drivers/net/wwan/t7xx/t7xx_port_trace.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2022 Intel Corporation.
   4  */
   5
   6 #include <linux/debugfs.h>
   7 #include <linux/relay.h>
   8 #include <linux/skbuff.h>
   9 #include <linux/wwan.h>
  10
  11 #include "t7xx_port.h"
  12 #include "t7xx_port_proxy.h"
  13 #include "t7xx_state_monitor.h"
  14
  15 #define T7XX_TRC_SUB_BUFF_SIZE          131072
  16 #define T7XX_TRC_N_SUB_BUFF             32
  17
  18 static struct dentry *t7xx_trace_create_buf_file_handler(const char *filename,
  19                                                          struct dentry *parent,
  20                                                          umode_t mode,
  21                                                          struct rchan_buf *buf,
  22                                                          int *is_global)
  23 {
  24         *is_global = 1;
  25         return debugfs_create_file(filename, mode, parent, buf,
  26                                    &relay_file_operations);
  27 }
  28
  29 static int t7xx_trace_remove_buf_file_handler(struct dentry *dentry)
  30 {
  31         debugfs_remove(dentry);
  32         return 0;
  33 }
  34
  35 static int t7xx_trace_subbuf_start_handler(struct rchan_buf *buf, void *subbuf,
  36                                            void *prev_subbuf, size_t prev_padding)
  37 {
  38         if (relay_buf_full(buf)) {
  39                 pr_err_ratelimited("Relay_buf full dropping traces");
  40                 return 0;
  41         }
  42
  43         return 1;
  44 }
  45
  46 static struct rchan_callbacks relay_callbacks = {
  47         .subbuf_start = t7xx_trace_subbuf_start_handler,
  48         .create_buf_file = t7xx_trace_create_buf_file_handler,
  49         .remove_buf_file = t7xx_trace_remove_buf_file_handler,
  50 };
  51
  52 static void t7xx_trace_port_uninit(struct t7xx_port *port)
  53 {
  54         struct dentry *debugfs_dir = port->t7xx_dev->debugfs_dir;
  55         struct rchan *relaych = port->log.relaych;
  56
  57         if (!relaych)
  58                 return;
  59
  60         relay_close(relaych);
  61         debugfs_remove_recursive(debugfs_dir);
  62 }
  63
  64 static int t7xx_trace_port_recv_skb(struct t7xx_port *port, struct sk_buff *skb)
  65 {
  66         struct rchan *relaych = port->log.relaych;
  67
  68         if (!relaych)
  69                 return -EINVAL;
  70
  71         relay_write(relaych, skb->data, skb->len);
  72         dev_kfree_skb(skb);
  73         return 0;
  74 }
  75
  76 static void t7xx_port_trace_md_state_notify(struct t7xx_port *port, unsigned int state)
  77 {
  78         struct rchan *relaych = port->log.relaych;
  79         struct dentry *debugfs_wwan_dir;
  80         struct dentry *debugfs_dir;
  81
  82         if (state != MD_STATE_READY || relaych)
  83                 return;
  84
  85         debugfs_wwan_dir = wwan_get_debugfs_dir(port->dev);
  86         if (IS_ERR(debugfs_wwan_dir))
  87                 return;
  88
  89         debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, debugfs_wwan_dir);
  90         if (IS_ERR_OR_NULL(debugfs_dir)) {
  91                 wwan_put_debugfs_dir(debugfs_wwan_dir);
  92                 dev_err(port->dev, "Unable to create debugfs for trace");
  93                 return;
  94         }
  95
  96         relaych = relay_open("relay_ch", debugfs_dir, T7XX_TRC_SUB_BUFF_SIZE,
  97                              T7XX_TRC_N_SUB_BUFF, &relay_callbacks, NULL);
  98         if (!relaych)
  99                 goto err_rm_debugfs_dir;
 100
 101         wwan_put_debugfs_dir(debugfs_wwan_dir);
 102         port->log.relaych = relaych;
 103         port->t7xx_dev->debugfs_dir = debugfs_dir;
 104         return;
 105
 106 err_rm_debugfs_dir:
 107         debugfs_remove_recursive(debugfs_dir);
 108         wwan_put_debugfs_dir(debugfs_wwan_dir);
 109         dev_err(port->dev, "Unable to create trace port %s", port->port_conf->name);
 110 }
 111
 112 struct port_ops t7xx_trace_port_ops = {
 113         .recv_skb = t7xx_trace_port_recv_skb,
 114         .uninit = t7xx_trace_port_uninit,
 115         .md_state_notify = t7xx_port_trace_md_state_notify,
 116 };