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