Re: [PATCH v15 02/10] Coresight: Add trace_id function to retrieving the trace ID

[Jie Gan <quic_jiegan@quicinc.com>]

On 3/5/2025 10:58 PM, Mike Leach wrote:
> Hi Jie
> 
> On Wed, 5 Mar 2025 at 13:27, Jie Gan <quic_jiegan@quicinc.com> wrote:
>>
>>
>>
>> On 3/5/2025 7:07 PM, Mike Leach wrote:
>>> Hi,
>>>
>>> On Mon, 3 Mar 2025 at 03:30, Jie Gan <quic_jiegan@quicinc.com> wrote:
>>>>
>>>> Add 'trace_id' function pointer in coresight_ops. It's responsible for retrieving
>>>> the device's trace ID.
>>>>
>>>> Co-developed-by: James Clark <james.clark@linaro.org>
>>>> Signed-off-by: James Clark <james.clark@linaro.org>
>>>> Reviewed-by: James Clark <james.clark@linaro.org>
>>>> Signed-off-by: Jie Gan <quic_jiegan@quicinc.com>
>>>> ---
>>>>    drivers/hwtracing/coresight/coresight-core.c  | 30 +++++++++++++++++++
>>>>    drivers/hwtracing/coresight/coresight-dummy.c | 13 +++++++-
>>>>    .../coresight/coresight-etm3x-core.c          |  1 +
>>>>    .../coresight/coresight-etm4x-core.c          |  1 +
>>>>    drivers/hwtracing/coresight/coresight-stm.c   | 11 +++++++
>>>>    drivers/hwtracing/coresight/coresight-tpda.c  | 11 +++++++
>>>>    include/linux/coresight.h                     |  5 ++++
>>>>    7 files changed, 71 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
>>>> index ab55e10d4b79..32aa07f4f8c1 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-core.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>>>> @@ -24,6 +24,7 @@
>>>>    #include "coresight-etm-perf.h"
>>>>    #include "coresight-priv.h"
>>>>    #include "coresight-syscfg.h"
>>>> +#include "coresight-trace-id.h"
>>>>
>>>>    /*
>>>>     * Mutex used to lock all sysfs enable and disable actions and loading and
>>>> @@ -1557,6 +1558,35 @@ void coresight_remove_driver(struct amba_driver *amba_drv,
>>>>    }
>>>>    EXPORT_SYMBOL_GPL(coresight_remove_driver);
>>>>
>>>> +int coresight_etm_get_trace_id(struct coresight_device *csdev, enum cs_mode mode,
>>>> +                              struct coresight_device *sink)
>>>> +{
>>>> +       int trace_id;
>>>> +       int cpu = source_ops(csdev)->cpu_id(csdev);
>>>> +
>>>
>>> This is a global funciton so need to check that this csdev is a
>>> source,. and does provide a cpu  function before calling it.
>>>
>>
>> Hi Mike,
>>
>> I put this function here because it's required by etm3x and etm4x. It's
>> intended to be called only by ETM devices, which are definitely source
>> devices and have a cpu function.
>>
> 
> I fully understand the intent, but for a function that can be accessed
> from anywhere, it is safer to validate input rather than assume any
> caller will always respect the input conditions.
> Lots of other places in the coresight drivers check that these
> functions exist before calling them.
> 

Hi Mike,

I agree with you. I will send another patch to fix it. Thanks for comment.

