cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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early_printk.c (3254B)

      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	case REV_ID_MAJOR_QCN550X:
    125		_prom_putchar = prom_putchar_ar71xx;
    126		break;
    127
    128	case REV_ID_MAJOR_AR9330:
    129	case REV_ID_MAJOR_AR9331:
    130		_prom_putchar = prom_putchar_ar933x;
    131		break;
    132
    133	default:
    134		_prom_putchar = prom_putchar_dummy;
    135		return;
    136	}
    137
    138	prom_enable_uart(id);
    139}
    140
    141void prom_putchar(char ch)
    142{
    143	if (!_prom_putchar)
    144		prom_putchar_init();
    145
    146	_prom_putchar(ch);
    147}