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From: Sascha Hauer <sha@pengutronix.de>
To: Marco Felsch <m.felsch@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH v2] ARM: i.MX8M: esdctl: split memory banks for devices with >4G
Date: Mon, 4 Sep 2023 12:02:57 +0200	[thread overview]
Message-ID: <20230904100257.GF189379@pengutronix.de> (raw)
In-Reply-To: <20230831144724.3424405-1-m.felsch@pengutronix.de>

Hi Marco,

On Thu, Aug 31, 2023 at 04:47:24PM +0200, Marco Felsch wrote:
> At the moment the whole available memory is added to one single memory
> bank "ram0". This can cause barebox chainload issues on devices with a
> huge amount of memory like the i.MX8MP-EVK which has 6G of RAM if the
> barebox pbl binary is to large.
> 
> The reason for this issues is that memory_bank_first_find_space()
> returns the memory area with the largest amount of free space on the
> first memory bank. So in case of Debix SOM-A 8G and i.MX8MP-EVK 6G this
> is the area crossing the 4G boundary. This cause the barebox pbl code to
> trigger a MMU exception once the early MMU gets enabled which is
> configured for sizes <=4G.
> 
> Split the memory space into two memory banks: "ram0" and "ram1" to fix
> this issue.

In the long run we'll need a proper solution for this. I think this
patch is fine for now, but please add a comment why we are doing this.
Otherwise we might remove this superfluous code at some point.

Sascha

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  reply	other threads:[~2023-09-04 10:04 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-31 14:47 Marco Felsch
2023-09-04 10:02 ` Sascha Hauer [this message]
2023-09-05  8:11   ` Marco Felsch
2023-09-04 14:44 ` Ahmad Fatoum
2023-09-05  8:10   ` Marco Felsch

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