| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame^] | 1 | * Software Delegated Exception Interface (SDEI) |
| 2 | |
| 3 | Firmware implementing the SDEI functions described in ARM document number |
| 4 | ARM DEN 0054A ("Software Delegated Exception Interface") can be used by |
| 5 | Linux to receive notification of events such as those generated by |
| 6 | firmware-first error handling, or from an IRQ that has been promoted to |
| 7 | a firmware-assisted NMI. |
| 8 | |
| 9 | The interface provides a number of API functions for registering callbacks |
| 10 | and enabling/disabling events. Functions are invoked by trapping to the |
| 11 | privilege level of the SDEI firmware (specified as part of the binding |
| 12 | below) and passing arguments in a manner specified by the "SMC Calling |
| 13 | Convention (ARM DEN 0028B): |
| 14 | |
| 15 | r0 => 32-bit Function ID / return value |
| 16 | {r1 - r3} => Parameters |
| 17 | |
| 18 | Note that the immediate field of the trapping instruction must be set |
| 19 | to #0. |
| 20 | |
| 21 | The SDEI_EVENT_REGISTER function registers a callback in the kernel |
| 22 | text to handle the specified event number. |
| 23 | |
| 24 | The sdei node should be a child node of '/firmware' and have required |
| 25 | properties: |
| 26 | |
| 27 | - compatible : should contain: |
| 28 | * "arm,sdei-1.0" : For implementations complying to SDEI version 1.x. |
| 29 | |
| 30 | - method : The method of calling the SDEI firmware. Permitted |
| 31 | values are: |
| 32 | * "smc" : SMC #0, with the register assignments specified in this |
| 33 | binding. |
| 34 | * "hvc" : HVC #0, with the register assignments specified in this |
| 35 | binding. |
| 36 | Example: |
| 37 | firmware { |
| 38 | sdei { |
| 39 | compatible = "arm,sdei-1.0"; |
| 40 | method = "smc"; |
| 41 | }; |
| 42 | }; |