drivers/net/wwan/iosm/iosm_ipc_trace.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2020-2021 Intel Corporation.
   4  */
   5
   6 #include <linux/wwan.h>
   7 #include "iosm_ipc_trace.h"
   8
   9 /* sub buffer size and number of sub buffer */
  10 #define IOSM_TRC_SUB_BUFF_SIZE 131072
  11 #define IOSM_TRC_N_SUB_BUFF 32
  12
  13 #define IOSM_TRC_FILE_PERM 0600
  14
  15 #define IOSM_TRC_DEBUGFS_TRACE "trace"
  16 #define IOSM_TRC_DEBUGFS_TRACE_CTRL "trace_ctrl"
  17
  18 /**
  19  * ipc_trace_port_rx - Receive trace packet from cp and write to relay buffer
  20  * @ipc_imem:   Pointer to iosm_imem structure
  21  * @skb:        Pointer to struct sk_buff
  22  */
  23 void ipc_trace_port_rx(struct iosm_imem *ipc_imem, struct sk_buff *skb)
  24 {
  25         struct iosm_trace *ipc_trace = ipc_imem->trace;
  26
  27         if (ipc_trace->ipc_rchan)
  28                 relay_write(ipc_trace->ipc_rchan, skb->data, skb->len);
  29
  30         dev_kfree_skb(skb);
  31 }
  32
  33 /* Creates relay file in debugfs. */
  34 static struct dentry *
  35 ipc_trace_create_buf_file_handler(const char *filename,
  36                                   struct dentry *parent,
  37                                   umode_t mode,
  38                                   struct rchan_buf *buf,
  39                                   int *is_global)
  40 {
  41         *is_global = 1;
  42         return debugfs_create_file(filename, mode, parent, buf,
  43                                    &relay_file_operations);
  44 }
  45
  46 /* Removes relay file from debugfs. */
  47 static int ipc_trace_remove_buf_file_handler(struct dentry *dentry)
  48 {
  49         debugfs_remove(dentry);
  50         return 0;
  51 }
  52
  53 static int ipc_trace_subbuf_start_handler(struct rchan_buf *buf, void *subbuf,
  54                                           void *prev_subbuf,
  55                                           size_t prev_padding)
  56 {
  57         if (relay_buf_full(buf)) {
  58                 pr_err_ratelimited("Relay_buf full dropping traces");
  59                 return 0;
  60         }
  61
  62         return 1;
  63 }
  64
  65 /* Relay interface callbacks */
  66 static struct rchan_callbacks relay_callbacks = {
  67         .subbuf_start = ipc_trace_subbuf_start_handler,
  68         .create_buf_file = ipc_trace_create_buf_file_handler,
  69         .remove_buf_file = ipc_trace_remove_buf_file_handler,
  70 };
  71
  72 /* Copy the trace control mode to user buffer */
  73 static ssize_t ipc_trace_ctrl_file_read(struct file *filp, char __user *buffer,
  74                                         size_t count, loff_t *ppos)
  75 {
  76         struct iosm_trace *ipc_trace = filp->private_data;
  77         char buf[16];
  78         int len;
  79
  80         mutex_lock(&ipc_trace->trc_mutex);
  81         len = snprintf(buf, sizeof(buf), "%d\n", ipc_trace->mode);
  82         mutex_unlock(&ipc_trace->trc_mutex);
  83
  84         return simple_read_from_buffer(buffer, count, ppos, buf, len);
  85 }
  86
  87 /* Open and close the trace channel depending on user input */
  88 static ssize_t ipc_trace_ctrl_file_write(struct file *filp,
  89                                          const char __user *buffer,
  90                                          size_t count, loff_t *ppos)
  91 {
  92         struct iosm_trace *ipc_trace = filp->private_data;
  93         unsigned long val;
  94         int ret;
  95
  96         ret = kstrtoul_from_user(buffer, count, 10, &val);
