hvc: dcc: Add earlycon support

// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2010, 2014 The Linux Foundation. All rights reserved.  */

#include <linux/console.h>

#include <linux/init.h>

#include <linux/serial.h>

#include <linux/serial_core.h>

#include <asm/dcc.h>

#include <asm/processor.h>

#define DCC_STATUS_RX		(1 << 30)

#define DCC_STATUS_TX		(1 << 29)

static void dcc_uart_console_putchar(struct uart_port *port, int ch)

{

	while (__dcc_getstatus() & DCC_STATUS_TX)

		cpu_relax();

	__dcc_putchar(ch);

}

static void dcc_early_write(struct console *con, const char *s, unsigned n)

{

	struct earlycon_device *dev = con->data;

	uart_console_write(&dev->port, s, n, dcc_uart_console_putchar);

}

static int __init dcc_early_console_setup(struct earlycon_device *device,

					  const char *opt)

{

	device->con->write = dcc_early_write;

	return 0;

}

EARLYCON_DECLARE(dcc, dcc_early_console_setup);

static int hvc_dcc_put_chars(uint32_t vt, const char *buf, int count)

{

	int i;