[coreboot] TCPA support

Thomas Jourdan tjourdan at neuf.fr
Sun Nov 23 11:09:30 CET 2008

Hi all

I'm working on porting Coreboot v2 to the MSC-CXB-CD945 com express card
(http://www.msc-ge.com/frame/en/produkte/com/com_express/cxb_cd945.html). The design is close to the Kontron 986LCD-M, so it won't be too hard.

This board has an Infineon SLB 9635 TPM 1.2 chip, on the LPC bridge, for
all the TCPA stuffs. I'd like to support this chip (I need it for
applicaitons we developped on the board), and in a general way, try to
add TCPA support in coreboot.

The TCG ACPI Specification tells us :

"A TCG platform MAY provide an ACPI device object representing the TPM
in the ACPI namespace, if the bus where the TPM is located is not PNP
capable or the bus is not exposed to the OS for PNP operations."

I will not focus too much on the ACPI table at first but I'd like to add
the device in the Config.lb. I'd like to have confirmation on the syntax
I'll have to use in the Config.lb file. 

Here is the result of lspnp :

00:08 IFX0102 Infineon Trusted Platform Module
    state = active
        io 0x4e-0x4f
        io 0x1670-0x167f
        mem 0xfed40000-0xfed44fff
        irq 11

The device is a PNP device : if I don't add an entry for this device in
the Config.lb file, will coreboot be able to read and allocate himself
the resources ?

If I add an entry, I was thinking about this : 

device pci 1f.0 on # LPC bridge
	chip drivers/tpm/slb9635

Then I define resources functions in my driver.

Do I need to add an entry like this "device pnp ... on end" ? I don't
really understand how this works. It only seems suitable for super i/o
logical functions.

By the way I (of course) don't have the datasheet of the component, just
the TPM linux driver source code from trust.rub.de, and traces from
acpidump, lspnp...

Last question : when the board will be supported, I'll send patches to
the mailing list. The original bios was developped by phoenix. For my
personnal usage, I may re-use ACPI and SMBIOS tables extracted from this
bios. But, for the patches I'll send, am I allowed to use them ?


PS : this thread is not meant to become a fight between DRM / free
software. I don't like DRM and stuffs like this but I must admit that
the TPM chip is usefull for some kind of applications.

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