| 1 | What: /sys/kernel/debug/dcc/.../ready |
| 2 | Date: December 2022 |
| 3 | Contact: Souradeep Chowdhury <[email protected]> |
| 4 | Description: |
| 5 | This file is used to check the status of the dcc |
| 6 | hardware if it's ready to receive user configurations. |
| 7 | A 'Y' here indicates dcc is ready. |
| 8 | |
| 9 | What: /sys/kernel/debug/dcc/.../trigger |
| 10 | Date: December 2022 |
| 11 | Contact: Souradeep Chowdhury <[email protected]> |
| 12 | Description: |
| 13 | This is the debugfs interface for manual software |
| 14 | triggers. The trigger can be invoked by writing '1' |
| 15 | to the file. |
| 16 | |
| 17 | What: /sys/kernel/debug/dcc/.../config_reset |
| 18 | Date: December 2022 |
| 19 | Contact: Souradeep Chowdhury <[email protected]> |
| 20 | Description: |
| 21 | This file is used to reset the configuration of |
| 22 | a dcc driver to the default configuration. When '1' |
| 23 | is written to the file, all the previous addresses |
| 24 | stored in the driver gets removed and users need to |
| 25 | reconfigure addresses again. |
| 26 | |
| 27 | What: /sys/kernel/debug/dcc/.../[list-number]/config |
| 28 | Date: December 2022 |
| 29 | Contact: Souradeep Chowdhury <[email protected]> |
| 30 | Description: |
| 31 | This stores the addresses of the registers which |
| 32 | can be read in case of a hardware crash or manual |
| 33 | software triggers. The input addresses type |
| 34 | can be one of following dcc instructions: read, |
| 35 | write, read-write, and loop type. The lists need to |
| 36 | be configured sequentially and not in a overlapping |
| 37 | manner; e.g. users can jump to list x only after |
| 38 | list y is configured and enabled. The input format for |
| 39 | each type is as follows: |
| 40 | |
| 41 | i) Read instruction |
| 42 | |
| 43 | :: |
| 44 | |
| 45 | echo R <addr> <n> <bus> >/sys/kernel/debug/dcc/../[list-number]/config |
| 46 | |
| 47 | where: |
| 48 | |
| 49 | <addr> |
| 50 | The address to be read. |
| 51 | |
| 52 | <n> |
| 53 | The addresses word count, starting from address <1>. |
| 54 | Each word is 32 bits (4 bytes). If omitted, defaulted |
| 55 | to 1. |
| 56 | |
| 57 | <bus type> |
| 58 | The bus type, which can be either 'apb' or 'ahb'. |
| 59 | The default is 'ahb' if leaved out. |
| 60 | |
| 61 | ii) Write instruction |
| 62 | |
| 63 | :: |
| 64 | |
| 65 | echo W <addr> <n> <bus type> > /sys/kernel/debug/dcc/../[list-number]/config |
| 66 | |
| 67 | where: |
| 68 | |
| 69 | <addr> |
| 70 | The address to be written. |
| 71 | |
| 72 | <n> |
| 73 | The value to be written at <addr>. |
| 74 | |
| 75 | <bus type> |
| 76 | The bus type, which can be either 'apb' or 'ahb'. |
| 77 | |
| 78 | iii) Read-write instruction |
| 79 | |
| 80 | :: |
| 81 | |
| 82 | echo RW <addr> <n> <mask> > /sys/kernel/debug/dcc/../[list-number]/config |
| 83 | |
| 84 | where: |
| 85 | |
| 86 | <addr> |
| 87 | The address to be read and written. |
| 88 | |
| 89 | <n> |
| 90 | The value to be written at <addr>. |
| 91 | |
| 92 | <mask> |
| 93 | The value mask. |
| 94 | |
| 95 | iv) Loop instruction |
| 96 | |
| 97 | :: |
| 98 | |
| 99 | echo L <loop count> <address count> <address>... > /sys/kernel/debug/dcc/../[list-number]/config |
| 100 | |
| 101 | where: |
| 102 | |
| 103 | <loop count> |
| 104 | Number of iterations |
| 105 | |
| 106 | <address count> |
| 107 | total number of addresses to be written |
| 108 | |
| 109 | <address> |
| 110 | Space-separated list of addresses. |
| 111 | |
| 112 | What: /sys/kernel/debug/dcc/.../[list-number]/enable |
| 113 | Date: December 2022 |
| 114 | Contact: Souradeep Chowdhury <[email protected]> |
| 115 | Description: |
| 116 | This debugfs interface is used for enabling the |
| 117 | the dcc hardware. A file named "enable" is in the |
| 118 | directory list number where users can enable/disable |
| 119 | the specific list by writing boolean (1 or 0) to the |
| 120 | file. |
| 121 | |
| 122 | On enabling the dcc, all the addresses specified |
| 123 | by the user for the corresponding list is written |
| 124 | into dcc sram which is read by the dcc hardware |
| 125 | on manual or crash induced triggers. Lists must |
| 126 | be configured and enabled sequentially, e.g. list |
| 127 | 2 can only be enabled when list 1 have so. |