From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alban Bedel Date: Mon, 9 Dec 2013 19:09:08 +0100 Subject: [U-Boot] [PATCH] ARM: tegra: Use the IRAM for the early stack In-Reply-To: <52A5F95D.6020605@wwwdotorg.org> References: <1386608764-8173-1-git-send-email-alban.bedel@avionic-design.de> <52A5F95D.6020605@wwwdotorg.org> Message-ID: <20131209190908.76a281e8@avionic-0020> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Mon, 09 Dec 2013 10:09:49 -0700 Stephen Warren wrote: > On 12/09/2013 10:06 AM, Alban Bedel wrote: > > Unlike many other platforms the tegra platform has the luxury of > > already having the SDRAM running during the early init, and it is used > > for the early stack. However the memory test of the POST subsystem is > > expecting the SDRAM to be unused, and on tegra platforms the test fail > > to run as it destroy the stack. > > > > To fix the problem simply use the IRAM for the initial stack. > > Can't the POST code simply touch an unused RAM address? The memtest is run pre-relocation to in fact avoid having to take care about some special memory regions, beside the u-boot image and pre-relocation code. > There is IRAM content that needs to be preserved, so we need to make > sure we don't stomp on that. Examples are: > > * BIT (Boot Information Table) > * BCT that was used to boot the system > * Perhaps the whole IRAM is filled with code/data in the LP0 > suspend/resume case. BIC and BCT shouldn't be problem if enough IRAM is left for the relocation. After relocation the stack move to the SDRAM anyway. But for LP0 I don't really understand what the problem would be. Do the u-boot loading+relocation needs to be run when comming out of LP0? Alban