[PATCH v5 0/3] firmware: Add support for Qualcomm UEFI Secure Application

[Maximilian Luz <luzmaximilian@gmail.com>]

This series adds basic support for the QSEECOM interface used to
communicate with secure applications running in the TrustZone on certain
Qualcomm devices. In addition to that, it also provides a driver for
"uefisecapp", the secure application managing access to UEFI variables
on such platforms.

For a more detailed description, see the blurb of v1.

Previous versions:

 - V4: https://lore.kernel.org/lkml/72c0359a-eda6-30ea-0ec0-b7e9b804b87b@gmail.com/t/
 - V3: https://lore.kernel.org/lkml/20230305022119.1331495-4-luzmaximilian@gmail.com/t/
 - V2: https://lore.kernel.org/lkml/20230127184650.756795-1-luzmaximilian@gmail.com/
 - V1: https://lore.kernel.org/lkml/20220723224949.1089973-1-luzmaximilian@gmail.com/

Changes in v5:

 - Re-introduce a dedicated platform device for managing QSEECOM client
   devices. The device is now added via qcom_scm.c instead of the device
   tree (as has been done in v3).

 - Replace ucs2_strlcpy() with ucs2_strscpy()

 - Drop "firmware: qcom_scm: Clear scm pointer on probe failure" and
   sort out probe-related issue.

 - Clean up comments in qcom_qseecom_uefisecapp.c

Changes in v4:

 - Integrate the QSEECOM interface into qcom_scm.c instead of
   instantiating a custom device and requiring device-tree bindings for
   it. With that, drop the respective patches exporting SCM call
   functions from qcom_scm.c and the DT bindings.

 - Restructure management of DMA memory and move DMA mapping entirely
   into the app_send() command, removing the need for DMA handling in
   app client drivers.

 - Add support for EFI's query_variable_info() call.

 - Move UCS-2 string helpers to lib/ucs2_string.c (introduces patch 1).

 - Add fix for related cleanup-issue in qcom_scm.c (introduces patch 2).

 (Refer to individual patches for more details.)

Changes in v3:

 - Fix doc comment in qcom_scm.c
 - Rebase on top of latest changes to qcom_scm.

Changes in v2:

 - Bind the qseecom interface to a device.

 - Establish a device link between the new qseecom device and the SCM
   device to ensure proper PM and remove ordering.

 - Remove the compatible for uefisecapp. Instead, introduce a compatible
   for the qseecom device. This directly reflects ACPI tables and the
   QCOM0476 device described therein, which is responsible for the
   secure app / qseecom interface (i.e., the same purpose).

   Client devices representing apps handled by the kernel (such as
   uefisecapp) are now directly instantiated by the qseecom driver,
   based on the respective platform-specific compatible.

 - Rename the base name (qctree -> qseecom) to allow differentiation
   between old (qseecom) and new (smcinvoke) interfaces to the trusted
   execution environment. This directly reflects downstream naming by
   Qualcomm.

Maximilian Luz (3):
  lib/ucs2_string: Add UCS-2 strscpy function
  firmware: qcom_scm: Add support for Qualcomm Secure Execution
    Environment SCM interface
  firmware: Add support for Qualcomm UEFI Secure Application

 MAINTAINERS                                |  12 +
 drivers/firmware/Kconfig                   |  33 +
 drivers/firmware/Makefile                  |   2 +
 drivers/firmware/qcom_qseecom.c            | 130 +++
 drivers/firmware/qcom_qseecom_uefisecapp.c | 869 +++++++++++++++++++++
 drivers/firmware/qcom_scm.c                | 392 ++++++++++
 include/linux/firmware/qcom/qcom_qseecom.h |  46 ++
 include/linux/firmware/qcom/qcom_scm.h     |  21 +
 include/linux/ucs2_string.h                |   1 +
 lib/ucs2_string.c                          |  35 +
 10 files changed, 1541 insertions(+)
 create mode 100644 drivers/firmware/qcom_qseecom.c
 create mode 100644 drivers/firmware/qcom_qseecom_uefisecapp.c
 create mode 100644 include/linux/firmware/qcom/qcom_qseecom.h

-- 
2.41.0