/*
* Linux WiMAX
* Collection of tools to manage debug operations.
*
*
* Copyright (C) 2005-2007 Intel Corporation
* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
*
* Don't #include this file directly, read on!
*
*
* EXECUTING DEBUGGING ACTIONS OR NOT
*
* The main thing this framework provides is decission power to take a
* debug action (like printing a message) if the current debug level
* allows it.
*
* The decission power is at two levels: at compile-time (what does
* not make it is compiled out) and at run-time. The run-time
* selection is done per-submodule (as they are declared by the user
* of the framework).
*
* A call to d_test(L) (L being the target debug level) returns true
* if the action should be taken because the current debug levels
* allow it (both compile and run time).
*
* It follows that a call to d_test() that can be determined to be
* always false at compile time will get the code depending on it
* compiled out by optimization.
*
*
* DEBUG LEVELS
*
* It is up to the caller to define how much a debugging level is.
*
* Convention sets 0 as "no debug" (so an action marked as debug level 0
* will always be taken). The increasing debug levels are used for
* increased verbosity.
*
*
* USAGE
*
* Group the code in modules and submodules inside each module [which
* in most cases maps to Linux modules and .c files that compose
* those].
*
*
* For each module, there is:
*
* - a MODULENAME (single word, legal C identifier)
*
* - a debug-levels.h header file that declares the list of
* submodules and that is included by all .c files that use
* the debugging tools. The file name can be anything.
*
* - some (optional) .c code to manipulate the runtime debug levels
* through debugfs.
*
* The debug-levels.h file would look like:
*
* #ifndef __debug_levels__h__
* #define __debug_levels__h__
*
* #define D_MODULENAME modulename
* #define D_MASTER 10
*
* #include <linux/wimax/debug.h>
*
* enum d_module {
* D_SUBMODULE_DECLARE(submodule_1),
* D_SUBMODULE_DECLARE(submodule_2),
* ...
* D_SUBMODULE_DECLARE(submodule_N)
* };
*
* #endif
*
* D_MASTER is the maximum compile-time debug level; any debug actions
* above this will be out. D_MODULENAME is the module name (legal C
* identifier), which has to be unique for each module (to avoid
* namespace collisions during linkage). Note those #defines need to
* be done before #including debug.h
*
* We declare N different submodules whose debug level can be
* independently controlled during runtime.
*
* In a .c file of the module (and only in one of them), define the
* following code:
*
* struct d_level D_LEVEL[] = {
* D_SUBMODULE_DEFINE(submodule_1),
* D_SUBMODULE_DEFINE(submodule_2),
* ...
* D_SUBMODULE_DEFINE(submodule_N),
* };
* size_t D_LEVEL_SIZE = ARRAY_SIZE(D_LEVEL);
*
* Externs for d_level_MODULENAME and d_level_size_MODULENAME are used
* and declared in this file using the D_LEVEL and D_LEVEL_SIZE macros
* #defined also in this file.
*
* To manipulate from user space the levels, create a debugfs dentry
* and then register each submodule with:
*
* result = d_level_register_debugfs("PREFIX_", submodule_X, parent);
* if (result < 0)
* goto error;
*
* Where PREFIX_ is a name of your chosing. This will create debugfs
* file with a single numeric value that can be use to tweak it. To
* remove the entires, just use debugfs_remove_recursive() on 'parent'.
*
* NOTE: remember that even if this will show attached to some
* particular instance of a device, the settings are *global*.
*
*
* On each submodule (for example, .c files), the debug infrastructure
* should be included like this:
*
* #define D_SUBMODULE submodule_x // matches one in debug-levels.h
* #include "debug-levels.h"
*
* after #including all your include files.
*
*
* Now you can use the d_*() macros below [d_test(), d_fnstart(),
* d_fnend(), d_printf(), d_dump()].
*
* If their debug level is greater than D_MASTER, they will be
* compiled out.
*
* If their debug level is lower or equal than D_MASTER but greater
* than the current debug level of their submodule, they'll be
* ignored.
*
* Otherwise, the action will be performed.
*/
#ifndef __debug__h__
#define __debug__h__
#include <linux/types.h>
#include <linux/device.h>
/* Backend stuff */
/*
* Debug backend: generate a message header from a 'struct device'
*
* @head: buffer where to place the header
* @head_size: length of @head
* @dev: pointer to device used to generate a header from. If NULL,
* an empty ("") header is generated.
