blob: cbcb0121c84de5557852e641bcff6248881480e2 [file] [log] [blame]
Hiral Patel4d7007b2013-02-12 17:01:02 -08001/*
2 * Copyright 2012 Cisco Systems, Inc. All rights reserved.
3 *
4 * This program is free software; you may redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 2 of the License.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
9 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
10 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
11 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
12 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
13 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
14 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
15 * SOFTWARE.
16 */
17
18#include <linux/module.h>
19#include <linux/errno.h>
20#include <linux/debugfs.h>
21#include "fnic.h"
22
23static struct dentry *fnic_trace_debugfs_root;
24static struct dentry *fnic_trace_debugfs_file;
25static struct dentry *fnic_trace_enable;
26
27/*
28 * fnic_trace_ctrl_open - Open the trace_enable file
29 * @inode: The inode pointer.
30 * @file: The file pointer to attach the trace enable/disable flag.
31 *
32 * Description:
33 * This routine opens a debugsfs file trace_enable.
34 *
35 * Returns:
36 * This function returns zero if successful.
37 */
38static int fnic_trace_ctrl_open(struct inode *inode, struct file *filp)
39{
40 filp->private_data = inode->i_private;
41 return 0;
42}
43
44/*
45 * fnic_trace_ctrl_read - Read a trace_enable debugfs file
46 * @filp: The file pointer to read from.
47 * @ubuf: The buffer to copy the data to.
48 * @cnt: The number of bytes to read.
49 * @ppos: The position in the file to start reading from.
50 *
51 * Description:
52 * This routine reads value of variable fnic_tracing_enabled
53 * and stores into local @buf. It will start reading file at @ppos and
54 * copy up to @cnt of data to @ubuf from @buf.
55 *
56 * Returns:
57 * This function returns the amount of data that was read.
58 */
59static ssize_t fnic_trace_ctrl_read(struct file *filp,
60 char __user *ubuf,
61 size_t cnt, loff_t *ppos)
62{
63 char buf[64];
64 int len;
65 len = sprintf(buf, "%u\n", fnic_tracing_enabled);
66
67 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
68}
69
70/*
71 * fnic_trace_ctrl_write - Write to trace_enable debugfs file
72 * @filp: The file pointer to write from.
73 * @ubuf: The buffer to copy the data from.
74 * @cnt: The number of bytes to write.
75 * @ppos: The position in the file to start writing to.
76 *
77 * Description:
78 * This routine writes data from user buffer @ubuf to buffer @buf and
79 * sets fnic_tracing_enabled value as per user input.
80 *
81 * Returns:
82 * This function returns the amount of data that was written.
83 */
84static ssize_t fnic_trace_ctrl_write(struct file *filp,
85 const char __user *ubuf,
86 size_t cnt, loff_t *ppos)
87{
88 char buf[64];
89 unsigned long val;
90 int ret;
91
92 if (cnt >= sizeof(buf))
93 return -EINVAL;
94
95 if (copy_from_user(&buf, ubuf, cnt))
96 return -EFAULT;
97
98 buf[cnt] = 0;
99
100 ret = kstrtoul(buf, 10, &val);
101 if (ret < 0)
102 return ret;
103
104 fnic_tracing_enabled = val;
105 (*ppos)++;
106
107 return cnt;
108}
109
110/*
111 * fnic_trace_debugfs_open - Open the fnic trace log
112 * @inode: The inode pointer
113 * @file: The file pointer to attach the log output
114 *
115 * Description:
116 * This routine is the entry point for the debugfs open file operation.
117 * It allocates the necessary buffer for the log, fills the buffer from
118 * the in-memory log and then returns a pointer to that log in
119 * the private_data field in @file.
120 *
121 * Returns:
122 * This function returns zero if successful. On error it will return
123 * a negative error value.
124 */
125static int fnic_trace_debugfs_open(struct inode *inode,
126 struct file *file)
127{
128 fnic_dbgfs_t *fnic_dbg_prt;
129 fnic_dbg_prt = kzalloc(sizeof(fnic_dbgfs_t), GFP_KERNEL);
130 if (!fnic_dbg_prt)
131 return -ENOMEM;
132
133 fnic_dbg_prt->buffer = vmalloc((3*(trace_max_pages * PAGE_SIZE)));
134 if (!fnic_dbg_prt->buffer) {
135 kfree(fnic_dbg_prt);
136 return -ENOMEM;
137 }
138 memset((void *)fnic_dbg_prt->buffer, 0,
139 (3*(trace_max_pages * PAGE_SIZE)));
140 fnic_dbg_prt->buffer_len = fnic_get_trace_data(fnic_dbg_prt);
141 file->private_data = fnic_dbg_prt;
142 return 0;
143}
144
145/*
146 * fnic_trace_debugfs_lseek - Seek through a debugfs file
147 * @file: The file pointer to seek through.
148 * @offset: The offset to seek to or the amount to seek by.
149 * @howto: Indicates how to seek.
150 *
151 * Description:
152 * This routine is the entry point for the debugfs lseek file operation.
153 * The @howto parameter indicates whether @offset is the offset to directly
154 * seek to, or if it is a value to seek forward or reverse by. This function
155 * figures out what the new offset of the debugfs file will be and assigns
156 * that value to the f_pos field of @file.
