From: Detlev Zundel <dzu@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 1/3] Revert "i.MX28: Enable additional DRAM address bits"
Date: Fri, 04 May 2012 11:15:05 +0200 [thread overview]
Message-ID: <m28vh85mue.fsf@lamuella.denx.de> (raw)
In-Reply-To: <201205031641.10748.marex@denx.de> (Marek Vasut's message of "Thu, 3 May 2012 16:41:10 +0200")
Hi Marek,
> Dear Detlev Zundel,
>
>> Hi Marek,
>>
>> [...]
>>
>> >> - Why was the change made in the first place and for what OOT port?
>> >
>> > Change of a DRAM configuration register that enabled additional
>> > address bit, at address 512MB of DRAM. Though this caused memory hole
>> > on our M28 module with 256MB of DRAM, which _is_ mainline. X board is
>> > OOT and never will be mainlined I guess.
>>
>> I still do not understand this fully. What exactly is this "memory
>> hole" and why is it fatal? As far as I can remember, there are always
>> some holes in the adress map, so why is this special?
>
> No, this one created this layout on our 256 MB module:
>
> [chunk of memory][<- same thing][chunk of memory][<- same thing]
>
> so get_ram_size() didn't work with it and it actually overwrote part
> of the U-
> Boot etc.
Ah, so it created what I would call a "memory mirroring" or "memory
aliasing", right? Now I understand the problem, thanks.
Cheers
Detlev
--
This is not the first time my views on some topic have inspired in
someone the desire to psychoanalyze me. Previous experience leads me
to ask about your couch. Is it comfortable? Are its springs in good
shape? -- Jonh McCarthy
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de
prev parent reply other threads:[~2012-05-04 9:15 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-02 22:14 [U-Boot] [PATCH 1/3] Revert "i.MX28: Enable additional DRAM address bits" Marek Vasut
2012-05-02 22:14 ` [U-Boot] [PATCH 2/3] M28: Scan only first 512 MB of DRAM to avoid memory wraparound Marek Vasut
2012-05-02 22:14 ` [U-Boot] [PATCH 3/3] i.MX28: Increase the delay after DRAM init Marek Vasut
2012-05-02 22:55 ` Fabio Estevam
2012-05-02 23:27 ` Marek Vasut
2012-05-03 8:12 ` Detlev Zundel
2012-05-03 13:31 ` Marek Vasut
2012-05-03 14:27 ` Detlev Zundel
2012-05-03 14:39 ` Marek Vasut
2012-05-03 15:34 ` Marek Vasut
2012-05-04 9:16 ` Detlev Zundel
2012-05-03 8:11 ` [U-Boot] [PATCH 1/3] Revert "i.MX28: Enable additional DRAM address bits" Detlev Zundel
2012-05-03 13:36 ` Marek Vasut
2012-05-03 14:30 ` Detlev Zundel
2012-05-03 14:41 ` Marek Vasut
2012-05-04 9:15 ` Detlev Zundel [this message]
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