Change in coreboot[master]: sb/intel/common: Refactor _PRT generation to support GSI-based tables

[Nico Huber (Code Review)]

Attention is currently required from: Tim Wawrzynczak, Angel Pons, Patrick Rudolph.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/50857 )

Change subject: sb/intel/common: Refactor _PRT generation to support GSI-based tables
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Patch Set 14:

(9 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/50857/comment/bc907216_6883295b 
PS14, Line 10: insteade
Nit, *instead*

Patchset:

PS14: 
Sorry for leaving this unattended for long. Ping me to test
the next iteration if necessary (I think we should test it).

File src/southbridge/intel/common/acpi_pirq_gen.h:

https://review.coreboot.org/c/coreboot/+/50857/comment/44682f27_f384cbbc 
PS14, Line 28: 	PIRQ_MAX = PIRQ_H,
With `PIRQ_NONE` removed, this is the last valid index now.

https://review.coreboot.org/c/coreboot/+/50857/comment/52535877_c340ffde 
PS14, Line 47: dveices
*devices*

https://review.coreboot.org/c/coreboot/+/50857/comment/fea8157b_d977b4e9 
PS14, Line 69: PIRQ_MAX
PIRQ_MAX is the last valid index, not the count of PIRQs.

https://review.coreboot.org/c/coreboot/+/50857/comment/7a79e7ed_f0171648 
PS14, Line 69: 	unsigned int gsi[PIRQ_MAX];
             : 	char source_path[PIRQ_MAX][DEVICE_PATH_MAX];
This could be a union, just to emphasize that they are mutually exclusive.

https://review.coreboot.org/c/coreboot/+/50857/comment/5f6082ac_55040a53 
PS14, Line 79: num_devs
This made me think for a second what it's about. I suppose it's
the map length?

Left this resolved first, but it really isn't the number of devices...
The "physical" thing that is enumerated is the pins.

File src/southbridge/intel/common/acpi_pirq_gen.c:

https://review.coreboot.org/c/coreboot/+/50857/comment/24809153_4a1f2e76 
PS14, Line 58: 16
This little number is nowhere to be found in the new implementation.

File src/southbridge/intel/common/rcba_pirq.c:

https://review.coreboot.org/c/coreboot/+/50857/comment/fceb1126_f7e176d2 
PS14, Line 85: 		pin_irq_map[num_devs].pic_pirq = map_pirq(dev, int_pin);
I don't think gen_apic_route() would be too happy if we leave .apic_gsi unset? ;)