1/*
2 *  linux/drivers/scsi/esas2r/esas2r_log.c
3 *      For use with ATTO ExpressSAS R6xx SAS/SATA RAID controllers
4 *
5 *  Copyright (c) 2001-2013 ATTO Technology, Inc.
6 *  (mailto:linuxdrivers@attotech.com)
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version 2
11 * of the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 *
18 * NO WARRANTY
19 * THE PROGRAM IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OR
20 * CONDITIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED INCLUDING, WITHOUT
21 * LIMITATION, ANY WARRANTIES OR CONDITIONS OF TITLE, NON-INFRINGEMENT,
22 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Each Recipient is
23 * solely responsible for determining the appropriateness of using and
24 * distributing the Program and assumes all risks associated with its
25 * exercise of rights under this Agreement, including but not limited to
26 * the risks and costs of program errors, damage to or loss of data,
27 * programs or equipment, and unavailability or interruption of operations.
28 *
29 * DISCLAIMER OF LIABILITY
30 * NEITHER RECIPIENT NOR ANY CONTRIBUTORS SHALL HAVE ANY LIABILITY FOR ANY
31 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING WITHOUT LIMITATION LOST PROFITS), HOWEVER CAUSED AND
33 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
34 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
35 * USE OR DISTRIBUTION OF THE PROGRAM OR THE EXERCISE OF ANY RIGHTS GRANTED
36 * HEREUNDER, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES
37 *
38 * You should have received a copy of the GNU General Public License
39 * along with this program; if not, write to the Free Software
40 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
41 * USA.
42 */
43
44#include "esas2r.h"
45
46/*
47 * this module within the driver is tasked with providing logging functionality.
48 * the event_log_level module parameter controls the level of messages that are
49 * written to the system log.  the default level of messages that are written
50 * are critical and warning messages.  if other types of messages are desired,
51 * one simply needs to load the module with the correct value for the
52 * event_log_level module parameter.  for example:
53 *
54 * insmod <module> event_log_level=1
55 *
56 * will load the module and only critical events will be written by this module
57 * to the system log.  if critical, warning, and information-level messages are
58 * desired, the correct value for the event_log_level module parameter
59 * would be as follows:
60 *
61 * insmod <module> event_log_level=3
62 */
63
64#define EVENT_LOG_BUFF_SIZE 1024
65
66static long event_log_level = ESAS2R_LOG_DFLT;
67
68module_param(event_log_level, long, S_IRUGO | S_IRUSR);
69MODULE_PARM_DESC(event_log_level,
70		 "Specifies the level of events to report to the system log.  Critical and warning level events are logged by default.");
71
72/* A shared buffer to use for formatting messages. */
73static char event_buffer[EVENT_LOG_BUFF_SIZE];
74
75/* A lock to protect the shared buffer used for formatting messages. */
76static DEFINE_SPINLOCK(event_buffer_lock);
77
78/**
79 * translates an esas2r-defined logging event level to a kernel logging level.
80 *
81 * @param [in] level the esas2r-defined logging event level to translate
82 *
83 * @return the corresponding kernel logging level.
84 */
85static const char *translate_esas2r_event_level_to_kernel(const long level)
86{
87	switch (level) {
88	case ESAS2R_LOG_CRIT:
89		return KERN_CRIT;
90
91	case ESAS2R_LOG_WARN:
92		return KERN_WARNING;
93
94	case ESAS2R_LOG_INFO:
95		return KERN_INFO;
96
97	case ESAS2R_LOG_DEBG:
98	case ESAS2R_LOG_TRCE:
99	default:
100		return KERN_DEBUG;
101	}
102}
103
104/**
105 * the master logging function.  this function will format the message as
106 * outlined by the formatting string, the input device information and the
107 * substitution arguments and output the resulting string to the system log.
108 *
109 * @param [in] level  the event log level of the message
110 * @param [in] dev    the device information
111 * @param [in] format the formatting string for the message
112 * @param [in] args   the substition arguments to the formatting string
113 *
114 * @return 0 on success, or -1 if an error occurred.
