core: using native interrupt handlers

[etienne-lms]

Adds a section in core architecture documentation to describe interrupt controllers API functions.
These commits are based on stalled P-R #192.

The 1st commit describes the API since OP-TEE/optee_os#6354 has been merged.
The 2nd commit is an RFC describing the API as per P-R OP-TEE/optee_os#6361.

[etienne-lms]

@jbech-linaro, i think the 1st change should be merged before next tag. It descrides the existing implmentation. I'll remove the 2nd commit and will post it upon OP-TEE/optee_os#6361 completion.

[etienne-lms]

I have remove the description related to P-R #6361, used a specific section for main controller info, rephrased a bit the description and add interrupt_call_handlers() info.
I think this change should in next tag documentation.

[etienne-lms]

comments addressed.

[jenswikl]

With my last comment addressed:
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>

[etienne-lms]

I've sqaushed the fixup commits + the change below (missing quotes around function labels), and applied your review tag. Thanks for the review.

     - ``interrupt_mask()`` and ``interrupt_unmask()`` to respectively
-      mask or unmask an interrupt.
-      Masking of an enabled interrupt temporarily disables the interrupt
-      while unmasking enables a previously masked interrupt. interrpt_mask()
-      and interrpt_unmask() are allowed to be called from an interrupt
-      context, but interrupt_enable() and interrupt_disable() not so.
+      mask or unmask an interrupt. Masking of an enabled interrupt
+      temporarily disables the interrupt while unmasking enables a
+      previously masked interrupt. ``interrupt_mask()`` and
+      ``interrupt_unmask()`` are allowed to be called from an interrupt
+      context, but ``interrupt_enable()`` and ``interrupt_disable()`` not so.

Note: the last 'so' sound strange to me.

[jockebech]

Not sure why this pass on readthedocs, since I see both Error and warnings when looking that the readthedocs log. I noticed that when building this locally:

/home/jyx/devel/optee_projects/optee_docs/architecture/core.rst:419: ERROR: Unexpected indentation.
/home/jyx/devel/optee_projects/optee_docs/architecture/core.rst:411: ERROR: Unknown target name: "interrupt.h".
looking for now-outdated files... none found
pickling environment... done
checking consistency... done
preparing documents... done
writing output... [100%] index
/home/jyx/devel/optee_projects/optee_docs/architecture/core.rst:468: WARNING: undefined label: '_notifications'

[etienne-lms]

Thanks @jbech-linaro. Indeed I forgot to test building the doc.
Now it should be ok with the appended fixup commit.

[etienne-lms]

comments addressed

[jockebech]

Thanks @etienne-lms

Reviewed-by: Joakim Bech <joakim.bech@linaro.org>

[etienne-lms]

@jenswi-linaro, I guess your review tag still applies.

[jenswikl]

@jenswi-linaro, I guess your review tag still applies.

Yes :-)

[etienne-lms]

fixup commits squashed
review tags applied
thanks for the fixes