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 17 #include <asm/mach-ath79/ath79.h> 18 #include <asm/mach-ath79/ar71xx_regs.h> 19 #include <asm/mach-ath79/ar933x_uart.h> 20 21 static void (*_prom_putchar) (unsigned char); 22 23 static inline void prom_putchar_wait(void __iomem *reg, u32 mask, u32 val) 24 { 25 u32 t; 26 27 do { 28 t = __raw_readl(reg); 29 if ((t & mask) == val) 30 break; 31 } while (1); 32 } 33 34 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) 35 36 static void prom_putchar_ar71xx(unsigned char ch) 37 { 38 void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE)); 39 40 prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY); 41 __raw_writel(ch, base + UART_TX * 4); 42 prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY); 43 } 44 45 static void prom_putchar_ar933x(unsigned char ch) 46 { 47 void __iomem *base = (void __iomem *)(KSEG1ADDR(AR933X_UART_BASE)); 48 49 prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR, 50 AR933X_UART_DATA_TX_CSR); 51 __raw_writel(AR933X_UART_DATA_TX_CSR | ch, base + AR933X_UART_DATA_REG); 52 prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR, 53 AR933X_UART_DATA_TX_CSR); 54 } 55 56 static void prom_putchar_dummy(unsigned char ch) 57 { 58 /* nothing to do */ 59 } 60 61 static void prom_putchar_init(void) 62 { 63 void __iomem *base; 64 u32 id; 65 66 base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE)); 67 id = __raw_readl(base + AR71XX_RESET_REG_REV_ID); 68 id &= REV_ID_MAJOR_MASK; 69 70 switch (id) { 71 case REV_ID_MAJOR_AR71XX: 72 case REV_ID_MAJOR_AR7240: 73 case REV_ID_MAJOR_AR7241: 74 case REV_ID_MAJOR_AR7242: 75 case REV_ID_MAJOR_AR913X: 76 case REV_ID_MAJOR_AR9341: 77 case REV_ID_MAJOR_AR9342: 78 case REV_ID_MAJOR_AR9344: 79 case REV_ID_MAJOR_QCA9556: 80 case REV_ID_MAJOR_QCA9558: 81 _prom_putchar = prom_putchar_ar71xx; 82 break; 83 84 case REV_ID_MAJOR_AR9330: 85 case REV_ID_MAJOR_AR9331: 86 _prom_putchar = prom_putchar_ar933x; 87 break; 88 89 default: 90 _prom_putchar = prom_putchar_dummy; 91 break; 92 } 93 } 94 95 void prom_putchar(unsigned char ch) 96 { 97 if (!_prom_putchar) 98 prom_putchar_init(); 99 100 _prom_putchar(ch); 101 } 102