SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Like any other device on the PCIe fabric, the RC has its own 4-KiB configuration space, where RC local configuration registers are stored.
Since the RC configuration registers are programmed by the RC itself, no remote access over the PCIe wire (Cfg TLP) is required. Local DIF accesses (CS) are used instead.
However, some register fields normally defined as read-only by the PCI standard are actually programmable over DIF (see Section 24.9.4.9.2), which may cause a standard software driver to fail. In that case, the CS-writability of those fields has to be disabled by reprogramming the located in the PCIe controller port logic bit PCIECTRL_PL_DBI_RO_WR_EN[0] CX_DBI_RO_WR_EN to 0b0. Note that this is normally done after CS-writable fields have been configured by the non-standard initialization "firmware", thus making the RC’s configuration space PCI compliant.
The Section 24.9.4.8.2.2 and Section 24.9.4.8.2.3 only covers configuration of an EP function by an RC, using actual Configuration TLPs (transport layer packets).