Re: [PATCH v7 01/15] coresight: trace-id: Add API to dynamically assign Trace ID values
From: Suzuki K Poulose
Date: Tue Jan 17 2023 - 10:55:04 EST
On 17/01/2023 13:02, Mike Leach wrote:
On Mon, 16 Jan 2023 at 14:16, Suzuki K Poulose <suzuki.poulose@xxxxxxx> wrote:
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@xxxxxxxxxx>
---
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.
OK, thanks.
The only thing I get out of checkpatch.pl for this patch (and indeed
the entire set) is:
WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
Ah, sorry. It is not the checkpatch, but git am complained. Sorry for
the confusion.
Cheers
Suzuki