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'.