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path: root/drivers/char/tpm/tpm_tis_spi.c
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* tpm_tis_spi: Add small delay after last transferPeter Huewe2017-05-25
| | | | | | | | | | | | | | | | | | | | | | | | commit 5cc0101d1f88500f8901d01b035af743215d4c3a upstream. Testing the implementation with a Raspberry Pi 2 showed that under some circumstances its SPI master erroneously releases the CS line before the transfer is complete, i.e. before the end of the last clock. In this case the TPM ignores the transfer and misses for example the GO command. The driver is unable to detect this communication problem and will wait for a command response that is never going to arrive, timing out eventually. As a workaround, the small delay ensures that the CS line is held long enough, even with a faulty SPI master. Other SPI masters are not affected, except for a negligible performance penalty. Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> Signed-off-by: Peter Huewe <peter.huewe@infineon.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Benoit Houyere <benoit.houyere@st.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tpm_tis_spi: Remove limitation of transfers to MAX_SPI_FRAMESIZE bytesPeter Huewe2017-05-25
| | | | | | | | | | | | | | | | | | commit 591e48c26ced7c455751eef27fb5963e902c2137 upstream. Limiting transfers to MAX_SPI_FRAMESIZE was not expected by the upper layers, as tpm_tis has no such limitation. Add a loop to hide that limitation. v2: Moved scope of spi_message to the top as requested by Jarkko Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> Signed-off-by: Peter Huewe <peter.huewe@infineon.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Benoit Houyere <benoit.houyere@st.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tpm_tis_spi: Check correct byte for wait state indicatorPeter Huewe2017-05-25
| | | | | | | | | | | | | | | | | commit e110cc69dc2ad679d6d478df636b99b14e6fbbc9 upstream. Wait states are signaled in the last byte received from the TPM in response to the header, not the first byte. Check rx_buf[3] instead of rx_buf[0]. Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> Signed-off-by: Peter Huewe <peter.huewe@infineon.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Benoit Houyere <benoit.houyere@st.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tpm_tis_spi: Abort transfer when too many wait states are signaledPeter Huewe2017-05-25
| | | | | | | | | | | | | | | | | commit 975094ddc369a32f27210248bdd9bbd153061b00 upstream. Abort the transfer with ETIMEDOUT when the TPM signals more than TPM_RETRY wait states. Continuing with the transfer in this state will only lead to arbitrary failures in other parts of the code. Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> Signed-off-by: Peter Huewe <peter.huewe@infineon.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Benoit Houyere <benoit.houyere@st.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tpm_tis_spi: Use single function to transfer dataPeter Huewe2017-05-25
| | | | | | | | | | | | | | | | | | | | | commit f848f2143ae42dc0918400039257a893835254d1 upstream. The algorithm for sending data to the TPM is mostly identical to the algorithm for receiving data from the TPM, so a single function is sufficient to handle both cases. This is a prequisite for all the other fixes, so we don't have to fix everything twice (send/receive) v2: u16 instead of u8 for the length. Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> Signed-off-by: Peter Huewe <peter.huewe@infineon.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Benoit Houyere <benoit.houyere@st.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tpm/tpm_tis_spi: Add support for spi phyChristophe Ricard2016-06-25
Spi protocol standardized by the TCG is now supported by most of TPM vendors. It supports SPI Bit Protocol as describe in the TCG PTP specification (chapter 6.4.6 SPI Bit Protocol). Irq mode is not supported. This commit is based on the initial work by Peter Huewe. Signed-off-by: Peter Huewe <peter.huewe@infineon.com> Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Stefan Berger <stefanb@linux.vnet.ibm.com> Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>