Hi
-----Original Message----- From: Suzuki K Poulose suzuki.poulose@arm.com Sent: Wednesday, December 18, 2024 9:38 AM To: Mao Jinlong quic_jinlmao@quicinc.com; Mike Leach mike.leach@linaro.org; James Clark James.Clark@arm.com; Rob Herring robh@kernel.org; Krzysztof Kozlowski krzk+dt@kernel.org; Conor Dooley conor+dt@kernel.org; Mathieu Poirier mathieu.poirier@linaro.org; Bjorn Andersson andersson@kernel.org; Konrad Dybcio konradybcio@kernel.org Cc: coresight@lists.linaro.org; linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; linux-arm- msm@vger.kernel.org Subject: Re: [PATCH v6 2/2] coresight: Add label sysfs node support
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 ?
No - absolutely not. If we use label to name devices then we have to validate that the string is a correctly formed device name and that it has not been previously used.
Using the canonical driver selected names works best as we are guaranteed a unique name and the information label can be used to provide flexible context information that best matches the users requirements.
Mike
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,@@ -396,6 +427,7 @@ const struct device_type coresight_dev_type[] = { }, [CORESIGHT_DEV_TYPE_HELPER] = { .name = "helper",
.groups = coresight_helper_groups,
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