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
66 static long event_log_level = ESAS2R_LOG_DFLT;
67
68 module_param(event_log_level, long, S_IRUGO | S_IRUSR);
69 MODULE_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. */
73 static char event_buffer[EVENT_LOG_BUFF_SIZE];
74
75 /* A lock to protect the shared buffer used for formatting messages. */
76 static 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 */
85 static 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 */
116 static 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 memset(buffer, 0, buflen);
134
135 /*
136 * format the level onto the beginning of the string and do
137 * some pointer arithmetic to move the pointer to the point
138 * where the actual message can be inserted.
139 */
140
141 if (dev == NULL) {
142 snprintf(buffer, buflen, fmt_nodev, slevel,
143 ESAS2R_DRVR_NAME);
144 } else {
145 snprintf(buffer, buflen, fmt_dev, slevel,
146 ESAS2R_DRVR_NAME,
147 (dev->driver ? dev->driver->name : "unknown"),
148 (dev->bus ? dev->bus->name : "unknown"),
149 dev_name(dev));
150 }
151
152 buffer += strlen(event_buffer);
153 buflen -= strlen(event_buffer);
154
155 retval = vsnprintf(buffer, buflen, format, args);
156 if (retval < 0) {
157 spin_unlock_irqrestore(&event_buffer_lock, flags);
158 return -1;
159 }
160
161 /*
162 * Put a line break at the end of the formatted string so that
163 * we don't wind up with run-on messages.
164 */
165 printk("%s\n", event_buffer);
166
167 spin_unlock_irqrestore(&event_buffer_lock, flags);
168 }
169
170 return 0;
171 }
172
173 /**
174 * formats and logs a message to the system log.
175 *
176 * @param [in] level the event level of the message
177 * @param [in] format the formating string for the message
178 * @param [in] ... the substitution arguments to the formatting string
179 *
180 * @return 0 on success, or -1 if an error occurred.
181 */
182 int esas2r_log(const long level, const char *format, ...)
183 {
184 int retval = 0;
185 va_list args;
186
187 va_start(args, format);
188
189 retval = esas2r_log_master(level, NULL, format, args);
190
191 va_end(args);
192
193 return retval;
194 }
195
196 /**
197 * formats and logs a message to the system log. this message will include
198 * device information.
199 *
200 * @param [in] level the event level of the message
201 * @param [in] dev the device information
202 * @param [in] format the formatting string for the message
203 * @param [in] ... the substitution arguments to the formatting string
204 *
205 * @return 0 on success, or -1 if an error occurred.
206 */
207 int esas2r_log_dev(const long level,
208 const struct device *dev,
209 const char *format,
210 ...)
211 {
212 int retval = 0;
213 va_list args;
214
215 va_start(args, format);
216
217 retval = esas2r_log_master(level, dev, format, args);
218
219 va_end(args);
220
221 return retval;
222 }
223
224 /**
225 * formats and logs a message to the system log. this message will include
226 * device information.
227 *
228 * @param [in] level the event level of the message
229 * @param [in] buf
230 * @param [in] len
231 *
232 * @return 0 on success, or -1 if an error occurred.
233 */
234 int esas2r_log_hexdump(const long level,
235 const void *buf,
236 size_t len)
237 {
238 if (level <= event_log_level) {
239 print_hex_dump(translate_esas2r_event_level_to_kernel(level),
240 "", DUMP_PREFIX_OFFSET, 16, 1, buf,
241 len, true);
242 }
243
244 return 1;
245 }