CoreSight

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Re: [PATCH v2 1/3] Coresight: Add coresight dummy driver

by Mike Leach

Hi, A few additional comments.... On Tue, 28 Mar 2023 at 10:24, Hao Zhang <quic_hazha(a)quicinc.com> wrote: > > Hi Suzuki, > > On 3/28/2023 4:35 PM, Suzuki K Poulose wrote: > > On 28/03/2023 08:22, Hao Zhang wrote: > >> Hi Mike, > >> > >> On 3/27/2023 11:58 PM, Mike Leach wrote: > >>> Hi, > >>> > >>> On Fri, 24 Mar 2023 at 06:16, Hao Zhang <quic_hazha(a)quicinc.com> wrote: > >>>> > >>>> Some Coresight devices that HLOS don't have permission to access > >>>> or configure. Such as Coresight sink EUD, some TPDMs etc. So there > >>>> need driver to register dummy devices as Coresight devices. 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 <quic_hazha(a)quicinc.com> > >>>> --- > >>>> drivers/hwtracing/coresight/Kconfig | 11 ++ > >>>> drivers/hwtracing/coresight/Makefile | 1 + > >>>> drivers/hwtracing/coresight/coresight-dummy.c | 176 > >>>> ++++++++++++++++++ > >>>> 3 files changed, 188 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..2d4eb3e546eb > >>>> --- /dev/null > >>>> +++ b/drivers/hwtracing/coresight/coresight-dummy.c > >>>> @@ -0,0 +1,176 @@ > >>>> +// 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(dummy_devs, "dummy"); > >>>> + minor nit: can we have dummy_source and dummy_sink as the device names to make it clear at the first level what these are without having to look at the attributes? > >>>> +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_info(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_info(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_info(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_info(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_sink dummy_sink_ops = { > >>>> + .enable = dummy_sink_enable, > >>>> + .disable = dummy_sink_disable, > >>>> +}; > >>>> + > >>>> +static const struct coresight_ops dummy_cs_ops = { > >>>> + .source_ops = &dummy_source_ops, > >>>> + .sink_ops = &dummy_sink_ops, > >>>> +}; > >>>> + > >>>> +static int dummy_probe(struct platform_device *pdev) > >>>> +{ > >>>> + int ret, trace_id; > >>>> + struct device *dev = &pdev->dev; > >>>> + struct coresight_platform_data *pdata; > >>>> + struct dummy_drvdata *drvdata; > >>>> + struct coresight_desc desc = { 0 }; > >>>> + > >>>> + desc.name = coresight_alloc_device_name(&dummy_devs, dev); > >>>> + if (!desc.name) > >>>> + return -ENOMEM; > >>>> + > >>>> + 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); > >>>> + > >>>> + if (of_property_read_bool(pdev->dev.of_node, > >>>> "qcom,dummy-source")) { > >>>> + desc.type = CORESIGHT_DEV_TYPE_SOURCE; > >>>> + desc.subtype.source_subtype = > >>>> + CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS; > >>>> + } else if (of_property_read_bool(pdev->dev.of_node, > >>>> + "qcom,dummy-sink")) { It would simplify things if the compatibles were arm,coresight-dummy-source and arm,coresight-dummy-sink - and drop the two additional attributes, using of_device_is_compatible() here. > >>>> + desc.type = CORESIGHT_DEV_TYPE_SINK; > >>>> + desc.subtype.sink_subtype = > >>>> CORESIGHT_DEV_SUBTYPE_SINK_BUFFER; > >>> > >>> This will break the automatic sink selection on a system