Register type RWL-S are NOT locked after the first write

[lindadong919]

Hello,

Our test found the RWL-S type registers are writable more than once, e.g. fuse_key_manifest_pk_hash[], fuse_owner_pk_hash, fuse_idevid_cert_attr[], fuse_idevid_manuf_hsm_id[], fuse_fmc_key_manifest_svn, fuse_runtime_svn[], fuse_lms_verify, fuse_lms_revocation, fuse_soc_stepping_id, fuse_life_cycle.

Can you please take a look?

Thanks,
Linda Dong

[calebofearth]

Hi Linda,

This is the intended behavior. These registers are designed to be "lockable", but not write-once. ("RWL-S" stands for Read-Write-Lock--Sticky). During the boot flow, SoC shall populate the fuses and then set the fuse wr done bit, as described in the Integration spec and in the CPTRA_FUSE_WR_DONE register. Setting CPTRA_FUSE_WR_DONE locks the fuses from any subsequent writes until cold reset.

I do see an ambiguous statement in the Integration spec (here) that should be clarified. The intent is that Fuses are only programmable at a specific stage during boot up, and never again during runtime. I submitted a PR to clarify the spec.

[lindadong919]

Hi Caleb, Thank you very much for your quick response. I understand the function now. Regards, Linda From: Caleb ***@***.***> Sent: Monday, September 30, 2024 10:11 AM To: chipsalliance/caliptra-rtl ***@***.***> Cc: Linda Dong ***@***.***>; Author ***@***.***> Subject: Re: [chipsalliance/caliptra-rtl] Register type RWL-S are NOT locked after the first write (Issue #596) Closed #596<#596> as completed via #597<#597>. — Reply to this email directly, view it on GitHub<#596 (comment)>, or unsubscribe<https:/notifications/unsubscribe-auth/BB7PKUM4V6XXR2VB5S34NELZZGA35AVCNFSM6AAAAABO77DA66VHI2DSMVQWIX3LMV45UABCJFZXG5LFIV3GK3TUJZXXI2LGNFRWC5DJN5XDWMJUGQ2TSNZZHA3TGMQ>. You are receiving this because you authored the thread.Message ID: ***@***.******@***.***>> The information contained in this e-mail is considered confidential of SK hynix memory solutions America Inc. and intended only for the persons addressed or copied in this e-mail. Any unauthorized use, dissemination of the information, or copying of this message is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email.