Re: [PATCH v4 RESEND 2/3] coresight: Add support to get static id for system trace sources

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 09/10/2024 11:37, Jinlong Mao wrote:
> 
> 
> On 2024/10/9 17:50, Suzuki K Poulose wrote:
>> On 10/09/2024 11:01, Mao Jinlong wrote:
>>> Dynamic trace id was introduced in coresight subsystem, so trace id is
>>> allocated dynamically. However, some hardware ATB source has static 
>>> trace
>>> id and it cannot be changed via software programming. For such source,
>>> it can call coresight_get_static_trace_id to get the fixed trace id from
>>> device node and pass id to coresight_trace_id_get_static_system_id to
>>> reserve the id.
>>>
>>> Signed-off-by: Mao Jinlong <quic_jinlmao@quicinc.com>
>>
>> This patch is technically doing two different things :
>>
>> 1. Support for reading the static traceid from the firmware. (users of 
>> which comes later in Dummy)
>>
>> 2. Support for allocating a "specific" traceid for system sources.
>>
>>
>> Both the names are a bit similar and could be confusing.
>>
>> For (1), I don't think we need to add a helper like that. See my 
>> comments below, and drop all of that from here this patch.
> 
> Hi Suzuki,
> 
> This helper will be common for other new drivers in future.
> Some other driver will use it, not only for dummy driver.

Ok, fair enough. But couldn't we still use the fwnode_xx directly from
the "helper" rather than defining of_xxx. That way it should work for
ACPI based systems too.

> 
> Thanks
> Jinlong Mao
> 
>>
>>
>>> ---
>>>   .../hwtracing/coresight/coresight-platform.c  | 26 +++++++++++++
>>>   .../hwtracing/coresight/coresight-trace-id.c  | 38 ++++++++++++++-----
>>>   .../hwtracing/coresight/coresight-trace-id.h  |  9 +++++
>>>   include/linux/coresight.h                     |  1 +
>>>   4 files changed, 64 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/ 
>>> drivers/hwtracing/coresight/coresight-platform.c
>>> index 64e171eaad82..703abf0fa3f9 100644
>>> --- a/drivers/hwtracing/coresight/coresight-platform.c
>>> +++ b/drivers/hwtracing/coresight/coresight-platform.c
>>> @@ -183,6 +183,18 @@ static int of_coresight_get_cpu(struct device *dev)
>>>       return cpu;
>>>   }
>>> +/*
>>> + * of_coresight_get_trace_id: Get the atid of a source device.
>>> + *
>>> + * Returns 0 on success.
>>> + */
>>> +static int of_coresight_get_static_trace_id(struct device *dev, u32 
>>> *id)
>>> +{
>>> +
>>> +    return of_property_read_u32(dev->of_node, "arm,static-trace-id", 
>>> id);
>>> +}
>>> +
>>> +

Drop these ^^


>>>   /*
>>>    * of_coresight_parse_endpoint : Parse the given output endpoint @ep
>>>    * and fill the connection information in @pdata->out_conns
>>> @@ -317,6 +329,11 @@ static inline int of_coresight_get_cpu(struct 
>>> device *dev)
>>>   {
>>>       return -ENODEV;
>>>   }
>>> +
>>> +static inline int of_coresight_get_static_trace_id(struct device 
>>> *dev, u32 *id)
>>> +{
>>> +    return -ENODEV;
>>> +}
>>>   #endif
>>
>>
>>>   #ifdef CONFIG_ACPI
>>> @@ -796,6 +813,15 @@ int coresight_get_cpu(struct device *dev)
>>>   }
>>>   EXPORT_SYMBOL_GPL(coresight_get_cpu);
>>> +int coresight_get_static_trace_id(struct device *dev, u32 *id)
>>> +{
>>> +    if (!is_of_node(dev->fwnode))
>>> +        return -EINVAL;
>>> +
>>> +    return of_coresight_get_static_trace_id(dev, id);
>>
>> Please could we not directly use :
>>
>> fwnode_property_read_u32(dev_fwnode(dev), "arm,static-trace-id", 
>> &traceid) in the dummy driver ?

	return fwnode_property_read_u32(dev_fwnode(dev), "arm,static-trace-id", 
id);


