[linux-block.git] / drivers / tty / serial / earlycon-arm-semihost.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2012 ARM Ltd.
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * Adapted for ARM and earlycon:
 * Copyright (C) 2014 Linaro Ltd.
 * Author: Rob Herring <robh@kernel.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <linux/kernel.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/serial_core.h>

#ifdef CONFIG_THUMB2_KERNEL
#define SEMIHOST_SWI	"0xab"
#else
#define SEMIHOST_SWI	"0x123456"
#endif

/*
 * Semihosting-based debug console
 */
static void smh_putc(struct uart_port *port, int c)
{
#ifdef CONFIG_ARM64
	asm volatile("mov  x1, %0\n"
		     "mov  x0, #3\n"
		     "hlt  0xf000\n"
		     : : "r" (&c) : "x0", "x1", "memory");
#else
	asm volatile("mov  r1, %0\n"
		     "mov  r0, #3\n"
		     "svc  " SEMIHOST_SWI "\n"
		     : : "r" (&c) : "r0", "r1", "memory");
#endif
}

static void smh_write(struct console *con, const char *s, unsigned n)
{
	struct earlycon_device *dev = con->data;
	uart_console_write(&dev->port, s, n, smh_putc);
}

static int
__init early_smh_setup(struct earlycon_device *device, const char *opt)
{
	device->con->write = smh_write;
	return 0;
}
EARLYCON_DECLARE(smh, early_smh_setup);
Commit	Line	Data
e3b3d0f5	1	// SPDX-License-Identifier: GPL-2.0
d50d7269 RH	2	/*
	3	* Copyright (C) 2012 ARM Ltd.
	4	* Author: Marc Zyngier <marc.zyngier@arm.com>
	5	*
	6	* Adapted for ARM and earlycon:
	7	* Copyright (C) 2014 Linaro Ltd.
	8	* Author: Rob Herring <robh@kernel.org>
	9	*
	10	* This program is free software: you can redistribute it and/or modify
	11	* it under the terms of the GNU General Public License version 2 as
	12	* published by the Free Software Foundation.
	13	*
	14	* This program is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	* GNU General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU General Public License
	20	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	21	*/
	22	#include <linux/kernel.h>
	23	#include <linux/console.h>
	24	#include <linux/init.h>
	25	#include <linux/serial_core.h>
	26
	27	#ifdef CONFIG_THUMB2_KERNEL
	28	#define SEMIHOST_SWI "0xab"
	29	#else
	30	#define SEMIHOST_SWI "0x123456"
	31	#endif
	32
	33	/*
	34	* Semihosting-based debug console
	35	*/
	36	static void smh_putc(struct uart_port *port, int c)
	37	{
	38	#ifdef CONFIG_ARM64
	39	asm volatile("mov x1, %0\n"
	40	"mov x0, #3\n"
	41	"hlt 0xf000\n"
	42	: : "r" (&c) : "x0", "x1", "memory");
	43	#else
	44	asm volatile("mov r1, %0\n"
	45	"mov r0, #3\n"
	46	"svc " SEMIHOST_SWI "\n"
	47	: : "r" (&c) : "r0", "r1", "memory");
	48	#endif
	49	}
	50
	51	static void smh_write(struct console con, const char s, unsigned n)
	52	{
	53	struct earlycon_device *dev = con->data;
	54	uart_console_write(&dev->port, s, n, smh_putc);
	55	}
	56
8f975fe4 BX	57	static int
8f975fe4 BX	58	__init early_smh_setup(struct earlycon_device device, const char opt)
d50d7269 RH	59	{
	60	device->con->write = smh_write;
	61	return 0;
	62	}
	63	EARLYCON_DECLARE(smh, early_smh_setup);