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