where perf is > >>> looking for a default sink and the dummy sink is closest / first > >>> discovered. > >>> > >>> i.e. when perf record -e cs_etm// <options> > >>> is used to trace a program in linux, a dummy sink appearing in the > >>> coresight tree with this designation may be selected. > >>> > >>> This needs to be corrected, probably with a unique sub-type that > >>> appears before the CORESIGHT_DEV_SUBTYPE_SINK_BUFFER value in the enum > >>> as the selection is based on >= CORESIGHT_DEV_SUBTYPE_SINK_BUFFER. > >>> > > > > Good point Mike. > > > >>> By implication adding a new value - will possibly affect other code > >>> using the enum values so will need to be checked > >>> > >>> Regards > >>> > >>> Mike > >>> > >> > >> Thanks for your comments, I will add a new sub-type for dummy sink and > >> check the impact of it. > > > > Please keep this as the lowest priority, something like: > > > > 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, > > CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM, > > }; > > > > This should be fine without any impact on the existing code, as we > > expect the driver modules to be updated with the new core module. > > > > Suzuki > > > > Sure, I will take your advice in the next version of patch. > > Thanks, > Hao > > > > >> > >> Thanks, > >> Hao > >> > >>> > >>>> + } else { > >>>> + dev_info(dev, "Device type not set\n"); > >>>> + return -EINVAL; > >>>> + } > >>>> + > >>>> + desc.ops = &dummy_cs_ops; > >>>> + 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); > >>>> + > >>>> + trace_id = coresight_trace_id_get_system_id(); > >>>> + if (trace_id < 0) { > >>>> + ret = trace_id; > >>>> + goto cs_unregister; > >>>> + } > >>>> + drvdata->traceid = (u8)trace_id; > >>>> + Number of issues here:- 1) Why are sinks being given a trace ID? - they do not need them. 2) how is the trace ID communicated to the underlying hardware system? - there appears to be no way of doing this here. Without this you cannot guarantee that there will not be clashes. Although your use case may mitigate against this - for this to be a generic module there must be a way to ensure the IDs can be discovered externally. 3) Trace IDs are a limited resource - most sources allocate on enable, release on disable / reset - this would be preferable. Regards Mike > >>>> + pm_runtime_enable(dev); > >>>> + dev_info(dev, "Dummy device initialized\n"); > >>>> + > >>>> + return 0; > >>>> + > >>>> +cs_unregister: > >>>> + coresight_unregister(drvdata->csdev); > >>>> + > >>>> + return ret; > >>>> +} > >>>> + > >>>> +static int dummy_remove(struct platform_device *pdev) > >>>> +{ > >>>> + struct dummy_drvdata *drvdata = platform_get_drvdata(pdev); > >>>> + struct device *dev = &pdev->dev; > >>>> + > >>>> + coresight_trace_id_put_system_id(drvdata->traceid); > >>>> + pm_runtime_disable(dev); > >>>> + coresight_unregister(drvdata->csdev); > >>>> + return 0; > >>>> +} > >>>> + > >>>> +static const struct of_device_id dummy_match[] = { > >>>> + {.compatible = "qcom,coresight-dummy"}, > >>>> + {}, > >>>> +}; > >>>> + > >>>> +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 source driver"); > >>>> -- > >>>> 2.17.1 > >>>> > >>> > >>> > > -- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK

