Based recent discussions on LKML, provide preliminary bits of tpm_tis_core
dependent drivers. Includes only bare essentials but can be extended later
on case by case. This way some people may even want to read it later on.
Cc: Jonathan Corbet <[email protected]>
CC: Daniel P. Smith <[email protected]>
Cc: Lino Sanfilippo <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Peter Huewe <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Alexander Steffen <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
Documentation/security/tpm/index.rst | 1 +
Documentation/security/tpm/tpm_tis.rst | 30 ++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
create mode 100644 Documentation/security/tpm/tpm_tis.rst
diff --git a/Documentation/security/tpm/index.rst b/Documentation/security/tpm/index.rst
index fc40e9f23c85..f27a17f60a96 100644
--- a/Documentation/security/tpm/index.rst
+++ b/Documentation/security/tpm/index.rst
@@ -5,6 +5,7 @@ Trusted Platform Module documentation
.. toctree::
tpm_event_log
+ tpm_tis
tpm_vtpm_proxy
xen-tpmfront
tpm_ftpm_tee
diff --git a/Documentation/security/tpm/tpm_tis.rst b/Documentation/security/tpm/tpm_tis.rst
new file mode 100644
index 000000000000..3cec0216a169
--- /dev/null
+++ b/Documentation/security/tpm/tpm_tis.rst
@@ -0,0 +1,30 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================
+TPM FIFO interface Driver
+=========================
+
+FIFO (First-In-First-Out) is the name of the hardware interface used by the
+`tpm_tis_core` dependent drivers. The prefix "tis" is named after TPM
+Interface Specification, which is the hardware interface specification for
+TPM 1.x chips.
+
+Communication is based on a 5 KiB buffer shared by the TPM chip through a
+hardware bus or memory map. The buffer is further split to five equal size
+buffers, which provide equivalent sets of registers for communication
+between CPU and TPM. The communication end points are called *localities*
+in the TCG terminology.
+
+When a kernel wants to send a commands to the TPM chip, it first reserves
+locality 0 by setting `requestUse` bit in `TPM_ACCESS` register. The bit is
+cleared by the chip when the access is granted. Once completed its
+communication, it sets `activeLocity` bit in the same register.
+
+Pending localities are served in order by the chip descending orderm and
+one at a time:
+
+- Locality 0 has the lowest priority.
+- Locality 5 has the highest priotiy.
+
+Further information on purpose and meaning of the localities can be found
+from section 3.2 of TCG PC Client Platform TPM Profile Specification.
--
2.40.1
Some remarks below that I noticed after sending this.
On Mon Mar 4, 2024 at 11:27 PM EET, Jarkko Sakkinen wrote:
> Based recent discussions on LKML, provide preliminary bits of tpm_tis_core
s/Based/ Based on/
> dependent drivers. Includes only bare essentials but can be extended later
> on case by case. This way some people may even want to read it later on.
>
> Cc: Jonathan Corbet <[email protected]>
> CC: Daniel P. Smith <[email protected]>
> Cc: Lino Sanfilippo <[email protected]>
> Cc: Jason Gunthorpe <[email protected]>
> Cc: Peter Huewe <[email protected]>
> Cc: James Bottomley <[email protected]>
> Cc: Alexander Steffen <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Jarkko Sakkinen <[email protected]>
> ---
> Documentation/security/tpm/index.rst | 1 +
> Documentation/security/tpm/tpm_tis.rst | 30 ++++++++++++++++++++++++++
> 2 files changed, 31 insertions(+)
> create mode 100644 Documentation/security/tpm/tpm_tis.rst
>
> diff --git a/Documentation/security/tpm/index.rst b/Documentation/security/tpm/index.rst
> index fc40e9f23c85..f27a17f60a96 100644
> --- a/Documentation/security/tpm/index.rst
> +++ b/Documentation/security/tpm/index.rst
> @@ -5,6 +5,7 @@ Trusted Platform Module documentation
> .. toctree::
>
> tpm_event_log
> + tpm_tis
> tpm_vtpm_proxy
> xen-tpmfront
> tpm_ftpm_tee
> diff --git a/Documentation/security/tpm/tpm_tis.rst b/Documentation/security/tpm/tpm_tis.rst
> new file mode 100644
> index 000000000000..3cec0216a169
> --- /dev/null
> +++ b/Documentation/security/tpm/tpm_tis.rst
> @@ -0,0 +1,30 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=========================
> +TPM FIFO interface Driver
> +=========================
> +
> +FIFO (First-In-First-Out) is the name of the hardware interface used by the
> +`tpm_tis_core` dependent drivers. The prefix "tis" is named after TPM
> +Interface Specification, which is the hardware interface specification for
> +TPM 1.x chips.
> +
> +Communication is based on a 5 KiB buffer shared by the TPM chip through a
> +hardware bus or memory map. The buffer is further split to five equal size
s/to/into/
> +buffers, which provide equivalent sets of registers for communication
> +between CPU and TPM. The communication end points are called *localities*
> +in the TCG terminology.
> +
> +When a kernel wants to send a commands to the TPM chip, it first reserves
s/a kernel/kernel/
s/a commands/commands/
> +locality 0 by setting `requestUse` bit in `TPM_ACCESS` register. The bit is
> +cleared by the chip when the access is granted. Once completed its
> +communication, it sets `activeLocity` bit in the same register.
s/it sets/kernel relinquishes reservation by setting/
> +
> +Pending localities are served in order by the chip descending orderm and
> +one at a time:
"Pending localities are served in descending order and one at a time:"
> +
> +- Locality 0 has the lowest priority.
> +- Locality 5 has the highest priotiy.
