/* * 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 [31mCONFIG_THUMB2_KERNEL[0m #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 [31mCONFIG_ARM64[0m 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); |