On 16/05/2024 04:56, 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. Reserve trace id
> for this kind of hardware source.
>
> Signed-off-by: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> ---
> .../hwtracing/coresight/coresight-platform.c | 26 +++++++++++++++++++
> .../hwtracing/coresight/coresight-trace-id.c | 24 +++++++++++++++++
> .../hwtracing/coresight/coresight-trace-id.h | 11 ++++++++
> include/linux/coresight.h | 1 +
> 4 files changed, 62 insertions(+)
>
> diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
> index 9d550f5697fa..d3e22a2608df 100644
> --- a/drivers/hwtracing/coresight/coresight-platform.c
> +++ b/drivers/hwtracing/coresight/coresight-platform.c
> @@ -183,6 +183,17 @@ 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_trace_id(struct device *dev, u32 *id)
> +{
> +
> + return of_property_read_u32(dev->of_node, "trace-id", id);
> +}
> +
> /*
> * of_coresight_parse_endpoint : Parse the given output endpoint @ep
> * and fill the connection information in @pdata->out_conns
> @@ -315,6 +326,12 @@ static inline int of_coresight_get_cpu(struct device *dev)
> {
> return -ENODEV;
> }
> +
> +static int of_coresight_get_trace_id(struct device *dev, u32 *id)
> +{
> + return -ENODEV;
> +}
> +
> #endif
>
> #ifdef CONFIG_ACPI
> @@ -794,6 +811,15 @@ int coresight_get_cpu(struct device *dev)
> }
> EXPORT_SYMBOL_GPL(coresight_get_cpu);
>
> +int coresight_get_trace_id(struct device *dev, u32 *id)
> +{
> + if (!is_of_node(dev->fwnode))
> + return -EINVAL;
> +
> + return of_coresight_get_trace_id(dev, id);
> +}
> +EXPORT_SYMBOL_GPL(coresight_get_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..536a34e9de6f 100644
> --- a/drivers/hwtracing/coresight/coresight-trace-id.c
> +++ b/drivers/hwtracing/coresight/coresight-trace-id.c
> @@ -110,6 +110,24 @@ static int coresight_trace_id_alloc_new_id(struct coresight_trace_id_map *id_map
> return id;
> }
>
> +static int coresight_trace_id_set(int id, struct coresight_trace_id_map *id_map)
> +{
> + unsigned long flags;
> +
> + spin_lock_irqsave(&id_map_lock, flags);
> +
> + if (WARN(!IS_VALID_CS_TRACE_ID(id), "Invalid Trace ID %d\n", id))
> + return -EINVAL;
> + if (WARN(test_bit(id, id_map->used_ids), "ID is already used: %d\n", id))
> + return -EINVAL;
Do these returns not skip unlocking the spinlock?
It might be slightly fewer changes if we update the existing
coresight_trace_id_alloc_new_id() to add a new "only_preferred" option.
Then use the existing system id allocator which already handles the lock
and unlock properly:
static int coresight_trace_id_map_get_system_id(struct
coresight_trace_id_map *id_map, int id,
bool only_preferred)
{
...
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, id, true,
only_preferred);
spin_unlock_irqrestore(&id_map_lock, flags);
...
I suppose the end result is the same as your implementation, but it
trades making one existing function slightly more complicated instead of
adding some new ones.
