1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
4 */
5
6 #include <linux/coresight.h>
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/of.h>
10 #include <linux/platform_device.h>
11 #include <linux/pm_runtime.h>
12
13 #include "coresight-priv.h"
14 #include "coresight-trace-id.h"
15
16 struct dummy_drvdata {
17 struct device *dev;
18 struct coresight_device *csdev;
19 u8 traceid;
20 };
21
22 DEFINE_CORESIGHT_DEVLIST(source_devs, "dummy_source");
23 DEFINE_CORESIGHT_DEVLIST(sink_devs, "dummy_sink");
24
dummy_source_enable(struct coresight_device * csdev,struct perf_event * event,enum cs_mode mode,__maybe_unused struct coresight_path * path)25 static int dummy_source_enable(struct coresight_device *csdev,
26 struct perf_event *event, enum cs_mode mode,
27 __maybe_unused struct coresight_path *path)
28 {
29 if (!coresight_take_mode(csdev, mode))
30 return -EBUSY;
31
32 dev_dbg(csdev->dev.parent, "Dummy source enabled\n");
33
34 return 0;
35 }
36
dummy_source_disable(struct coresight_device * csdev,struct perf_event * event)37 static void dummy_source_disable(struct coresight_device *csdev,
38 struct perf_event *event)
39 {
40 coresight_set_mode(csdev, CS_MODE_DISABLED);
41 dev_dbg(csdev->dev.parent, "Dummy source disabled\n");
42 }
43
dummy_source_trace_id(struct coresight_device * csdev,__maybe_unused enum cs_mode mode,__maybe_unused struct coresight_device * sink)44 static int dummy_source_trace_id(struct coresight_device *csdev, __maybe_unused enum cs_mode mode,
45 __maybe_unused struct coresight_device *sink)
46 {
47 struct dummy_drvdata *drvdata;
48
49 drvdata = dev_get_drvdata(csdev->dev.parent);
50
51 return drvdata->traceid;
52 }
53
dummy_sink_enable(struct coresight_device * csdev,enum cs_mode mode,void * data)54 static int dummy_sink_enable(struct coresight_device *csdev, enum cs_mode mode,
55 void *data)
56 {
57 dev_dbg(csdev->dev.parent, "Dummy sink enabled\n");
58
59 return 0;
60 }
61
dummy_sink_disable(struct coresight_device * csdev)62 static int dummy_sink_disable(struct coresight_device *csdev)
63 {
64 dev_dbg(csdev->dev.parent, "Dummy sink disabled\n");
65
66 return 0;
67 }
68
69 static const struct coresight_ops_source dummy_source_ops = {
70 .enable = dummy_source_enable,
71 .disable = dummy_source_disable,
72 };
73
74 static const struct coresight_ops dummy_source_cs_ops = {
75 .trace_id = dummy_source_trace_id,
76 .source_ops = &dummy_source_ops,
77 };
78
79 static const struct coresight_ops_sink dummy_sink_ops = {
80 .enable = dummy_sink_enable,
81 .disable = dummy_sink_disable,
82 };
83
84 static const struct coresight_ops dummy_sink_cs_ops = {
85 .sink_ops = &dummy_sink_ops,
86 };
87
88 /* User can get the trace id of dummy source from this node. */
traceid_show(struct device * dev,struct device_attribute * attr,char * buf)89 static ssize_t traceid_show(struct device *dev,
90 struct device_attribute *attr, char *buf)
91 {
92 unsigned long val;
93 struct dummy_drvdata *drvdata = dev_get_drvdata(dev->parent);
94
95 val = drvdata->traceid;
96 return sysfs_emit(buf, "%#lx\n", val);
97 }
98 static DEVICE_ATTR_RO(traceid);
99
100 static struct attribute *coresight_dummy_attrs[] = {
101 &dev_attr_traceid.attr,
102 NULL,
103 };
104
105 static const struct attribute_group coresight_dummy_group = {
106 .attrs = coresight_dummy_attrs,
107 };
108
109 static const struct attribute_group *coresight_dummy_groups[] = {
110 &coresight_dummy_group,
