1 /* 2 * Atheros AR7XXX/AR9XXX SoC early printk support 3 * 4 * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org> 5 * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License version 2 as published 9 * by the Free Software Foundation. 10 */ 11 12 #include <linux/io.h> 13 #include <linux/errno.h> 14 #include <linux/serial_reg.h> 15 #include <asm/addrspace.h> 16 #include <asm/setup.h> 17 18 #include <asm/mach-ath79/ath79.h> 19 #include <asm/mach-ath79/ar71xx_regs.h> 20 #include <asm/mach-ath79/ar933x_uart.h> 21 22 static void (*_prom_putchar)(char); 23 24 static inline void prom_putchar_wait(void __iomem *reg, u32 mask, u32 val) 25 { 26 u32 t; 27 28 do { 29 t = __raw_readl(reg); 30 if ((t & mask) == val) 31 break; 32 } while (1); 33 } 34 35 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) 36 37 static void prom_putchar_ar71xx(char ch) 38 { 39 void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE)); 40 41 prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY); 42 __raw_writel((unsigned char)ch, base + UART_TX * 4); 43 prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY); 44 } 45 46 static void prom_putchar_ar933x(char ch) 47 { 48 void __iomem *base = (void __iomem *)(KSEG1ADDR(AR933X_UART_BASE)); 49 50 prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR, 51 AR933X_UART_DATA_TX_CSR); 52 __raw_writel(AR933X_UART_DATA_TX_CSR | (unsigned char)ch, 53 base + AR933X_UART_DATA_REG); 54 prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR, 55 AR933X_UART_DATA_TX_CSR); 56 } 57 58 static void prom_putchar_dummy(char ch) 59 { 60 /* nothing to do */ 61 } 62 63 static void prom_putchar_init(void) 64 { 65 void __iomem *base; 66 u32 id; 67 68 base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE)); 69 id = __raw_readl(base + AR71XX_RESET_REG_REV_ID); 70 id &= REV_ID_MAJOR_MASK; 71 72 switch (id) { 73 case REV_ID_MAJOR_AR71XX: 74 case REV_ID_MAJOR_AR7240: 75 case REV_ID_MAJOR_AR7241: 76 case REV_ID_MAJOR_AR7242: 77 case REV_ID_MAJOR_AR913X: 78 case REV_ID_MAJOR_AR9341: 79 case REV_ID_MAJOR_AR9342: 80 case REV_ID_MAJOR_AR9344: 81 case REV_ID_MAJOR_QCA9556: 82 case REV_ID_MAJOR_QCA9558: 83 _prom_putchar = prom_putchar_ar71xx; 84 break; 85 86 case REV_ID_MAJOR_AR9330: 87 case REV_ID_MAJOR_AR9331: 88 _prom_putchar = prom_putchar_ar933x; 89 break; 90 91 default: 92 _prom_putchar = prom_putchar_dummy; 93 break; 94 } 95 } 96 97 void prom_putchar(char ch) 98 { 99 if (!_prom_putchar) 100 prom_putchar_init(); 101 102 _prom_putchar(ch); 103 } 104