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