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 }
183