Introduction of Coresight Dummy subunit
The Coresight Dummy subunit is for Coresight Dummy component, there are
some specific Coresight devices that HLOS don't have permission to access.
Such as some TPDMs, they would be configured in NON-HLOS side, but it's
necessary to build Coresight path for it to debug. So there need driver
to register dummy devices as Coresight devices.
Commit link:
https://git.codelinaro.org/clo/linux-kernel/coresight/-/tree/coresight-dummy-v3
changes in V3:
1. Use API "dev_dbg" to replace "dev_info". -- Suzuki K Poulose
2. Drop "qcom" property and take it as a dummy framework.
-- Suzuki K Poulose
3. Add new sub-type "CORESIGHT_DEV_SUBTYPE_SINK_DUMMY" to support
coresight dummy module -- Mike Leach
4. Use compatibles "arm,coresight-dummy-source" and
"arm,coresight-dummy-sink" to replace property "qcom,dummy-source" and
"qcom,dummy-sink". -- Mike Leach
5. Define source_devs and sink_devs DEVLIST to replace dummy_devs, make
it clear at the first level. -- Mike Leach
6. Modify subject of YAML patch, drop "YAML schema". -- Krzysztof Kozlowski
7. Drop some redundant items and correct syntax errors in yaml file.
-- Krzysztof Kozlowski/Rob Herring
8. Correct required property of yaml file, constrain out ports to
dummy-source and in ports to dummy-sink. -- Mike Leach
9. Drop "Sysfs files and directories" contents of coresight-dummy.rst.
-- Suzuki K Poulose/Greg Kroah-Hartman
10.Correct syntax errors of coresight-dummy.rst. -- Bagas Sanjaya
Changes in V2:
1. Declare dummy_init and dummy_exit as static to fix missing-prototypes
warnings. -- kernel test robot
2. Fix the errors of coresight-dummy yaml file. -- Rob Herring
Hao Zhang (3):
Coresight: Add coresight dummy driver
dt-bindings: arm: Add Coresight Dummy Trace
Documentation: trace: Add documentation for Coresight Dummy Trace
.../bindings/arm/arm,coresight-dummy.yaml | 101 ++++++++++
.../trace/coresight/coresight-dummy.rst | 34 ++++
drivers/hwtracing/coresight/Kconfig | 11 ++
drivers/hwtracing/coresight/Makefile | 1 +
drivers/hwtracing/coresight/coresight-dummy.c | 179 ++++++++++++++++++
include/linux/coresight.h | 1 +
6 files changed, 327 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/arm,coresight-dummy.yaml
create mode 100644 Documentation/trace/coresight/coresight-dummy.rst
create mode 100644 drivers/hwtracing/coresight/coresight-dummy.c
--
2.17.1
Some Coresight devices that kernel don't have permission to access or
configure. So there need driver to register dummy devices as Coresight
devices. It may also be used to define components that may not have
any programming interfaces (e.g, static links), so that paths can be
established in the driver. Provide Coresight API for dummy device
operations, such as enabling and disabling dummy devices. Build the
Coresight path for dummy sink or dummy source for debugging.
Signed-off-by: Hao Zhang <[email protected]>
---
drivers/hwtracing/coresight/Kconfig | 11 ++
drivers/hwtracing/coresight/Makefile | 1 +
drivers/hwtracing/coresight/coresight-dummy.c | 179 ++++++++++++++++++
include/linux/coresight.h | 1 +
4 files changed, 192 insertions(+)
create mode 100644 drivers/hwtracing/coresight/coresight-dummy.c
diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index 2b5bbfffbc4f..06f0a7594169 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -236,4 +236,15 @@ config CORESIGHT_TPDA
To compile this driver as a module, choose M here: the module will be
called coresight-tpda.
+
+config CORESIGHT_DUMMY
+ tristate "Dummy driver support"
+ help
+ Enables support for dummy driver. Dummy driver can be used for
+ CoreSight sources/sinks that are owned and configured by some
+ other subsystem and use Linux drivers to configure rest of trace
+ path.
