// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Atheros AR7XXX/AR9XXX SoC early printk support
 *
 *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
 *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
 */

#include <linux/io.h>
#include <linux/errno.h>
#include <linux/serial.h>
#include <linux/serial_reg.h>
#include <asm/addrspace.h>
#include <asm/setup.h>

#include <asm/mach-ath79/ath79.h>
#include <asm/mach-ath79/ar71xx_regs.h>
#include <asm/mach-ath79/ar933x_uart.h>

static void (*_prom_putchar)(char);

static inline void prom_putchar_wait(void __iomem *reg, u32 val)
{
        u32 t;

        do {
                t = __raw_readl(reg);
                if ((t & val) == val)
                        break;
        } while (1);
}

static void prom_putchar_ar71xx(char ch)
{
        void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));

        prom_putchar_wait(base + UART_LSR * 4, UART_LSR_BOTH_EMPTY);
        __raw_writel((unsigned char)ch, base + UART_TX * 4);
        prom_putchar_wait(base + UART_LSR * 4, UART_LSR_BOTH_EMPTY);
}

static void prom_putchar_ar933x(char ch)
{
        void __iomem *base = (void __iomem *)(KSEG1ADDR(AR933X_UART_BASE));

        prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR);
        __raw_writel(AR933X_UART_DATA_TX_CSR | (unsigned char)ch,
                     base + AR933X_UART_DATA_REG);
        prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR);
}

static void prom_putchar_dummy(char ch)
{
        /* nothing to do */
}

static void prom_enable_uart(u32 id)
{
        void __iomem *gpio_base;
        u32 uart_en;
        u32 t;

        switch (id) {
        case REV_ID_MAJOR_AR71XX:
                uart_en = AR71XX_GPIO_FUNC_UART_EN;
                break;

        case REV_ID_MAJOR_AR7240:
        case REV_ID_MAJOR_AR7241:
        case REV_ID_MAJOR_AR7242:
                uart_en = AR724X_GPIO_FUNC_UART_EN;
                break;

        case REV_ID_MAJOR_AR913X:
                uart_en = AR913X_GPIO_FUNC_UART_EN;
                break;

        case REV_ID_MAJOR_AR9330:
        case REV_ID_MAJOR_AR9331:
                uart_en = AR933X_GPIO_FUNC_UART_EN;
                break;

        case REV_ID_MAJOR_AR9341:
        case REV_ID_MAJOR_AR9342:
        case REV_ID_MAJOR_AR9344:
                /* TODO */
        default:
                return;
        }

        gpio_base = (void __iomem *)KSEG1ADDR(AR71XX_GPIO_BASE);
        t = __raw_readl(gpio_base + AR71XX_GPIO_REG_FUNC);
        t |= uart_en;
        __raw_writel(t, gpio_base + AR71XX_GPIO_REG_FUNC);
}

static void prom_putchar_init(void)
{
        void __iomem *base;
        u32 id;

        base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE));
        id = __raw_readl(base + AR71XX_RESET_REG_REV_ID);
        id &= REV_ID_MAJOR_MASK;

        switch (id) {
        case REV_ID_MAJOR_AR71XX:
        case REV_ID_MAJOR_AR7240:
        case REV_ID_MAJOR_AR7241:
        case REV_ID_MAJOR_AR7242:
        case REV_ID_MAJOR_AR913X:
        case REV_ID_MAJOR_AR9341:
        case REV_ID_MAJOR_AR9342:
        case REV_ID_MAJOR_AR9344:
        case REV_ID_MAJOR_QCA9533:
        case REV_ID_MAJOR_QCA9533_V2:
        case REV_ID_MAJOR_QCA9556:
        case REV_ID_MAJOR_QCA9558:
        case REV_ID_MAJOR_TP9343:
        case REV_ID_MAJOR_QCA956X:
        case REV_ID_MAJOR_QCN550X:
                _prom_putchar = prom_putchar_ar71xx;
                break;

        case REV_ID_MAJOR_AR9330:
        case REV_ID_MAJOR_AR9331:
                _prom_putchar = prom_putchar_ar933x;
                break;

        default:
                _prom_putchar = prom_putchar_dummy;
                return;
        }

        prom_enable_uart(id);
}

void prom_putchar(char ch)
{
        if (!_prom_putchar)
                prom_putchar_init();

        _prom_putchar(ch);
}