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Date:      Sun, 3 Apr 2022 23:44:29 -0700
From:      Mark Millard <marklmi@yahoo.com>
To:        Free BSD <freebsd-arm@freebsd.org>
Subject:   RPi4B's got a PMIC replacement, so now there are Rev 1.5 variants with matching firmware requirements; more
Message-ID:  <BC0F3716-4598-4D9B-924D-35DF219A40FE@yahoo.com>
References:  <BC0F3716-4598-4D9B-924D-35DF219A40FE.ref@yahoo.com>

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The 2022-Feb-08 https://forums.raspberrypi.com/viewtopic.php?t=3D329299
reports about v1.5 (via a "Moderator" "Engineer"):

QUOTE
The PMIC has been changed. Needs firmware from April 21 or later.
. . .
The bootloader has supported this since Apr 2021 (previous default =
release).
END QUOTE


I will note that, separately from this, the 2021-Nov-24

https://forums.raspberrypi.com/viewtopic.php?t=3D324653

reports about the stepping with the C0T labeling (via a "Moderator" =
"Engineer"):

QUOTE
Any current production of 8GB will be C0 anyway.
. . .
And just informationally, the C0 stepping fixed a bug in the accessible =
memory region for one of the peripherals, and improved some power gating =
on some HW blocks. The first means a driver no longer needs bounce =
buffers, and the second we save a tiny amount of power.
END QUOTE

Other sources report the EMMC2 bus addressing as no longer limited to 1 =
GB
and the PCIe interface addressing as no longer limited to 3 GB. The
following information is listed (in a different form) in

https://github.com/raspberrypi/linux/issues/3210#issuecomment-680007995 =
:

Old (B0T): emmc2bus dma-ranges ending in 40 00 00 00
New (C0T): emmc2bus dma-ranges ending in fc 00 00 00

(Not visible via a separate .dtb file: the device tree is dynamically
adjusted to match the stepping before being handed over to later =
stages.)

=46rom what I've seen checking on the web and the like, it looks like =
the
C0T stepping usage is not limited to the 8 GiByte RPi4B's (or even 8 and
4 GiByte): 2 GiByte examples are also reported as having been received.


=46rom what I saw, U-Boot had some 0xff800000UL instance with a matching
size of 0x800000UL that was proposed as changed to 0xffc00000UL and
0x400000UL to avoid overlapping newly updated ARM/VideoCore firmware
memory use. (I'm unsure if this is related to the wider addressing
ranges reported above leading things to have been moved around.) The
reference is from 2021-Jun-17:

https://www.mail-archive.com/u-boot@lists.denx.de/msg409182.html

I do not know the first U-Boot release to have a change for the type
of issue.


Overall I do not know the implications for FreeBSD's status. I only have
access to older RPi4B's.

=3D=3D=3D
Mark Millard
marklmi at yahoo.com




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