linux/drivers/tty/serial/earlycon-riscv-sbi.c
Anup Patel c77bf3607a
tty/serial: Add RISC-V SBI debug console based earlycon
We extend the existing RISC-V SBI earlycon support to use the new
RISC-V SBI debug console extension.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20231124070905.1043092-4-apatel@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-01-10 07:04:04 -08:00

53 lines
1.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* RISC-V SBI based earlycon
*
* Copyright (C) 2018 Anup Patel <anup@brainfault.org>
*/
#include <linux/kernel.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/serial_core.h>
#include <asm/sbi.h>
static void sbi_putc(struct uart_port *port, unsigned char c)
{
sbi_console_putchar(c);
}
static void sbi_0_1_console_write(struct console *con,
const char *s, unsigned int n)
{
struct earlycon_device *dev = con->data;
uart_console_write(&dev->port, s, n, sbi_putc);
}
static void sbi_dbcn_console_write(struct console *con,
const char *s, unsigned int n)
{
int ret;
while (n) {
ret = sbi_debug_console_write(s, n);
if (ret < 0)
break;
s += ret;
n -= ret;
}
}
static int __init early_sbi_setup(struct earlycon_device *device,
const char *opt)
{
if (sbi_debug_console_available)
device->con->write = sbi_dbcn_console_write;
else if (IS_ENABLED(CONFIG_RISCV_SBI_V01))
device->con->write = sbi_0_1_console_write;
else
return -ENODEV;
return 0;
}
EARLYCON_DECLARE(sbi, early_sbi_setup);