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Subject: Re: [PATCH v7 2/2] fTPM: add documentation for ftpm driver
To:     Sasha Levin <sashal@kernel.org>, peterhuewe@gmx.de,
        jarkko.sakkinen@linux.intel.com, jgg@ziepe.ca
Cc:     corbet@lwn.net, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-integrity@vger.kernel.org,
        linux-kernel@microsoft.com, thiruan@microsoft.com,
        bryankel@microsoft.com, tee-dev@lists.linaro.org,
        ilias.apalodimas@linaro.org, sumit.garg@linaro.org
References: <20190625201341.15865-1-sashal@kernel.org>
 <20190625201341.15865-3-sashal@kernel.org>
From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <fa526626-9eae-98ba-5127-6a4105781a41@infradead.org>
Date:   Tue, 25 Jun 2019 16:13:32 -0700
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On 6/25/19 1:13 PM, Sasha Levin wrote:
> This patch adds basic documentation to describe the new fTPM driver.
> 
> Signed-off-by: Sasha Levin <sashal@kernel.org>

Acked-by: Randy Dunlap <rdunlap@infradead.org>

Thanks.

> ---
>  Documentation/security/tpm/index.rst        |  1 +
>  Documentation/security/tpm/tpm_ftpm_tee.rst | 31 +++++++++++++++++++++
>  2 files changed, 32 insertions(+)
>  create mode 100644 Documentation/security/tpm/tpm_ftpm_tee.rst
> 
> diff --git a/Documentation/security/tpm/index.rst b/Documentation/security/tpm/index.rst
> index af77a7bbb070..15783668644f 100644
> --- a/Documentation/security/tpm/index.rst
> +++ b/Documentation/security/tpm/index.rst
> @@ -4,4 +4,5 @@ Trusted Platform Module documentation
>  
>  .. toctree::
>  
> +   tpm_ftpm_tee
>     tpm_vtpm_proxy
> diff --git a/Documentation/security/tpm/tpm_ftpm_tee.rst b/Documentation/security/tpm/tpm_ftpm_tee.rst
> new file mode 100644
> index 000000000000..48de0dcec0f6
> --- /dev/null
> +++ b/Documentation/security/tpm/tpm_ftpm_tee.rst
> @@ -0,0 +1,31 @@
> +=============================================
> +Firmware TPM Driver
> +=============================================
> +
> +| Authors:
> +| Thirupathaiah Annapureddy <thiruan@microsoft.com>
> +| Sasha Levin <sashal@kernel.org>
> +
> +This document describes the firmware Trusted Platform Module (fTPM)
> +device driver.
> +
> +Introduction
> +============
> +
> +This driver is a shim for firmware implemented in ARM's TrustZone
> +environment. The driver allows programs to interact with the TPM in the same
> +way they would interact with a hardware TPM.
> +
> +Design
> +======
> +
> +The driver acts as a thin layer that passes commands to and from a TPM
> +implemented in firmware. The driver itself doesn't contain much logic and is
> +used more like a dumb pipe between firmware and kernel/userspace.
> +
> +The firmware itself is based on the following paper:
> +https://www.microsoft.com/en-us/research/wp-content/uploads/2017/06/ftpm1.pdf
> +
> +When the driver is loaded it will expose ``/dev/tpmX`` character devices to
> +userspace which will enable userspace to communicate with the firmware TPM
> +through this device.
> 


-- 
~Randy