LXR linux/arch/mips/ath79/early

   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
  22static void (*_prom_putchar)(char);
  23
  24static 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
  37static 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
  46static 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
  58static void prom_putchar_dummy(char ch)
  59{
  60        /* nothing to do */
  61}
  62
  63static void prom_enable_uart(u32 id)
  64{
  65        void __iomem *gpio_base;
  66        u32 uart_en;
  67        u32 t;
  68
  69        switch (id) {
  70        case REV_ID_MAJOR_AR71XX:
  71                uart_en = AR71XX_GPIO_FUNC_UART_EN;
  72                break;
  73
  74        case REV_ID_MAJOR_AR7240:
  75        case REV_ID_MAJOR_AR7241:
  76        case REV_ID_MAJOR_AR7242:
  77                uart_en = AR724X_GPIO_FUNC_UART_EN;
  78                break;
  79
  80        case REV_ID_MAJOR_AR913X:
  81                uart_en = AR913X_GPIO_FUNC_UART_EN;
  82                break;
  83
  84        case REV_ID_MAJOR_AR9330:
  85        case REV_ID_MAJOR_AR9331:
  86                uart_en = AR933X_GPIO_FUNC_UART_EN;
  87                break;
  88
  89        case REV_ID_MAJOR_AR9341:
  90        case REV_ID_MAJOR_AR9342:
  91        case REV_ID_MAJOR_AR9344:
  92                /* TODO */
  93        default:
  94                return;
  95        }
  96
  97        gpio_base = (void __iomem *)KSEG1ADDR(AR71XX_GPIO_BASE);
  98        t = __raw_readl(gpio_base + AR71XX_GPIO_REG_FUNC);
  99        t |= uart_en;
 100        __raw_writel(t, gpio_base + AR71XX_GPIO_REG_FUNC);
 101}
 102
 103static void prom_putchar_init(void)
 104{
 105        void __iomem *base;
 106        u32 id;
 107
 108        base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE));
 109        id = __raw_readl(base + AR71XX_RESET_REG_REV_ID);
 110        id &= REV_ID_MAJOR_MASK;
 111
 112        switch (id) {
 113        case REV_ID_MAJOR_AR71XX:
 114        case REV_ID_MAJOR_AR7240:
 115        case REV_ID_MAJOR_AR7241:
 116        case REV_ID_MAJOR_AR7242:
 117        case REV_ID_MAJOR_AR913X:
 118        case REV_ID_MAJOR_AR9341:
 119        case REV_ID_MAJOR_AR9342:
 120        case REV_ID_MAJOR_AR9344:
 121        case REV_ID_MAJOR_QCA9533:
 122        case REV_ID_MAJOR_QCA9533_V2:
 123        case REV_ID_MAJOR_QCA9556:
 124        case REV_ID_MAJOR_QCA9558:
 125        case REV_ID_MAJOR_TP9343:
 126        case REV_ID_MAJOR_QCA956X:
 127                _prom_putchar = prom_putchar_ar71xx;
 128                break;
 129
 130        case REV_ID_MAJOR_AR9330:
 131        case REV_ID_MAJOR_AR9331:
 132                _prom_putchar = prom_putchar_ar933x;
 133                break;
 134
 135        default:
 136                _prom_putchar = prom_putchar_dummy;
 137                return;
 138        }
 139
 140        prom_enable_uart(id);
 141}
 142
 143void prom_putchar(char ch)
 144{
 145        if (!_prom_putchar)
 146                prom_putchar_init();
 147
 148        _prom_putchar(ch);
 149}
 150