Re: [PATCH v2 1/3] ftpm: dt-binding: add dts documentation for fTPM driver

From: Sasha Levin
Date: Wed Apr 10 2019 - 13:54:04 EST


On Wed, Apr 10, 2019 at 02:03:16PM -0300, Jason Gunthorpe wrote:
On Wed, Apr 10, 2019 at 12:01:37PM -0500, Rob Herring wrote:
On Wed, Apr 10, 2019 at 11:19 AM Sasha Levin <sashal@xxxxxxxxxx> wrote:
>
> On Tue, Apr 09, 2019 at 04:18:29PM -0500, Rob Herring wrote:
> >On Tue, Apr 9, 2019 at 1:50 PM Sasha Levin <sashal@xxxxxxxxxx> wrote:
> >>
> >> The parameters are similar to the ones used by IBM's vTPM and the
> >> various I2C tpm drivers.
> >
> >Bindings describe h/w (or firmware interfaces in this case), not drivers.
> >
> >>
> >> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> >> .../bindings/security/tpm/tpm_ftpm_tee.txt | 13 +++++++++++++
> >> .../devicetree/bindings/vendor-prefixes.txt | 1 +
> >> 2 files changed, 14 insertions(+)
> >> create mode 100644 Documentation/devicetree/bindings/security/tpm/tpm_ftpm_tee.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/security/tpm/tpm_ftpm_tee.txt b/Documentation/devicetree/bindings/security/tpm/tpm_ftpm_tee.txt
> >> new file mode 100644
> >> index 000000000000..20fca67a56c4
> >> +++ b/Documentation/devicetree/bindings/security/tpm/tpm_ftpm_tee.txt
> >> @@ -0,0 +1,13 @@
> >> +Required properties:
> >> +- compatible: should be "microsoft,ftpm"
> >> +- linux,sml-base: 64-bit base address of the reserved memory allocated
> >> + for the firmware event log
> >> +- linux,sml-size: size of the memory allocated for the firmware event log
> >
> >Firmware is defining linux specific properties? What if I want to run
> >BSD? We should use 'reg' here instead.
>
> This is based on already existing code that defines these names, see
> tpm_read_log_of() in drivers/char/tpm/eventlog/of.c .

BTW, that probably needs updating to handle endianness correctly.

IIRC this legacy IBM code has broken endianness in the firmware..

All that stuff in read_log_of, and the related DT stuff, is historical
IBM special case-ness and should not be copied into new things.

The fTPM driver does not use it on it's own, so I guess I can just drop
this patch then?

--
Thanks,
Sasha