+
+ To compile this driver as a module, choose M here: the module will be
+ called coresight-dummy.
endif
diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
index 33bcc3f7b8ae..995d3b2c76df 100644
--- a/drivers/hwtracing/coresight/Makefile
+++ b/drivers/hwtracing/coresight/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_CORESIGHT_TPDA) += coresight-tpda.o
coresight-cti-y := coresight-cti-core.o coresight-cti-platform.o \
coresight-cti-sysfs.o
obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o
+obj-$(CONFIG_CORESIGHT_DUMMY) += coresight-dummy.o
diff --git a/drivers/hwtracing/coresight/coresight-dummy.c b/drivers/hwtracing/coresight/coresight-dummy.c
new file mode 100644
index 000000000000..1fb8b3d1c170
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-dummy.c
@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/coresight.h>
+#include <linux/of.h>
+#include <linux/pm_runtime.h>
+
+#include "coresight-priv.h"
+#include "coresight-trace-id.h"
+
+struct dummy_drvdata {
+ struct device *dev;
+ struct coresight_device *csdev;
+ int traceid;
+};
+
+DEFINE_CORESIGHT_DEVLIST(source_devs, "dummy_source");
+DEFINE_CORESIGHT_DEVLIST(sink_devs, "dummy_sink");
+
+static int dummy_source_enable(struct coresight_device *csdev,
+ struct perf_event *event, u32 mode)
+{
+ struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ dev_dbg(drvdata->dev, "Dummy source enabled\n");
+
+ return 0;
+}
+
+static void dummy_source_disable(struct coresight_device *csdev,
+ struct perf_event *event)
+{
+ struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ dev_dbg(drvdata->dev, "Dummy source disabled\n");
+}
+
+static int dummy_sink_enable(struct coresight_device *csdev, u32 mode,
+ void *data)
+{
+ struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ dev_dbg(drvdata->dev, "Dummy sink enabled\n");
+
+ return 0;
+}
+
+static int dummy_sink_disable(struct coresight_device *csdev)
+{
+ struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ dev_dbg(drvdata->dev, "Dummy sink disabled\n");
+
+ return 0;
+}
+
+static const struct coresight_ops_source dummy_source_ops = {
+ .enable = dummy_source_enable,
+ .disable = dummy_source_disable,
+};
+
+static const struct coresight_ops dummy_source_cs_ops = {
+ .source_ops = &dummy_source_ops,
+};
+
+static const struct coresight_ops_sink dummy_sink_ops = {
+ .enable = dummy_sink_enable,
+ .disable = dummy_sink_disable,
+};
+
+static const struct coresight_ops dummy_sink_cs_ops = {
+ .sink_ops = &dummy_sink_ops,
+};
+
+static int dummy_probe(struct platform_device *pdev)
+{
+ int trace_id;
+ struct device *dev = &pdev->dev;
+ struct device_node *node = dev->of_node;
+ struct coresight_platform_data *pdata;
+ struct dummy_drvdata *drvdata;
+ struct coresight_desc desc = { 0 };
+
+ if (of_device_is_compatible(node, "arm,coresight-dummy-source")) {
+ trace_id = coresight_trace_id_get_system_id();
+ if (trace_id < 0)
+ return trace_id;
+
+ desc.name = coresight_alloc_device_name(&source_devs, dev);
+ if (!desc.name)
+ return -ENOMEM;
+
+ desc.type = CORESIGHT_DEV_TYPE_SOURCE;
+ desc.subtype.source_subtype =
+ CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS;
+ desc.ops = &dummy_source_cs_ops;
+ } else if (of_device_is_compatible(node, "arm,coresight-dummy-sink")) {
+ desc.name = coresight_alloc_device_name(&sink_devs, dev);
+ if (!desc.name)
+ return -ENOMEM;
+
+ desc.type = CORESIGHT_DEV_TYPE_SINK;
+ desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_DUMMY;
+ desc.ops = &dummy_sink_cs_ops;
+ } else {
+ dev_err(dev, "Device type not set\n");
+ return -EINVAL;
+ }
+
+ pdata = coresight_get_platform_data(dev);
+ if (IS_ERR(pdata))
+ return PTR_ERR(pdata);
+ pdev->dev.platform_data = pdata;
+
+ drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
+ if (!drvdata)
+ return -ENOMEM;
+
+ drvdata->dev = &pdev->dev;
+ platform_set_drvdata(pdev, drvdata);
