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authorYijie Yang <yijie.yang@oss.qualcomm.com>2026-08-11 16:46:47 +0800
committerRob Herring (Arm) <robh@kernel.org>2026-08-15 15:46:52 -0500
commite1c13aed4a1641550e8c9518c96f016e1d52d09b (patch)
tree61c2297688373db165cc857b7c7adcb147a5c419 /Documentation/ABI/testing/debugfs-driver-dcc
downloadlinux-stable-e1c13aed4a1641550e8c9518c96f016e1d52d09b.tar.gz
linux-stable-e1c13aed4a1641550e8c9518c96f016e1d52d09b.zip
dt-bindings: interconnect: qcom-bwmon: Add Maili cpu-bwmon compatiblegrafted
Add the Qualcomm Maili SoC compatible string for the CPU bandwidth monitor (BWMONv4). This falls back to the sdm845-bwmon compatible, consistent with the existing pattern used by other recent SoCs such as sm8750 and kaanapali. Signed-off-by: Yijie Yang <yijie.yang@oss.qualcomm.com> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com> Reviewed-by: Jingyi Wang <jingyi.wang@oss.qualcomm.com> Link: https://patch.msgid.link/20260811-bwmon-v2-1-80f7f150ab9e@oss.qualcomm.com Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
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+What: /sys/kernel/debug/dcc/.../ready
+Date: December 2022
+Contact: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+ This file is used to check the status of the dcc
+ hardware if it's ready to receive user configurations.
+ A 'Y' here indicates dcc is ready.
+
+What: /sys/kernel/debug/dcc/.../trigger
+Date: December 2022
+Contact: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+ This is the debugfs interface for manual software
+ triggers. The trigger can be invoked by writing '1'
+ to the file.
+
+What: /sys/kernel/debug/dcc/.../config_reset
+Date: December 2022
+Contact: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+ This file is used to reset the configuration of
+ a dcc driver to the default configuration. When '1'
+ is written to the file, all the previous addresses
+ stored in the driver gets removed and users need to
+ reconfigure addresses again.
+
+What: /sys/kernel/debug/dcc/.../[list-number]/config
+Date: December 2022
+Contact: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+ This stores the addresses of the registers which
+ can be read in case of a hardware crash or manual
+ software triggers. The input addresses type
+ can be one of following dcc instructions: read,
+ write, read-write, and loop type. The lists need to
+ be configured sequentially and not in a overlapping
+ manner; e.g. users can jump to list x only after
+ list y is configured and enabled. The input format for
+ each type is as follows:
+
+ i) Read instruction
+
+ ::
+
+ echo R <addr> <n> <bus> >/sys/kernel/debug/dcc/../[list-number]/config
+
+ where:
+
+ <addr>
+ The address to be read.
+
+ <n>
+ The addresses word count, starting from address <1>.
+ Each word is 32 bits (4 bytes). If omitted, defaulted
+ to 1.
+
+ <bus type>
+ The bus type, which can be either 'apb' or 'ahb'.
+ The default is 'ahb' if leaved out.
+
+ ii) Write instruction
+
+ ::
+
+ echo W <addr> <n> <bus type> > /sys/kernel/debug/dcc/../[list-number]/config
+
+ where:
+
+ <addr>
+ The address to be written.
+
+ <n>
+ The value to be written at <addr>.
+
+ <bus type>
+ The bus type, which can be either 'apb' or 'ahb'.
+
+ iii) Read-write instruction
+
+ ::
+
+ echo RW <addr> <n> <mask> > /sys/kernel/debug/dcc/../[list-number]/config
+
+ where:
+
+ <addr>
+ The address to be read and written.
+
+ <n>
+ The value to be written at <addr>.
+
+ <mask>
+ The value mask.
+
+ iv) Loop instruction
+
+ ::
+
+ echo L <loop count> <address count> <address>... > /sys/kernel/debug/dcc/../[list-number]/config
+
+ where:
+
+ <loop count>
+ Number of iterations
+
+ <address count>
+ total number of addresses to be written
+
+ <address>
+ Space-separated list of addresses.
+
+What: /sys/kernel/debug/dcc/.../[list-number]/enable
+Date: December 2022
+Contact: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+ This debugfs interface is used for enabling the
+ the dcc hardware. A file named "enable" is in the
+ directory list number where users can enable/disable
+ the specific list by writing boolean (1 or 0) to the
+ file.
+
+ On enabling the dcc, all the addresses specified
+ by the user for the corresponding list is written
+ into dcc sram which is read by the dcc hardware
+ on manual or crash induced triggers. Lists must
+ be configured and enabled sequentially, e.g. list
+ 2 can only be enabled when list 1 have so.