Re: [PATCH v9 1/3] docs: Add support for TPM devices over I2C bus

[Stefan Berger <stefanb@linux.ibm.com>]

On 3/27/23 14:12, 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.
> 
> ---
> V4:
> Incorporate Cedric & Stefan's comments
> 
> - Added example for ast2600-evb
> - Corrected statement about arm virtual machine.
> 
> ---
> V6:
> Incorporated review comments from Stefan.
> 
> ---
> V8:
> 
> Incorporate review comments from Joel and Stefan
> 
> - Removed the rainier example
> - Added step required to configure on ast2600-evb
> ---
>   docs/specs/tpm.rst | 21 +++++++++++++++++++++
>   1 file changed, 21 insertions(+)
> 
> diff --git a/docs/specs/tpm.rst b/docs/specs/tpm.rst
> index 535912a92b..efe124a148 100644
> --- a/docs/specs/tpm.rst
> +++ b/docs/specs/tpm.rst
> @@ -21,12 +21,16 @@ 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.
>   
> +An I2C device support is also provided which can be instantiated in the Arm
> +based emulation machines. This device only supports the TPM 2 protocol.
> +
>   CRB interface
>   -------------
>   
> @@ -348,6 +352,23 @@ 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 ast2600-evb bmc machine is emulated and you want to use a TPM device
> +attached to I2C bus, use the following command line:
> +
> +.. code-block:: console
> +
> +  qemu-system-arm -M ast2600-evb -nographic \
> +    -kernel arch/arm/boot/zImage \
> +    -dtb arch/arm/boot/dts/aspeed-ast2600-evb.dtb \
> +    -initrd 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
> +
> +  For testing, use this command to load the driver to the correct address
> +
> +  echo tpm_tis_i2c 0x2e > /sys/bus/i2c/devices/i2c-12/new_device
> +
>   In case SeaBIOS is used as firmware, it should show the TPM menu item
>   after entering the menu with 'ESC'.
>   

Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>