https://github.com/torvalds/linux
Tip revision: 44c026a73be8038f03dbdeef028b642880cf1511 authored by Linus Torvalds on 21 May 2023, 21:05:48 UTC
Linux 6.4-rc3
Linux 6.4-rc3
Tip revision: 44c026a
early_printk.c
// 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);
}