drivers: qcom: ramblur: configure pIMEM access

Configure memory access to enable execution of Trusted Applications.

OP-TEE and its Trusted Applications execute from pIMEM, a region protected
by the

drivers: qcom: ramblur: configure pIMEM access

Configure memory access to enable execution of Trusted Applications.

OP-TEE and its Trusted Applications execute from pIMEM, a region protected
by the RAMBLUR IP block.

RAMBLUR provides anti-rollback protection as well as confidentiality and
integrity guarantees for the memory region under its control.

Any agent accessing the pIMEM-protected region performs normal reads or
writes to the pIMEM address range in the SNoC. The SNoC routes these
transactions to the pIMEM slave port, and pIMEM remasters them to DDR.

For write transactions, pIMEM applies the required cryptographic
operations before committing data to DDR.

For read transactions, pIMEM applies the corresponding cryptographic
operations before returning the data from DDR to the requesting master.

The reserved DDR region used by pIMEM to store cryptographically
processed data and associated cryptographic state is referred to as the
pIMEM vault.

With the current U-Boot (tag 2026.01-rc3), the pIMEM Vault DDR
reservation is derived from the TZ node in U-Boot’s built-in device tree
(specifically the trusted_apps_mem reserved-memory node).

U-Boot uses this node to construct the EFI memory map that is later
passed to the kernel.

A future update will remove this dependency on the built-in device tree.
Instead, U-Boot will obtain the memory configuration directly from SMEM.
Because of this transition, the current version of the driver does not
generate a DT overlay for U-Boot to consume.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez@oss.qualcomm.com>
Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
Reviewed-by: Tony Hamilton <tonyh@qti.qualcomm.com>

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