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/*
* Copyright 2003 Digi International (www.digi.com)
* Scott H Kilau <Scott_Kilau at digi dot com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*
* NOTE TO LINUX KERNEL HACKERS: DO NOT REFORMAT THIS CODE!
*
* This is shared code between Digi's CVS archive and the
* Linux Kernel sources.
* Changing the source just for reformatting needlessly breaks
* our CVS diff history.
*
* Send any bug fixes/changes to: Eng.Linux at digi dot com.
* Thank you.
*
*/
/* $Id: dgap_trace.c,v 1.1 2009/10/23 14:01:57 markh Exp $ */
#include <linux/kernel.h>
#include <linux/sched.h> /* For jiffies, task states */
#include <linux/interrupt.h> /* For tasklet and interrupt structs/defines */
#include <linux/vmalloc.h>
#include "dgap_driver.h"
#include "dgap_trace.h"
#define TRC_TO_CONSOLE 1
/* file level globals */
static char *dgap_trcbuf; /* the ringbuffer */
#if defined(TRC_TO_KMEM)
static int dgap_trcbufi = 0; /* index of the tilde at the end of */
#endif
extern int dgap_trcbuf_size; /* size of the ringbuffer */
#if defined(TRC_TO_KMEM)
static DEFINE_SPINLOCK(dgap_tracef_lock);
#endif
#if 0
#if !defined(TRC_TO_KMEM) && !defined(TRC_TO_CONSOLE)
void dgap_tracef(const char *fmt, ...)
{
return;
}
#else /* !defined(TRC_TO_KMEM) && !defined(TRC_TO_CONSOLE) */
void dgap_tracef(const char *fmt, ...)
{
va_list ap;
char buf[TRC_MAXMSG+1];
size_t lenbuf;
int i;
static int failed = FALSE;
# if defined(TRC_TO_KMEM)
unsigned long flags;
#endif
if(failed)
return;
# if defined(TRC_TO_KMEM)
DGAP_LOCK(dgap_tracef_lock, flags);
#endif
/* Format buf using fmt and arguments contained in ap. */
va_start(ap, fmt);
i = vsprintf(buf, fmt, ap);
va_end(ap);
lenbuf = strlen(buf);
# if defined(TRC_TO_KMEM)
{
static int initd=0;
/*
* Now, in addition to (or instead of) printing this stuff out
* (which is a buffered operation), also tuck it away into a
* corner of memory which can be examined post-crash in kdb.
*/
if (!initd) {
dgap_trcbuf = (char *) vmalloc(dgap_trcbuf_size);
if(!dgap_trcbuf) {
failed = TRUE;
printk("dgap: tracing init failed!\n");
return;
}
memset(dgap_trcbuf, '\0', dgap_trcbuf_size);
dgap_trcbufi = 0;
initd++;
printk("dgap: tracing enabled - " TRC_DTRC
" 0x%lx 0x%x\n",
(unsigned long)dgap_trcbuf,
dgap_trcbuf_size);
}
# if defined(TRC_ON_OVERFLOW_WRAP_AROUND)
/*
* This is the less CPU-intensive way to do things. We simply
* wrap around before we fall off the end of the buffer. A
* tilde (~) demarcates the current end of the trace.
*
* This method should be used if you are concerned about race
* conditions as it is less likely to affect the timing of
* things.
*/
if (dgap_trcbufi + lenbuf >= dgap_trcbuf_size) {
/* We are wrapping, so wipe out the last tilde. */
dgap_trcbuf[dgap_trcbufi] = '\0';
/* put the new string at the beginning of the buffer */
dgap_trcbufi = 0;
}
strcpy(&dgap_trcbuf[dgap_trcbufi], buf);
dgap_trcbufi += lenbuf;
dgap_trcbuf[dgap_trcbufi] = '~';
# elif defined(TRC_ON_OVERFLOW_SHIFT_BUFFER)
/*
* This is the more CPU-intensive way to do things. If we
* venture into the last 1/8 of the buffer, we shift the
* last 7/8 of the buffer forward, wiping out the first 1/8.
* Advantage: No wrap-around, only truncation from the
* beginning.
*
* This method should not be used if you are concerned about
* timing changes affecting the behaviour of the driver (ie,
* race conditions).
*/
strcpy(&dgap_trcbuf[dgap_trcbufi], buf);
dgap_trcbufi += lenbuf;
dgap_trcbuf[dgap_trcbufi] = '~';
dgap_trcbuf[dgap_trcbufi+1] = '\0';
/* If we're near the end of the trace buffer... */
if (dgap_trcbufi > (dgap_trcbuf_size/8)*7) {
/* Wipe out the first eighth to make some more room. */
strcpy(dgap_trcbuf, &dgap_trcbuf[dgap_trcbuf_size/8]);
dgap_trcbufi = strlen(dgap_trcbuf)-1;
/* Plop overflow message at the top of the buffer. */
bcopy(TRC_OVERFLOW, dgap_trcbuf, strlen(TRC_OVERFLOW));
}
# else
# error "TRC_ON_OVERFLOW_WRAP_AROUND or TRC_ON_OVERFLOW_SHIFT_BUFFER?"
# endif
}
DGAP_UNLOCK(dgap_tracef_lock, flags);
# endif /* defined(TRC_TO_KMEM) */
}
#endif /* !defined(TRC_TO_KMEM) && !defined(TRC_TO_CONSOLE) */
#endif
/*
* dgap_tracer_free()
*
*
*/
void dgap_tracer_free(void)
{
if(dgap_trcbuf)
vfree(dgap_trcbuf);
}
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