+
+ desc.pdata = pdev->dev.platform_data;
+ desc.dev = &pdev->dev;
+ drvdata->csdev = coresight_register(&desc);
+ if (IS_ERR(drvdata->csdev))
+ return PTR_ERR(drvdata->csdev);
+
+ drvdata->traceid = (u8)trace_id;
+
+ pm_runtime_enable(dev);
+ dev_dbg(dev, "Dummy device initialized\n");
+
+ return 0;
+}
+
+static int dummy_remove(struct platform_device *pdev)
+{
+ struct dummy_drvdata *drvdata = platform_get_drvdata(pdev);
+ struct device *dev = &pdev->dev;
+
+ pm_runtime_disable(dev);
+ coresight_unregister(drvdata->csdev);
+ return 0;
+}
+
+static const struct of_device_id dummy_match[] = {
+ {.compatible = "arm,coresight-dummy-source"},
+ {.compatible = "arm,coresight-dummy-sink"},
+ {},
+};
+
+static struct platform_driver dummy_driver = {
+ .probe = dummy_probe,
+ .remove = dummy_remove,
+ .driver = {
+ .name = "coresight-dummy",
+ .of_match_table = dummy_match,
+ },
+};
+
+static int __init dummy_init(void)
+{
+ return platform_driver_register(&dummy_driver);
+}
+module_init(dummy_init);
+
+static void __exit dummy_exit(void)
+{
+ platform_driver_unregister(&dummy_driver);
+}
+module_exit(dummy_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("CoreSight dummy driver");
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index f19a47b9bb5a..6db4b49751cf 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -45,6 +45,7 @@ enum coresight_dev_type {
};
enum coresight_dev_subtype_sink {
+ CORESIGHT_DEV_SUBTYPE_SINK_DUMMY,
CORESIGHT_DEV_SUBTYPE_SINK_PORT,
CORESIGHT_DEV_SUBTYPE_SINK_BUFFER,
CORESIGHT_DEV_SUBTYPE_SINK_SYSMEM,
--
2.17.1
Add documentation for Coresight Dummy Trace under trace/coresight.
Signed-off-by: Hao Zhang <[email protected]>
---
.../trace/coresight/coresight-dummy.rst | 34 +++++++++++++++++++
1 file changed, 34 insertions(+)
create mode 100644 Documentation/trace/coresight/coresight-dummy.rst
diff --git a/Documentation/trace/coresight/coresight-dummy.rst b/Documentation/trace/coresight/coresight-dummy.rst
new file mode 100644
index 000000000000..d0f73253f694
--- /dev/null
+++ b/Documentation/trace/coresight/coresight-dummy.rst
@@ -0,0 +1,34 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============================
+Coresight Dummy Trace Module
+=============================
+
+ :Author: Hao Zhang <[email protected]>
+ :Date: April 2023
+
+Introduction
+---------------------------
+
+Coresight Dummy Trace Module is for the specific devices that kernel
+don't have permission to access or configure, e.g., CoreSight TPDMs
+on Qualcomm platforms. So there need driver to register dummy devices
+as Coresight devices. It may also be used to define components that
+may not have any programming interfaces (e.g, static links), so that
+paths can be established in the driver. Provide Coresight API for
+dummy device operations, such as enabling and disabling dummy devices.
+Build the Coresight path for dummy sink or dummy source for debugging.
+
+Config details
+---------------------------
+
+There are two types of nodes, dummy sink and dummy source. The nodes
+should be observed at the below coresight path::
+
+ ``/sys/bus/coresight/devices``.
+
+e.g.::
+
+ / $ ls -l /sys/bus/coresight/devices | grep dummy
+ dummy0 -> ../../../devices/platform/soc@0/soc@0:dummy_source/dummy0
+ dummy1 -> ../../../devices/platform/soc@0/soc@0:dummy_sink/dummy1
--
2.17.1
On 22/04/2023 08:37, Hao Zhang wrote:
> Some Coresight devices that kernel don't have permission to access or
> configure. So there need driver to register dummy devices as Coresight
> devices. It may also be used to define components that may not have
> any programming interfaces (e.g, static links), so that paths can be
> established in the driver. Provide Coresight API for dummy device
> operations, such as enabling and disabling dummy devices. Build the
> Coresight path for dummy sink or dummy source for debugging.
