Hi Michael, > -----Original Message----- > From: U-Boot <[email protected]> On Behalf Of Michael Walle > Sent: Monday, December 20, 2021 6:23 PM > To: Sahil Malhotra (OSS) <[email protected]> > Cc: ZHIZHIKIN Andrey <[email protected]>; Clément > Faure <[email protected]>; Gaurav Jain <[email protected]>; > Pankaj Gupta <[email protected]>; Priyanka Jain > <[email protected]>; [email protected]; Varun Sethi > <[email protected]>; Ye Li <[email protected]> > Subject: [EXT] Re: [PATCH 1/2] fsl-layerscape: add dtb overlay feature > > Caution: EXT Email > > Hi Sahil, > > Am 2021-12-10 07:33, schrieb Sahil Malhotra (OSS): > >> DT nodes can be statically disabled if we know that they are held by > >> HAB and are not released to NS World. > >> > >> OP-TEE does set the status itself via dt_enable_secure_status(), > >> which should present the properly configured FDT when U-Boot takes > over. > > Yes, OP-TEE set the status by dt_enable_secure_status() in DTB overlay > > which gets merged with DTB provided for Linux bootup and then Linux > > boots with merged DTB. > > But u-boot uses the DTB embedded in its image. How can we modify that > > DTB or merge DTB overlay passed by OP-TEE with uboot DTB ? > > But then u-boot has the "wrong" dtb. What is the reason, there is an overlay > instead of a whole dtb? what if the overlay doesn't match the dtb? "wrong" dtb means that uboot will not be aware of CAAM job ring which is taken by OP-TEE and uboot on LS platforms currently use JR0, which is not being used by any other entity in LS bootflow.
We don't use DTB in OP-TEE, but when we use CAAM in OP-TEE, OP-TEE reserves One Job Ring for its use and that is communicated to Kernel using DTB overlay. > what if the overlay doesn't match the dtb? I didn't get this point, can you please elaborate a little. Regards, Sahil Malhotra
