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Message-ID: <59c01308-075c-5108-9019-47ee1ba1210c@quicinc.com>
Date: Thu, 5 Jan 2023 10:47:45 +0530
From: Souradeep Chowdhury <quic_schowdhu@...cinc.com>
To: Bagas Sanjaya <bagasdotme@...il.com>,
<linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
Linux Documentation <linux-doc@...r.kernel.org>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
Devicetree <devicetree@...r.kernel.org>
CC: Alex Elder <elder@...aro.org>,
Bjorn Andersson <andersson@...nel.org>,
Andy Gross <agross@...nel.org>,
Konrad Dybcio <konrad.dybcio@...ainline.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Sai Prakash Ranjan <quic_saipraka@...cinc.com>,
"Sibi Sankar" <quic_sibis@...cinc.com>,
Rajendra Nayak <quic_rjendra@...cinc.com>,
Vinod Koul <vkoul@...nel.org>
Subject: Re: [PATCH 2/2] soc: qcom: dcc: rewrite description of dcc sysfs
files
On 12/30/2022 7:20 PM, Bagas Sanjaya wrote:
> 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: Bagas Sanjaya <bagasdotme@...il.com>
> ---
> Documentation/ABI/testing/debugfs-driver-dcc | 142 ++++++++++---------
> 1 file changed, 76 insertions(+), 66 deletions(-)
>
> diff --git a/Documentation/ABI/testing/debugfs-driver-dcc b/Documentation/ABI/testing/debugfs-driver-dcc
> index a00f4502885b58..27ed5919d21b9c 100644
> --- a/Documentation/ABI/testing/debugfs-driver-dcc
> +++ b/Documentation/ABI/testing/debugfs-driver-dcc
> @@ -3,115 +3,125 @@ Date: December 2022
> Contact: Souradeep Chowdhury <quic_schowdhu@...cinc.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@...cinc.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@...cinc.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@...cinc.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@...cinc.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.
Acked-by:Souradeep Chowdhury <quic_schowdhu@...cinc.com>
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