  97         if (ret)
  98                 return ret;
  99
 100         mutex_lock(&ipc_trace->trc_mutex);
 101         if (val == TRACE_ENABLE && ipc_trace->mode != TRACE_ENABLE) {
 102                 ipc_trace->channel = ipc_imem_sys_port_open(ipc_trace->ipc_imem,
 103                                                             ipc_trace->chl_id,
 104                                                             IPC_HP_CDEV_OPEN);
 105                 if (!ipc_trace->channel) {
 106                         ret = -EIO;
 107                         goto unlock;
 108                 }
 109                 ipc_trace->mode = TRACE_ENABLE;
 110         } else if (val == TRACE_DISABLE && ipc_trace->mode != TRACE_DISABLE) {
 111                 ipc_trace->mode = TRACE_DISABLE;
 112                 /* close trace channel */
 113                 ipc_imem_sys_port_close(ipc_trace->ipc_imem,
 114                                         ipc_trace->channel);
 115                 relay_flush(ipc_trace->ipc_rchan);
 116         }
 117         ret = count;
 118 unlock:
 119         mutex_unlock(&ipc_trace->trc_mutex);
 120         return ret;
 121 }
 122
 123 static const struct file_operations ipc_trace_fops = {
 124         .open = simple_open,
 125         .write = ipc_trace_ctrl_file_write,
 126         .read  = ipc_trace_ctrl_file_read,
 127 };
 128
 129 /**
 130  * ipc_trace_init - Create trace interface & debugfs entries
 131  * @ipc_imem:   Pointer to iosm_imem structure
 132  *
 133  * Returns: Pointer to trace instance on success else NULL
 134  */
 135 struct iosm_trace *ipc_trace_init(struct iosm_imem *ipc_imem)
 136 {
 137         struct ipc_chnl_cfg chnl_cfg = { 0 };
 138         struct iosm_trace *ipc_trace;
 139
 140         ipc_chnl_cfg_get(&chnl_cfg, IPC_MEM_CTRL_CHL_ID_3);
 141         ipc_imem_channel_init(ipc_imem, IPC_CTYPE_CTRL, chnl_cfg,
 142                               IRQ_MOD_OFF);
 143
 144         ipc_trace = kzalloc(sizeof(*ipc_trace), GFP_KERNEL);
 145         if (!ipc_trace)
 146                 return NULL;
 147
 148         ipc_trace->mode = TRACE_DISABLE;
 149         ipc_trace->dev = ipc_imem->dev;
 150         ipc_trace->ipc_imem = ipc_imem;
 151         ipc_trace->chl_id = IPC_MEM_CTRL_CHL_ID_3;
 152
 153         mutex_init(&ipc_trace->trc_mutex);
 154
 155         ipc_trace->ctrl_file = debugfs_create_file(IOSM_TRC_DEBUGFS_TRACE_CTRL,
 156                                                    IOSM_TRC_FILE_PERM,
 157                                                    ipc_imem->debugfs_dir,
 158                                                    ipc_trace, &ipc_trace_fops);
 159
 160         ipc_trace->ipc_rchan = relay_open(IOSM_TRC_DEBUGFS_TRACE,
 161                                           ipc_imem->debugfs_dir,
 162                                           IOSM_TRC_SUB_BUFF_SIZE,
 163                                           IOSM_TRC_N_SUB_BUFF,
 164                                           &relay_callbacks, NULL);
 165
 166         return ipc_trace;
 167 }
 168
 169 /**
 170  * ipc_trace_deinit - Closing relayfs, removing debugfs entries
 171  * @ipc_trace: Pointer to the iosm_trace data struct
 172  */
 173 void ipc_trace_deinit(struct iosm_trace *ipc_trace)
 174 {
 175         if (!ipc_trace)
 176                 return;
 177
 178         debugfs_remove(ipc_trace->ctrl_file);
 179         relay_close(ipc_trace->ipc_rchan);
 180         mutex_destroy(&ipc_trace->trc_mutex);
 181         kfree(ipc_trace);
 182 }