115 */
116static int esas2r_log_master(const long level,
117			     const struct device *dev,
118			     const char *format,
119			     va_list args)
120{
121	if (level <= event_log_level) {
122		unsigned long flags = 0;
123		int retval = 0;
124		char *buffer = event_buffer;
125		size_t buflen = EVENT_LOG_BUFF_SIZE;
126		const char *fmt_nodev = "%s%s: ";
127		const char *fmt_dev = "%s%s [%s, %s, %s]";
128		const char *slevel =
129			translate_esas2r_event_level_to_kernel(level);
130
131		spin_lock_irqsave(&event_buffer_lock, flags);
132
133		if (buffer == NULL) {
134			spin_unlock_irqrestore(&event_buffer_lock, flags);
135			return -1;
136		}
137
138		memset(buffer, 0, buflen);
139
140		/*
141		 * format the level onto the beginning of the string and do
142		 * some pointer arithmetic to move the pointer to the point
143		 * where the actual message can be inserted.
144		 */
145
146		if (dev == NULL) {
147			snprintf(buffer, buflen, fmt_nodev, slevel,
148				 ESAS2R_DRVR_NAME);
149		} else {
150			snprintf(buffer, buflen, fmt_dev, slevel,
151				 ESAS2R_DRVR_NAME,
152				 (dev->driver ? dev->driver->name : "unknown"),
153				 (dev->bus ? dev->bus->name : "unknown"),
154				 dev_name(dev));
155		}
156
157		buffer += strlen(event_buffer);
158		buflen -= strlen(event_buffer);
159
160		retval = vsnprintf(buffer, buflen, format, args);
161		if (retval < 0) {
162			spin_unlock_irqrestore(&event_buffer_lock, flags);
163			return -1;
164		}
165
166		/*
167		 * Put a line break at the end of the formatted string so that
168		 * we don't wind up with run-on messages.
169		 */
170		printk("%s\n", event_buffer);
171
172		spin_unlock_irqrestore(&event_buffer_lock, flags);
173	}
174
175	return 0;
176}
177
178/**
179 * formats and logs a message to the system log.
180 *
181 * @param [in] level  the event level of the message
182 * @param [in] format the formating string for the message
183 * @param [in] ...    the substitution arguments to the formatting string
184 *
185 * @return 0 on success, or -1 if an error occurred.
186 */
187int esas2r_log(const long level, const char *format, ...)
188{
189	int retval = 0;
190	va_list args;
191
192	va_start(args, format);
193
194	retval = esas2r_log_master(level, NULL, format, args);
195
196	va_end(args);
197
198	return retval;
199}
200
201/**
202 * formats and logs a message to the system log.  this message will include
203 * device information.
204 *
205 * @param [in] level   the event level of the message
206 * @param [in] dev     the device information
207 * @param [in] format  the formatting string for the message
208 * @param [in] ...     the substitution arguments to the formatting string
209 *
210 * @return 0 on success, or -1 if an error occurred.
211 */
212int esas2r_log_dev(const long level,
213		   const struct device *dev,
214		   const char *format,
215		   ...)
216{
217	int retval = 0;
218	va_list args;
219
220	va_start(args, format);
221
222	retval = esas2r_log_master(level, dev, format, args);
223
224	va_end(args);
225
226	return retval;
227}
228
229/**
230 * formats and logs a message to the system log.  this message will include
231 * device information.
232 *
233 * @param [in] level   the event level of the message
234 * @param [in] buf
235 * @param [in] len
236 *
237 * @return 0 on success, or -1 if an error occurred.
238 */
239int esas2r_log_hexdump(const long level,
240		       const void *buf,
241		       size_t len)
242{
243	if (level <= event_log_level) {
244		print_hex_dump(translate_esas2r_event_level_to_kernel(level),
245			       "", DUMP_PREFIX_OFFSET, 16, 1, buf,
246			       len, true);
247	}
248
249	return 1;
250}
251