* Software Delegated Exception Interface (SDEI)
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Firmware implementing the SDEI functions described in ARM document number
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ARM DEN 0054A ("Software Delegated Exception Interface") can be used by
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Linux to receive notification of events such as those generated by
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firmware-first error handling, or from an IRQ that has been promoted to
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a firmware-assisted NMI.
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The interface provides a number of API functions for registering callbacks
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and enabling/disabling events. Functions are invoked by trapping to the
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privilege level of the SDEI firmware (specified as part of the binding
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below) and passing arguments in a manner specified by the "SMC Calling
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Convention (ARM DEN 0028B):
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r0 => 32-bit Function ID / return value
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{r1 - r3} => Parameters
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Note that the immediate field of the trapping instruction must be set
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to #0.
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The SDEI_EVENT_REGISTER function registers a callback in the kernel
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text to handle the specified event number.
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The sdei node should be a child node of '/firmware' and have required
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properties:
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- compatible : should contain:
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* "arm,sdei-1.0" : For implementations complying to SDEI version 1.x.
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- method : The method of calling the SDEI firmware. Permitted
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values are:
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* "smc" : SMC #0, with the register assignments specified in this
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binding.
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* "hvc" : HVC #0, with the register assignments specified in this
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binding.
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Example:
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firmware {
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sdei {
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compatible = "arm,sdei-1.0";
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method = "smc";
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};
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};
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