[U-Boot] [PATCH 00/18] Introduce SPI TPM v2.0 support

[Miquel Raynal]

Hi Tom,

On Tue, 20 Mar 2018 10:04:55 -0400, Tom Rini <trini at konsulko.com> wrote:

> On Tue, Mar 20, 2018 at 02:36:56PM +0100, Miquel Raynal wrote:
> > Hi Tom,
> > 
> > Sorry for the delay.
> > 
> > On Fri, 9 Mar 2018 07:18:40 -0500, Tom Rini <trini at konsulko.com> wrote:
> >   
> > > On Fri, Mar 09, 2018 at 08:53:40AM +0100, Miquel Raynal wrote:  
> > > > Hi Tom,
> > > > 
> > > > On Thu, 8 Mar 2018 12:20:30 -0500, Tom Rini <trini at konsulko.com> wrote:
> > > >     
> > > > > On Thu, Mar 08, 2018 at 04:40:03PM +0100, Miquel Raynal wrote:
> > > > >     
> > > > > > Current U-Boot supports TPM v1.2 specification. The new specification
> > > > > > (v2.0) is not backward compatible and renames/introduces several
> > > > > > functions.
> > > > > > 
> > > > > > This series introduces a new SPI driver following the TPM v2.0
> > > > > > specification. It has been tested on a ST TPM but should be usable with
> > > > > > others v2.0 compliant chips.
> > > > > > 
> > > > > > Then, basic functionalities are introduced one by one for the v2.0
> > > > > > specification. The INIT command now can receive a parameter to
> > > > > > distinguish further TPMv1/TPMv2 commands. After that, the library itself
> > > > > > will know which one is pertinent and will return a special error if the
> > > > > > desired command is not supported for the selected specification.      
> > > > > 
> > > > > Thanks for doing all of this.  Can you please enable this feature on
> > > > > sandbox and/or an x86 QEMU variant where I assume we could also then
> > > > > setup automated testing?
> > > > >     
> > > > 
> > > > Not sure I understand your request correctly: the TPM commands are
> > > > already available in the sandbox (I don't see what I could add), I just
> > > > extended the current set of commands.
> > > > 
> > > > However, even with these commands, we won't be able to test them in a
> > > > sandbox unless with an actual device.
> > > > 
> > > > I probably miss something, can you explain a bit more what you would
> > > > like?    
> > > 
> > > Can we add a valid TPM via QEMU and then test it that way?  If so, we
> > > should enable the TPM code on qemu-x86_64 (and, well, if we can pass it
> > > on other arches, other QEMU targets) and write some test/py/tests/ code
> > > that exercises the TPM commands.  Does that make sense?
> > >   
> > 
> > I suppose this is doable, but for what I know, the effort is
> > consequent. TPM 2.0 are not compatible at all with TPM 1.x , the
> > packets exchanged at TPM level are completely different. Hence, I
> > think there is almost nothing that we can take from the TPM 1.x
> > implementation already existing in QEMU.  
> 
> Ah, OK.  I thought QEMU had a TPM 2.0 implementation now too, but I see
> I'm mistaken.
> 
> > I am certain we all would benefit such a contribution, however I'm
> > not sure I could handle that anytime soon.
> > 
> > About the series, I think it would be better that I change a macro name
> > ("STRINGIFY", which is wrongly named), I will send a v2 soon, can you
> > tell me its status otherwise?  
> 
> We have the usual linux/stringify.h header available, so yes, you should
> make use of that.

Actually the name is misleading as I don't want to "stringify".

I am looking for a way to easily fill a buffer of bytes from integer
values, ie:

u32 value = 0x12345678;
u8 buf[x] = { MACRO(value), ...} to be {0x12, 0x34, 0x56, 0x78, ...}


>  And I still would like to see tests written, even if
> they can only be executed on $board with $TPM attached via $interface,
> with those 3 variables documented so that others can try it out too.
> Does that make sense?  Thanks!

I see some TPM tests for v1.x, I can probably add some there. This will
test the library functions but not the "user" commands.

To test the commands, I suggest following the lines I inserted in my
cover letter, but maybe I can put it also in some documentation?

Would this fit your expectations?

[1] https://lists.denx.de/pipermail/u-boot/2018-March/322286.html

Thanks,
Miquèl


-- 
Miquel Raynal, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com