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 };
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