> +
> +Further information on purpose and meaning of the localities can be found
> +from section 3.2 of TCG PC Client Platform TPM Profile Specification.
s/on purpose/on the purpose/
BR, Jarkko
On 3/4/24 13:27, Jarkko Sakkinen wrote:
> Based recent discussions on LKML, provide preliminary bits of tpm_tis_core
> dependent drivers. Includes only bare essentials but can be extended later
> on case by case. This way some people may even want to read it later on.
>
> Cc: Jonathan Corbet <[email protected]>
> CC: Daniel P. Smith <[email protected]>
> Cc: Lino Sanfilippo <[email protected]>
> Cc: Jason Gunthorpe <[email protected]>
> Cc: Peter Huewe <[email protected]>
> Cc: James Bottomley <[email protected]>
> Cc: Alexander Steffen <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Jarkko Sakkinen <[email protected]>
> ---
> Documentation/security/tpm/index.rst | 1 +
> Documentation/security/tpm/tpm_tis.rst | 30 ++++++++++++++++++++++++++
> 2 files changed, 31 insertions(+)
> create mode 100644 Documentation/security/tpm/tpm_tis.rst
>
> diff --git a/Documentation/security/tpm/tpm_tis.rst b/Documentation/security/tpm/tpm_tis.rst
> new file mode 100644
> index 000000000000..3cec0216a169
> --- /dev/null
> +++ b/Documentation/security/tpm/tpm_tis.rst
> @@ -0,0 +1,30 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=========================
> +TPM FIFO interface Driver
> +=========================
> +
> +FIFO (First-In-First-Out) is the name of the hardware interface used by the
> +`tpm_tis_core` dependent drivers. The prefix "tis" is named after TPM
> +Interface Specification, which is the hardware interface specification for
> +TPM 1.x chips.
> +
> +Communication is based on a 5 KiB buffer shared by the TPM chip through a
> +hardware bus or memory map. The buffer is further split to five equal size
> +buffers, which provide equivalent sets of registers for communication
> +between CPU and TPM. The communication end points are called *localities*
> +in the TCG terminology.
> +
> +When a kernel wants to send a commands to the TPM chip, it first reserves
> +locality 0 by setting `requestUse` bit in `TPM_ACCESS` register. The bit is
> +cleared by the chip when the access is granted. Once completed its
> +communication, it sets `activeLocity` bit in the same register.
Is that activeLocality ?
> +
> +Pending localities are served in order by the chip descending orderm and
> +one at a time:
> +
> +- Locality 0 has the lowest priority.
> +- Locality 5 has the highest priotiy.
priority.
> +
> +Further information on purpose and meaning of the localities can be found
> +from section 3.2 of TCG PC Client Platform TPM Profile Specification.
--
#Randy
On Tue Mar 5, 2024 at 12:53 AM EET, Randy Dunlap wrote:
>
>
> On 3/4/24 13:27, Jarkko Sakkinen wrote:
> > Based recent discussions on LKML, provide preliminary bits of tpm_tis_core
> > dependent drivers. Includes only bare essentials but can be extended later
> > on case by case. This way some people may even want to read it later on.
> >
> > Cc: Jonathan Corbet <[email protected]>
> > CC: Daniel P. Smith <[email protected]>
> > Cc: Lino Sanfilippo <[email protected]>
> > Cc: Jason Gunthorpe <[email protected]>
> > Cc: Peter Huewe <[email protected]>
> > Cc: James Bottomley <[email protected]>
> > Cc: Alexander Steffen <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Cc: [email protected]
> > Cc: [email protected]
> > Signed-off-by: Jarkko Sakkinen <[email protected]>
> > ---
> > Documentation/security/tpm/index.rst | 1 +
> > Documentation/security/tpm/tpm_tis.rst | 30 ++++++++++++++++++++++++++
> > 2 files changed, 31 insertions(+)
> > create mode 100644 Documentation/security/tpm/tpm_tis.rst
> >
>
> > diff --git a/Documentation/security/tpm/tpm_tis.rst b/Documentation/security/tpm/tpm_tis.rst
> > new file mode 100644
> > index 000000000000..3cec0216a169
> > --- /dev/null
> > +++ b/Documentation/security/tpm/tpm_tis.rst
> > @@ -0,0 +1,30 @@
> > +.. SPDX-License-Identifier: GPL-2.0
> > +
> > +=========================
> > +TPM FIFO interface Driver
> > +=========================
> > +
> > +FIFO (First-In-First-Out) is the name of the hardware interface used by the
> > +`tpm_tis_core` dependent drivers. The prefix "tis" is named after TPM
> > +Interface Specification, which is the hardware interface specification for
> > +TPM 1.x chips.
> > +
> > +Communication is based on a 5 KiB buffer shared by the TPM chip through a
> > +hardware bus or memory map. The buffer is further split to five equal size
> > +buffers, which provide equivalent sets of registers for communication
> > +between CPU and TPM. The communication end points are called *localities*
> > +in the TCG terminology.
> > +
> > +When a kernel wants to send a commands to the TPM chip, it first reserves
> > +locality 0 by setting `requestUse` bit in `TPM_ACCESS` register. The bit is
> > +cleared by the chip when the access is granted. Once completed its
> > +communication, it sets `activeLocity` bit in the same register.
>
> Is that activeLocality ?
Yes.
>
> > +
> > +Pending localities are served in order by the chip descending orderm and
> > +one at a time:
> > +
> > +- Locality 0 has the lowest priority.
> > +- Locality 5 has the highest priotiy.
>
> priority.
>
> > +
> > +Further information on purpose and meaning of the localities can be found
> > +from section 3.2 of TCG PC Client Platform TPM Profile Specification.
Thanks for the remarks. Too many typos but at least I think the story is
is understandable and describes pretty well key elements of tpm_tis_core.
BR, Jarkko