drivers/scsi/snic/snic_trc.c

   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 *
  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
  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
  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
 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
 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 */