xref: /openbmc/linux/drivers/scsi/snic/snic_trc.c (revision dfb99b05)
1 // SPDX-License-Identifier: GPL-2.0-only
2 // Copyright 2014 Cisco Systems, Inc.  All rights reserved.
3 
4 #include <linux/module.h>
5 #include <linux/mempool.h>
6 #include <linux/errno.h>
7 #include <linux/vmalloc.h>
8 
9 #include "snic_io.h"
10 #include "snic.h"
11 
12 /*
13  * snic_get_trc_buf : Allocates a trace record and returns.
14  */
15 struct snic_trc_data *
snic_get_trc_buf(void)16 snic_get_trc_buf(void)
17 {
18 	struct snic_trc *trc = &snic_glob->trc;
19 	struct snic_trc_data *td = NULL;
20 	unsigned long flags;
21 
22 	spin_lock_irqsave(&trc->lock, flags);
23 	td = &trc->buf[trc->wr_idx];
24 	trc->wr_idx++;
25 
26 	if (trc->wr_idx == trc->max_idx)
27 		trc->wr_idx = 0;
28 
29 	if (trc->wr_idx != trc->rd_idx) {
30 		spin_unlock_irqrestore(&trc->lock, flags);
31 
32 		goto end;
33 	}
34 
35 	trc->rd_idx++;
36 	if (trc->rd_idx == trc->max_idx)
37 		trc->rd_idx = 0;
38 
39 	td->ts = 0;	/* Marker for checking the record, for complete data*/
40 	spin_unlock_irqrestore(&trc->lock, flags);
41 
42 end:
43 
44 	return td;
45 } /* end of snic_get_trc_buf */
46 
47 /*
48  * snic_fmt_trc_data : Formats trace data for printing.
49  */
50 static int
snic_fmt_trc_data(struct snic_trc_data * td,char * buf,int buf_sz)51 snic_fmt_trc_data(struct snic_trc_data *td, char *buf, int buf_sz)
52 {
53 	int len = 0;
54 	struct timespec64 tmspec;
55 
56 	jiffies_to_timespec64(td->ts, &tmspec);
57 
58 	len += snprintf(buf, buf_sz,
59 			"%llu.%09lu %-25s %3d %4x %16llx %16llx %16llx %16llx %16llx\n",
60 			tmspec.tv_sec,
61 			tmspec.tv_nsec,
62 			td->fn,
63 			td->hno,
64 			td->tag,
65 			td->data[0], td->data[1], td->data[2], td->data[3],
66 			td->data[4]);
67 
68 	return len;
69 } /* end of snic_fmt_trc_data */
70 
71 /*
72  * snic_get_trc_data : Returns a formatted trace buffer.
73  */
74 int
snic_get_trc_data(char * buf,int buf_sz)75 snic_get_trc_data(char *buf, int buf_sz)
76 {
77 	struct snic_trc_data *td = NULL;
78 	struct snic_trc *trc = &snic_glob->trc;
79 	unsigned long flags;
80 
81 	spin_lock_irqsave(&trc->lock, flags);
82 	if (trc->rd_idx == trc->wr_idx) {
83 		spin_unlock_irqrestore(&trc->lock, flags);
84 
85 		return -1;
86 	}
87 	td = &trc->buf[trc->rd_idx];
88 
89 	if (td->ts == 0) {
90 		/* write in progress. */
91 		spin_unlock_irqrestore(&trc->lock, flags);
92 
93 		return -1;
94 	}
95 
96 	trc->rd_idx++;
97 	if (trc->rd_idx == trc->max_idx)
98 		trc->rd_idx = 0;
99 	spin_unlock_irqrestore(&trc->lock, flags);
100 
101 	return snic_fmt_trc_data(td, buf, buf_sz);
102 } /* end of snic_get_trc_data */
103 
104 /*
105  * snic_trc_init() : Configures Trace Functionality for snic.
106  */
107 int
snic_trc_init(void)108 snic_trc_init(void)
109 {
110 	struct snic_trc *trc = &snic_glob->trc;
111 	void *tbuf = NULL;
112 	int tbuf_sz = 0, ret;
113 
114 	tbuf_sz = (snic_trace_max_pages * PAGE_SIZE);
115 	tbuf = vzalloc(tbuf_sz);
116 	if (!tbuf) {
117 		SNIC_ERR("Failed to Allocate Trace Buffer Size. %d\n", tbuf_sz);
118 		SNIC_ERR("Trace Facility not enabled.\n");
119 		ret = -ENOMEM;
120 
121 		return ret;
122 	}
123 
124 	trc->buf = (struct snic_trc_data *) tbuf;
125 	spin_lock_init(&trc->lock);
126 
127 	snic_trc_debugfs_init();
128 
129 	trc->max_idx = (tbuf_sz / SNIC_TRC_ENTRY_SZ);
130 	trc->rd_idx = trc->wr_idx = 0;
131 	trc->enable = true;
132 	SNIC_INFO("Trace Facility Enabled.\n Trace Buffer SZ %lu Pages.\n",
133 		  tbuf_sz / PAGE_SIZE);
134 	ret = 0;
135 
136 	return ret;
137 } /* end of snic_trc_init */
138 
139 /*
140  * snic_trc_free : Releases the trace buffer and disables the tracing.
141  */
142 void
snic_trc_free(void)143 snic_trc_free(void)
144 {
145 	struct snic_trc *trc = &snic_glob->trc;
146 
147 	trc->enable = false;
148 	snic_trc_debugfs_term();
149 
150 	if (trc->buf) {
151 		vfree(trc->buf);
152 		trc->buf = NULL;
153 	}
154 
155 	SNIC_INFO("Trace Facility Disabled.\n");
156 } /* end of snic_trc_free */
157