>
> Signed-off-by: Hao Zhang <[email protected]>
> ---
> drivers/hwtracing/coresight/Kconfig | 11 ++
> drivers/hwtracing/coresight/Makefile | 1 +
> drivers/hwtracing/coresight/coresight-dummy.c | 179 ++++++++++++++++++
> include/linux/coresight.h | 1 +
> 4 files changed, 192 insertions(+)
> create mode 100644 drivers/hwtracing/coresight/coresight-dummy.c
>
> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> index 2b5bbfffbc4f..06f0a7594169 100644
> --- a/drivers/hwtracing/coresight/Kconfig
> +++ b/drivers/hwtracing/coresight/Kconfig
> @@ -236,4 +236,15 @@ config CORESIGHT_TPDA
>
> To compile this driver as a module, choose M here: the module will be
> called coresight-tpda.
> +
> +config CORESIGHT_DUMMY
> + tristate "Dummy driver support"
> + help
> + Enables support for dummy driver. Dummy driver can be used for
> + CoreSight sources/sinks that are owned and configured by some
> + other subsystem and use Linux drivers to configure rest of trace
> + path.
> +
> + To compile this driver as a module, choose M here: the module will be
> + called coresight-dummy.
> endif
> diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
> index 33bcc3f7b8ae..995d3b2c76df 100644
> --- a/drivers/hwtracing/coresight/Makefile
> +++ b/drivers/hwtracing/coresight/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_CORESIGHT_TPDA) += coresight-tpda.o
> coresight-cti-y := coresight-cti-core.o coresight-cti-platform.o \
> coresight-cti-sysfs.o
> obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o
> +obj-$(CONFIG_CORESIGHT_DUMMY) += coresight-dummy.o
> diff --git a/drivers/hwtracing/coresight/coresight-dummy.c b/drivers/hwtracing/coresight/coresight-dummy.c
> new file mode 100644
> index 000000000000..1fb8b3d1c170
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/coresight-dummy.c
> @@ -0,0 +1,179 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/coresight.h>
> +#include <linux/of.h>
> +#include <linux/pm_runtime.h>
> +
> +#include "coresight-priv.h"
> +#include "coresight-trace-id.h"
> +
> +struct dummy_drvdata {
> + struct device *dev;
> + struct coresight_device *csdev;
> + int traceid;
> +};
> +
> +DEFINE_CORESIGHT_DEVLIST(source_devs, "dummy_source");
> +DEFINE_CORESIGHT_DEVLIST(sink_devs, "dummy_sink");
> +
> +static int dummy_source_enable(struct coresight_device *csdev,
> + struct perf_event *event, u32 mode)
> +{
> + struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> +
> + dev_dbg(drvdata->dev, "Dummy source enabled\n");
> +
> + return 0;
> +}
> +
> +static void dummy_source_disable(struct coresight_device *csdev,
> + struct perf_event *event)
> +{
> + struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> +
> + dev_dbg(drvdata->dev, "Dummy source disabled\n");
> +}
> +
> +static int dummy_sink_enable(struct coresight_device *csdev, u32 mode,
> + void *data)
> +{
> + struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> +
> + dev_dbg(drvdata->dev, "Dummy sink enabled\n");
> +
> + return 0;
> +}
> +
> +static int dummy_sink_disable(struct coresight_device *csdev)
> +{
> + struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> +
> + dev_dbg(drvdata->dev, "Dummy sink disabled\n");
> +
> + return 0;
> +}
> +
> +static const struct coresight_ops_source dummy_source_ops = {
> + .enable = dummy_source_enable,
> + .disable = dummy_source_disable,
> +};
> +
> +static const struct coresight_ops dummy_source_cs_ops = {
> + .source_ops = &dummy_source_ops,
> +};
> +
> +static const struct coresight_ops_sink dummy_sink_ops = {
> + .enable = dummy_sink_enable,
> + .disable = dummy_sink_disable,
> +};
> +
> +static const struct coresight_ops dummy_sink_cs_ops = {
> + .sink_ops = &dummy_sink_ops,
> +};
> +
> +static int dummy_probe(struct platform_device *pdev)
> +{
> + int trace_id;
> + struct device *dev = &pdev->dev;
> + struct device_node *node = dev->of_node;
> + struct coresight_platform_data *pdata;
> + struct dummy_drvdata *drvdata;
> + struct coresight_desc desc = { 0 };
> +
> + if (of_device_is_compatible(node, "arm,coresight-dummy-source")) {
> + trace_id = coresight_trace_id_get_system_id();
Why is this needed ? If at all we need something, this must be
explicitly asked for. How is this used ?
