The icc_commit_set() function, used by the debugfs interface, checks
the validity of the global cur_path pointer using IS_ERR_OR_NULL().
However, in the specific case where cur_path is NULL, while
IS_ERR_OR_NULL(NULL) correctly evaluates to true, the subsequent call
to PTR_ERR(NULL) returns 0.
This causes the function to return a success code (0) instead of an
error, misleading the user into believing their bandwidth request was
successfully committed when, in fact, no operation was performed.
Fix this by adding an explicit check to return -EINVAL if cur_path is
NULL. This prevents silent failures and ensures that an invalid
operational sequence is immediately and clearly reported as an error.
Fixes: 770c69f037 ("interconnect: Add debugfs test client")
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Link: https://lore.kernel.org/r/20251010151447.2289779-1-visitorckw@gmail.com
Signed-off-by: Georgi Djakov <djakov@kernel.org>
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 09c6ecd394 ("regmap: Add support for writing to regmap registers via debugfs")
[1] commit 37215da555 ("clk: Add support for setting clk_rate via debugfs")
Signed-off-by: Mike Tipton <quic_mdtipton@quicinc.com>
Link: https://lore.kernel.org/r/20230807142914.12480-4-quic_mdtipton@quicinc.com
Signed-off-by: Georgi Djakov <djakov@kernel.org>
