Commit bbc23a07 authored by Alexander Steffen's avatar Alexander Steffen Committed by Jarkko Sakkinen

tpm: Add tpm_tis_i2c backend for tpm_tis_core

Implement the TCG I2C Interface driver, as specified in the TCG PC
Client Platform TPM Profile (PTP) specification for TPM 2.0 v1.04
revision 14, section 8, I2C Interface Definition.

This driver supports Guard Times. That is, if required by the TPM, the
driver has to wait by a vendor-specific time after each I2C read/write.
The specific time is read from the TPM_I2C_INTERFACE_CAPABILITY register.

Unfortunately, the TCG specified almost but not quite compatible
register addresses. Therefore, the TIS register addresses need to be
mapped to I2C ones. The locality is stripped because for now, only
locality 0 is supported.

Add a sanity check to I2C reads of e.g. TPM_ACCESS and TPM_STS. This is
to detect communication errors and issues due to non-standard behaviour
(E.g. the clock stretching quirk in the BCM2835, see 4dbfb5f4). In
case the sanity check fails, attempt a retry.
Co-developed-by: default avatarJohannes Holland <johannes.holland@infineon.com>
Signed-off-by: default avatarJohannes Holland <johannes.holland@infineon.com>
Co-developed-by: default avatarAmir Mizinski <amirmizi6@gmail.com>
Signed-off-by: default avatarAmir Mizinski <amirmizi6@gmail.com>
Signed-off-by: default avatarAlexander Steffen <Alexander.Steffen@infineon.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
parent f25534a6
......@@ -74,6 +74,18 @@ config TCG_TIS_SPI_CR50
If you have a H1 secure module running Cr50 firmware on SPI bus,
say Yes and it will be accessible from within Linux.
config TCG_TIS_I2C
tristate "TPM Interface Specification 1.3 Interface / TPM 2.0 FIFO Interface - (I2C - generic)"
depends on I2C
select CRC_CCITT
select TCG_TIS_CORE
help
If you have a TPM security chip, compliant with the TCG TPM PTP
(I2C interface) specification and connected to an I2C bus master,
say Yes and it will be accessible from within Linux.
To compile this driver as a module, choose M here;
the module will be called tpm_tis_i2c.
config TCG_TIS_SYNQUACER
tristate "TPM Interface Specification 1.2 Interface / TPM 2.0 FIFO Interface (MMIO - SynQuacer)"
depends on ARCH_SYNQUACER || COMPILE_TEST
......
......@@ -29,6 +29,7 @@ tpm_tis_spi-$(CONFIG_TCG_TIS_SPI_CR50) += tpm_tis_spi_cr50.o
obj-$(CONFIG_TCG_TIS_I2C_CR50) += tpm_tis_i2c_cr50.o
obj-$(CONFIG_TCG_TIS_I2C) += tpm_tis_i2c.o
obj-$(CONFIG_TCG_TIS_I2C_ATMEL) += tpm_i2c_atmel.o
obj-$(CONFIG_TCG_TIS_I2C_INFINEON) += tpm_i2c_infineon.o
obj-$(CONFIG_TCG_TIS_I2C_NUVOTON) += tpm_i2c_nuvoton.o
......
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