[top_earlgrey] Area optimizations for production

[msfschaffner]

Description

This is a tracker for area optimizations that are in flight for Earlgrey PROD.

Planned for RC1:

• kmac: Switch PRNG from Trivium to Bivium [kmac] Switch PRNG stream cipher primitive from Trivium to Bivium #22021
• entropy_src: reduce depth of esfinal FIFO [entropy_src] Rework swread packer FIFO, reduce esfinal FIFO depth #22041
• uart: reduce TX buffer size from 128B to 32B [uart] Reduce TX FIFO depth from 128B to 32B #22026
• uart: reduce RX buffer size from 128B to 64B [uart] Reduce RX FIFO depth from 128B to 64B #22046
• rv_core_ibex: remove 8 performance counters [rv_core_ibex,rtl] Reduce number of performance counters #22047
• csrng: more fine-grained parametrization of AES to remove unneeded datapaths [aes, csrng] Reduce area of unmasked AES core inside CSRNG #22056
• csrng: remove redundant state copies in state database [csrng] Avoid redundant state copies for debugging and read out in state database #22064

Planned for RC2:

• flash_ctrl: Share the scrambling module between two banks [flash_ctrl] Share flash_scrambling module among banks #22045
• entropy_src: reduce depth of observe FIFO [entropy_src] Reduce depth of Observe FIFO #22087

Planned for RC3:6000

• [i2c,rtl] Change FF-based FIFOs to SRAM-based ones #22159

Deferred:
- [ ] Reverting of #22045 due to problems found in #22089; deferred because likely not a bug, see #22191 It turned out to be an RTL bug but this got fixed by #22276

The list only contains optimizations that have been approved. More ideas are captured in this document.

[msfschaffner]

FYI @zi-v @arnonsha @msfschaffner @OTshimeon
This is where we track approved optimizations.

[andreaskurth]

Closing as completed (at least for now).