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_console.c (3210B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Joshua Henderson <joshua.henderson@microchip.com>
      4 * Copyright (C) 2015 Microchip Technology Inc.  All rights reserved.
      5 */
      6#include <asm/mach-pic32/pic32.h>
      7#include <asm/fw/fw.h>
      8#include <asm/setup.h>
      9
     10#include "pic32mzda.h"
     11#include "early_pin.h"
     12
     13/* Default early console parameters */
     14#define EARLY_CONSOLE_PORT	1
     15#define EARLY_CONSOLE_BAUDRATE	115200
     16
     17#define UART_ENABLE		BIT(15)
     18#define UART_ENABLE_RX		BIT(12)
     19#define UART_ENABLE_TX		BIT(10)
     20#define UART_TX_FULL		BIT(9)
     21
     22/* UART1(x == 0) - UART6(x == 5) */
     23#define UART_BASE(x)	((x) * 0x0200)
     24#define U_MODE(x)	UART_BASE(x)
     25#define U_STA(x)	(UART_BASE(x) + 0x10)
     26#define U_TXR(x)	(UART_BASE(x) + 0x20)
     27#define U_BRG(x)	(UART_BASE(x) + 0x40)
     28
     29static void __iomem *uart_base;
     30static char console_port = -1;
     31
     32static int __init configure_uart_pins(int port)
     33{
     34	switch (port) {
     35	case 1:
     36		pic32_pps_input(IN_FUNC_U2RX, IN_RPB0);
     37		pic32_pps_output(OUT_FUNC_U2TX, OUT_RPG9);
     38		break;
     39	case 5:
     40		pic32_pps_input(IN_FUNC_U6RX, IN_RPD0);
     41		pic32_pps_output(OUT_FUNC_U6TX, OUT_RPB8);
     42		break;
     43	default:
     44		return -1;
     45	}
     46
     47	return 0;
     48}
     49
     50static void __init configure_uart(char port, int baud)
     51{
     52	u32 pbclk;
     53
     54	pbclk = pic32_get_pbclk(2);
     55
     56	__raw_writel(0, uart_base + U_MODE(port));
     57	__raw_writel(((pbclk / baud) / 16) - 1, uart_base + U_BRG(port));
     58	__raw_writel(UART_ENABLE, uart_base + U_MODE(port));
     59	__raw_writel(UART_ENABLE_TX | UART_ENABLE_RX,
     60		     uart_base + PIC32_SET(U_STA(port)));
     61}
     62
     63static void __init setup_early_console(char port, int baud)
     64{
     65	if (configure_uart_pins(port))
     66		return;
     67
     68	console_port = port;
     69	configure_uart(console_port, baud);
     70}
     71
     72static char * __init pic32_getcmdline(void)
     73{
     74	/*
     75	 * arch_mem_init() has not been called yet, so we don't have a real
     76	 * command line setup if using CONFIG_CMDLINE_BOOL.
     77	 */
     78#ifdef CONFIG_CMDLINE_OVERRIDE
     79	return CONFIG_CMDLINE;
     80#else
     81	return fw_getcmdline();
     82#endif
     83}
     84
     85static int __init get_port_from_cmdline(char *arch_cmdline)
     86{
     87	char *s;
     88	int port = -1;
     89
     90	if (!arch_cmdline || *arch_cmdline == '\0')
     91		goto _out;
     92
     93	s = strstr(arch_cmdline, "earlyprintk=");
     94	if (s) {
     95		s = strstr(s, "ttyS");
     96		if (s)
     97			s += 4;
     98		else
     99			goto _out;
    100
    101		port = (*s) - '0';
    102	}
    103
    104_out:
    105	return port;
    106}
    107
    108static int __init get_baud_from_cmdline(char *arch_cmdline)
    109{
    110	char *s;
    111	int baud = -1;
    112
    113	if (!arch_cmdline || *arch_cmdline == '\0')
    114		goto _out;
    115
    116	s = strstr(arch_cmdline, "earlyprintk=");
    117	if (s) {
    118		s = strstr(s, "ttyS");
    119		if (s)
    120			s += 6;
    121		else
    122			goto _out;
    123
    124		baud = 0;
    125		while (*s >= '0' && *s <= '9')
    126			baud = baud * 10 + *s++ - '0';
    127	}
    128
    129_out:
    130	return baud;
    131}
    132
    133void __init fw_init_early_console(char port)
    134{
    135	char *arch_cmdline = pic32_getcmdline();
    136	int baud = -1;
    137
    138	uart_base = ioremap(PIC32_BASE_UART, 0xc00);
    139
    140	baud = get_baud_from_cmdline(arch_cmdline);
    141	if (port == -1)
    142		port = get_port_from_cmdline(arch_cmdline);
    143
    144	if (port == -1)
    145		port = EARLY_CONSOLE_PORT;
    146
    147	if (baud == -1)
    148		baud = EARLY_CONSOLE_BAUDRATE;
    149
    150	setup_early_console(port, baud);
    151}
    152
    153void prom_putchar(char c)
    154{
    155	if (console_port >= 0) {
    156		while (__raw_readl(
    157				uart_base + U_STA(console_port)) & UART_TX_FULL)
    158			;
    159
    160		__raw_writel(c, uart_base + U_TXR(console_port));
    161	}
    162}