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
sclp_early_write(struct console * con,const char * s,unsigned int len)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
register_early_console(void)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
setup_early_printk(char * buf)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(buf, "sclp"))
40 return 0;
41 register_early_console();
42 return 0;
43 }
44 early_param("earlyprintk", setup_early_printk);
45