36de48de85
This is an optimised implementation of early printk() for the DECstation. After the recent conversion to a MIPS-specific generic routine using a character-by-character output the performance dropped significantly. This change reverts to the previous speed -- even at 9600 bps of the serial console the difference is visible with a naked eye; I presume for a framebuffer it is even worse (it may depend on exactly which one is used though). Additionally the change includes a fix for a problem that the old implementation had -- the format used would not actually limit the length of the string output. This new implementation uses a local buffer to deal with it -- even with this additional copying it is much faster than the generic function. Plus this driver is registered much earlier than the generic one, allowing one to see critical messages, such as one about an incorrect CPU setting used, that are produced beforehand. :-) Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
47 lines
1 KiB
C
47 lines
1 KiB
C
/*
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* arch/mips/dec/prom/console.c
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*
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* DECstation PROM-based early console support.
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*
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* Copyright (C) 2004, 2007 Maciej W. Rozycki
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/console.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <asm/dec/prom.h>
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static void __init prom_console_write(struct console *con, const char *s,
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unsigned int c)
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{
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char buf[81];
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unsigned int chunk = sizeof(buf) - 1;
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while (c > 0) {
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if (chunk > c)
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chunk = c;
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memcpy(buf, s, chunk);
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buf[chunk] = '\0';
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prom_printf("%s", buf);
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s += chunk;
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c -= chunk;
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}
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}
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static struct console promcons __initdata = {
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.name = "prom",
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.write = prom_console_write,
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.flags = CON_BOOT | CON_PRINTBUFFER,
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.index = -1,
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};
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void __init register_prom_console(void)
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{
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register_console(&promcons);
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}
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