase + reg); 45 } 46 47 static inline int soc_is_mt7628(void) 48 { 49 return IS_ENABLED(CONFIG_SOC_MT7620) && 50 (__raw_readl(chipid_membase) == MT7628_CHIP_NAME1); 51 } 52 53 static void find_uart_base(void) 54 { 55 int i; 56 57 if (!soc_is_mt7628()) 58 return; 59 60 for (i = 0; i < 3; i++) { 61 u32 reg = uart_r32(UART_REG_LCR + (0x100 * i)); 62 63 if (!reg) 64 continue; 65 66 uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE + 67 (0x100 * i)); 68 break; 69 } 70 } 71 72 void prom_putchar(char ch) 73 { 74 if (!init_complete) { 75 find_uart_base(); 76 init_complete = 1; 77 } 78 79 if (IS_ENABLED(CONFIG_SOC_MT7621) || soc_is_mt7628()) { 80 uart_w32((unsigned char)ch, UART_TX); 81 while ((uart_r32(UART_REG_LSR) & UART_LSR_THRE) == 0) 82 ; 83 } else { 84 while ((uart_r32(UART_REG_LSR_RT2880) & UART_LSR_THRE) == 0) 85 ; 86 uart_w32((unsigned char)ch, UART_REG_TX); 87 while ((uart_r32(UART_REG_LSR_RT2880) & UART_LSR_THRE) == 0) 88 ; 89 } 90 } 91