Hi
On Thu, 17 Jul 2025 at 13:54, Mao Jinlong <quic_jinlmao@xxxxxxxxxxx> wrote:
>
> For some coresight components like CTI and TPDM, there could be
> numerous of them. From the node name, we can only get the type and
> register address of the component. We can't identify the HW or the
> system the component belongs to. Add label sysfs node support for
> showing the intuitive name of the device.
>
> Signed-off-by: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> Reviewed-by: Mike Leach <mike.leach@xxxxxxxxxx>
> ---
> .../testing/sysfs-bus-coresight-devices-cti | 6 ++
> .../sysfs-bus-coresight-devices-dummy-source | 6 ++
> .../testing/sysfs-bus-coresight-devices-etb10 | 6 ++
> .../testing/sysfs-bus-coresight-devices-etm3x | 6 ++
> .../testing/sysfs-bus-coresight-devices-etm4x | 6 ++
> .../sysfs-bus-coresight-devices-funnel | 6 ++
> .../testing/sysfs-bus-coresight-devices-stm | 6 ++
> .../testing/sysfs-bus-coresight-devices-tmc | 6 ++
> .../testing/sysfs-bus-coresight-devices-tpdm | 6 ++
> .../testing/sysfs-bus-coresight-devices-trbe | 6 ++
> drivers/hwtracing/coresight/coresight-sysfs.c | 71 ++++++++++++++++++-
> 11 files changed, 129 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-cti b/Documentation/ABI/testing/sysfs-bus-coresight-devices-cti
> index a97b70f588da..55367bbc696f 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-cti
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-cti
> @@ -239,3 +239,9 @@ Date: March 2020
> KernelVersion: 5.7
> Contact: Mike Leach or Mathieu Poirier
> Description: (Write) Clear all channel / trigger programming.
> +
> +What: /sys/bus/coresight/devices/<cti-name>/label
> +Date: Jul 2025
> +KernelVersion 6.17
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (Read) Show hardware context information of device.
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-dummy-source b/Documentation/ABI/testing/sysfs-bus-coresight-devices-dummy-source
> index 0830661ef656..9a11bd5b15cc 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-dummy-source
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-dummy-source
> @@ -13,3 +13,9 @@ KernelVersion: 6.14
> Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> Description: (R) Show the trace ID that will appear in the trace stream
> coming from this trace entity.
> +
> +What: /sys/bus/coresight/devices/dummy_source<N>/label
> +Date: Jul 2025
> +KernelVersion 6.17
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (Read) Show hardware context information of device.
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etb10 b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etb10
> index 9a383f6a74eb..ff1f89795188 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etb10
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etb10
> @@ -19,6 +19,12 @@ Description: (RW) Disables write access to the Trace RAM by stopping the
> into the Trace RAM following the trigger event is equal to the
> value stored in this register+1 (from ARM ETB-TRM).
>
> +What: /sys/bus/coresight/devices/<memory_map>.etb/label
> +Date: Jul 2025
> +KernelVersion 6.17
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (Read) Show hardware context information of device.
> +
> What: /sys/bus/coresight/devices/<memory_map>.etb/mgmt/rdp
> Date: March 2016
> KernelVersion: 4.7
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm3x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm3x
> index 271b57c571aa..743f26619c69 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm3x
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm3x
> @@ -251,6 +251,12 @@ KernelVersion: 4.4
> Contact: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Description: (RO) Holds the cpu number this tracer is affined to.
>
> +What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/label
> +Date: Jul 2025
> +KernelVersion 6.17
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (Read) Show hardware context information of device.
> +
> What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/mgmt/etmccr
> Date: September 2015
> KernelVersion: 4.4
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
> index a0425d70d009..e6a584a4b040 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
> @@ -329,6 +329,12 @@ Contact: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Description: (RW) Access the selected single show PE comparator control
> register.
>
> +What: /sys/bus/coresight/devices/etm<N>/label
> +Date: Jul 2025
> +KernelVersion 6.17
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (Read) Show hardware context information of device.
> +
> What: /sys/bus/coresight/devices/etm<N>/mgmt/trcoslsr
> Date: April 2015
> KernelVersion: 4.01
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-funnel b/Documentation/ABI/testing/sysfs-bus-coresight-devices-funnel
> index d75acda5e1b3..5578fa5f6f02 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-funnel
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-funnel
> @@ -10,3 +10,9 @@ Date: November 2014
> KernelVersion: 3.19
> Contact: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Description: (RW) Defines input port priority order.
> +
> +What: /sys/bus/coresight/devices/<memory_map>.funnel/label
> +Date: Jul 2025
> +KernelVersion 6.17
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (Read) Show hardware context information of device.
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-stm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-stm
> index 53e1f4815d64..c3a81978e30b 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-stm
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-stm
> @@ -51,3 +51,9 @@ KernelVersion: 4.7
> Contact: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Description: (RW) Holds the trace ID that will appear in the trace stream
> coming from this trace entity.
> +
> +What: /sys/bus/coresight/devices/<memory_map>.stm/label
> +Date: Jul 2025
> +KernelVersion 6.17
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (Read) Show hardware context information of device.
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc
> index 339cec3b2f1a..9554f4f453a3 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc
> @@ -107,3 +107,9 @@ Contact: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> Description: (RW) Current Coresight TMC-ETR buffer mode selected. But user could
> only provide a mode which is supported for a given ETR device. This
> file is available only for TMC ETR devices.
