dt-bindings: Add spss_utils documentation

Qualcomm Technologies, Inc. Secure Processor SubSystem Utilities (spss_utils)

The Secure Processor SubSystem (SPSS) is a dedicated subsystem for security.

It has its own CPU, memories, and cryptographic engine.

It shall provide cryptographic services to other subsystems.

The SPSS firmware is loaded by PIL driver.

The communication with SPSS is done via spcom driver, using glink.

The spss_utils driver selects the SPSS firmware file,

according to a dedicated fuse and the platform HW version.

Required properties:

-compatible : should be "qcom,spss_utils"

-qcom,spss-fuse1-addr: fuse1 register physical address

-qcom,spss-fuse1-bit: fuse1 relevant bit

-qcom,spss-fuse2-addr: fuse2 register physical address

-qcom,spss-fuse2-bit: fuse2 relevant bit

-qcom,spss-dev-firmware-name: dev firmware file name

-qcom,spss-test-firmware-name: test firmware file name

-qcom,spss-prod-firmware-name: production firmware file name

-qcom,spss-debug-reg-addr: debug register physical address

-qcom,spss-emul-type-reg-addr: soc emulation type register physical address

Example:

   qcom,spss_utils {

      compatible = "qcom,spss-utils";

      qcom,spss-fuse1-addr = <0x007841c4>;

      qcom,spss-fuse1-bit = <27>;

      qcom,spss-fuse2-addr = <0x007841c4>;

      qcom,spss-fuse2-bit = <26>;

      qcom,spss-dev-firmware-name  = "spss1d";  /* 8 chars max */

      qcom,spss-test-firmware-name = "spss1t";  /* 8 chars max */

      qcom,spss-prod-firmware-name = "spss1p";  /* 8 chars max */

      qcom,spss-debug-reg-addr = <0x01886020>;

      qcom,spss-emul-type-reg-addr = <0x01fc8004>;

   };