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| -rw-r--r-- | Documentation/ABI/testing/debugfs-driver-dcc | 142 |
1 files changed, 76 insertions, 66 deletions
diff --git a/Documentation/ABI/testing/debugfs-driver-dcc b/Documentation/ABI/testing/debugfs-driver-dcc index a00f4502885b..27ed5919d21b 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@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. |