> + if (trace_id < 0)
> + return trace_id;
> +
> + desc.name = coresight_alloc_device_name(&source_devs, dev);
> + if (!desc.name)
> + return -ENOMEM;
> +
> + desc.type = CORESIGHT_DEV_TYPE_SOURCE;
> + desc.subtype.source_subtype =
> + CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS;
> + desc.ops = &dummy_source_cs_ops;
> + } else if (of_device_is_compatible(node, "arm,coresight-dummy-sink")) {
> + desc.name = coresight_alloc_device_name(&sink_devs, dev);
> + if (!desc.name)
> + return -ENOMEM;
> +
> + desc.type = CORESIGHT_DEV_TYPE_SINK;
> + desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_DUMMY;
> + desc.ops = &dummy_sink_cs_ops;
> + } else {
> + dev_err(dev, "Device type not set\n");
> + return -EINVAL;
> + }
> +
> + pdata = coresight_get_platform_data(dev);
> + if (IS_ERR(pdata))
> + return PTR_ERR(pdata);
> + pdev->dev.platform_data = pdata;
> +
> + drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
> + if (!drvdata)
> + return -ENOMEM;
If we have allocated a traceid, we must clean it up here and/or at
device removal.
> +
> + drvdata->dev = &pdev->dev;
> + platform_set_drvdata(pdev, drvdata);
> +
> + desc.pdata = pdev->dev.platform_data;
> + desc.dev = &pdev->dev;
> + drvdata->csdev = coresight_register(&desc);
> + if (IS_ERR(drvdata->csdev))
> + return PTR_ERR(drvdata->csdev);
> +
> + drvdata->traceid = (u8)trace_id;
Where/how is this used ?
Suzuki
Hi Suzuki,
On 4/24/2023 8:09 PM, Suzuki K Poulose wrote:
> On 22/04/2023 08:37, Hao Zhang wrote:
>> Some Coresight devices that kernel don't have permission to access or
>> configure. So there need driver to register dummy devices as Coresight
>> devices. It may also be used to define components that may not have
>> any programming interfaces (e.g, static links), so that paths can be
>> established in the driver. Provide Coresight API for dummy device
>> operations, such as enabling and disabling dummy devices. Build the
>> Coresight path for dummy sink or dummy source for debugging.
>>
>> Signed-off-by: Hao Zhang <[email protected]>
>> ---
>> drivers/hwtracing/coresight/Kconfig | 11 ++
>> drivers/hwtracing/coresight/Makefile | 1 +
>> drivers/hwtracing/coresight/coresight-dummy.c | 179 ++++++++++++++++++
>> include/linux/coresight.h | 1 +
>> 4 files changed, 192 insertions(+)
>> create mode 100644 drivers/hwtracing/coresight/coresight-dummy.c
>>
>> diff --git a/drivers/hwtracing/coresight/Kconfig
>> b/drivers/hwtracing/coresight/Kconfig
>> index 2b5bbfffbc4f..06f0a7594169 100644
>> --- a/drivers/hwtracing/coresight/Kconfig
>> +++ b/drivers/hwtracing/coresight/Kconfig
>> @@ -236,4 +236,15 @@ config CORESIGHT_TPDA
>> To compile this driver as a module, choose M here: the module
>> will be
>> called coresight-tpda.
>> +
>> +config CORESIGHT_DUMMY
>> + tristate "Dummy driver support"
>> + help
>> + Enables support for dummy driver. Dummy driver can be used for
>> + CoreSight sources/sinks that are owned and configured by some
>> + other subsystem and use Linux drivers to configure rest of trace
>> + path.
>> +
>> + To compile this driver as a module, choose M here: the module
>> will be
>> + called coresight-dummy.
