On 10/24/2017 09:00 PM, Sumit Garg wrote: >> -----Original Message----- >> From: York Sun >> Sent: Tuesday, October 24, 2017 8:00 PM >> To: Sumit Garg <sumit.g...@nxp.com>; u-boot@lists.denx.de >> Cc: Ruchika Gupta <ruchika.gu...@nxp.com>; Prabhakar Kushwaha >> <prabhakar.kushw...@nxp.com>; Z.q. Hou <zhiqiang....@nxp.com>; Pankaj >> Gupta <pankaj.gu...@nxp.com>; Arun Pathak <arun.pat...@nxp.com>; Sahil >> Malhotra <sahil.malho...@nxp.com> >> Subject: Re: [PATCH 2/2] armv8: sec_firmware: Add support for loadables in >> FIT >> >> On 10/23/2017 09:21 PM, Sumit Garg wrote: >> <snip> >>>> >>>> Sumit, >>>> >>>> If I understand you correctly, you are parsing the secure firmware >>>> FIT image to find the loadable node and store the 64-bit load address >>>> in the scratch registers. How do you determine which scratch registers to >> use? >>>> >>>> York >>> >>> Yes your understanding is correct. The scratch registers which I used are as >> follows: >>> >>> For Chassis gen 3 platforms: >>> /* Assign addresses to loadable ptrs */ >>> loadable_l = &gur->scratchrw[4]; >>> loadable_h = &gur->scratchrw[5]; >>> >>> For Chassis gen 2 platforms: >>> /* Assign addresses to loadable ptrs */ >>> loadable_l = &scfg->scratchrw[2]; >>> loadable_h = &scfg->scratchrw[3]; >>> >>> I choose above scratch registers to avoid any conflict with usage of >>> scratch registers in Boot-ROM, u-boot and PPA. >> >> I see you write to these scratch registers but never read from them. >> What's the purpose to store the address in them? >> >> York > > These scratch registers are used to communicate loadable address to PPA > similar > to how return address is communicated in boot-location pointer registers to > PPA. > > PPA uses this loadable address (Trusted OS address) to initialize Trusted OS.
OK. So these registers are actually consumed by PPA image. That makes more sense. York _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
