Hello Lukas, On Thu, Nov 23, 2023 at 09:59:43AM +0100, Lukas Wunner wrote: > On Wed, Nov 22, 2023 at 04:15:18PM +0100, Francesco Dolcini wrote: > > On Wed, Nov 22, 2023 at 12:29:49PM +0100, Lukas Wunner wrote: > > > On Wed, Nov 22, 2023 at 12:33:58AM +0100, Francesco Dolcini wrote: > > > > Not to mention that I was able to see the driver probe succeed in a > > > > similar setup to the one you are describing in the commit message > > > > (different board, arm64, but nothing done by the platform firmware). > > > > > > Hm, is the RST# pin even connected on that board? > > > > Yes, it's connected and it is asserted/de-asserted (aka toggled) during > > startup from the HW reset circuit. However this is not implementing the > > reset sequence you are implementing here. > > Section 4.5 of the datasheet seems to indicate that unless the sequence > in Figure 3 is observed, the TPM may enter a defense mode against > dictionary attacks "from which a recovery is very complex or even not > possible." > > Simply toggling the RST# pin might therefore not be sufficient to ensure > the TPM is operable.
I am trying to follow-up with infineon on this regard, do you already have any insight from them maybe? Maybe this procedure is relevant only when the device is in "security defense state"? Francesco
