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/deb

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 <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Georgi Djakov <[email protected]>

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interconnect: Add interconnect_graph file to debugfs

The interconnect graphs can be difficult to understand and the current
"interconnect_summary" file doesn't even display links in any way.

Add a

interconnect: Add interconnect_graph file to debugfs

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 <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Reviewed-by: Bjorn Andersson <[email protected]>
Signed-off-by: Georgi Djakov <[email protected]>

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docs: driver-api: make interconnect title quieter

This makes it consistent with the other headings in the Linux driver
implementer's API guide.

Signed-off-by: Louis Taylor <[email protected]>
Signed

docs: driver-api: make interconnect title quieter

This makes it consistent with the other headings in the Linux driver
implementer's API guide.

Signed-off-by: Louis Taylor <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>

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

This is intended for Kernel hackers audience.

Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Reviewed-by: Georgi Djakov <ge

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

This is intended for Kernel hackers audience.

Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Reviewed-by: Georgi Djakov <[email protected]>

show more ...