2 years, 3 months

Re: [BUG] perf: No samples found when using kcore + coresight

by James Clark

On 28/03/2023 01:53, Yang Shi wrote: > Hi Leo, > > Just follow up on this one. Any update? > Hi Yang, Sorry no update on this yet from me. I was just finishing off "coresight: Fix CTI module refcount leak by making it a helper device" which I hope to post in the next day or two and then I will start on this. James > Thanks, > Yang > > On Mon, Mar 13, 2023 at 5:36 PM Leo Yan <leo.yan(a)linaro.org> wrote: >> >> On Mon, Mar 13, 2023 at 11:15:44AM -0700, Yang Shi wrote: >> >> [...] >> >>>> Just a quick summary, here we have two issues: >>>> >>>> - With command: >>>> perf record -e cs_etm/@tmc_etf63/k --kcore --per-thread \ >>>> -- taskset --cpu-list 1 uname", >>>> >>>> perf doesn't enable "text poke" attribution. >>> >>> No, it enables "text poke" and perf fails to decode coresight trace >>> data too. It doesn't matter whether "--kcore" is after or before "-e >>> cs/etm/@tmc_etf63/k". >> >> Understand now. Thanks for correction, if so we can ignore this one. >> >> Leo

2 years, 3 months

Re: [PATCH v2 1/3] Coresight: Add coresight dummy driver

by Suzuki K Poulose

On 28/03/2023 08:22, Hao Zhang wrote: > Hi Mike, > > On 3/27/2023 11:58 PM, Mike Leach wrote: >> Hi, >> >> On Fri, 24 Mar 2023 at 06:16, Hao Zhang <quic_hazha(a)quicinc.com> wrote: >>> >>> Some Coresight devices that HLOS don't have permission to access >>> or configure. Such as Coresight sink EUD, some TPDMs etc. So there >>> need driver to register dummy devices as Coresight devices. 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 <quic_hazha(a)quicinc.com> >>> --- >>> drivers/hwtracing/coresight/Kconfig | 11 ++ >>> drivers/hwtracing/coresight/Makefile | 1 + >>> drivers/hwtracing/coresight/coresight-dummy.c | 176 ++++++++++++++++++ >>> 3 files changed, 188 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..2d4eb3e546eb >>> --- /dev/null >>> +++ b/drivers/hwtracing/coresight/coresight-dummy.c >>> @@ -0,0 +1,176 @@ >>> +// 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(dummy_devs, "dummy"); >>> + >>> +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_info(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_info(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_info(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_info(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_sink dummy_sink_ops = { >>> + .enable = dummy_sink_enable, >>> + .disable = dummy_sink_disable, >>> +}; >>> + >>> +static const struct coresight_ops dummy_cs_ops = { >>> + .source_ops = &dummy_source_ops, >>> + .sink_ops = &dummy_sink_ops, >>> +}; >>> + >>> +static int dummy_probe(struct platform_device *pdev) >>> +{ >>> + int ret, trace_id; >>> + struct device *dev = &pdev->dev; >>> + struct coresight_platform_data *pdata; >>> + struct dummy_drvdata *drvdata; >>> + struct coresight_desc desc = { 0 }; >>> + >>> + desc.name = coresight_alloc_device_name(&dummy_devs, dev); >>> + if (!desc.name) >>> + return -ENOMEM; >>> + >>> + 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); >>> + >>> + if (of_property_read_bool(pdev->dev.of_node, >>> "qcom,dummy-source")) { >>> + desc.type = CORESIGHT_DEV_TYPE_SOURCE; >>> + desc.subtype.source_subtype = >>> + >>> CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS; >>> + } else if (of_property_read_bool(pdev->dev.of_node, >>> + "qcom,dummy-sink")) { >>> + desc.type = CORESIGHT_DEV_TYPE_SINK; >>> + desc.subtype.sink_subtype = >>> CORESIGHT_DEV_SUBTYPE_SINK_BUFFER; >> >> This will break the automatic sink selection on a system where perf is >> looking for a default sink and the dummy sink is closest / first >> discovered. >> >> i.e. when perf record -e cs_etm// <options> >> is used to trace a program in linux, a dummy sink appearing in the >> coresight tree with this designation may be selected. >> >> This needs to be corrected, probably with a unique sub-type that >> appears before the CORESIGHT_DEV_SUBTYPE_SINK_BUFFER value in the enum >> as the selection is based on >= CORESIGHT_DEV_SUBTYPE_SINK_BUFFER. >> Good point Mike. >> By implication adding a new value - will possibly affect other code >> using the enum values so will need to be checked >> >> Regards >> >> Mike >> > > Thanks for your comments, I will add a new sub-type for dummy sink and > check the impact of it. Please keep this as the lowest priority, something like: 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, CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM, }; This should be fine without any impact on the existing code, as we expect the driver modules to be updated with the new core module. Suzuki > > Thanks, > Hao > >> >>> + } else { >>> + dev_info(dev, "Device type not set\n"); >>> + return -EINVAL; >>> + } >>> + >>> + desc.ops = &dummy_cs_ops; >>> + 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); >>> + >>> + trace_id = coresight_trace_id_get_system_id(); >>> + if (trace_id < 0) { >>> + ret = trace_id; >>> + goto cs_unregister; >>> + } >>> + drvdata->traceid = (u8)trace_id; >>> + >>> + pm_runtime_enable(dev); >>> + dev_info(dev, "Dummy device initialized\n"); >>> + >>> + return 0; >>> + >>> +cs_unregister: >>> + coresight_unregister(drvdata->csdev); >>> + >>> + return ret; >>> +} >>> + >>> +static int dummy_remove(struct platform_device *pdev) >>> +{ >>> + struct dummy_drvdata *drvdata = platform_get_drvdata(pdev); >>> + struct device *dev = &pdev->dev; >>> + >>> + coresight_trace_id_put_system_id(drvdata->traceid); >>> + pm_runtime_disable(dev); >>> + coresight_unregister(drvdata->csdev); >>> + return 0; >>> +} >>> + >>> +static const struct of_device_id dummy_match[] = { >>> + {.compatible = "qcom,coresight-dummy"}, >>> + {}, >>> +}; >>> + >>> +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 source driver"); >>> -- >>> 2.17.1 >>> >> >>

