Commit 13763fb9 authored by Bagas Sanjaya's avatar Bagas Sanjaya Committed by Bjorn Andersson
Browse files

soc: qcom: dcc: rewrite description of dcc sysfs files 



The description of dcc sysfs files is somewhat confusing and not effective.
Rewrite it to be clear.

While at it, also use literal code block for config sysfs examples and
remove redundant examples that are obvious.

Signed-off-by: default avatarBagas Sanjaya <bagasdotme@gmail.com>
Acked-by: default avatarSouradeep Chowdhury <quic_schowdhu@quicinc.com>
Signed-off-by: default avatarBjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221230135030.17002-3-bagasdotme@gmail.com
parent dc2f5a49

Documentation/ABI/testing/debugfs-driver-dcc

+76 −66
Original line number Diff line number Diff line
@@ -3,115 +3,125 @@ 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

		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 user can simply enter a 1 against

		the debugfs file and enable a manual trigger.

		Example:

		echo  1 > /sys/kernel/debug/dcc/.../trigger

		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. 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

		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

		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:

		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 Type Instruction

	        i) Read instruction



		   echo R <1> <2> <3> >/sys/kernel/debug/dcc/../[list-number]/config

		   ::



		   1->Address to be considered for reading the value.

		     echo R <addr> <n> <bus> >/sys/kernel/debug/dcc/../[list-number]/config



		   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.

		   where:



		   3->Can be 'apb' or 'ahb' which indicates if it is apb or ahb

		      bus respectively. If not entered ahb is considered.

		   <addr>

			The address to be read.



		ii) Write Type Instruction

		   <n>

			The addresses word count, starting from address <1>.

			Each word is 32 bits (4 bytes). If omitted, defaulted

			to 1.



		    echo W <1> <2> <3> > /sys/kernel/debug/dcc/../[list-number]/config

		   <bus type>

			The bus type, which can be either 'apb' or 'ahb'.

			The default is 'ahb' if leaved out.



		    1->Address to be considered for writing the value.

		ii) Write instruction



		    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.

		      echo W <addr> <n> <bus type> > /sys/kernel/debug/dcc/../[list-number]/config



	        iii) Read Modify Write type instruction

		    where:



		     echo RW <1> <2> <3> > /sys/kernel/debug/dcc/../[list-number]/config

		    <addr>

			The address to be written.



		     1->The address which needs to be considered for read then write.

		    <n>

			The value to be written at <addr>.



		     2->The value that needs to be written on the address.

		    <bus type>

			The bus type, which can be either 'apb' or 'ahb'.



		     3->The mask of the value to be written.

	        iii) Read-write instruction



		iv) Loop Type Instruction

		     ::



		    echo L <1> <2> <3> > /sys/kernel/debug/dcc/../[list-number]/config

		       echo RW <addr> <n> <mask> > /sys/kernel/debug/dcc/../[list-number]/config



		    1->The loop count, the number of times the value of the addresses will be

		       captured.

		     where:



		    2->The address count, total number of addresses to be entered in this

		       instruction.

		     <addr>

			The address to be read and written.



		    3->The series of addresses to be entered separated by a space like <addr1>

		       <addr2>... and so on.

		     <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. 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

		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 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)
 
		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.