Linux Kernel Driver for Atmel's AT97SC3204T I2C TPM (for Beaglebone)
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patches Support for DTB-I2C selector Feb 22, 2013
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README.md Update README.md to note deprecation Feb 5, 2015
patch_kernel.sh A better README, feedback for patch script, p0 for old i2c1-bb patch. Jan 27, 2013
tpm.h Using style from Infineon I2C driver. insmod tpm_i2c_atmel is causing a Nov 12, 2012
tpm_i2c_atmel.c Converted i2c_msg to C99 format. Mar 3, 2013

README.md

ATMEL's AT97SC3204T I2C TPM

NOTE: Support exists in mainline Linux now.

Instructions (Kernel):

The following few steps will add the I2C TPM as a tristate in drivers/char/tpm. You will need to configure your board to include the TPM on the correct I2C bus. Atmel's I2C TPM has an address of 0x29. You can add:

{ I2C_BOARD_INFO("tpm_i2c_atmel", 0x29), }

to the i2c_board_info struct used by the I2C bus.

  1. Patch your system board to include tpm_i2c_atmel with the I2C bus and address of the TPM.
  2. Insert support for the TPM: [tpm-i2c-atmel] $ bash ./patch_kernel.sh /kernel/source This moves the source into drivers/char/tpm, and adds support to Kconfig & Makefile.
  3. Add your preference for CONFIG_TCG_TIS_I2C_ATMEL.
  4. Compile your kernel.

Beaglebone (A5+) (Kernel):

For a BeagleBone, in addition to the above steps, there are two included patches to (1) enable the I2C-2 bus, and (2) add the I2C TPM at address 0x29 on I2C-2.

  1. Follow the above
  2. Apply patches: (for Linux 3.7, only patch bb-ra5-add-tpm-i2c-atmel-3.7.patch)
[kernel-dir] $ patch -p0 < /tpm-i2c-atmel/patches/bb-ra5-add-i2c1.patch
[kernel-dir] $ patch -p0 < /tpm-i2c-atmel/patches/bb-ra5-add-tpm-i2c-atmel.patch

Beaglebone (A5+) (Module):

If you would like the Atmel I2C TPM driver as a module built outside of the kernel you can checkout the beaglebone branch and modify tpm_i2c_atmel.c to specify the I2C bus and address (though should not change).

  1. (Optional) Patch your board-am335xevm.c using patches/bb-ra5-add-i2c1.patch. [kernel-dir] $ patch -p0 < /tpm-i2c-atmel/bb-ra5-add-i2c1.patch This will enable the I2C-2 bus. The BeagleBone SRM identifies I2C-2 for use with peripherals.
  2. git checkout -b beaglebone beaglebone
  3. KERNEL_DIR=/location CROSS_COMPILER=/location/bin/arm-linux- make
  4. Copy the .ko to the BeagleBone: insmod ./tpm_i2c_atmel.ko

Other:

The TPM will need initialization; TrouSerS's tpm_tools can do this from userspace.

  1. git clone git://trousers.git.sourceforge.net/gitroot/trousers/trousers
  2. git clone git://trousers.git.sourceforge.net/gitroot/trousers/tpm-tools
  3. Follow the directions for both, tpm-tools depends on TrouSerS.
  4. ./tpm-tools/src/tpm_mgmt/tpm_startup

Note: newer versions of the Linux Kernel support TPM initialization and self test. We expect U-boot to have issued a startup and self test, similar to platforms implementing TPM in BIOS.