2 years, 3 months

Re: [PATCH v2 1/3] Coresight: Add coresight dummy driver

by Mike Leach

Hi, On Fri, 24 Mar 2023 at 06:16, Hao Zhang <quic_hazha(a)quicinc.com> wrote: > > Some Coresight devices that HLOS don't have permission to access > or configure. Such as Coresight sink EUD, some TPDMs etc. So there > need driver to register dummy devices as Coresight devices. 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 <quic_hazha(a)quicinc.com> > --- > drivers/hwtracing/coresight/Kconfig | 11 ++ > drivers/hwtracing/coresight/Makefile | 1 + > drivers/hwtracing/coresight/coresight-dummy.c | 176 ++++++++++++++++++ > 3 files changed, 188 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..2d4eb3e546eb > --- /dev/null > +++ b/drivers/hwtracing/coresight/coresight-dummy.c > @@ -0,0 +1,176 @@ > +// 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(dummy_devs, "dummy"); > + > +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_info(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_info(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_info(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_info(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_sink dummy_sink_ops = { > + .enable = dummy_sink_enable, > + .disable = dummy_sink_disable, > +}; > + > +static const struct coresight_ops dummy_cs_ops = { > + .source_ops = &dummy_source_ops, > + .sink_ops = &dummy_sink_ops, > +}; > + > +static int dummy_probe(struct platform_device *pdev) > +{ > + int ret, trace_id; > + struct device *dev = &pdev->dev; > + struct coresight_platform_data *pdata; > + struct dummy_drvdata *drvdata; > + struct coresight_desc desc = { 0 }; > + > + desc.name = coresight_alloc_device_name(&dummy_devs, dev); > + if (!desc.name) > + return -ENOMEM; > + > + 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); > + > + if (of_property_read_bool(pdev->dev.of_node, "qcom,dummy-source")) { > + desc.type = CORESIGHT_DEV_TYPE_SOURCE; > + desc.subtype.source_subtype = > + CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS; > + } else if (of_property_read_bool(pdev->dev.of_node, > + "qcom,dummy-sink")) { > + desc.type = CORESIGHT_DEV_TYPE_SINK; > + desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER; This will break the automatic sink selection on a system where perf is looking for a default sink and the dummy sink is closest / first discovered. i.e. when perf record -e cs_etm// <options> is used to trace a program in linux, a dummy sink appearing in the coresight tree with this designation may be selected. This needs to be corrected, probably with a unique sub-type that appears before the CORESIGHT_DEV_SUBTYPE_SINK_BUFFER value in the enum as the selection is based on >= CORESIGHT_DEV_SUBTYPE_SINK_BUFFER. By implication adding a new value - will possibly affect other code using the enum values so will need to be checked Regards Mike > + } else { > + dev_info(dev, "Device type not set\n"); > + return -EINVAL; > + } > + > + desc.ops = &dummy_cs_ops; > + 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); > + > + trace_id = coresight_trace_id_get_system_id(); > + if (trace_id < 0) { > + ret = trace_id; > + goto cs_unregister; > + } > + drvdata->traceid = (u8)trace_id; > + > + pm_runtime_enable(dev); > + dev_info(dev, "Dummy device initialized\n"); > + > + return 0; > + > +cs_unregister: > + coresight_unregister(drvdata->csdev); > + > + return ret; > +} > + > +static int dummy_remove(struct platform_device *pdev) > +{ > + struct dummy_drvdata *drvdata = platform_get_drvdata(pdev); > + struct device *dev = &pdev->dev; > + > + coresight_trace_id_put_system_id(drvdata->traceid); > + pm_runtime_disable(dev); > + coresight_unregister(drvdata->csdev); > + return 0; > +} > + > +static const struct of_device_id dummy_match[] = { > + {.compatible = "qcom,coresight-dummy"}, > + {}, > +}; > + > +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 source driver"); > -- > 2.17.1 > -- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK

