tree c88b410143785a6fb36eec763f393cf48060f12b
parent 29b7c571d4e2ee1631c001dceff5bd0e18657ad1
author Philipp Wagner <phw@lowrisc.org> 1626428965 +0100
committer Philipp Wagner <mail@philipp-wagner.com> 1626598741 +0100

[otbn] Change URND and RND_PREFETCH CSR indices

The CSR indexes in OTBN are meant to be following the address map
specified in the RISC-V Privileged Specification, which gives ranges for
custom read-only, and read-writable CSRs (in M mode). The recent
addition of RND_PREFIX didn't follow these rules. This commit assigns
new addresses to URND (a read-only CSR) and RND_PREFETCH (a read-write
CSR):

Read/write CSRs:
  RND_PREFETCH is now at 0x7D8 (before: 0xFC1)

Read-only CSRs:
  RND          is now at 0xFC0 (unchanged)
  URND         is now at 0xFC1 (before: 0xFC2)

RTL, DV and ISS have been updated. No software has been using these CSRs
yet.

Signed-off-by: Philipp Wagner <phw@lowrisc.org>