From: Bakul Shah <bakul@bitblocks.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] raspberry pi 4 arm64 test image
Date: Wed, 21 Aug 2019 15:18:09 -0700 [thread overview]
Message-ID: <20190821221816.796EA1570CEA@mail.bitblocks.com> (raw)
In-Reply-To: Your message of "Wed, 21 Aug 2019 23:59:28 +0200." <3468103FF6FA1E43500C7F1B15610D60@felloff.net>
On Wed, 21 Aug 2019 23:59:28 +0200 cinap_lenrek@felloff.net wrote:
cinap_lenrek@felloff.net writes:
> > The firmware on a pi4 with 2GB or 4GB RAM will only report 1GB.
> > I believe you need to look at the board id (or probe for invalid
> > addresses as in the teg2 kernel) to find out the real amount.
>
> oh dear. i dont even know the expected physical memory map...
> i guess that ram is continuous block at [0-0xfc000000). but
> some memory might be reserved...
>
> on what method does it report only 1GB?
>
> i know of 3 methods so far:
>
> - atags
> - device tree /memory/reg property
> - firmware property request (getramsize() in vcore.c)
>
> for me getramsize() returns zero for both base and limit so its
> completely useless.
>
> i'm currently using device tree method, but the code assumes that
> there is a single block entry. lets see if that lies as well with
> the debug kernel.
The device tree has two entries.
offset:0
lenght:0x3c400000
offset:0x40000000
length:0xbc000000
next prev parent reply other threads:[~2019-08-21 22:18 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-21 21:59 cinap_lenrek
2019-08-21 22:18 ` Bakul Shah [this message]
2019-08-22 7:07 ` Richard Miller
2019-08-22 8:58 ` Steve Simon
2019-08-22 20:26 ` Charles Forsyth
-- strict thread matches above, loose matches on Subject: below --
2019-08-23 20:15 cinap_lenrek
2019-08-21 23:58 cinap_lenrek
2019-08-22 4:37 ` Bakul Shah
2019-08-21 22:24 cinap_lenrek
2019-08-21 21:35 cinap_lenrek
2019-08-21 19:53 cinap_lenrek
2019-08-21 20:02 ` Richard Miller
2019-08-21 22:20 ` Bakul Shah
2019-08-21 17:56 cinap_lenrek
2019-08-21 19:20 ` Bakul Shah
2019-08-21 19:25 ` Richard Miller
2019-08-21 20:05 ` Richard Miller
2019-08-21 20:27 ` Bakul Shah
2019-08-21 19:57 ` Richard Miller
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