From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Date: Mon, 9 Nov 2015 08:19:48 -0700 Subject: [U-Boot] [PATCH 4/4] ARM: tegra210: gpu: configure WPR region In-Reply-To: <20151109143654.GB11362@ulmo.nvidia.com> References: <1445230624-30314-1-git-send-email-acourbot@nvidia.com> <1445230624-30314-5-git-send-email-acourbot@nvidia.com> <56310CE8.3050107@wwwdotorg.org> <20151109143654.GB11362@ulmo.nvidia.com> Message-ID: <5640B994.7050307@wwwdotorg.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 11/09/2015 07:36 AM, Thierry Reding wrote: > On Wed, Oct 28, 2015 at 11:59:04AM -0600, Stephen Warren wrote: >> On 10/18/2015 10:57 PM, Alexandre Courbot wrote: >>> T210's GPU secure firmware loading requires a write-protected region >>> to be set up. >>> >>> This patch reserves the upper 256KB of RAM as the WPR region and locks >>> it so the kernel can initiate secure firmware loading. >> >> On T210, it's the responsibility of nvtboot (which runs before U-Boot) to >> set up any and all carve-outs. This code should not be necessary, and indeed >> I expect the registers it touches can't actually be programmed from U-Boot, >> which runs in non-secure mode after WPR is already locked. > > Can we document this assumption somewhere? It's entirely possible that > someone might want to run U-Boot without nvtboot That's not currently a supported use-case. > , in which case nvtboot > would still need to be responsible for setting this up. I assume s/nvtboot/whatever other bootloader is in use/? > Or if it isn't > we could still point at some location where the interactions between a > first stage bootloader and U-Boot are documented. > > Do we have a document of this kind already? The L4T U-Boot source code:-)