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

Suzuki K Poulose
2024-12-18T09:51:19Z

On 17/12/2024 06:33, Mao Jinlong 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@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(+)

Do you think we need to name the devices using the label ? Or is this
enough ?

Suzuki

>
> 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@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@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@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@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@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 */