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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/mips/ath79/early_printk.c
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// SPDX-License-Identifier: GPL-2.0-only

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/*

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 *  Atheros AR7XXX/AR9XXX SoC early printk support

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 *

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 *  Copyright (C) 2008-2011 Gabor Juhos <[email protected]>

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 *  Copyright (C) 2008 Imre Kaloz <[email protected]>

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 */

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#include <linux/io.h>

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#include <linux/errno.h>

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#include <linux/serial.h>

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#include <linux/serial_reg.h>

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#include <asm/addrspace.h>

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#include <asm/setup.h>

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

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

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

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static void (*_prom_putchar)(char);

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

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{

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	u32 t;

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	do {

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		t = __raw_readl(reg);

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		if ((t & val) == val)

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			break;

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	} while (1);

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}

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static void prom_putchar_ar71xx(char ch)

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{

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	void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));

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	prom_putchar_wait(base + UART_LSR * 4, UART_LSR_BOTH_EMPTY);

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	__raw_writel((unsigned char)ch, base + UART_TX * 4);

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	prom_putchar_wait(base + UART_LSR * 4, UART_LSR_BOTH_EMPTY);

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}

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static void prom_putchar_ar933x(char ch)

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{

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	void __iomem *base = (void __iomem *)(KSEG1ADDR(AR933X_UART_BASE));

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	prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR);

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	__raw_writel(AR933X_UART_DATA_TX_CSR | (unsigned char)ch,

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		     base + AR933X_UART_DATA_REG);

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	prom_putchar_wait(base + AR933X_UART_DATA_REG, AR933X_UART_DATA_TX_CSR);

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}

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static void prom_putchar_dummy(char ch)

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{

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	/* nothing to do */

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}

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static void prom_enable_uart(u32 id)

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{

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	void __iomem *gpio_base;

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	u32 uart_en;

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	u32 t;

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	switch (id) {

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	case REV_ID_MAJOR_AR71XX:

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		uart_en = AR71XX_GPIO_FUNC_UART_EN;

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		break;

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	case REV_ID_MAJOR_AR7240:

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	case REV_ID_MAJOR_AR7241:

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	case REV_ID_MAJOR_AR7242:

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		uart_en = AR724X_GPIO_FUNC_UART_EN;

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		break;

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	case REV_ID_MAJOR_AR913X:

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		uart_en = AR913X_GPIO_FUNC_UART_EN;

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		break;

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	case REV_ID_MAJOR_AR9330:

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	case REV_ID_MAJOR_AR9331:

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		uart_en = AR933X_GPIO_FUNC_UART_EN;

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		break;

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	case REV_ID_MAJOR_AR9341:

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	case REV_ID_MAJOR_AR9342:

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	case REV_ID_MAJOR_AR9344:

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		/* TODO */

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	default:

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		return;

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	}

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	gpio_base = (void __iomem *)KSEG1ADDR(AR71XX_GPIO_BASE);

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	t = __raw_readl(gpio_base + AR71XX_GPIO_REG_FUNC);

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	t |= uart_en;

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	__raw_writel(t, gpio_base + AR71XX_GPIO_REG_FUNC);

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}

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static void prom_putchar_init(void)

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{

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	void __iomem *base;

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	u32 id;

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	base = (void __iomem *)(KSEG1ADDR(AR71XX_RESET_BASE));

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	id = __raw_readl(base + AR71XX_RESET_REG_REV_ID);

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	id &= REV_ID_MAJOR_MASK;

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	switch (id) {

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	case REV_ID_MAJOR_AR71XX:

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	case REV_ID_MAJOR_AR7240:

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	case REV_ID_MAJOR_AR7241:

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	case REV_ID_MAJOR_AR7242:

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	case REV_ID_MAJOR_AR913X:

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	case REV_ID_MAJOR_AR9341:

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	case REV_ID_MAJOR_AR9342:

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	case REV_ID_MAJOR_AR9344:

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	case REV_ID_MAJOR_QCA9533:

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	case REV_ID_MAJOR_QCA9533_V2:

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	case REV_ID_MAJOR_QCA9556:

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	case REV_ID_MAJOR_QCA9558:

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	case REV_ID_MAJOR_TP9343:

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	case REV_ID_MAJOR_QCA956X:

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	case REV_ID_MAJOR_QCN550X:

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		_prom_putchar = prom_putchar_ar71xx;

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		break;

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	case REV_ID_MAJOR_AR9330:

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	case REV_ID_MAJOR_AR9331:

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		_prom_putchar = prom_putchar_ar933x;

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		break;

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	default:

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		_prom_putchar = prom_putchar_dummy;

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		return;

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	}

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	prom_enable_uart(id);

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}

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void prom_putchar(char ch)

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{

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	if (!_prom_putchar)

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		prom_putchar_init();

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	_prom_putchar(ch);

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}

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