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