*/
static inline
void __d_head(char *head, size_t head_size,
struct device *dev)
{
if (dev == NULL)
head[0] = 0;
else if ((unsigned long)dev < 4096) {
printk(KERN_ERR "E: Corrupt dev %p\n", dev);
WARN_ON(1);
} else
snprintf(head, head_size, "%s %s: ",
dev_driver_string(dev), dev_name(dev));
}
/*
* Debug backend: log some message if debugging is enabled
*
* @l: intended debug level
* @tag: tag to prefix the message with
* @dev: 'struct device' associated to this message
* @f: printf-like format and arguments
*
* Note this is optimized out if it doesn't pass the compile-time
* check; however, it is *always* compiled. This is useful to make
* sure the printf-like formats and variables are always checked and
* they don't get bit rot if you have all the debugging disabled.
*/
#define _d_printf(l, tag, dev, f, a...) \
do { \
char head[64]; \
if (!d_test(l)) \
break; \
__d_head(head, sizeof(head), dev); \
printk(KERN_ERR "%s%s%s: " f, head, __func__, tag, ##a); \
} while (0)
/*
* CPP sintatic sugar to generate A_B like symbol names when one of
* the arguments is a a preprocessor #define.
*/
#define __D_PASTE__(varname, modulename) varname##_##modulename
#define __D_PASTE(varname, modulename) (__D_PASTE__(varname, modulename))
#define _D_SUBMODULE_INDEX(_name) (D_SUBMODULE_DECLARE(_name))
/*
* Store a submodule's runtime debug level and name
*/
struct d_level {
u8 level;
const char *name;
};
/*
* List of available submodules and their debug levels
*
* We call them d_level_MODULENAME and d_level_size_MODULENAME; the
* macros D_LEVEL and D_LEVEL_SIZE contain the name already for
* convenience.
*
* This array and the size are defined on some .c file that is part of
* the current module.
*/
#define D_LEVEL __D_PASTE(d_level, D_MODULENAME)
#define D_LEVEL_SIZE __D_PASTE(d_level_size, D_MODULENAME)
extern struct d_level D_LEVEL[];
extern size_t D_LEVEL_SIZE;
/*
* Frontend stuff
*
*
* Stuff you need to declare prior to using the actual "debug" actions
* (defined below).
*/
#ifndef D_MODULENAME
#error D_MODULENAME is not defined in your debug-levels.h file
/**
* D_MODULE - Name of the current module
*
* #define in your module's debug-levels.h, making sure it is
* unique. This has to be a legal C identifier.
*/
#define D_MODULENAME undefined_modulename
#endif
#ifndef D_MASTER
#warning D_MASTER not defined, but debug.h included! [see docs]
/**
* D_MASTER - Compile time maximum debug level
*
* #define in your debug-levels.h file to the maximum debug level the
* runtime code will be allowed to have. This allows you to provide a
* main knob.
*
* Anything above that level will be optimized out of the compile.
*
* Defaults to zero (no debug code compiled in).
*
* Maximum one definition per module (at the debug-levels.h file).
*/
#define D_MASTER 0
#endif
#ifndef D_SUBMODULE
#error D_SUBMODULE not defined, but debug.h included! [see docs]
/**
* D_SUBMODULE - Name of the current submodule
*
* #define in your submodule .c file before #including debug-levels.h
* to the name of the current submodule as previously declared and
* defined with D_SUBMODULE_DECLARE() (in your module's
* debug-levels.h) and D_SUBMODULE_DEFINE().
*
* This is used to provide runtime-control over the debug levels.
*
* Maximum one per .c file! Can be shared among different .c files
* (meaning they belong to the same submodule categorization).
*/
#define D_SUBMODULE undefined_module
#endif
/**
* D_SUBMODULE_DECLARE - Declare a submodule for runtime debug level control
*
* @_name: name of the submodule, restricted to the chars that make up a
* valid C identifier ([a-zA-Z0-9_]).
*
* Declare in the module's debug-levels.h header file as:
*
* enum d_module {
* D_SUBMODULE_DECLARE(submodule_1),
* D_SUBMODULE_DECLARE(submodule_2),
* D_SUBMODULE_DECLARE(submodule_3),
* };
*
* Some corresponding .c file needs to have a matching
* D_SUBMODULE_DEFINE().
