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