>> endif
>> diff --git a/drivers/hwtracing/coresight/Makefile
>> b/drivers/hwtracing/coresight/Makefile
>> index 33bcc3f7b8ae..995d3b2c76df 100644
>> --- a/drivers/hwtracing/coresight/Makefile
>> +++ b/drivers/hwtracing/coresight/Makefile
>> @@ -30,3 +30,4 @@ obj-$(CONFIG_CORESIGHT_TPDA) += coresight-tpda.o
>> coresight-cti-y := coresight-cti-core.o coresight-cti-platform.o \
>> coresight-cti-sysfs.o
>> obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o
>> +obj-$(CONFIG_CORESIGHT_DUMMY) += coresight-dummy.o
>> diff --git a/drivers/hwtracing/coresight/coresight-dummy.c
>> b/drivers/hwtracing/coresight/coresight-dummy.c
>> new file mode 100644
>> index 000000000000..1fb8b3d1c170
>> --- /dev/null
>> +++ b/drivers/hwtracing/coresight/coresight-dummy.c
>> @@ -0,0 +1,179 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights
>> reserved.
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/coresight.h>
>> +#include <linux/of.h>
>> +#include <linux/pm_runtime.h>
>> +
>> +#include "coresight-priv.h"
>> +#include "coresight-trace-id.h"
>> +
>> +struct dummy_drvdata {
>> + struct device *dev;
>> + struct coresight_device *csdev;
>> + int traceid;
>> +};
>> +
>> +DEFINE_CORESIGHT_DEVLIST(source_devs, "dummy_source");
>> +DEFINE_CORESIGHT_DEVLIST(sink_devs, "dummy_sink");
>> +
>> +static int dummy_source_enable(struct coresight_device *csdev,
>> + struct perf_event *event, u32 mode)
>> +{
>> + struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>> +
>> + dev_dbg(drvdata->dev, "Dummy source enabled\n");
>> +
>> + return 0;
>> +}
>> +
>> +static void dummy_source_disable(struct coresight_device *csdev,
>> + struct perf_event *event)
>> +{
>> + struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>> +
>> + dev_dbg(drvdata->dev, "Dummy source disabled\n");
>> +}
>> +
>> +static int dummy_sink_enable(struct coresight_device *csdev, u32 mode,
>> + void *data)
>> +{
>> + struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>> +
>> + dev_dbg(drvdata->dev, "Dummy sink enabled\n");
>> +
>> + return 0;
>> +}
>> +
>> +static int dummy_sink_disable(struct coresight_device *csdev)
>> +{
>> + struct dummy_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>> +
>> + dev_dbg(drvdata->dev, "Dummy sink disabled\n");
>> +
>> + return 0;
>> +}
>> +
>> +static const struct coresight_ops_source dummy_source_ops = {
>> + .enable = dummy_source_enable,
>> + .disable = dummy_source_disable,
>> +};
>> +
>> +static const struct coresight_ops dummy_source_cs_ops = {
>> + .source_ops = &dummy_source_ops,
>> +};
>> +
>> +static const struct coresight_ops_sink dummy_sink_ops = {
>> + .enable = dummy_sink_enable,
>> + .disable = dummy_sink_disable,
>> +};
>> +
>> +static const struct coresight_ops dummy_sink_cs_ops = {
>> + .sink_ops = &dummy_sink_ops,
>> +};
>> +
>> +static int dummy_probe(struct platform_device *pdev)
>> +{
>> + int trace_id;
>> + struct device *dev = &pdev->dev;
>> + struct device_node *node = dev->of_node;
>> + struct coresight_platform_data *pdata;
>> + struct dummy_drvdata *drvdata;
>> + struct coresight_desc desc = { 0 };
>> +
>> + if (of_device_is_compatible(node, "arm,coresight-dummy-source")) {
>> + trace_id = coresight_trace_id_get_system_id();
>
> Why is this needed ? If at all we need something, this must be
> explicitly asked for. How is this used ?
> >
>> + if (trace_id < 0)
>> + return trace_id;
>> +
>> + desc.name = coresight_alloc_device_name(&source_devs, dev);
>> + if (!desc.name)
>> + return -ENOMEM;
>> +
>> + desc.type = CORESIGHT_DEV_TYPE_SOURCE;
>> + desc.subtype.source_subtype =
>> + CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS;
>> + desc.ops = &dummy_source_cs_ops;
>> + } else if (of_device_is_compatible(node,
>> "arm,coresight-dummy-sink")) {
>> + desc.name = coresight_alloc_device_name(&sink_devs, dev);
>> + if (!desc.name)
>> + return -ENOMEM;
>> +
>> + desc.type = CORESIGHT_DEV_TYPE_SINK;
>> + desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_DUMMY;
>> + desc.ops = &dummy_sink_cs_ops;
>> + } else {
>> + dev_err(dev, "Device type not set\n");
>> + return -EINVAL;
>> + }
>> +
>> + pdata = coresight_get_platform_data(dev);
>> + if (IS_ERR(pdata))
>> + return PTR_ERR(pdata);
>> + pdev->dev.platform_data = pdata;
>> +
>> + drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
>> + if (!drvdata)
>> + return -ENOMEM;
>
> If we have allocated a traceid, we must clean it up here and/or at
> device removal.
