Configuring the Security Configuration Registers

Tegra has separate registers for configuring bridge client security and bridge firewalls, known as security configuration registers (SCRs). SCRs are either configured by the platform or re-configured for custom platforms. The custom configuration is provided using MB2 BCT at the MB2 stage. The SRC configuration file is available at:

<top>/drive-foundation/platform-config/platform/t23x/common/bct/firewall/tegra234-firewall-config-base.dtsi

Format of the entries in dtsi:

reg@XYZ

{       exclusion-info = <2>;       value = <0x80000000>; }
;

Exclusion-info is a bit-map (4 bits) with each bit signifying the following:

BIT[0] - SC7 SKIP
BIT[1:2] - PROGRAM_IN
   0 -> BEFORE_MB2
   1 -> MB2
   2 -> AFTER_MB2
BIT[3] - PRODUCTION ONLY

MB2 will program the SCRs only if the PROGRAM_IN field is set to MB2. SCRs that are to be programmed only on platforms with production fuses blown have PRODUCTION_ONLY flag set in exclusion-info. MB2 will check if the fuses are blown and programs the SCRs.