2 years, 3 months

[PATCH] coresight: cti: Check if the CPU activated for the CPU CTI

by Tao Zhang

Check whether the CPU corresponding to the CPU CTI is activated. If it is not activated, the CPU CTI node should not exist, and an error will be returned in the initialization function. Signed-off-by: Tao Zhang <quic_taozha(a)quicinc.com> --- drivers/hwtracing/coresight/coresight-cti-core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c index 277c890..aaa83ae 100644 --- a/drivers/hwtracing/coresight/coresight-cti-core.c +++ b/drivers/hwtracing/coresight/coresight-cti-core.c @@ -899,10 +899,12 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) drvdata->config.hw_powered = true; /* set up device name - will depend if cpu bound or otherwise */ - if (drvdata->ctidev.cpu >= 0) + if (drvdata->ctidev.cpu >= 0) { + if (!cpu_active(drvdata->ctidev.cpu)) + return -ENXIO; cti_desc.name = devm_kasprintf(dev, GFP_KERNEL, "cti_cpu%d", drvdata->ctidev.cpu); - else + } else cti_desc.name = coresight_alloc_device_name(&cti_sys_devs, dev); if (!cti_desc.name) return -ENOMEM; -- 2.7.4

2 years, 3 months

Re: [PATCH v2 3/3] Documentation: trace: Add documentation for Coresight Dummy Trace

by Suzuki K Poulose

On 24/03/2023 06:16, Hao Zhang wrote: > Add documentation for Coresight Dummy Trace under trace/coresight. > > Signed-off-by: Hao Zhang <quic_hazha(a)quicinc.com> > --- > .../trace/coresight/coresight-dummy.rst | 58 +++++++++++++++++++ > 1 file changed, 58 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..819cabab8623 > --- /dev/null > +++ b/Documentation/trace/coresight/coresight-dummy.rst > @@ -0,0 +1,58 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +============================= > +Coresight Dummy Trace Module > +============================= > + > + :Author: Hao Zhang <quic_hazha(a)quicinc.com> > + :Date: March 2023 > + > +Introduction > +--------------------------- > + > +Coresight Dummy Trace Module is for the specific devices that HLOS don't Please do not use cryptic abbreviations, please use "kernel" > +have permission to access or configure. Such as Coresight sink EUD, some > +TPDMs etc. Say "e.g., CoreSight TPDMs on Qualcomm platforms.: So there need driver to register dummy devices as Coresight > +devices. Add: "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. I think the following content may not be needed as they are part of the standard source/sink type devices, nothing specific to dummy devices. --- vvvvv --- > + > +Sysfs files and directories > +--------------------------- > + > +Root: ``/sys/bus/coresight/devices/dummy<N>`` > + > +---- > + > +:File: ``enable_source`` (RW) > +:Notes: > + - > 0 : enable the datasets of dummy source. > + > + - = 0 : disable the datasets of dummy source. > + > +:Syntax: > + ``echo 1 > enable_source`` > + > +---- > + > +:File: ``enable_sink`` (RW) > +:Notes: > + - > 0 : enable the datasets of dummy sink. > + > + - = 0 : disable the datasets of dummy sink. > + > +:Syntax: > + ``echo 1 > enable_sink`` > + > +---- > + --- You may remove the above ^^^ ---- > +Config details > +--------------------------- > + > +There are two types of nodes, dummy sink and dummy source. The nodes > +should be observed at the coresight path > +"/sys/bus/coresight/devices". > +e.g. > +/sys/bus/coresight/devices # ls -l | grep dummy > +dummy0 -> ../../../devices/platform/soc@0/soc@0:dummy_source/dummy0 > +dummy1 -> ../../../devices/platform/soc@0/soc@0:dummy_sink/dummy1 Suzuki

