kernel/linux.git/Documentation/driver-api/interconnect.rst, branch v6.19.11

interconnect: Add debugfs test client

2023-08-22T18:04:50+00:00

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

interconnect: Add interconnect_graph file to debugfs

2019-12-16T07:49:54+00:00

The interconnect graphs can be difficult to understand and the current "interconnect_summary" file doesn't even display links in any way. Add a new "interconnect_graph" file to debugfs in the graphviz "dot" format which describes interconnect providers, nodes and links. The file is human-readable and can be visualized by piping through graphviz. Example: ssh $TARGET cat /sys/kernel/debug/interconnect/interconnect_graph \ | dot -Tsvg > interconnect_graph.svg Signed-off-by: Leonard Crestez Reviewed-by: Greg Kroah-Hartman Reviewed-by: Bjorn Andersson Signed-off-by: Georgi Djakov

docs: driver-api: make interconnect title quieter

2019-11-07T20:17:24+00:00

This makes it consistent with the other headings in the Linux driver implementer's API guide. Signed-off-by: Louis Taylor Signed-off-by: Jonathan Corbet

docs: interconnect.rst: add it to the driver-api guide

2019-07-15T12:20:28+00:00

This is intended for Kernel hackers audience. Signed-off-by: Mauro Carvalho Chehab Reviewed-by: Georgi Djakov