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

[Suzuki K Poulose <suzuki.poulose@xxxxxxx>]

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@xxxxxxxxxxx>
> >
> > 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 *