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89175cf766
Use the early sclp code to provide a boot console. This boot console is available if the kernel parameter "earlyprintk" has been specified, just like it works for other architectures that also provide an early boot console. This makes debugging of early problems much easier, since now we finally have working console output even before memory detection is running. The boot console will be automatically disabled as soon as another console will be registered. Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
35 lines
784 B
C
35 lines
784 B
C
/*
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* Copyright IBM Corp. 2017
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*/
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#include <linux/console.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <asm/sclp.h>
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static void sclp_early_write(struct console *con, const char *s, unsigned int len)
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{
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__sclp_print_early(s, len);
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}
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static struct console sclp_early_console = {
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.name = "earlysclp",
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.write = sclp_early_write,
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.flags = CON_PRINTBUFFER | CON_BOOT,
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.index = -1,
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};
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static int __init setup_early_printk(char *buf)
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{
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if (early_console)
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return 0;
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/* Accept only "earlyprintk" and "earlyprintk=sclp" */
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if (buf && strncmp(buf, "sclp", 4))
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return 0;
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if (!sclp.has_linemode && !sclp.has_vt220)
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return 0;
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early_console = &sclp_early_console;
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register_console(early_console);
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return 0;
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}
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early_param("earlyprintk", setup_early_printk);
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