Re: [PATCH 1/3] docs: Add support for TPM devices over I2C bus

[Ninad Palsule <ninad@linux.vnet.ibm.com>]

On 3/24/23 3:01 AM, Cédric Le Goater wrote:
> On 3/24/23 06:11, Ninad Palsule wrote:
>> Hello Cedric,
>>
>> Joel helped me to configure the device and we are able to configure 
>> tpm device on ast2600-evb.
>>
>> I will include this example in the documentation.
>>
>> # uname -a
>> Linux ast2600-evb 6.1.15 #1 SMP Thu Mar 23 20:48:29 CDT 2023 armv7l 
>> GNU/Linux
>> # cat /etc/os-release
>> NAME=Buildroot
>> VERSION=2023.02-dirty
>> ID=buildroot
>> VERSION_ID=2023.02
>> PRETTY_NAME="Buildroot 2023.02"
>>
>> # echo tpm_tis_i2c 0x2e > /sys/bus/i2c/devices/i2c-12/new_device
>> [   59.681684] tpm_tis_i2c 12-002e: 2.0 TPM (device-id 0x1, rev-id 1)
>> [   59.703190] tpm tpm0: A TPM error (256) occurred attempting the 
>> self test
>> [   59.705215] tpm tpm0: starting up the TPM manually
>> [   59.892917] i2c i2c-12: new_device: Instantiated device 
>> tpm_tis_i2c at 0x2e
>> # cd /sys/class/tpm/tpm0
>> # ls
>> dev                pcr-sha256         power              uevent
>> device             pcr-sha384         subsystem
>> pcr-sha1           pcr-sha512         tpm_version_major
>
>
> Nice. Did you need any special support in the kernel ?
>
> I could update this image for avocado tests :
>
> https://github.com/legoater/qemu-aspeed-boot/tree/master/images/ast2600-evb/buildroot-2023.02

Kernel need a TPM i2c driver support. I built it with following head on 
dev-6.1 branch. You also need to run "echo" command I mentioned above to 
instantiate the device. Also start the swtpm as provided in my earlier mail.

$ git rev-parse HEAD
0e94476a8892056a9242bcd75e59e7d2b92ac435

Thanks,

Ninad


>
> Thanks,
>
> C.