drivers/hwtracing/coresight/coresight-dummy.c

   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
  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
  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
  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
  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. */
  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
 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
 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");