[coreboot-gerrit] [M] Change in coreboot[main]: riscv/mb/qemu: fix DRAM probing

[ron minnich (Code Review)]

Attention is currently required from: Arthur Heymans, Arthur Heymans, Philipp Hug.

ron minnich has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/36486?usp=email )

Change subject: riscv/mb/qemu: fix DRAM probing
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Patch Set 9:

(4 comments)

Patchset:

PS9: 
I had a few questions.

File src/arch/riscv/ramdetect.c:

https://review.coreboot.org/c/coreboot/+/36486/comment/31d456c6_f61d5590 :
PS9, Line 21: #define insn_size 4
Is this true in an era of compact instruction extension? I no longer know.
Should insn_size be define somewhere in <arch/...>?

https://review.coreboot.org/c/coreboot/+/36486/comment/19ace76c_4b7b7f97 :
PS9, Line 29: 	 */
Can we ensure we never build with compact instrutions enabled? I'd be fine with that.

https://review.coreboot.org/c/coreboot/+/36486/comment/f2207e23_717c9969 :
PS9, Line 35: 	uintptr_t addr = dram_start + (size * MiB) - sizeof(uint32_t);
Should we make sure dram_start is 32-bit aligned, in case of someone doing something silly? it would be a pain to take an alignment trap here. Or should the probe be for read8, just to be sure?