From: Stephen Warren <swarren@nvidia.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 09/14] tegra: Add warmboot implementation
Date: Fri, 13 Jan 2012 16:08:40 -0700 [thread overview]
Message-ID: <4F10B978.2000200@nvidia.com> (raw)
In-Reply-To: <CAPnjgZ2Ht7vCo=29FChDW0LaxkEX-xoL_5OUgatZQs+igfZ7AQ@mail.gmail.com>
On 01/13/2012 04:05 PM, Simon Glass wrote:
> On Fri, Jan 13, 2012 at 2:04 PM, Yen Lin <yelin@nvidia.com> wrote:
>> On Fri, 2012-01-13 at 11:34 -0800, Simon Glass wrote:
>>> On Tue, Jan 10, 2012 at 10:30 AM, Stephen Warren <swarren@nvidia.com> wrote:
>>>> On 12/26/2011 12:33 PM, Simon Glass wrote:
...
>>> But there a few questions here. Firstly it seems that it saves some
>>> memory speed info to scratch2 but never restores it. Then it restores
>>> CPU speed from scratch3 but I can't see where it saves it. Does Yen
>>> have any comments on that? Apparently it works because we have been
>>> using it, but... If it is saving things that are never restored I
>>> could dump that and reduce the code size.
>>>
>>
>> U-boot code saves sdram parameters to scratch2, scratch4, and scratch 24
>> registers, so when system resumes, bootrom can restore sdram parameters
>> from these registers.
>>
>> The scratch3 register content was saved by kernel before suspend, and is
>> used by the warmboot code to restore PLLX settings.
>
> Thanks for the info.
>
> On resume I do not see it using scratch2, 4 or 24 within U-Boot. Are
> those used in the kernel?
The Tegra boot ROM (which contains the power-on code for the AVP) is
what interprets these, according to Yen above.
One question for Yen: Why doesn't the boot ROM read the SDRAM parameters
from the BCT like it does during a cold boot? Perhaps there's some
interaction with clock settings, so the boot ROM needs to know the
clock/voltage/... state the kernel was in when suspending, rather than
just using the "usual" cold boot settings?
> I should add something to document this so the kernel people can match
> up when that side of it goes up stream.
--
nvpublic
next prev parent reply other threads:[~2012-01-13 23:08 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-26 19:32 [U-Boot] [PATCH 0/14] tegra: warmboot (suspend / resume) support Simon Glass
2011-12-26 19:32 ` [U-Boot] [PATCH 01/14] Add AES crypto library Simon Glass
2012-01-08 5:49 ` Mike Frysinger
2012-01-08 8:57 ` Marek Vasut
2012-01-08 9:09 ` Mike Frysinger
2012-01-08 10:40 ` Marek Vasut
2012-01-08 16:35 ` Simon Glass
2011-12-26 19:32 ` [U-Boot] [PATCH 02/14] tegra: Move ap20.h header into arch location Simon Glass
2011-12-26 19:32 ` [U-Boot] [PATCH 03/14] tegra: Add crypto library for warmboot code Simon Glass
2012-01-08 5:51 ` Mike Frysinger
2012-01-08 16:42 ` Simon Glass
2011-12-26 19:32 ` [U-Boot] [PATCH 04/14] tegra: Add flow, gp_padctl, fuse, sdram headers Simon Glass
2011-12-26 19:32 ` [U-Boot] [PATCH 05/14] tegra: Add tegra_get_chip_type() to detect SKU Simon Glass
2012-01-09 23:24 ` Stephen Warren
2012-01-12 19:35 ` Simon Glass
2012-01-12 19:48 ` Stephen Warren
2012-01-13 21:06 ` Simon Glass
2011-12-26 19:32 ` [U-Boot] [PATCH 06/14] tegra: Add EMC support for optimal memory timings Simon Glass
2012-01-09 23:38 ` Stephen Warren
2012-01-12 20:43 ` Simon Glass
2012-01-13 17:47 ` Simon Glass
2011-12-26 19:33 ` [U-Boot] [PATCH 07/14] tegra: Add PMU to manage power supplies Simon Glass
2012-01-10 17:56 ` Stephen Warren
2012-01-12 23:17 ` Simon Glass
2012-01-12 23:43 ` Stephen Warren
2012-01-12 23:55 ` Simon Glass
2011-12-26 19:33 ` [U-Boot] [PATCH 08/14] tegra: Set up PMU for Nvidia boards Simon Glass
2012-01-10 18:02 ` Stephen Warren
2012-01-12 23:42 ` Simon Glass
2011-12-26 19:33 ` [U-Boot] [PATCH 09/14] tegra: Add warmboot implementation Simon Glass
2012-01-10 18:30 ` Stephen Warren
2012-01-13 19:34 ` Simon Glass
2012-01-13 22:04 ` Yen Lin
2012-01-13 23:05 ` Simon Glass
2012-01-13 23:08 ` Stephen Warren [this message]
2012-01-14 0:04 ` Yen Lin
2011-12-26 19:33 ` [U-Boot] [PATCH 10/14] tegra: Setup PMC scratch info from ap20 setup Simon Glass
2011-12-26 19:33 ` [U-Boot] [PATCH 11/14] tegra: Set up warmboot code on Nvidia boards Simon Glass
2011-12-26 19:33 ` [U-Boot] [PATCH 12/14] tegra: Set vdd_core and vdd_cpu to high Simon Glass
2012-01-10 18:40 ` Stephen Warren
2012-01-13 17:55 ` Simon Glass
2011-12-26 19:33 ` [U-Boot] [PATCH 13/14] tegra: Add EMC settings for Seaboard, Harmony Simon Glass
2012-01-10 18:46 ` Stephen Warren
2012-01-12 23:05 ` Simon Glass
2012-01-12 23:42 ` Stephen Warren
2012-01-12 23:54 ` Simon Glass
2012-01-13 0:01 ` Stephen Warren
2012-01-13 0:05 ` Simon Glass
2012-01-13 0:10 ` Stephen Warren
2012-01-13 0:18 ` Simon Glass
2011-12-26 19:33 ` [U-Boot] [PATCH 14/14] tegra: Enable LP0 on Seaboard Simon Glass
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