Manage NCRISC IRAM transfer on NCRISC on Wormhole #17805
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This saves IRAM space for the kernel, and allows later patches to optimize NCRISC initialization more. This is only enabled on Wormhole because a memory arbiter bug prevents NCRISC from safely reading instructions from L1 on Grayskull. We need to reset NCRISC when switching from executing in L1 to executing in IRAM, because otehrwise we were seeing odd behavior where it was sometimes misexecuting kernel code.
By moving the NCRISC kernel copy into the NCRISC firmware (on wormhole) we can do it in parallel with setting up CBs.
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Ticket
#17307
Problem description
Currently brisc triggers loading the NCRISC kernel into IRAM, and later polls until it's complete before starting the NCRISC firmware and telling it to load the kernel.
What's changed
We can instead move the NCRISC firmware into L1 to allow it to manage loading the kernel. This is only possible on wormhole, because blackhole runs the kernel from L1 and grayskull has a bug that prevents NCRISC from safely running code from L1. We still need to reset the RISC to switch from executing in L1 to executing in IRAM, but that's a quick operation.
This allows NCRISC to load CBs at the same time as it loads the kernel into IRAM, which saves time. In a future patch it will also allow NCRISC to start loading the next kernel before BRISC finishes cleanup for the previous kernel.
Checklist