> >> +
>> + drvdata->dev = &pdev->dev;
>> + platform_set_drvdata(pdev, drvdata);
>> +
>> + desc.pdata = pdev->dev.platform_data;
>> + desc.dev = &pdev->dev;
>> + drvdata->csdev = coresight_register(&desc);
>> + if (IS_ERR(drvdata->csdev))
>> + return PTR_ERR(drvdata->csdev);
>> +
>> + drvdata->traceid = (u8)trace_id;
>
> Where/how is this used ?
>
> Suzuki
>
This is required for ATID filtering funtion which is our HW design for
ETR, we need to set traceid/atid for etm, stm and tpda. Therefore, it's
needed if the type of dummy source is etm. This part is waiting for
upstream. I will remove it now and upstream it as the part of ATID
filtering in the further.
Thanks,
Hao
On Sat, Apr 22, 2023 at 03:37:14PM +0800, Hao Zhang wrote:
> +Introduction
> +---------------------------
> +
> +Coresight Dummy Trace Module is for the specific devices that kernel
> +don't have permission to access or configure, e.g., CoreSight TPDMs
> +on Qualcomm platforms. So there need driver to register dummy devices
> +as Coresight devices. It may also be used to define components that
> +may not have any programming interfaces (e.g, static links), so that
> +paths can be established in the driver. Provide Coresight API for
> +dummy device operations, such as enabling and disabling dummy devices.
> +Build the Coresight path for dummy sink or dummy source for debugging.
> +
> +Config details
> +---------------------------
> +
> +There are two types of nodes, dummy sink and dummy source. The nodes
> +should be observed at the below coresight path::
> +
> + ``/sys/bus/coresight/devices``.
> +
> +e.g.::
> +
> + / $ ls -l /sys/bus/coresight/devices | grep dummy
> + dummy0 -> ../../../devices/platform/soc@0/soc@0:dummy_source/dummy0
> + dummy1 -> ../../../devices/platform/soc@0/soc@0:dummy_sink/dummy1
The wording confuses me, so I have to make the improv:
---- >8 ----
diff --git a/Documentation/trace/coresight/coresight-dummy.rst b/Documentation/trace/coresight/coresight-dummy.rst
index 7cb59f080c8892..f0a92669288b0c 100644
--- a/Documentation/trace/coresight/coresight-dummy.rst
+++ b/Documentation/trace/coresight/coresight-dummy.rst
@@ -8,27 +8,25 @@ Coresight Dummy Trace Module
:Date: May 2023
Introduction
----------------------------
+------------
-Coresight Dummy Trace Module is for the specific devices that kernel
-don't have permission to access or configure, e.g., CoreSight TPDMs
-on Qualcomm platforms. So there need driver to register dummy devices
-as Coresight devices. It may also be used to define components that
-may not have any programming interfaces (e.g, static links), so that
-paths can be established in the driver. Provide Coresight API for
-dummy device operations, such as enabling and disabling dummy devices.
-Build the Coresight path for dummy sink or dummy source for debugging.
+The Coresight dummy trace module is for the specific devices that kernel don't
+have permission to access or configure, e.g., CoreSight TPDMs on Qualcomm
+platforms. For these devices, a dummy driver is needed to register them as
+Coresight devices. The module may also be used to define components that may
+not have any programming interfaces (e.g, static links), so that paths can be
+created in the driver. It provides Coresight API for operations on dummy
+devices, such as enabling and disabling them. It also provides the Coresight
+dummy sink/source paths for debugging.
Config details
----------------------------
+--------------
-There are two types of nodes, dummy sink and dummy source. The nodes
-should be observed at the below coresight path::
+There are two types of nodes, dummy sink and dummy source. These nodes
+are available at ``/sys/bus/coresight/devices``.
