Most manufacturers take standardized IP and IP-providers provide an appropriate linux drivers. Few manufacturers are willing to develop and maintain their own GIC hardware and GIC driver, most of the time they just take the ARM standard GIC.
The fact that Apple does not provide drivers is a consequence of the Apple business model.
And the fact that the ARM ISA does not stipulate a unique GIC is actually a strength. It makes the architecture more versatile and suitable for evolution (maybe Apple found out that the ARM standard GIC is not complete enough for them).
The mistakes are already happening. There are RISC-V processors being shipped with unfinished extensions and weird MMUs and now Linux has to decide whether to support those or only support finished standards
Most manufacturers take standardized IP and IP-providers provide an appropriate linux drivers. Few manufacturers are willing to develop and maintain their own GIC hardware and GIC driver, most of the time they just take the ARM standard GIC.
The fact that Apple does not provide drivers is a consequence of the Apple business model. And the fact that the ARM ISA does not stipulate a unique GIC is actually a strength. It makes the architecture more versatile and suitable for evolution (maybe Apple found out that the ARM standard GIC is not complete enough for them).