[U-Boot] [PATCH 1/3] common: board: support systems with where RAM ends beyond 4GB

Stephen Warren swarren at wwwdotorg.org
Thu Jan 22 19:06:33 CET 2015


On 01/20/2015 08:56 AM, Tom Warren wrote:
> I've merged that patch series w/u-boot-tegra/next and /master, done a MAKEALL -s tegra, and rebased against ARM /master and pushed to denx.de.
>
> Stephen - please test and if it looks OK, I'll prepare a PR.

This works great on my Jetson TK1. Thanks.

>
>> -----Original Message-----
>> From: Tom Warren
>> Sent: Tuesday, January 20, 2015 8:28 AM
>> To: 'Stephen Warren'; u-boot at lists.denx.de; Simon Glass; Stephen Warren
>> Cc: Tom Rini
>> Subject: RE: [U-Boot] [PATCH 1/3] common: board: support systems with
>> where RAM ends beyond 4GB
>>
>> Sorry, missed this. Yes, looks good to me. I can apply it to u-boot-
>> tegra/master, or TomR can take it in to master U-Boot directly.
>>
>> Tom
>>
>>> -----Original Message-----
>>> From: Stephen Warren [mailto:swarren at wwwdotorg.org]
>>> Sent: Monday, January 19, 2015 3:57 PM
>>> To: u-boot at lists.denx.de; Simon Glass; Tom Warren; Stephen Warren
>>> Cc: Tom Rini
>>> Subject: Re: [U-Boot] [PATCH 1/3] common: board: support systems with
>>> where RAM ends beyond 4GB
>>>
>>> On 12/23/2014 10:34 AM, Stephen Warren wrote:
>>>> From: Stephen Warren <swarren at nvidia.com>
>>>>
>>>> Some systems have so much RAM that the end of RAM is beyond 4GB.
>> An
>>>> example would be a Tegra124 system (where RAM starts at 2GB
>>>> physical) that has more than 2GB of RAM.
>>>>
>>>> In this case, we can gd->ram_size to represent the actual RAM size,
>>>> so that the actual RAM size is passed to the OS. This is useful if
>>>> the OS implements LPAE, and can actually use the "extra" RAM.
>>>>
>>>> However, U-Boot does not implement LPAE and so must deal with 32-bit
>>>> physical addresses. To this end, we enhance
>>>> board_get_usable_ram_top() to detect the "over-sized" case, and
>>>> limit the relocation addres so that it fits into 32-bits of physical address
>> space.
>>>
>>> TomW, TomR, does this series look good?
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