| 1 | // SPDX-License-Identifier: GPL-2.0 |
|---|---|
| 2 | /* |
| 3 | * Copyright IBM Corp. 2017 |
| 4 | */ |
| 5 | |
| 6 | #include <linux/console.h> |
| 7 | #include <linux/kernel.h> |
| 8 | #include <linux/init.h> |
| 9 | #include <asm/setup.h> |
| 10 | #include <asm/sclp.h> |
| 11 | |
| 12 | static void sclp_early_write(struct console *con, const char *s, unsigned int len) |
| 13 | { |
| 14 | __sclp_early_printk(s, len); |
| 15 | } |
| 16 | |
| 17 | static struct console sclp_early_console = { |
| 18 | .name = "earlysclp", |
| 19 | .write = sclp_early_write, |
| 20 | .flags = CON_PRINTBUFFER | CON_BOOT, |
| 21 | .index = -1, |
| 22 | }; |
| 23 | |
| 24 | void __init register_early_console(void) |
| 25 | { |
| 26 | if (early_console) |
| 27 | return; |
| 28 | if (!sclp.has_linemode && !sclp.has_vt220) |
| 29 | return; |
| 30 | early_console = &sclp_early_console; |
| 31 | register_console(early_console); |
| 32 | } |
| 33 | |
| 34 | static int __init setup_early_printk(char *buf) |
| 35 | { |
| 36 | if (early_console) |
| 37 | return 0; |
| 38 | /* Accept only "earlyprintk" and "earlyprintk=sclp" */ |
| 39 | if (buf && !str_has_prefix(str: buf, prefix: "sclp")) |
| 40 | return 0; |
| 41 | register_early_console(); |
| 42 | return 0; |
| 43 | } |
| 44 | early_param("earlyprintk", setup_early_printk); |
| 45 |