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SubjectRe: [PATCH v7 01/15] coresight: trace-id: Add API to dynamically assign Trace ID values
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Hi Mike

On 16/01/2023 12:49, Mike Leach wrote:
> The existing mechanism to assign Trace ID values to sources is limited
> and does not scale for larger multicore / multi trace source systems.
>
> The API introduces functions that reserve IDs based on availabilty
> represented by a coresight_trace_id_map structure. This records the
> used and free IDs in a bitmap.
>
> CPU bound sources such as ETMs use the coresight_trace_id_get_cpu_id
> coresight_trace_id_put_cpu_id pair of functions. The API will record
> the ID associated with the CPU. This ensures that the same ID will be
> re-used while perf events are active on the CPU. The put_cpu_id function
> will pend release of the ID until all perf cs_etm sessions are complete.
>
> For backward compatibility the functions will attempt to use the same
> CPU IDs as the legacy system would have used if these are still available.
>
> Non-cpu sources, such as the STM can use coresight_trace_id_get_system_id /
> coresight_trace_id_put_system_id.
>
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> ---
> drivers/hwtracing/coresight/Makefile | 2 +-
> .../hwtracing/coresight/coresight-trace-id.c | 265 ++++++++++++++++++
> .../hwtracing/coresight/coresight-trace-id.h | 156 +++++++++++
> include/linux/coresight-pmu.h | 10 +
> 4 files changed, 432 insertions(+), 1 deletion(-)
> create mode 100644 drivers/hwtracing/coresight/coresight-trace-id.c
> create mode 100644 drivers/hwtracing/coresight/coresight-trace-id.h
>
> diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
> index b6c4a48140ec..329a0c704b87 100644
> --- a/drivers/hwtracing/coresight/Makefile
> +++ b/drivers/hwtracing/coresight/Makefile
> @@ -6,7 +6,7 @@ obj-$(CONFIG_CORESIGHT) += coresight.o
> coresight-y := coresight-core.o coresight-etm-perf.o coresight-platform.o \
> coresight-sysfs.o coresight-syscfg.o coresight-config.o \
> coresight-cfg-preload.o coresight-cfg-afdo.o \
> - coresight-syscfg-configfs.o
> + coresight-syscfg-configfs.o coresight-trace-id.o
> obj-$(CONFIG_CORESIGHT_LINK_AND_SINK_TMC) += coresight-tmc.o
> coresight-tmc-y := coresight-tmc-core.o coresight-tmc-etf.o \
> coresight-tmc-etr.o
> diff --git a/drivers/hwtracing/coresight/coresight-trace-id.c b/drivers/hwtracing/coresight/coresight-trace-id.c
> new file mode 100644
> index 000000000000..9b85c376cb12
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/coresight-trace-id.c
> @@ -0,0 +1,265 @@
> +// SPDX-License-Identifier: GPL-2.0

...

> +int coresight_trace_id_read_cpu_id(int cpu)
> +{
> + return _coresight_trace_id_read_cpu_id(cpu);
> +}
> +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);
> +}
> +EXPORT_SYMBOL_GPL(coresight_trace_id_get_system_id);
> +
> +void coresight_trace_id_put_system_id(int id)
> +{
> + coresight_trace_id_map_put_system_id(&id_map_default, id);
> +}
> +EXPORT_SYMBOL_GPL(coresight_trace_id_put_system_id);
> +
> +void coresight_trace_id_perf_start(void)
> +{
> + atomic_inc(&perf_cs_etm_session_active);
> +}
> +EXPORT_SYMBOL_GPL(coresight_trace_id_perf_start);
> +
> +void coresight_trace_id_perf_stop(void)
> +{
> + if (!atomic_dec_return(&perf_cs_etm_session_active))
> + coresight_trace_id_release_all_pending();
> +}
> +EXPORT_SYMBOL_GPL(coresight_trace_id_perf_stop);
> +

This blank new line at the end of the file generates a checkpatch
warning for me. I have fixed it locally and applied it.

> diff --git a/drivers/hwtracing/coresight/coresight-trace-id.h b/drivers/hwtracing/coresight/coresight-trace-id.h


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