FYI: Testing for RPi4B (and other BCM2711 device) SoC revisions
Mark Millard via freebsd-arm <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.arm |
|---|---|
| Message-ID | <[email protected]> |
Looks like EDK2 is getting work on dealing with the updated
BCM2711 vintages that do not require as many workarounds or
imposed limitations.
https://github.com/jlinton/edk2-platforms/commit/769d36d6d400b1dac2ec5e8a7b3eebd0a4751b8b
has AML code based on the following sort of logic
#define ID_CHIPREV 0xfc404000
. . .
OperationRegion (CHPR, SystemMemory, ID_CHIPREV, 0x4)
Field (CHPR, DWordAcc, NoLock, Preserve) {
SOCI, 32
}
if ((SOCI & 0xFF) >= 0x20)
. . .
else
. . .
(Not bothering with which file contains which text here.)
This (and the not shown code) is described with:
QUOTE
The newer BCM2711 SoC's don't have a DMA constraint on the emmc2
controller. So we don't need to do the 1M translation. Lets
allow the AML to detect the SoC revision and return a different
_DMA resource.
END QUOTE
My guess is that the above presumes that the context
has already been established to be a BCM2711 one.
Note: I'm not AML literate. So I'm guessing
interpretations for the code shown.
===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)
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