*/
#define D_SUBMODULE_DECLARE(_name) __D_SUBMODULE_##_name
/**
* D_SUBMODULE_DEFINE - Define a submodule for runtime debug level control
*
* @_name: name of the submodule, restricted to the chars that make up a
* valid C identifier ([a-zA-Z0-9_]).
*
* Use once per module (in some .c file) as:
*
* static
* struct d_level d_level_SUBMODULENAME[] = {
* D_SUBMODULE_DEFINE(submodule_1),
* D_SUBMODULE_DEFINE(submodule_2),
* D_SUBMODULE_DEFINE(submodule_3),
* };
* size_t d_level_size_SUBDMODULENAME = ARRAY_SIZE(d_level_SUBDMODULENAME);
*
* Matching D_SUBMODULE_DECLARE()s have to be present in a
* debug-levels.h header file.
*/
#define D_SUBMODULE_DEFINE(_name) \
[__D_SUBMODULE_##_name] = { \
.level = 0, \
.name = #_name \
}
/* The actual "debug" operations */
/**
* d_test - Returns true if debugging should be enabled
*
* @l: intended debug level (unsigned)
*
* If the master debug switch is enabled and the current settings are
* higher or equal to the requested level, then debugging
* output/actions should be enabled.
*
* NOTE:
*
* This needs to be coded so that it can be evaluated in compile
* time; this is why the ugly BUG_ON() is placed in there, so the
* D_MASTER evaluation compiles all out if it is compile-time false.
*/
#define d_test(l) \
({ \
unsigned __l = l; /* type enforcer */ \
(D_MASTER) >= __l \
&& ({ \
BUG_ON(_D_SUBMODULE_INDEX(D_SUBMODULE) >= D_LEVEL_SIZE);\
D_LEVEL[_D_SUBMODULE_INDEX(D_SUBMODULE)].level >= __l; \
}); \
})
/**
* d_fnstart - log message at function start if debugging enabled
*
* @l: intended debug level
* @_dev: 'struct device' pointer, NULL if none (for context)
* @f: printf-like format and arguments
*/
#define d_fnstart(l, _dev, f, a...) _d_printf(l, " FNSTART", _dev, f, ## a)
/**
* d_fnend - log message at function end if debugging enabled
*
* @l: intended debug level
* @_dev: 'struct device' pointer, NULL if none (for context)
* @f: printf-like format and arguments
*/
#define d_fnend(l, _dev, f, a...) _d_printf(l, " FNEND", _dev, f, ## a)
/**
* d_printf - log message if debugging enabled
*
* @l: intended debug level
* @_dev: 'struct device' pointer, NULL if none (for context)
* @f: printf-like format and arguments
*/
#define d_printf(l, _dev, f, a...) _d_printf(l, "", _dev, f, ## a)
/**
* d_dump - log buffer hex dump if debugging enabled
*
* @l: intended debug level
* @_dev: 'struct device' pointer, NULL if none (for context)
* @f: printf-like format and arguments
*/
#define d_dump(l, dev, ptr, size) \
do { \
char head[64]; \
if (!d_test(l)) \
break; \
__d_head(head, sizeof(head), dev); \
print_hex_dump(KERN_ERR, head, 0, 16, 1, \
((void *) ptr), (size), 0); \
} while (0)
/**
* Export a submodule's debug level over debugfs as PREFIXSUBMODULE
*
* @prefix: string to prefix the name with
* @submodule: name of submodule (not a string, just the name)
* @dentry: debugfs parent dentry
*
* Returns: 0 if ok, < 0 errno on error.
*
* For removing, just use debugfs_remove_recursive() on the parent.
*/
#define d_level_register_debugfs(prefix, name, parent) \
({ \
int rc; \
struct dentry *fd; \
struct dentry *verify_parent_type = parent; \
fd = debugfs_create_u8( \
prefix #name, 0600, verify_parent_type, \
&(D_LEVEL[__D_SUBMODULE_ ## name].level)); \
rc = PTR_ERR(fd); \
if (IS_ERR(fd) && rc != -ENODEV) \
printk(KERN_ERR "%s: Can't create debugfs entry %s: " \
"%d\n", __func__, prefix #name, rc); \
else \
rc = 0; \
rc; \
})
#endif /* #ifndef __debug__h__ */