Jie

> Regards
> 
> Mike
> 
>> Jie
>>
>>>> +       switch (mode) {
>>>> +       case CS_MODE_SYSFS:
>>>> +               trace_id = coresight_trace_id_get_cpu_id(cpu);
>>>> +               break;
>>>> +       case CS_MODE_PERF:
>>>> +               if (WARN_ON(!sink))
>>>> +                       return -EINVAL;
>>>> +
>>>> +               trace_id = coresight_trace_id_get_cpu_id_map(cpu, &sink->perf_sink_id_map);
>>>> +               break;
>>>> +       default:
>>>> +               trace_id = -EINVAL;
>>>> +               break;
>>>> +       }
>>>> +
>>>> +       if (!IS_VALID_CS_TRACE_ID(trace_id))
>>>> +               dev_err(&csdev->dev,
>>>> +                       "Failed to allocate trace ID on CPU%d\n", cpu);
>>>> +
>>>> +       return trace_id;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(coresight_etm_get_trace_id);
>>>> +
>>>>    MODULE_LICENSE("GPL v2");
>>>>    MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
>>>>    MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
>>>> diff --git a/drivers/hwtracing/coresight/coresight-dummy.c b/drivers/hwtracing/coresight/coresight-dummy.c
>>>> index 9be53be8964b..b5692ba358c1 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-dummy.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-dummy.c
>>>> @@ -41,6 +41,16 @@ static void dummy_source_disable(struct coresight_device *csdev,
>>>>           dev_dbg(csdev->dev.parent, "Dummy source disabled\n");
>>>>    }
>>>>
>>>> +static int dummy_source_trace_id(struct coresight_device *csdev, __maybe_unused enum cs_mode mode,
>>>> +                                __maybe_unused struct coresight_device *sink)
>>>> +{
>>>> +       struct dummy_drvdata *drvdata;
>>>> +
>>>> +       drvdata = dev_get_drvdata(csdev->dev.parent);
>>>> +
>>>> +       return drvdata->traceid;
>>>> +}
>>>> +
>>>>    static int dummy_sink_enable(struct coresight_device *csdev, enum cs_mode mode,
>>>>                                   void *data)
>>>>    {
>>>> @@ -62,7 +72,8 @@ static const struct coresight_ops_source dummy_source_ops = {
>>>>    };
>>>>
>>>>    static const struct coresight_ops dummy_source_cs_ops = {
>>>> -       .source_ops = &dummy_source_ops,
>>>> +       .trace_id       = dummy_source_trace_id,
>>>> +       .source_ops     = &dummy_source_ops,
>>>>    };
>>>>
>>>>    static const struct coresight_ops_sink dummy_sink_ops = {
>>>> diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
>>>> index c103f4c70f5d..c1dda4bc4a2f 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
>>>> @@ -704,6 +704,7 @@ static const struct coresight_ops_source etm_source_ops = {
>>>>    };
>>>>
>>>>    static const struct coresight_ops etm_cs_ops = {
>>>> +       .trace_id       = coresight_etm_get_trace_id,
>>>>           .source_ops     = &etm_source_ops,
>>>>    };
>>>>
>>>> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
>>>> index 2c1a60577728..cfd116b87460 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
>>>> @@ -1067,6 +1067,7 @@ static const struct coresight_ops_source etm4_source_ops = {
>>>>    };
>>>>
>>>>    static const struct coresight_ops etm4_cs_ops = {
>>>> +       .trace_id       = coresight_etm_get_trace_id,
>>>>           .source_ops     = &etm4_source_ops,
>>>>    };
>>>>
>>>> diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
>>>> index b581a30a1cd9..aca25b5e3be2 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-stm.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-stm.c
>>>> @@ -281,12 +281,23 @@ static void stm_disable(struct coresight_device *csdev,
>>>>           }
>>>>    }
>>>>
>>>> +static int stm_trace_id(struct coresight_device *csdev, __maybe_unused enum cs_mode mode,
>>>> +                       __maybe_unused struct coresight_device *sink)
>>>> +{
>>>> +       struct stm_drvdata *drvdata;
>>>> +
>>>> +       drvdata = dev_get_drvdata(csdev->dev.parent);
>>>> +
>>>> +       return drvdata->traceid;
>>>> +}
>>>> +
>>>>    static const struct coresight_ops_source stm_source_ops = {
>>>>           .enable         = stm_enable,
>>>>           .disable        = stm_disable,
>>>>    };
>>>>
>>>>    static const struct coresight_ops stm_cs_ops = {
>>>> +       .trace_id       = stm_trace_id,
>>>>           .source_ops     = &stm_source_ops,
>>>>    };
>>>>
>>>> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
>>>> index 573da8427428..94c2201fc8d3 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-tpda.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-tpda.c
>>>> @@ -241,12 +241,23 @@ static void tpda_disable(struct coresight_device *csdev,
>>>>           dev_dbg(drvdata->dev, "TPDA inport %d disabled\n", in->dest_port);
>>>>    }
>>>>
>>>> +static int tpda_trace_id(struct coresight_device *csdev, __maybe_unused enum cs_mode mode,
>>>> +                        __maybe_unused struct coresight_device *sink)
>>>> +{
>>>> +       struct tpda_drvdata *drvdata;
>>>> +
>>>> +       drvdata = dev_get_drvdata(csdev->dev.parent);
>>>> +
>>>> +       return drvdata->atid;
>>>> +}
>>>> +
>>>>    static const struct coresight_ops_link tpda_link_ops = {
>>>>           .enable         = tpda_enable,
>>>>           .disable        = tpda_disable,
>>>>    };
>>>>
>>>>    static const struct coresight_ops tpda_cs_ops = {
>>>> +       .trace_id       = tpda_trace_id,
>>>>           .link_ops       = &tpda_link_ops,
>>>>    };
>>>>
>>>> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
>>>> index c7cd5886c908..ce9a5e71b261 100644
>>>> --- a/include/linux/coresight.h
>>>> +++ b/include/linux/coresight.h
>>>> @@ -335,6 +335,7 @@ enum cs_mode {
>>>>           CS_MODE_PERF,
>>>>    };
>>>>
>>>> +#define coresight_ops(csdev)   csdev->ops
>>>>    #define source_ops(csdev)      csdev->ops->source_ops
>>>>    #define sink_ops(csdev)                csdev->ops->sink_ops
>>>>    #define link_ops(csdev)                csdev->ops->link_ops
>>>> @@ -421,6 +422,8 @@ struct coresight_ops_panic {
>>>>    };
>>>>
>>>>    struct coresight_ops {
>>>> +       int (*trace_id)(struct coresight_device *csdev, enum cs_mode mode,
>>>> +                       struct coresight_device *sink);
>>>>           const struct coresight_ops_sink *sink_ops;
>>>>           const struct coresight_ops_link *link_ops;
>>>>           const struct coresight_ops_source *source_ops;
>>>> @@ -709,4 +712,6 @@ int coresight_init_driver(const char *drv, struct amba_driver *amba_drv,
>>>>
>>>>    void coresight_remove_driver(struct amba_driver *amba_drv,
>>>>                                struct platform_driver *pdev_drv);
>>>> +int coresight_etm_get_trace_id(struct coresight_device *csdev, enum cs_mode mode,
>>>> +                              struct coresight_device *sink);
>>>>    #endif         /* _LINUX_COREISGHT_H */
>>>> --
>>>> 2.34.1
>>>>
>>>
>>>
>>
> 
>