111 NULL,
112 };
113
dummy_probe(struct platform_device * pdev)114 static int dummy_probe(struct platform_device *pdev)
115 {
116 struct device *dev = &pdev->dev;
117 struct device_node *node = dev->of_node;
118 struct coresight_platform_data *pdata;
119 struct dummy_drvdata *drvdata;
120 struct coresight_desc desc = { 0 };
121 int ret = 0, trace_id = 0;
122
123 drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
124 if (!drvdata)
125 return -ENOMEM;
126
127 if (of_device_is_compatible(node, "arm,coresight-dummy-source")) {
128
129 desc.name = coresight_alloc_device_name(&source_devs, dev);
130 if (!desc.name)
131 return -ENOMEM;
132
133 desc.type = CORESIGHT_DEV_TYPE_SOURCE;
134 desc.subtype.source_subtype =
135 CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS;
136 desc.ops = &dummy_source_cs_ops;
137 desc.groups = coresight_dummy_groups;
138
139 ret = coresight_get_static_trace_id(dev, &trace_id);
140 if (!ret) {
141 /* Get the static id if id is set in device tree. */
142 ret = coresight_trace_id_get_static_system_id(trace_id);
143 if (ret < 0) {
144 dev_err(dev, "Fail to get static id.\n");
145 return ret;
146 }
147 } else {
148 /* Get next available id if id is not set in device tree. */
149 trace_id = coresight_trace_id_get_system_id();
150 if (trace_id < 0) {
151 ret = trace_id;
152 return ret;
153 }
154 }
155 drvdata->traceid = (u8)trace_id;
156
157 } else if (of_device_is_compatible(node, "arm,coresight-dummy-sink")) {
158 desc.name = coresight_alloc_device_name(&sink_devs, dev);
159 if (!desc.name)
160 return -ENOMEM;
161
162 desc.type = CORESIGHT_DEV_TYPE_SINK;
163 desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_DUMMY;
164 desc.ops = &dummy_sink_cs_ops;
165 } else {
166 dev_err(dev, "Device type not set\n");
167 return -EINVAL;
168 }
169
170 pdata = coresight_get_platform_data(dev);
171 if (IS_ERR(pdata)) {
172 ret = PTR_ERR(pdata);
173 goto free_id;
174 }
175 pdev->dev.platform_data = pdata;
176
177 drvdata->dev = &pdev->dev;
178 platform_set_drvdata(pdev, drvdata);
179
180 desc.pdata = pdev->dev.platform_data;
181 desc.dev = &pdev->dev;
182 drvdata->csdev = coresight_register(&desc);
183 if (IS_ERR(drvdata->csdev)) {
184 ret = PTR_ERR(drvdata->csdev);
185 goto free_id;
186 }
187
188 pm_runtime_enable(dev);
189 dev_dbg(dev, "Dummy device initialized\n");
190
191 ret = 0;
192 goto out;
193
194 free_id:
195 if (IS_VALID_CS_TRACE_ID(drvdata->traceid))
196 coresight_trace_id_put_system_id(drvdata->traceid);
197
198 out:
199 return ret;
200 }
201
dummy_remove(struct platform_device * pdev)202 static void dummy_remove(struct platform_device *pdev)
203 {
204 struct dummy_drvdata *drvdata = platform_get_drvdata(pdev);
205 struct device *dev = &pdev->dev;
206
207 if (IS_VALID_CS_TRACE_ID(drvdata->traceid))
208 coresight_trace_id_put_system_id(drvdata->traceid);
209 pm_runtime_disable(dev);
210 coresight_unregister(drvdata->csdev);
211 }
212
213 static const struct of_device_id dummy_match[] = {
214 {.compatible = "arm,coresight-dummy-source"},
215 {.compatible = "arm,coresight-dummy-sink"},
216 {},
217 };
218
219 static struct platform_driver dummy_driver = {
220 .probe = dummy_probe,
221 .remove = dummy_remove,
222 .driver = {
223 .name = "coresight-dummy",
224 .of_match_table = dummy_match,
225 },
226 };
227
228 module_platform_driver(dummy_driver);
229
230 MODULE_LICENSE("GPL");
231 MODULE_DESCRIPTION("CoreSight dummy driver");
232