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 21static void (*_prom_putchar) (unsigned char); 22 23static 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 34static void prom_putchar_ar71xx(unsigned char ch) 35{ 36 void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE)); 37 38 prom_putchar_wait(base + UART_LSR * 4, UART_LSR_THRE, UART_LSR_THRE); 39 __raw_writel(ch, base + UART_TX * 4); 40 prom_putchar_wait(base + UART_LSR * 4, UART_LSR_THRE, UART_LSR_THRE); 41} 42 43static void prom_putchar_ar933x(unsigned 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 | ch, base + AR933X_UART_DATA_REG); 50 prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR, 51 AR933X_UART_DATA_TX_CSR); 52} 53 54static void prom_putchar_dummy(unsigned char ch) 55{ 56 /* nothing to do */ 57} 58 59static void prom_putchar_init(void) 60{ 61 void __iomem *base; 62 u32 id; 63 64 base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE)); 65 id = __raw_readl(base + AR71XX_RESET_REG_REV_ID); 66 id &= REV_ID_MAJOR_MASK; 67 68 switch (id) { 69 case REV_ID_MAJOR_AR71XX: 70 case REV_ID_MAJOR_AR7240: 71 case REV_ID_MAJOR_AR7241: 72 case REV_ID_MAJOR_AR7242: 73 case REV_ID_MAJOR_AR913X: 74 _prom_putchar = prom_putchar_ar71xx; 75 break; 76 77 case REV_ID_MAJOR_AR9330: 78 case REV_ID_MAJOR_AR9331: 79 _prom_putchar = prom_putchar_ar933x; 80 break; 81 82 default: 83 _prom_putchar = prom_putchar_dummy; 84 break; 85 } 86} 87 88void prom_putchar(unsigned char ch) 89{ 90 if (!_prom_putchar) 91 prom_putchar_init(); 92 93 _prom_putchar(ch); 94} 95