- ``/sys/bus/coresight/devices``.
+Example output::
-e.g.::
-
- / $ ls -l /sys/bus/coresight/devices | grep dummy
+ $ ls -l /sys/bus/coresight/devices | grep dummy
dummy_sink0 -> ../../../devices/platform/soc@0/soc@0:sink/dummy_sink0
dummy_source0 -> ../../../devices/platform/soc@0/soc@0:source/dummy_source0
Thanks.
--
An old man doll... just what I always wanted! - Clara
Hi Bagas,
On 5/10/2023 12:29 PM, Bagas Sanjaya wrote:
> On Sat, Apr 22, 2023 at 03:37:14PM +0800, Hao Zhang wrote:
>> +Introduction
>> +---------------------------
>> +
>> +Coresight Dummy Trace Module is for the specific devices that kernel
>> +don't have permission to access or configure, e.g., CoreSight TPDMs
>> +on Qualcomm platforms. So there need driver to register dummy devices
>> +as Coresight devices. It may also be used to define components that
>> +may not have any programming interfaces (e.g, static links), so that
>> +paths can be established in the driver. Provide Coresight API for
>> +dummy device operations, such as enabling and disabling dummy devices.
>> +Build the Coresight path for dummy sink or dummy source for debugging.
>> +
>> +Config details
>> +---------------------------
>> +
>> +There are two types of nodes, dummy sink and dummy source. The nodes
>> +should be observed at the below coresight path::
>> +
>> + ``/sys/bus/coresight/devices``.
>> +
>> +e.g.::
>> +
>> + / $ ls -l /sys/bus/coresight/devices | grep dummy
>> + dummy0 -> ../../../devices/platform/soc@0/soc@0:dummy_source/dummy0
>> + dummy1 -> ../../../devices/platform/soc@0/soc@0:dummy_sink/dummy1
>
> The wording confuses me, so I have to make the improv:
>
> ---- >8 ----
> diff --git a/Documentation/trace/coresight/coresight-dummy.rst b/Documentation/trace/coresight/coresight-dummy.rst
> index 7cb59f080c8892..f0a92669288b0c 100644
> --- a/Documentation/trace/coresight/coresight-dummy.rst
> +++ b/Documentation/trace/coresight/coresight-dummy.rst
> @@ -8,27 +8,25 @@ Coresight Dummy Trace Module
> :Date: May 2023
>
> Introduction
> ----------------------------
> +------------
>
> -Coresight Dummy Trace Module is for the specific devices that kernel
> -don't have permission to access or configure, e.g., CoreSight TPDMs
> -on Qualcomm platforms. So there need driver to register dummy devices
> -as Coresight devices. It may also be used to define components that
> -may not have any programming interfaces (e.g, static links), so that
> -paths can be established in the driver. Provide Coresight API for
> -dummy device operations, such as enabling and disabling dummy devices.
> -Build the Coresight path for dummy sink or dummy source for debugging.
> +The Coresight dummy trace module is for the specific devices that kernel don't
> +have permission to access or configure, e.g., CoreSight TPDMs on Qualcomm
> +platforms. For these devices, a dummy driver is needed to register them as
> +Coresight devices. The module may also be used to define components that may
> +not have any programming interfaces (e.g, static links), so that paths can be
> +created in the driver. It provides Coresight API for operations on dummy
> +devices, such as enabling and disabling them. It also provides the Coresight
> +dummy sink/source paths for debugging.
>
> Config details
> ----------------------------
> +--------------
>
> -There are two types of nodes, dummy sink and dummy source. The nodes
> -should be observed at the below coresight path::
> +There are two types of nodes, dummy sink and dummy source. These nodes
> +are available at ``/sys/bus/coresight/devices``.
>
> - ``/sys/bus/coresight/devices``.
> +Example output::
>
> -e.g.::
> -
> - / $ ls -l /sys/bus/coresight/devices | grep dummy
> + $ ls -l /sys/bus/coresight/devices | grep dummy
> dummy_sink0 -> ../../../devices/platform/soc@0/soc@0:sink/dummy_sink0
> dummy_source0 -> ../../../devices/platform/soc@0/soc@0:source/dummy_source0
>
> Thanks.
>
Thanks for your review and comments, will update it in the next patch
series.
Thanks,
Hao