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/sclp.h>
10 
sclp_early_write(struct console * con,const char * s,unsigned int len)11 static void sclp_early_write(struct console *con, const char *s, unsigned int len)
12 {
13 	__sclp_early_printk(s, len);
14 }
15 
16 static struct console sclp_early_console = {
17 	.name  = "earlysclp",
18 	.write = sclp_early_write,
19 	.flags = CON_PRINTBUFFER | CON_BOOT,
20 	.index = -1,
21 };
22 
setup_early_printk(char * buf)23 static int __init setup_early_printk(char *buf)
24 {
25 	if (early_console)
26 		return 0;
27 	/* Accept only "earlyprintk" and "earlyprintk=sclp" */
28 	if (buf && !str_has_prefix(buf, "sclp"))
29 		return 0;
30 	if (!sclp.has_linemode && !sclp.has_vt220)
31 		return 0;
32 	early_console = &sclp_early_console;
33 	register_console(early_console);
34 	return 0;
35 }
36 early_param("earlyprintk", setup_early_printk);
37