[PATCH v3 0/6] Refactoring finding CPU phandles in DT

Alireza Sanaee
2025-07-18T10:29:41Z

This series refactor the way CPU IDs are retrieved from the device
tree.

Usually, there is a for loop that goes over every single CPU that can be
avoided. This also reduces the amount of NULL pointer checks in drivers.
I have abstracted away that loop and introduced a new function
(of_cpu_node_to_id) for this.

This patchset is a subset of [1], where I removed content and patches
relevant to hyper-threaded cores for DT. Based on the discussion, the
code refactor is still useful, hence this patchset.

[1]
https://lore.kernel.org/all/20250512080715.82-1-alireza.sanaee@huawei.co

Changes since v2:
- Addressed Jonathan Cameron's comments.
- Added reviewed-by tags.
- Added a new commit where I suggest simplfing the code in
arch_topology.c to remove the use of cpu_node on failure path.
- Improve documentation.
- Caught a bug in patch 1.
- Commit message fixed for patch 2.

Changes since v1:
- Rebased on top of the latest mainline.
- Addressed Krzysztof Kozlowski's comments -- Hopefully :-)
- Addressed Jonathan Cameron's comments.

Alireza Sanaee (6):
of: add infra for finding CPU id from phandle
arch_topology: drop the use of cpu_node in the pr_info
arch_topology: update CPU map to use of_cpu_phandle_to_id
coresight: cti: Use of_cpu_phandle_to_id for grabbing CPU id
coresight: Use of_cpu_phandle_to_id for grabbing CPU ID
perf/arm-dsu: refactor cpu id retrieval via new API
of_cpu_phandle_to_id

drivers/base/arch_topology.c | 22 ++++-----
.../coresight/coresight-cti-platform.c | 13 +----
.../hwtracing/coresight/coresight-platform.c | 15 +-----
drivers/of/cpu.c | 49 +++++++++++++++++++
drivers/perf/arm_dsu_pmu.c | 7 +--
include/linux/of.h | 9 ++++
6 files changed, 72 insertions(+), 43 deletions(-)

--
2.43.0