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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 take the inputs. A 'Y'
here indicates dcc is in a ready condition.
Example:
cat /sys/kernel/debug/dcc/.../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 user can simply enter a 1 against
the debugfs file and enable a manual trigger.
Example:
echo 1 > /sys/kernel/debug/dcc/.../trigger
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. This
means that all the previous addresses stored in
the driver gets removed and user needs to enter
the address values from the start.
Example:
echo 1 > /sys/kernel/debug/dcc/../config_reset
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
should be read in case of a hardware crash or
manual software triggers. The addresses entered here
are considered under all the 4 types of dcc
instructions Read type, Write type, Read Modify Write
type and Loop type. The lists need to be configured
sequentially and not in a overlapping manner. As an
example user can jump to list x only after list y is
configured and enabled. The format for entering all
types of instructions are explained in examples as
follows.
Example:
i)Read Type Instruction
echo R <1> <2> <3> >/sys/kernel/debug/dcc/../[list-number]/config
1->Address to be considered for reading the value.
2->The word count of the addresses, read n words
starting from address <1>. Each word is of 32 bits.
If not entered 1 is considered.
3->Can be 'apb' or 'ahb' which indicates if it is apb or ahb
bus respectively. If not entered ahb is considered.
ii)Write Type Instruction
echo W <1> <2> <3> > /sys/kernel/debug/dcc/../[list-number]/config
1->Address to be considered for writing the value.
2->The value that needs to be written at the location.
3->Can be a 'apb' or 'ahb' which indicates if it is apb or ahb
but respectively.
iii)Read Modify Write type instruction
echo RW <1> <2> <3> > /sys/kernel/debug/dcc/../[list-number]/config
1->The address which needs to be considered for read then write.
2->The value that needs to be written on the address.
3->The mask of the value to be written.
iv)Loop Type Instruction
echo L <1> <2> <3> > /sys/kernel/debug/dcc/../[list-number]/config
1->The loop count, the number of times the value of the addresses will be
captured.
2->The address count, total number of addresses to be entered in this
instruction.
3->The series of addresses to be entered separated by a space like <addr1>
<addr2>... and so on.
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. Enable file is kept under the
directory list number for which the user wants
to enable it. For example if the user wants to
enable list 1, then he should go for
echo 1 > /sys/kernel/debug/dcc/.../1/enable.
On enabling the dcc, all the addresses entered
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 should
be enabled sequentially.For example after configuring
addresses for list 1 and enabling it, a user can
proceed to enable list 2 or vice versa.
Example:
echo 0 > /sys/kernel/debug/dcc/.../[list-number]/enable
(disable dcc for the corresponding list number)
echo 1 > /sys/kernel/debug/dcc/.../[list-number]/enable
(enable dcc for the corresponding list number)
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