157 *
158 * Returns:
159 * This function returns the new offset if successful and returns a negative
160 * error if unable to process the seek.
161 */
162static loff_t fnic_trace_debugfs_lseek(struct file *file,
163 loff_t offset,
164 int howto)
165{
166 fnic_dbgfs_t *fnic_dbg_prt = file->private_data;
Al Viroeb5881d2013-06-17 17:44:23 +0400167 return fixed_size_llseek(file, offset, howto,
168 fnic_dbg_prt->buffer_len);
Hiral Patel4d7007b2013-02-12 17:01:02 -0800169}
170
171/*
172 * fnic_trace_debugfs_read - Read a debugfs file
173 * @file: The file pointer to read from.
174 * @ubuf: The buffer to copy the data to.
175 * @nbytes: The number of bytes to read.
176 * @pos: The position in the file to start reading from.
177 *
178 * Description:
179 * This routine reads data from the buffer indicated in the private_data
180 * field of @file. It will start reading at @pos and copy up to @nbytes of
181 * data to @ubuf.
182 *
183 * Returns:
184 * This function returns the amount of data that was read (this could be
185 * less than @nbytes if the end of the file was reached).
186 */
187static ssize_t fnic_trace_debugfs_read(struct file *file,
188 char __user *ubuf,
189 size_t nbytes,
190 loff_t *pos)
191{
192 fnic_dbgfs_t *fnic_dbg_prt = file->private_data;
193 int rc = 0;
194 rc = simple_read_from_buffer(ubuf, nbytes, pos,
195 fnic_dbg_prt->buffer,
196 fnic_dbg_prt->buffer_len);
197 return rc;
198}
199
200/*
201 * fnic_trace_debugfs_release - Release the buffer used to store
202 * debugfs file data
203 * @inode: The inode pointer
204 * @file: The file pointer that contains the buffer to release
205 *
206 * Description:
207 * This routine frees the buffer that was allocated when the debugfs
208 * file was opened.
209 *
210 * Returns:
211 * This function returns zero.
212 */
213static int fnic_trace_debugfs_release(struct inode *inode,
214 struct file *file)
215{
216 fnic_dbgfs_t *fnic_dbg_prt = file->private_data;
217
218 vfree(fnic_dbg_prt->buffer);
219 kfree(fnic_dbg_prt);
220 return 0;
221}
222
223static const struct file_operations fnic_trace_ctrl_fops = {
224 .owner = THIS_MODULE,
225 .open = fnic_trace_ctrl_open,
226 .read = fnic_trace_ctrl_read,
227 .write = fnic_trace_ctrl_write,
228};
229
230static const struct file_operations fnic_trace_debugfs_fops = {
231 .owner = THIS_MODULE,
232 .open = fnic_trace_debugfs_open,
233 .llseek = fnic_trace_debugfs_lseek,
234 .read = fnic_trace_debugfs_read,
235 .release = fnic_trace_debugfs_release,
236};
237
238/*
239 * fnic_trace_debugfs_init - Initialize debugfs for fnic trace logging
240 *
241 * Description:
242 * When Debugfs is configured this routine sets up the fnic debugfs
243 * file system. If not already created, this routine will create the
244 * fnic directory. It will create file trace to log fnic trace buffer
245 * output into debugfs and it will also create file trace_enable to
246 * control enable/disable of trace logging into trace buffer.
247 */
248int fnic_trace_debugfs_init(void)
249{
250 int rc = -1;
251 fnic_trace_debugfs_root = debugfs_create_dir("fnic", NULL);
252 if (!fnic_trace_debugfs_root) {
253 printk(KERN_DEBUG "Cannot create debugfs root\n");
254 return rc;
255 }
256 fnic_trace_enable = debugfs_create_file("tracing_enable",
257 S_IFREG|S_IRUGO|S_IWUSR,
258 fnic_trace_debugfs_root,
259 NULL, &fnic_trace_ctrl_fops);
260
261 if (!fnic_trace_enable) {
262 printk(KERN_DEBUG "Cannot create trace_enable file"
263 " under debugfs");
264 return rc;
265 }
266
267 fnic_trace_debugfs_file = debugfs_create_file("trace",
268 S_IFREG|S_IRUGO|S_IWUSR,
269 fnic_trace_debugfs_root,
270 NULL,
271 &fnic_trace_debugfs_fops);
272
273 if (!fnic_trace_debugfs_file) {
274 printk(KERN_DEBUG "Cannot create trace file under debugfs");
275 return rc;
276 }
277 rc = 0;
278 return rc;
279}
280
281/*
282 * fnic_trace_debugfs_terminate - Tear down debugfs infrastructure
283 *
284 * Description:
285 * When Debugfs is configured this routine removes debugfs file system
286 * elements that are specific to fnic trace logging.
287 */
288void fnic_trace_debugfs_terminate(void)
289{
290 if (fnic_trace_debugfs_file) {
291 debugfs_remove(fnic_trace_debugfs_file);
292 fnic_trace_debugfs_file = NULL;
293 }
294 if (fnic_trace_enable) {
295 debugfs_remove(fnic_trace_enable);
296 fnic_trace_enable = NULL;
297 }
298 if (fnic_trace_debugfs_root) {
299 debugfs_remove(fnic_trace_debugfs_root);
300 fnic_trace_debugfs_root = NULL;
301 }
302}