Attention is currently required from: Hung-Te Lin, Shelley Chen, Paul Menzel, Angel Pons, Jianjun Wang. Yu-Ping Wu has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/62359 )
Change subject: soc/mediatek: PCI: Assert PERST# at bootblock stage ......................................................................
Patch Set 10:
(1 comment)
Commit Message:
https://review.coreboot.org/c/coreboot/+/62359/comment/bb43ca9e_fbf57fc2 PS9, Line 14: 100ms
Something to keep in mind is that it only works as expected if `COLLECT_TIMESTAMPS` is enabled, but it's only `default y if ARCH_X86`.
COLLECT_TIMESTAMPS is enabled for ChromeOS (src/vendorcode/google/chromeos/Kconfig).
I think an implementation of `timestamp_get()` is needed for this to work.
I agree, although we cannot use the name "timestamp_get" because it already exists for getting the timestamp. Maybe timestamp_find(id)? Alternatively, even better we could rename the current timestamp_get() to timestamp_now().
If we assert PCIe reset in bootblock, we can use the `End of bootblock` timestamp to calculate the elapsed time.
Please measure the elapsed time from the end of PERST# assertion to TS_END_BOOTBLOCK. If it's small (compared to 100ms), then we could use TS_END_BOOTBLOCK as the assertion time. Otherwise, we might need to add a new item to the timestamp_id enum.