2992abe047
Say, a driver wants to have multiple console devices to pick from, you
would normally write down something like this:
CONSOLE_DRIVER(dev1);
CONSOLE_DRIVER(dev2);
Unfortunately, this means that you have to declare 10 cn routines,
instead of 5. It also isn't possible to initialize cn_arg on beforehand.
I noticed this restriction when I was implementing some of the console
bits for my vt(4) driver in my newcons branch. I have a single set of cn
routines (termcn_*) which are shared by all vt(4) console devices.
In order to solve this, I'm adding a separate consdev_ops structure,
which contains all the function pointers. This structure is referenced
through consdev's cn_ops field.
While there, I'm removing CONS_DRIVER() and cn_checkc, which have been
deprecated for years. They weren't used throughout the source, until the
Xen console driver showed up. CONSOLE_DRIVER() has been changed to do
the right thing. It now declares both the consdev and consdev_ops
structure and ties them together. In other words: this change doesn't
change the KPI for drivers that used the regular way of declaring
console devices.
If drivers want to use multiple console devices, they can do this as
follows:
static const struct consdev_ops mydriver_cnops = {
.cn_probe = mydriver_cnprobe,
...
};
static struct mydriver_softc cons0_softc = {
...
};
CONSOLE_DEVICE(cons0, mydriver_cnops, &cons0_softc);
static struct mydriver_softc cons1_softc = {
...
};
CONSOLE_DEVICE(cons1, mydriver_cnops, &cons1_softc);
Obtained from: //depot/user/ed/newcons/...
123 lines
4.3 KiB
C
123 lines
4.3 KiB
C
/*-
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* Copyright (c) 1988 University of Utah.
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* Copyright (c) 1991 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the Systems Programming Group of the University of Utah Computer
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* Science Department.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)cons.h 7.2 (Berkeley) 5/9/91
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* $FreeBSD$
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*/
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#ifndef _MACHINE_CONS_H_
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#define _MACHINE_CONS_H_
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struct consdev;
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struct tty;
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typedef void cn_probe_t(struct consdev *);
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typedef void cn_init_t(struct consdev *);
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typedef void cn_term_t(struct consdev *);
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typedef int cn_getc_t(struct consdev *);
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typedef void cn_putc_t(struct consdev *, int);
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struct consdev_ops {
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cn_probe_t *cn_probe;
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/* probe hardware and fill in consdev info */
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cn_init_t *cn_init;
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/* turn on as console */
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cn_term_t *cn_term;
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/* turn off as console */
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cn_getc_t *cn_getc;
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/* kernel getchar interface */
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cn_putc_t *cn_putc;
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/* kernel putchar interface */
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};
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struct consdev {
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const struct consdev_ops *cn_ops;
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/* console device operations. */
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short cn_pri; /* pecking order; the higher the better */
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void *cn_arg; /* drivers method argument */
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int cn_flags; /* capabilities of this console */
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char cn_name[SPECNAMELEN + 1]; /* console (device) name */
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};
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/* values for cn_pri - reflect our policy for console selection */
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#define CN_DEAD 0 /* device doesn't exist */
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#define CN_LOW 1 /* device is a last restort only */
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#define CN_NORMAL 2 /* device exists but is nothing special */
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#define CN_INTERNAL 3 /* "internal" bit-mapped display */
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#define CN_REMOTE 4 /* serial interface with remote bit set */
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/* Values for cn_flags. */
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#define CN_FLAG_NODEBUG 0x00000001 /* Not supported with debugger. */
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#define CN_FLAG_NOAVAIL 0x00000002 /* Temporarily not available. */
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#ifdef _KERNEL
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extern struct msgbuf consmsgbuf; /* Message buffer for constty. */
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extern struct tty *constty; /* Temporary virtual console. */
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#define CONSOLE_DEVICE(name, ops, arg) \
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static struct consdev name = { \
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.cn_ops = &ops, \
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.cn_arg = (arg), \
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}; \
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DATA_SET(cons_set, name)
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#define CONSOLE_DRIVER(name) \
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static const struct consdev_ops name##_consdev_ops = { \
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.cn_probe = name##_cnprobe, \
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.cn_init = name##_cninit, \
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.cn_term = name##_cnterm, \
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.cn_getc = name##_cngetc, \
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.cn_putc = name##_cnputc, \
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}; \
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CONSOLE_DEVICE(name##_consdev, name##_consdev_ops, NULL)
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/* Other kernel entry points. */
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void cninit(void);
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void cninit_finish(void);
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int cnadd(struct consdev *);
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void cnavailable(struct consdev *, int);
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void cnremove(struct consdev *);
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void cnselect(struct consdev *);
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int cncheckc(void);
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int cngetc(void);
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void cnputc(int);
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void cnputs(char *);
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int cnunavailable(void);
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void constty_set(struct tty *tp);
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void constty_clear(void);
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#endif /* _KERNEL */
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#endif /* !_MACHINE_CONS_H_ */
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