diff options
Diffstat (limited to 'drivers/staging/dgap/dgap_trace.c')
| -rw-r--r-- | drivers/staging/dgap/dgap_trace.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/drivers/staging/dgap/dgap_trace.c b/drivers/staging/dgap/dgap_trace.c new file mode 100644 index 000000000000..0f9a9569ea27 --- /dev/null +++ b/drivers/staging/dgap/dgap_trace.c @@ -0,0 +1,185 @@ +/* + * 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" + +#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); +} |