> +
> +What: /sys/bus/coresight/devices/<memory_map>.tmc/label
> +Date: Jul 2025
> +KernelVersion 6.17
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (Read) Show hardware context information of device.
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> index a341b08ae70b..e6d935e83042 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> @@ -272,3 +272,9 @@ KernelVersion 6.15
> Contact: Jinlong Mao (QUIC) <quic_jinlmao@xxxxxxxxxxx>, Tao Zhang (QUIC) <quic_taozha@xxxxxxxxxxx>
> Description:
> (RW) Set/Get the enablement of the individual lane.
> +
> +What: /sys/bus/coresight/devices/<tpdm-name>/label
> +Date: Jul 2025
> +KernelVersion 6.17
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (Read) Show hardware context information of device.
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-trbe b/Documentation/ABI/testing/sysfs-bus-coresight-devices-trbe
> index ad3bbc6fa751..2a5868ba3d6b 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-trbe
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-trbe
> @@ -12,3 +12,9 @@ Contact: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> Description: (Read) Shows if TRBE updates in the memory are with access
> and dirty flag updates as well. This value is fetched from
> the TRBIDR register.
> +
> +What: /sys/bus/coresight/devices/trbe<cpu>/label
> +Date: Jul 2025
> +KernelVersion 6.17
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (Read) Show hardware context information of device.
> diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
> index feadaf065b53..f7a0c9056854 100644
> --- a/drivers/hwtracing/coresight/coresight-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-sysfs.c
> @@ -7,6 +7,7 @@
> #include <linux/device.h>
> #include <linux/idr.h>
> #include <linux/kernel.h>
> +#include <linux/property.h>
>
> #include "coresight-priv.h"
> #include "coresight-trace-id.h"
> @@ -371,17 +372,81 @@ static ssize_t enable_source_store(struct device *dev,
> }
> static DEVICE_ATTR_RW(enable_source);
>
> +static ssize_t label_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> +
> + const char *str;
> + int ret;
> +
> + ret = fwnode_property_read_string(dev_fwnode(dev), "label", &str);
> + if (ret == 0)
> + return scnprintf(buf, PAGE_SIZE, "%s\n", str);
sysfs_emit() here.
> + else
> + return ret;
> +}
> +static DEVICE_ATTR_RO(label);
> +
> +static umode_t label_is_visible(struct kobject *kobj,
> + struct attribute *attr, int n)
> +{
> + struct device *dev = kobj_to_dev(kobj);
> +
> + if (attr == &dev_attr_label.attr) {
> + if (fwnode_property_present(dev_fwnode(dev), "label"))
> + return attr->mode;
> + else
> + return 0;
> + }
> +
> + return attr->mode;
> +}
> +
> static struct attribute *coresight_sink_attrs[] = {
> &dev_attr_enable_sink.attr,
> + &dev_attr_label.attr,
> NULL,
> };
> -ATTRIBUTE_GROUPS(coresight_sink);
> +
> +static struct attribute_group coresight_sink_group = {
> + .attrs = coresight_sink_attrs,
> + .is_visible = label_is_visible,
> +};
> +__ATTRIBUTE_GROUPS(coresight_sink);
>
> static struct attribute *coresight_source_attrs[] = {
> &dev_attr_enable_source.attr,
> + &dev_attr_label.attr,
> NULL,
> };
> -ATTRIBUTE_GROUPS(coresight_source);
> +
> +static struct attribute_group coresight_source_group = {
> + .attrs = coresight_source_attrs,
> + .is_visible = label_is_visible,
> +};
> +__ATTRIBUTE_GROUPS(coresight_source);
> +
> +static struct attribute *coresight_link_attrs[] = {
> + &dev_attr_label.attr,
> + NULL,
> +};
> +
> +static struct attribute_group coresight_link_group = {
> + .attrs = coresight_link_attrs,
> + .is_visible = label_is_visible,
> +};
> +__ATTRIBUTE_GROUPS(coresight_link);
> +
> +static struct attribute *coresight_helper_attrs[] = {
> + &dev_attr_label.attr,
> + NULL,
> +};
> +
> +static struct attribute_group coresight_helper_group = {
> + .attrs = coresight_helper_attrs,
> + .is_visible = label_is_visible,
> +};
> +__ATTRIBUTE_GROUPS(coresight_helper);
>
> const struct device_type coresight_dev_type[] = {
> [CORESIGHT_DEV_TYPE_SINK] = {
> @@ -390,6 +455,7 @@ const struct device_type coresight_dev_type[] = {
> },
> [CORESIGHT_DEV_TYPE_LINK] = {
> .name = "link",
> + .groups = coresight_link_groups,
> },
> [CORESIGHT_DEV_TYPE_LINKSINK] = {
> .name = "linksink",
> @@ -401,6 +467,7 @@ const struct device_type coresight_dev_type[] = {
> },
> [CORESIGHT_DEV_TYPE_HELPER] = {
> .name = "helper",
> + .groups = coresight_helper_groups,
> }
> };
> /* Ensure the enum matches the names and groups */
> --
> 2.25.1
>
with the above change
Reviewed-by: Mike Leach <mike.leach@xxxxxxxxxx>
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
