This series is the u-boot fix to a problem we encountered when enabling OPTEE/TrustZone on the WaRP7. The symptom is once TrustZone is activated the first page of CAAM registers becomes read-only, read-zero from the perspective of Linux and other non TrustZone contexts.
Offlining the problem with Peng Fan[1] we eventually came to realise the problem could be worked around by
1. Making Linux skip RNG initialisation - a set of patches should be hitting LKML to do just that.
2. Initialising the RNG either from u-boot or OPTEE. In this case u-boot is the right place to-do that because there's upstream code in u-boot that just works. Patch #2 does that for the WaRP7.
3. Ensuring the job-ring registers are assigned to the non TrustZone mode. On the i.MX7 after the BootROM runs the job-ring registers are assigned to TrustZone. Patch #1 does that for all CAAM hardware.
On point #3 this ordinarily isn't a problem because unless TrustZone is activated the restrictions on the job-ring registers don't kick in, its only after enabling TrustZone that Linux will loose access to the job-ring registers.
Finally should OPTEE or another TEE want to do things with the job-ring registers it will have sufficient privilege to assign whichever job-ring registers it wants to OPTEE/TEE but will naturally then have to arbitrate with Linux to inform the Kernel CAAM driver which job-ring registers it can and cannot access.
That arbitration process is for a future putative OPTEE/TEE CAAM driver to solve and is out of scope of this patchset.
[1] Thanks for all of your help BTW - Peng, there's no way this would be working without you giving direction on how.
Bryan O'Donoghue (2): drivers/crypto/fsl: assign job-rings to non-TrustZone warp7 : run sec_init for CAAM RNG
board/warp7/warp7.c | 6 +++++- drivers/crypto/fsl/jr.c | 9 +++++++++ drivers/crypto/fsl/jr.h | 1 + 3 files changed, 15 insertions(+), 1 deletion(-)