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

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

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

On 3/23/23 10:23 PM, Ninad Palsule wrote:
> Hello Cedric,
>
> I tried to use ast2600-evb machine but it is not getting any message 
> on I2C bus.
>
> Any suggestions?
>
> # Start the software TPM emulator.
>     $ swtpm socket --tpmstate dir=/tmp/mytpm1   --ctrl 
> type=unixio,path=/tmp/mytpm1/swtpm-sock   --tpm2   --log level=100
>
> # Start a qemu and point at swtpm. I am using i2c bus 12 and address 0x2e
>     $ ~/qemu/build/qemu-system-arm -M ast2600-evb -nographic -kernel 
> $IMAGEDIR/zImage -dtb $IMAGEDIR/aspeed-ast2600-evb.dtb -initrd 
> $IMAGEDIR/rootfs.cpio -chardev 
> socket,id=chrtpm,path=/tmp/mytpm1/swtpm-sock -tpmdev 
> emulator,id=tpm0,chardev=chrtpm -device 
> tpm-tis-i2c,tpmdev=tpm0,bus=aspeed.i2c.bus.12,address=0x2e
>
> # Inside the ast2600-evb machine. Insantiated the device
>     # echo 12 0x2e > /sys/bus/i2c/devices/i2c-12/new_device
>     [  158.265321] i2c i2c-12: new_device: Instantiated device 12 at 0x2e
>
> # Tried to instantiate TPM device but nothing happening on I2C bus.
>     # echo 12-002e > /sys/bus/i2c/drivers/tpm_tis_i2c/bind
>     sh: write error: No such device
>
> Thanks & Regards,
>
> Ninad Palsule
>
> On 3/23/23 2:49 AM, Cédric Le Goater wrote:
>> On 3/23/23 04:01, Ninad Palsule wrote:
>>> This is a documentation change for I2C TPM device support.
>>>
>>> Qemu already supports devices attached to ISA and sysbus.
>>> This drop adds support for the I2C bus attached TPM devices.
>>>
>>> Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
>>>
>>> ---
>>> V2:
>>>
>>> Incorporated Stephen's review comments
>>> - Added example in the document.
>>> ---
>>>   docs/specs/tpm.rst | 20 +++++++++++++++++++-
>>>   1 file changed, 19 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/docs/specs/tpm.rst b/docs/specs/tpm.rst
>>> index 535912a92b..bf7249b09c 100644
>>> --- a/docs/specs/tpm.rst
>>> +++ b/docs/specs/tpm.rst
>>> @@ -21,11 +21,15 @@ QEMU files related to TPM TIS interface:
>>>    - ``hw/tpm/tpm_tis_common.c``
>>>    - ``hw/tpm/tpm_tis_isa.c``
>>>    - ``hw/tpm/tpm_tis_sysbus.c``
>>> + - ``hw/tpm/tpm_tis_i2c.c``
>>>    - ``hw/tpm/tpm_tis.h``
>>>     Both an ISA device and a sysbus device are available. The former is
>>>   used with pc/q35 machine while the latter can be instantiated in the
>>> -Arm virt machine.
>>> +Arm virt machine. An I2C device support is also added which can be
>>> +instantiated in the arm based emulation machine. An I2C device is also
>>> +supported for the Arm virt machine. This device only supports the
>>> +TPM 2 protocol.
>>>     CRB interface
>>>   -------------
>>> @@ -348,6 +352,20 @@ In case an Arm virt machine is emulated, use 
>>> the following command line:
>>>       -drive if=pflash,format=raw,file=flash0.img,readonly=on \
>>>       -drive if=pflash,format=raw,file=flash1.img
>>>   +In case a Rainier bmc machine is emulated, use the following 
>>> command line:
>>> +
>>> +.. code-block:: console
>>> +
>>> +  qemu-system-arm -M rainier-bmc -nographic \
>>> +    -kernel ${IMAGEPATH}/fitImage-linux.bin \
>>> +    -dtb ${IMAGEPATH}/aspeed-bmc-ibm-rainier.dtb \
>>> +    -initrd ${IMAGEPATH}/obmc-phosphor-initramfs.rootfs.cpio.xz \
>>> +    -drive 
>>> file=${IMAGEPATH}/obmc-phosphor-image.rootfs.wic.qcow2,if=sd,index=2\
>>> +    -net nic -net 
>>> user,hostfwd=:127.0.0.1:2222-:22,hostfwd=:127.0.0.1:2443-:443\
>>> +    -chardev socket,id=chrtpm,path=/tmp/mytpm1/swtpm-sock \
>>> +    -tpmdev emulator,id=tpm0,chardev=chrtpm \
>>> +    -device tpm-tis-i2c,tpmdev=tpm0,bus=aspeed.i2c.bus.12,address=0x2e
>>
>>
>> The rainier images are not the easiest to find. Could we use an 
>> AST2600 EVB
>> machine instead and instantiate the device from user space ? see commit
>> 3302184f7f or 7a7308eae0.
>>
>> Thanks,
>>
>> C.
>>
>>>   In case SeaBIOS is used as firmware, it should show the TPM menu item
>>>   after entering the menu with 'ESC'.
>>