[PATCH v6 2/2] coresight: Add label sysfs node support

[Mike Leach]

Hi

On Tue, 17 Dec 2024 at 06:33, Mao Jinlong <quic_jinlmao at quicinc.com> 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 at quicinc.com>
> ---
>  .../testing/sysfs-bus-coresight-devices-cti   |  6 ++++
>  .../sysfs-bus-coresight-devices-funnel        |  6 ++++
>  .../testing/sysfs-bus-coresight-devices-tpdm  |  6 ++++
>  drivers/hwtracing/coresight/coresight-sysfs.c | 32 +++++++++++++++++++
>  4 files changed, 50 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-cti b/Documentation/ABI/testing/sysfs-bus-coresight-devices-cti
> index bf2869c413e7..909670e0451a 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:           Dec 2024
> +KernelVersion   6.14
> +Contact:        Mao Jinlong <quic_jinlmao at quicinc.com>
> +Description:    (Read) Show hardware context information of device.
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-funnel b/Documentation/ABI/testing/sysfs-bus-coresight-devices-funnel
> index d75acda5e1b3..944aad879aeb 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 at linaro.org>
>  Description:   (RW) Defines input port priority order.
> +
> +What:           /sys/bus/coresight/devices/<memory_map>.funnel/label
> +Date:           Dec 2024
> +KernelVersion   6.14
> +Contact:        Mao Jinlong <quic_jinlmao at quicinc.com>
> +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 bf710ea6e0ef..309802246398 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> @@ -257,3 +257,9 @@ Contact:    Jinlong Mao (QUIC) <quic_jinlmao at quicinc.com>, Tao Zhang (QUIC) <quic_t
>  Description:
>                 (RW) Set/Get the MSR(mux select register) for the CMB subunit
>                 TPDM.
> +
> +What:           /sys/bus/coresight/devices/<tpdm-name>/label
> +Date:           Dec 2024
> +KernelVersion   6.14
> +Contact:        Mao Jinlong <quic_jinlmao at quicinc.com>
> +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 a01c9e54e2ed..4af40cd7d75a 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"
> @@ -366,18 +367,47 @@ 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 = 0;
> +
> +       ret = fwnode_property_read_string(dev_fwnode(dev), "label", &str);
> +       if (ret == 0)
> +               return scnprintf(buf, PAGE_SIZE, "%s\n", str);
> +       else
> +               return ret;
> +}
> +static DEVICE_ATTR_RO(label);
> +
>  static struct attribute *coresight_sink_attrs[] = {
>         &dev_attr_enable_sink.attr,
> +       &dev_attr_label.attr,
>         NULL,
>  };
>  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 *coresight_link_attrs[] = {
> +       &dev_attr_label.attr,
> +       NULL,
> +};
> +ATTRIBUTE_GROUPS(coresight_link);
> +
> +static struct attribute *coresight_helper_attrs[] = {
> +       &dev_attr_label.attr,
> +       NULL,
> +};
> +ATTRIBUTE_GROUPS(coresight_helper);
> +
>  const struct device_type coresight_dev_type[] = {
>         [CORESIGHT_DEV_TYPE_SINK] = {
>                 .name = "sink",
> @@ -385,6 +415,7 @@ const struct device_type coresight_dev_type[] = {
>         },
>         [CORESIGHT_DEV_TYPE_LINK] = {
>                 .name = "link",
> +               .groups = coresight_link_groups,
>         },
>         [CORESIGHT_DEV_TYPE_LINKSINK] = {
>                 .name = "linksink",
> @@ -396,6 +427,7 @@ 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 */
> --
> 2.17.1
>

This is a clean and simple solution to this issue. In this form...

Reviewed-by: Mike Leach <mike.leach at linaro.org>

-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK