From 770c69f037c18cfaa37c3d6c6ef8bd257635513f Mon Sep 17 00:00:00 2001 From: Mike Tipton Date: Mon, 7 Aug 2023 07:29:14 -0700 Subject: interconnect: Add debugfs test client It's often useful during test, debug, and development to issue path votes from shell. Add a debugfs client for this purpose. Example usage: cd /sys/kernel/debug/interconnect/test-client/ # Configure node endpoints for the path from CPU to DDR on # qcom/sm8550. echo chm_apps > src_node echo ebi > dst_node # Get path between src_node and dst_node. This is only # necessary after updating the node endpoints. echo 1 > get # Set desired BW to 1GBps avg and 2GBps peak. echo 1000000 > avg_bw echo 2000000 > peak_bw # Vote for avg_bw and peak_bw on the latest path from "get". # Voting for multiple paths is possible by repeating this # process for different nodes endpoints. echo 1 > commit Allowing userspace to directly enable and set bus rates can be dangerous So, following in the footsteps of the regmap [0] and clk [1] frameworks, keep these userspace controls compile-time disabled without Kconfig options to enable them. Enabling this will require code changes to define INTERCONNECT_ALLOW_WRITE_DEBUGFS. [0] commit 09c6ecd39410 ("regmap: Add support for writing to regmap registers via debugfs") [1] commit 37215da5553e ("clk: Add support for setting clk_rate via debugfs") Signed-off-by: Mike Tipton Link: https://lore.kernel.org/r/20230807142914.12480-4-quic_mdtipton@quicinc.com Signed-off-by: Georgi Djakov --- Documentation/driver-api/interconnect.rst | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'Documentation/driver-api') diff --git a/Documentation/driver-api/interconnect.rst b/Documentation/driver-api/interconnect.rst index 5ed4f57a6bac..a92d0f277a1f 100644 --- a/Documentation/driver-api/interconnect.rst +++ b/Documentation/driver-api/interconnect.rst @@ -113,3 +113,28 @@ through dot to generate diagrams in many graphical formats:: $ cat /sys/kernel/debug/interconnect/interconnect_graph | \ dot -Tsvg > interconnect_graph.svg + +The ``test-client`` directory provides interfaces for issuing BW requests to +any arbitrary path. Note that for safety reasons, this feature is disabled by +default without a Kconfig to enable it. Enabling it requires code changes to +``#define INTERCONNECT_ALLOW_WRITE_DEBUGFS``. Example usage:: + + cd /sys/kernel/debug/interconnect/test-client/ + + # Configure node endpoints for the path from CPU to DDR on + # qcom/sm8550. + echo chm_apps > src_node + echo ebi > dst_node + + # Get path between src_node and dst_node. This is only + # necessary after updating the node endpoints. + echo 1 > get + + # Set desired BW to 1GBps avg and 2GBps peak. + echo 1000000 > avg_bw + echo 2000000 > peak_bw + + # Vote for avg_bw and peak_bw on the latest path from "get". + # Voting for multiple paths is possible by repeating this + # process for different nodes endpoints. + echo 1 > commit -- cgit v1.2.3