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