Suzuki


>>
>> The rest looks fine to me.
>>
>> Suzuki
>>
>>
>>> +}
>>> +EXPORT_SYMBOL_GPL(coresight_get_static_trace_id);
>>> +
>>>   struct coresight_platform_data *
>>>   coresight_get_platform_data(struct device *dev)
>>>   {
>>> diff --git a/drivers/hwtracing/coresight/coresight-trace-id.c b/ 
>>> drivers/hwtracing/coresight/coresight-trace-id.c
>>> index af5b4ef59cea..ca3c3de4683e 100644
>>> --- a/drivers/hwtracing/coresight/coresight-trace-id.c
>>> +++ b/drivers/hwtracing/coresight/coresight-trace-id.c
>>> @@ -11,6 +11,12 @@
>>>   #include "coresight-trace-id.h"
>>> +enum trace_id_flags {
>>> +    TRACE_ID_ANY = 0x0,
>>> +    TRACE_ID_PREFER_ODD = 0x1,
>>> +    TRACE_ID_REQ_STATIC = 0x2,
>>> +};
>>> +
>>>   /* Default trace ID map. Used on systems that don't require per 
>>> sink mappings */
>>>   static struct coresight_trace_id_map id_map_default;
>>> @@ -80,16 +86,19 @@ static int coresight_trace_id_find_odd_id(struct 
>>> coresight_trace_id_map *id_map)
>>>    * Otherwise allocate next available ID.
>>>    */
>>>   static int coresight_trace_id_alloc_new_id(struct 
>>> coresight_trace_id_map *id_map,
>>> -                       int preferred_id, bool prefer_odd_id)
>>> +                       int preferred_id, unsigned int flags)
>>>   {
>>>       int id = 0;
>>>       /* for backwards compatibility, cpu IDs may use preferred value */
>>> -    if (IS_VALID_CS_TRACE_ID(preferred_id) &&
>>> -        !test_bit(preferred_id, id_map->used_ids)) {
>>> -        id = preferred_id;
>>> -        goto trace_id_allocated;
>>> -    } else if (prefer_odd_id) {
>>> +    if (IS_VALID_CS_TRACE_ID(preferred_id)) {
>>> +        if (!test_bit(preferred_id, id_map->used_ids)) {
>>> +            id = preferred_id;
>>> +            goto trace_id_allocated;
>>> +        } else if (WARN((flags & TRACE_ID_REQ_STATIC), "Trace ID %d 
>>> is used.\n",
>>> +                    preferred_id))
>>> +            return -EINVAL;
>>> +    } else if (flags & TRACE_ID_PREFER_ODD) {
>>>       /* may use odd ids to avoid preferred legacy cpu IDs */
>>>           id = coresight_trace_id_find_odd_id(id_map);
>>>           if (id)
>>> @@ -175,7 +184,7 @@ static int coresight_trace_id_map_get_cpu_id(int 
>>> cpu, struct coresight_trace_id_
>>>        */
>>>       id = coresight_trace_id_alloc_new_id(id_map,
>>>                            CORESIGHT_LEGACY_CPU_TRACE_ID(cpu),
>>> -                         false);
>>> +                         TRACE_ID_ANY);
>>>       if (!IS_VALID_CS_TRACE_ID(id))
>>>           goto get_cpu_id_out_unlock;
>>> @@ -222,14 +231,15 @@ static void 
>>> coresight_trace_id_map_put_cpu_id(int cpu, struct coresight_trace_id
>>>       DUMP_ID_MAP(id_map);
>>>   }
>>> -static int coresight_trace_id_map_get_system_id(struct 
>>> coresight_trace_id_map *id_map)
>>> +static int coresight_trace_id_map_get_system_id(struct 
>>> coresight_trace_id_map *id_map,
>>> +                    int preferred_id, unsigned int traceid_flags)
>>>   {
>>>       unsigned long flags;
>>>       int id;
>>>       spin_lock_irqsave(&id_map_lock, flags);
>>>       /* prefer odd IDs for system components to avoid legacy CPU IDS */
>>> -    id = coresight_trace_id_alloc_new_id(id_map, 0, true);
>>> +    id = coresight_trace_id_alloc_new_id(id_map, preferred_id, 
>>> traceid_flags);
>>>       spin_unlock_irqrestore(&id_map_lock, flags);
>>>       DUMP_ID(id);
>>> @@ -271,10 +281,18 @@ EXPORT_SYMBOL_GPL(coresight_trace_id_read_cpu_id);
>>>   int coresight_trace_id_get_system_id(void)
>>>   {
>>> -    return coresight_trace_id_map_get_system_id(&id_map_default);
>>> +    return coresight_trace_id_map_get_system_id(&id_map_default, 0,
>>> +            TRACE_ID_PREFER_ODD);
>>>   }
>>>   EXPORT_SYMBOL_GPL(coresight_trace_id_get_system_id);
>>> +int coresight_trace_id_get_static_system_id(int trace_id)
>>> +{
>>> +    return coresight_trace_id_map_get_system_id(&id_map_default,
>>> +            trace_id, TRACE_ID_REQ_STATIC);
>>> +}
>>> +EXPORT_SYMBOL_GPL(coresight_trace_id_get_static_system_id);
>>> +
>>>   void coresight_trace_id_put_system_id(int id)
>>>   {
>>>       coresight_trace_id_map_put_system_id(&id_map_default, id);
>>> diff --git a/drivers/hwtracing/coresight/coresight-trace-id.h b/ 
>>> drivers/hwtracing/coresight/coresight-trace-id.h
>>> index 3797777d367e..ca2fdf31c835 100644
>>> --- a/drivers/hwtracing/coresight/coresight-trace-id.h
>>> +++ b/drivers/hwtracing/coresight/coresight-trace-id.h
>>> @@ -122,6 +122,15 @@ int coresight_trace_id_read_cpu_id(int cpu);
>>>    */
>>>   int coresight_trace_id_get_system_id(void);
>>> +/**
>>> + * Allocate a CoreSight static trace ID for a system component.
>>> + *
>>> + * Used to allocate static IDs for system trace sources such as 
>>> dummy source.
>>> + *
>>> + * return: Trace ID or -EINVAL if allocation is impossible.
>>> + */
>>> +int coresight_trace_id_get_static_system_id(int id);
>>> +
>>>   /**
>>>    * Release an allocated system trace ID.
>>>    *
>>> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
>>> index f09ace92176e..2cdc0b1cd536 100644
>>> --- a/include/linux/coresight.h
>>> +++ b/include/linux/coresight.h
>>> @@ -643,6 +643,7 @@ void coresight_relaxed_write64(struct 
>>> coresight_device *csdev,
>>>   void coresight_write64(struct coresight_device *csdev, u64 val, u32 
>>> offset);
>>>   extern int coresight_get_cpu(struct device *dev);
>>> +extern int coresight_get_static_trace_id(struct device *dev, u32 *id);
>>>   struct coresight_platform_data *coresight_get_platform_data(struct 
>>> device *dev);
>>>   struct coresight_connection *
>>
>