2 years, 3 months

Re: [PATCH v2 2/3] dt-bindings: arm: Add Coresight Dummy Trace YAML schema

by Suzuki K Poulose

On 24/03/2023 06:16, Hao Zhang wrote: > Add new coresight-dummy.yaml file describing the bindings required > to define coresight dummy trace in the device trees. > > Signed-off-by: Hao Zhang <quic_hazha(a)quicinc.com> > --- > .../bindings/arm/qcom,coresight-dummy.yaml | 118 ++++++++++++++++++ > 1 file changed, 118 insertions(+) > create mode 100644 Documentation/devicetree/bindings/arm/qcom,coresight-dummy.yaml > > diff --git a/Documentation/devicetree/bindings/arm/qcom,coresight-dummy.yaml b/Documentation/devicetree/bindings/arm/qcom,coresight-dummy.yaml > new file mode 100644 > index 000000000000..7b719b084d72 > --- /dev/null > +++ b/Documentation/devicetree/bindings/arm/qcom,coresight-dummy.yaml > @@ -0,0 +1,118 @@ > +# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause > +# Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved. > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/arm/qcom,coresight-dummy.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: QCOM Coresight Dummy component As mentioned in the previous email, please make this Arm CoreSight. This is not specific to Qcom, rather something the CoreSight driver exposes as a dummy framework. Otherwise looks good to me. Suzuki

2 years, 3 months

Re: [PATCH v2 1/3] Coresight: Add coresight dummy driver

by Suzuki K Poulose

On 24/03/2023 06:16, Hao Zhang wrote: > Some Coresight devices that HLOS don't have permission to access > or configure. Such as Coresight sink EUD, some TPDMs etc. So there > need driver to register dummy devices as Coresight devices. 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 <quic_hazha(a)quicinc.com> > --- > drivers/hwtracing/coresight/Kconfig | 11 ++ > drivers/hwtracing/coresight/Makefile | 1 + > drivers/hwtracing/coresight/coresight-dummy.c | 176 ++++++++++++++++++ > 3 files changed, 188 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..2d4eb3e546eb > --- /dev/null > +++ b/drivers/hwtracing/coresight/coresight-dummy.c > @@ -0,0 +1,176 @@ > +// 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(dummy_devs, "dummy"); > + > +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_info(drvdata->dev, "Dummy source enabled\n"); Please use dev_dbg everywher. > + > + 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_info(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_info(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_info(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_sink dummy_sink_ops = { > + .enable = dummy_sink_enable, > + .disable = dummy_sink_disable, > +}; > + > +static const struct coresight_ops dummy_cs_ops = { > + .source_ops = &dummy_source_ops, > + .sink_ops = &dummy_sink_ops, > +}; > + > +static int dummy_probe(struct platform_device *pdev) > +{ > + int ret, trace_id; > + struct device *dev = &pdev->dev; > + struct coresight_platform_data *pdata; > + struct dummy_drvdata *drvdata; > + struct coresight_desc desc = { 0 }; > + > + desc.name = coresight_alloc_device_name(&dummy_devs, dev); > + if (!desc.name) > + return -ENOMEM; > + > + 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); > + > + if (of_property_read_bool(pdev->dev.of_node, "qcom,dummy-source")) { I don't see any reason why this should be qcom,... Please could we use : "arm,coresight-", everywhere including the "dt" compatible ? > + desc.type = CORESIGHT_DEV_TYPE_SOURCE; > + desc.subtype.source_subtype = > + CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS; > + } else if (of_property_read_bool(pdev->dev.of_node, > + "qcom,dummy-sink")) { > + desc.type = CORESIGHT_DEV_TYPE_SINK; > + desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER; > + } else { > + dev_info(dev, "Device type not set\n"); > + return -EINVAL; > + } > + > + desc.ops = &dummy_cs_ops; > + 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); > + > + trace_id = coresight_trace_id_get_system_id(); > + if (trace_id < 0) { > + ret = trace_id; > + goto cs_unregister; > + } > + drvdata->traceid = (u8)trace_id; > + > + pm_runtime_enable(dev); > + dev_info(dev, "Dummy device initialized\n"); > + > + return 0; > + > +cs_unregister: > + coresight_unregister(drvdata->csdev); > + > + return ret; > +} > + > +static int dummy_remove(struct platform_device *pdev) > +{ > + struct dummy_drvdata *drvdata = platform_get_drvdata(pdev); > + struct device *dev = &pdev->dev; > + > + coresight_trace_id_put_system_id(drvdata->traceid); > + pm_runtime_disable(dev); > + coresight_unregister(drvdata->csdev); > + return 0; > +} > + > +static const struct of_device_id dummy_match[] = { > + {.compatible = "qcom,coresight-dummy"}, As mentioned above, "arm,coresight-dummy-device" ? This has nothing to do with qcom IP. qcom has a use for this. So, I would like to keep this "coresight" subsystem specific compatibles. May be we could even add other types too : i.e, arm,coresight-dummy-link-split, arm,coresight-dummy-link-merge Suzuki > + {}, > +}; > + > +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 source driver");

