LXR linux/arch/mips/ath79/early

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  Atheros AR7XXX/AR9XXX SoC early printk support
   4 *
   5 *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
   6 *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
   7 */
   8
   9#include <linux/io.h>
  10#include <linux/errno.h>
  11#include <linux/serial_reg.h>
  12#include <asm/addrspace.h>
  13#include <asm/setup.h>
  14
  15#include <asm/mach-ath79/ath79.h>
  16#include <asm/mach-ath79/ar71xx_regs.h>
  17#include <asm/mach-ath79/ar933x_uart.h>
  18
  19static void (*_prom_putchar)(char);
  20
  21static inline void prom_putchar_wait(void __iomem *reg, u32 mask, u32 val)
  22{
  23        u32 t;
  24
  25        do {
  26                t = __raw_readl(reg);
  27                if ((t & mask) == val)
  28                        break;
  29        } while (1);
  30}
  31
  32#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
  33
  34static void prom_putchar_ar71xx(char ch)
  35{
  36        void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));
  37
  38        prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY);
  39        __raw_writel((unsigned char)ch, base + UART_TX * 4);
  40        prom_putchar_wait(base + UART_LSR * 4, BOTH_EMPTY, BOTH_EMPTY);
  41}
  42
  43static void prom_putchar_ar933x(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 | (unsigned char)ch,
  50                     base + AR933X_UART_DATA_REG);
  51        prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR,
  52                          AR933X_UART_DATA_TX_CSR);
  53}
  54
  55static void prom_putchar_dummy(char ch)
  56{
  57        /* nothing to do */
  58}
  59
  60static void prom_enable_uart(u32 id)
  61{
  62        void __iomem *gpio_base;
  63        u32 uart_en;
  64        u32 t;
  65
  66        switch (id) {
  67        case REV_ID_MAJOR_AR71XX:
  68                uart_en = AR71XX_GPIO_FUNC_UART_EN;
  69                break;
  70
  71        case REV_ID_MAJOR_AR7240:
  72        case REV_ID_MAJOR_AR7241:
  73        case REV_ID_MAJOR_AR7242:
  74                uart_en = AR724X_GPIO_FUNC_UART_EN;
  75                break;
  76
  77        case REV_ID_MAJOR_AR913X:
  78                uart_en = AR913X_GPIO_FUNC_UART_EN;
  79                break;
  80
  81        case REV_ID_MAJOR_AR9330:
  82        case REV_ID_MAJOR_AR9331:
  83                uart_en = AR933X_GPIO_FUNC_UART_EN;
  84                break;
  85
  86        case REV_ID_MAJOR_AR9341:
  87        case REV_ID_MAJOR_AR9342:
  88        case REV_ID_MAJOR_AR9344:
  89                /* TODO */
  90        default:
  91                return;
  92        }
  93
  94        gpio_base = (void __iomem *)KSEG1ADDR(AR71XX_GPIO_BASE);
  95        t = __raw_readl(gpio_base + AR71XX_GPIO_REG_FUNC);
  96        t |= uart_en;
  97        __raw_writel(t, gpio_base + AR71XX_GPIO_REG_FUNC);
  98}
  99
 100static void prom_putchar_init(void)
 101{
 102        void __iomem *base;
 103        u32 id;
 104
 105        base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE));
 106        id = __raw_readl(base + AR71XX_RESET_REG_REV_ID);
 107        id &= REV_ID_MAJOR_MASK;
 108
 109        switch (id) {
 110        case REV_ID_MAJOR_AR71XX:
 111        case REV_ID_MAJOR_AR7240:
 112        case REV_ID_MAJOR_AR7241:
 113        case REV_ID_MAJOR_AR7242:
 114        case REV_ID_MAJOR_AR913X:
 115        case REV_ID_MAJOR_AR9341:
 116        case REV_ID_MAJOR_AR9342:
 117        case REV_ID_MAJOR_AR9344:
 118        case REV_ID_MAJOR_QCA9533:
 119        case REV_ID_MAJOR_QCA9533_V2:
 120        case REV_ID_MAJOR_QCA9556:
 121        case REV_ID_MAJOR_QCA9558:
 122        case REV_ID_MAJOR_TP9343:
 123        case REV_ID_MAJOR_QCA956X:
 124                _prom_putchar = prom_putchar_ar71xx;
 125                break;
 126
 127        case REV_ID_MAJOR_AR9330:
 128        case REV_ID_MAJOR_AR9331:
 129                _prom_putchar = prom_putchar_ar933x;
 130                break;
 131
 132        default:
 133                _prom_putchar = prom_putchar_dummy;
 134                return;
 135        }
 136
 137        prom_enable_uart(id);
 138}
 139
 140void prom_putchar(char ch)
 141{
 142        if (!_prom_putchar)
 143                prom_putchar_init();
 144
 145        _prom_putchar(ch);
 146}
 147