Re: [PATCH v3 4/4] tpm: add driver for cr50 on SPI

Jarkko Sakkinen
2019-08-09T20:31:12Z

On Tue, 2019-08-06 at 15:07 -0700, Stephen Boyd wrote:
> From: Andrey Pronin <apronin@chromium.org>
>
> Add TPM2.0 PTP FIFO compatible SPI interface for chips with Cr50
> firmware. The firmware running on the currently supported H1
> Secure Microcontroller requires a special driver to handle its
> specifics:
>
> - need to ensure a certain delay between spi transactions, or else
> the chip may miss some part of the next transaction;
> - if there is no spi activity for some time, it may go to sleep,
> and needs to be waken up before sending further commands;
> - access to vendor-specific registers.

Which Chromebook models have this chip?

If I had an access to one, how do I do kernel testing with it i.e.
how do I get it to boot initramfs and bzImage from a USB stick?

/Jarkko