Date: Fri, 7 May 2021 13:48:17 -0700 From: Mark Millard <marklmi@yahoo.com> To: freebsd-arm <freebsd-arm@freebsd.org> Subject: FYI: Testing for RPi4B (and other BCM2711 device) SoC revisions Message-ID: <51D7E4EF-F7DE-4AE8-97B0-97996E34D519@yahoo.com> References: <51D7E4EF-F7DE-4AE8-97B0-97996E34D519.ref@yahoo.com>
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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/769d36d6d400b1dac2ec5e8a7= b3eebd0a4751b8b 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) >=3D 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. =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
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