On 03/06/2024 10:43, Mao Jinlong wrote:
> Some dummy source has static trace id configured in HW and it cannot
> be changed via software programming. Configure the trace id in device
> tree and reserve the id when device probe.
>
> Signed-off-by: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> ---
> .../sysfs-bus-coresight-devices-dummy-source | 15 +++++
> drivers/hwtracing/coresight/coresight-dummy.c | 58 +++++++++++++++++--
> 2 files changed, 69 insertions(+), 4 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-coresight-devices-dummy-source
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-dummy-source b/Documentation/ABI/testing/sysfs-bus-coresight-devices-dummy-source
> new file mode 100644
> index 000000000000..d93c198115c9
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-dummy-source
> @@ -0,0 +1,15 @@
> +What: /sys/bus/coresight/devices/dummy_source<N>/enable_source
> +Date: June 2024
> +KernelVersion: 6.9
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (RW) Enable/disable tracing of dummy source. A sink should be activated
> + before enabling the source. The path of coresight components linking
> + the source to the sink is configured and managed automatically by the
> + coresight framework.
> +
> +What: /sys/bus/coresight/devices/dummy_source<N>/traceid
> +Date: June 2024
> +KernelVersion: 6.9
> +Contact: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> +Description: (R) Show the trace ID that will appear in the trace stream
> + coming from this trace entity.
> diff --git a/drivers/hwtracing/coresight/coresight-dummy.c b/drivers/hwtracing/coresight/coresight-dummy.c
> index ac70c0b491be..1f7133ac2c0b 100644
> --- a/drivers/hwtracing/coresight/coresight-dummy.c
> +++ b/drivers/hwtracing/coresight/coresight-dummy.c
> @@ -11,10 +11,12 @@
> #include <linux/pm_runtime.h>
>
> #include "coresight-priv.h"
> +#include "coresight-trace-id.h"
>
> struct dummy_drvdata {
> struct device *dev;
> struct coresight_device *csdev;
> + u8 traceid;
> };
>
> DEFINE_CORESIGHT_DEVLIST(source_devs, "dummy_source");
> @@ -67,6 +69,32 @@ static const struct coresight_ops dummy_sink_cs_ops = {
> .sink_ops = &dummy_sink_ops,
> };
>
> +/* User can get the trace id of dummy source from this node. */
> +static ssize_t traceid_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + unsigned long val;
> + struct dummy_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +
> + val = drvdata->traceid;
> + return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
> +}
> +static DEVICE_ATTR_RO(traceid);
> +
> +static struct attribute *coresight_dummy_attrs[] = {
> + &dev_attr_traceid.attr,
> + NULL,
> +};
> +
> +static const struct attribute_group coresight_dummy_group = {
> + .attrs = coresight_dummy_attrs,
> +};
> +
> +static const struct attribute_group *coresight_dummy_groups[] = {
> + &coresight_dummy_group,
> + NULL,
> +};
> +
> static int dummy_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> @@ -74,6 +102,11 @@ static int dummy_probe(struct platform_device *pdev)
> struct coresight_platform_data *pdata;
> struct dummy_drvdata *drvdata;
> struct coresight_desc desc = { 0 };
> + int ret, trace_id;
> +
> + drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
> + if (!drvdata)
> + return -ENOMEM;
>
> if (of_device_is_compatible(node, "arm,coresight-dummy-source")) {
>
> @@ -85,6 +118,24 @@ static int dummy_probe(struct platform_device *pdev)
> desc.subtype.source_subtype =
> CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS;
> desc.ops = &dummy_source_cs_ops;
> + desc.groups = coresight_dummy_groups;
> +
> + ret = coresight_get_source_traceid(dev, &trace_id);
> + if (!ret) {
> + ret = coresight_trace_id_get_system_id(trace_id);
> + if (ret < 0)
> + return ret;
> +
> + drvdata->traceid = ret;
> + } else {
> + trace_id = coresight_trace_id_get_system_id(0);
> + if (trace_id < 0) {
> + ret = trace_id;
> + return ret;
> + }
> + drvdata->traceid = (u8)trace_id;
> + }
> +
It's a bit weird to use ret in one version and trace_id in the other.
And one casts to (u8) but the other doesn't. I'm sure it all compiles to
the same in the end but it would be a bit more readable if it was more
consistent.
> } else if (of_device_is_compatible(node, "arm,coresight-dummy-sink")) {
> desc.name = coresight_alloc_device_name(&sink_devs, dev);
> if (!desc.name)
> @@ -103,10 +154,6 @@ static int dummy_probe(struct platform_device *pdev)
> 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);
>
> @@ -126,7 +173,10 @@ static void dummy_remove(struct platform_device *pdev)
> {
> struct dummy_drvdata *drvdata = platform_get_drvdata(pdev);
> struct device *dev = &pdev->dev;
> + struct device_node *node = dev->of_node;
>
> + if (of_device_is_compatible(node, "arm,coresight-dummy-source"))
> + coresight_trace_id_put_system_id(drvdata->traceid);
> pm_runtime_disable(dev);
> coresight_unregister(drvdata->csdev);
> }
