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1// SPDX-License-Identifier: GPL-2.02/*3 * RISC-V SBI based earlycon4 *5 * Copyright (C) 2018 Anup Patel <anup@brainfault.org>6 */7#include <linux/kernel.h>8#include <linux/console.h>9#include <linux/init.h>10#include <linux/serial_core.h>11#include <asm/sbi.h>12 13static void sbi_putc(struct uart_port *port, unsigned char c)14{15 sbi_console_putchar(c);16}17 18static void sbi_0_1_console_write(struct console *con,19 const char *s, unsigned int n)20{21 struct earlycon_device *dev = con->data;22 uart_console_write(&dev->port, s, n, sbi_putc);23}24 25static void sbi_dbcn_console_write(struct console *con,26 const char *s, unsigned int n)27{28 int ret;29 30 while (n) {31 ret = sbi_debug_console_write(s, n);32 if (ret < 0)33 break;34 35 s += ret;36 n -= ret;37 }38}39 40static int __init early_sbi_setup(struct earlycon_device *device,41 const char *opt)42{43 if (sbi_debug_console_available)44 device->con->write = sbi_dbcn_console_write;45 else if (IS_ENABLED(CONFIG_RISCV_SBI_V01))46 device->con->write = sbi_0_1_console_write;47 else48 return -ENODEV;49 50 return 0;51}52EARLYCON_DECLARE(sbi, early_sbi_setup);53