2 years, 3 months

[GIT PULL] coresight: Fixes for v6.3

by Suzuki K Poulose

Greg, Please find a couple of fixes for coresight self-hosted tracing for v6.3. Kindly consider pulling. Suzuki The following changes since commit eeac8ede17557680855031c6f305ece2378af326: Linux 6.3-rc2 (2023-03-12 16:36:44 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/coresight/linux.git tags/coresight-fixes-v6.3 for you to fetch changes up to 735e7b30a53a1679c050cddb73f5e5316105d2e3: coresight: etm4x: Do not access TRCIDR1 for identification (2023-03-21 12:31:02 +0000) ---------------------------------------------------------------- coresight: Fixes for v6.3 Fixes for coresight subsystem includes: - Fix etm4_enable_hw to program all the address comparator pairs (instead of half of them) - Do not access TRCIDR1 register without OSLK cleared in etm4_probe for mmio access. Signed-off-by: Suzuki K Poulose <suzuki.poulose(a)arm.com> ---------------------------------------------------------------- Steve Clevenger (1): coresight-etm4: Fix for() loop drvdata->nr_addr_cmp range bug Suzuki K Poulose (1): coresight: etm4x: Do not access TRCIDR1 for identification drivers/hwtracing/coresight/coresight-etm4x-core.c | 24 +++++++++------------- drivers/hwtracing/coresight/coresight-etm4x.h | 20 ++++++------------ 2 files changed, 16 insertions(+), 28 deletions(-)

2 years, 3 months

Re: [PATCH 0/7] coresight: etm4x: Migrate AMBA devices to platform driver

by Suzuki K Poulose

On 20/03/2023 14:17, Rob Herring wrote: > On Thu, Mar 16, 2023 at 10:05 PM Anshuman Khandual > <anshuman.khandual(a)arm.com> wrote: >> >> CoreSight ETM4x devices could be accessed either via MMIO (handled via >> amba_driver) or CPU system instructions (handled via platform driver). But >> this has the following issues : >> >> - Each new CPU comes up with its own PID and thus we need to keep on >> adding the "known" PIDs to get it working with AMBA driver. While >> the ETM4 architecture (and CoreSight architecture) defines way to >> identify a device as ETM4. Thus older kernels won't be able to >> "discover" a newer CPU, unless we add the PIDs. > > But v8.4 discourages MMIO access, so this problem will go away on its > own. Even if not, adding IDs to stable kernels is standard practice > whether it is PCI VID/PID, compatible string or AMBA PID. Yes, it would eventually go away. As for adding the PIDs, the fundamental issue is, unlike other drivers, except for the "PIDs" everything else is architected and each CPU has this PID alone different and we have plenty of CPUs implementaions out there. But all that said, since we added this as an AMBA driver in the first place (all for simply getting the apb_clk management), I am happy to choose the "Add PIDs to stable kernel approach" for this problem. > >> - With ACPI, the ETM4x devices have the same HID to identify the device >> irrespective of the mode of access. This creates a problem where two >> different drivers (both AMBA based driver and platform driver) would >> hook into the "HID" and could conflict. e.g., if AMBA driver gets >> hold of a non-MMIO device, the probe fails. If we have single driver >> hooked into the given "HID", we could handle them seamlessly, >> irrespective of the mode of access. > > Why are we changing DT for ACPI? Just always use the platform driver > for ACPI and leave DT systems alone. This was mainly due to (1), given we have a platform driver anyway for ACPI. As mentioned above, we could leave the DT alone. > >> - CoreSight is heavily dependent on the runtime power management. With >> ACPI, amba_driver doesn't get us anywhere with handling the power >> and thus one need to always turn the power ON to use them. Moving to >> platform driver gives us the power management for free. > > This sounds like an issue for any amba driver. If this is an issue, > solve it for everyone, not just work around it in one driver. This alone wouldn't be sufficient. We need a platform driver anyway to handle the two different modes in ACPI for ETMs. But this will be a an option for the other CoreSight components which are always MMIO. Thanks Suzuki > > When someone puts another primecell device into an ACPI system, are we > going to go do the same one-off change in that driver too? (We kind of > already did with SBSA UART...) > > Rob

2 years, 3 months

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