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/*
* 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);
}
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);
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