[meta-ti][master][PATCH v4 0/3] Add LUKS encryption with fTPM support

This patch series adds LUKS full disk encryption support using firmware TPM
(fTPM) for TI K3 platforms. The implementation provides hardware-backed
encryption with keys sealed by TPM running in OP-TEE and stored in eMMC RPMB.

Background:
TI K3 platforms do not have integrated discrete TPM hardware. To provide
TPM 2.0 functionality, this implementation uses firmware TPM (fTPM) - a
Trusted Application running in OP-TEE secure world. The fTPM provides
standard TPM 2.0 interfaces while leveraging ARM TrustZone for isolation
and eMMC RPMB (Replay Protected Memory Block) for secure persistent storage.

Key features:
- Conditional builds: Only enabled via MACHINE_FEATURES += "luks-encryption"
- No impact on default SDK builds
- In-place encryption on first boot
- TPM persistent handle for key storage (0x81080001)
- Secure key storage in eMMC RPMB via OP-TEE
- Security model similar to CIP Core

Use case:
This is designed for K3 platforms requiring secure boot and encrypted
storage, such as industrial automation, automotive, and IoT gateways where
discrete TPM chips are cost-prohibitive but security requirements demand
hardware-backed encryption.

Testing:
- Tested on AM62x platform with kernel 6.18
- First boot: Successful in-place LUKS encryption
- Subsequent boots: Successful TPM unsealing and boot

The series is structured as follows:
1. Kernel configuration for LUKS and crypto support
2. Encrypted boot initramfs infrastructure
3. LUKS encryption trigger integration in ti-core-initramfs

---
Changes in v4:
- remove encrypted-boot-common.inc and use existing ti-core-initramfs.inc
- Link to v3: https://lore.kernel.org/all/[email protected]/

Changes in v3:
 - remove separate sdimage.wks for encrypted boot, default works
 - update encrypted-boot-common.inc to use existing hook for adding TI_CORE_INITRAMFS_ENABLED dependency on luks-encryption flag
 - add logic to verify if partition has enough space for LUKS header before starting encryption

Changes in v2:
- changes to use existing ti-core-initramfs instead of adding separate
- cleanup in previous init script as per comments in v1
- /usr/bin/busybox logs updated to echo, mesg, info
- WORKDIR changed to UNPACKDIR
- Link to v1: https://lore.kernel.org/all/[email protected]/

Shiva Tripathi (3):
  linux-ti-staging: Add LUKS encryption config
  initramfs: Add LUKS encryption module with fTPM
  ti-core-initramfs: Add luks-encryption trigger

 .../machine/include/ti-core-initramfs.inc     |   2 +-
 .../linux/linux-ti-staging-6.18/luks-ftpm.cfg |  28 ++
 .../linux/linux-ti-staging_6.18.bb            |   9 +
 .../initramfs-module-luks-ftpm/luksftpm       | 341 ++++++++++++++++++
 .../initramfs-module-luks-ftpm_1.0.bb         |  41 +++
 .../packagegroup-ti-core-initramfs.bb         |   1 +
 6 files changed, 421 insertions(+), 1 deletion(-)
 create mode 100644 meta-ti-bsp/recipes-kernel/linux/linux-ti-staging-6.18/luks-ftpm.cfg
 create mode 100644 meta-ti-bsp/recipes-ti/initramfs/initramfs-module-luks-ftpm/luksftpm
 create mode 100644 meta-ti-bsp/recipes-ti/initramfs/initramfs-module-luks-ftpm_1.0.bb

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2.34.1