My Nuvoton 6xx in a Dell XPS-13 has been intermittently failing to work
(necessitating a reboot). The problem seems to be that the TPM gets into a
state where the partial self-test doesn't return TPM_RC_SUCCESS (meaning
all tests have run to completion), but instead returns TPM_RC_TESTING
(meaning some tests are still running in the background).  There are
various theories that resending the self-test command actually causes the
tests to restart and thus triggers more TPM_RC_TESTING returns until the
timeout is exceeded.

There are several issues here: firstly being we shouldn't slow down the
boot sequence waiting for the self test to complete once the TPM
backgrounds them.  It will actually make available all functions that have
passed and if it gets a failure return TPM_RC_FAILURE to every subsequent
command.  So the fix is to kick off self tests once and if they return
TPM_RC_TESTING log that as a backgrounded self test and continue on.  In
order to prevent other tpm users from seeing any TPM_RC_TESTING returns
(which it might if they send a command that needs a TPM subsystem which is
still under test), we loop in tpm_transmit_cmd until either a timeout or we
don't get a TPM_RC_TESTING return.

Finally, there have been observations of strange returns from a partial
test. One Nuvoton is occasionally returning TPM_RC_COMMAND_CODE, so treat
any unexpected return from a partial self test as an indication we need to
run a full self test.

[jarkko.sakkinen@linux.intel.com: cleaned up some klog messages and
 dropped tpm_transmit_check() helper function from James' original
 commit.]

Fixes: 2482b1bb ("tpm: Trigger only missing TPM 2.0 self tests")
Cc: stable@vger.kernel.org
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkine@linux.intel.com>

TPM2_CC_Create(0x153) and TPM2_CC_CreatePrimary (0x131) involve generation
of crypto keys which can be a computationally intensive task. The timeout
is set to 3min. Rather than increasing default timeout a new constant is
added, to not stall for too long on regular commands failures.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Discrete TPMs are often connected over slow serial buses which, on
some platforms, can have glitches causing bit flips.  If a bit does
flip it could cause an overrun if it's in one of the size parameters,
so sanity check that we're not overrunning the provided buffer when
doing a memcpy().
Signed-off-by: NJeremy Boone <jeremy.boone@nccgroup.trust>
Cc: stable@vger.kernel.org
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

Previously, if the last attempt to execute the selftest command failed with
RC_TESTING, there was still a call to tpm_msleep, even though no further
attempt would be made. This causes an unnecessary delay, therefore ensure
that if the last attempt fails the function is left immediately.

Also, instead of ensuring that the cumulated runtime of all attempts is
larger than the command duration for TPM2_SelfTest, ensure that there is at
least one attempt for which the delay is larger than the expected command
duration. This allows slow TPMs to execute all their tests in the
background, without slowing down faster TPMs that have finished their tests
earlier. If tests are still not finished even with this long delay, then
something is broken and the TPM is not used.

Fixes: 125a2210 ("tpm: React correctly to RC_TESTING from TPM 2.0 self
tests")
Signed-off-by: NAlexander Steffen <Alexander.Steffen@infineon.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

The local variable 'attrs' should have the type __be32 instead of u32.

Fixes: 58472f5c ("tpm: validate TPM 2.0 commands")
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>

The TPM can choose one of two ways to react to the TPM2_SelfTest command.
It can either run all self tests synchronously and then return RC_SUCCESS
once all tests were successful. Or it can choose to run the tests
asynchronously and return RC_TESTING immediately while the self tests still
execute in the background.

The previous implementation apparently was not aware of those possibilities
and attributed RC_TESTING to some prototype chips instead. With this change
the return code of TPM2_SelfTest is interpreted correctly, i.e. the self
test result is polled if and only if RC_TESTING is received.

Unfortunately, the polling cannot be done in the most straightforward way.
If RC_TESTING is received, ideally the code should now poll the
selfTestDone bit in the STS register, as this avoids sending more commands,
that might interrupt self tests executing in the background and thus
prevent them from ever completing. But it cannot be guaranteed that this
bit is correctly implemented for all devices, so the next best thing would
be to use TPM2_GetTestResult to query the test result. But the response to
that command can be very long, and the code currently lacks the
capabilities for efficient unmarshalling, so it is difficult to execute
this command.

Therefore, we simply run the TPM2_SelfTest command in a loop, which should
complete eventually, since we only request the execution of self tests that
have not yet been done.
Signed-off-by: NAlexander Steffen <Alexander.Steffen@infineon.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

In order to avoid delaying the code longer than necessary while still
giving the TPM enough time to execute the self tests asynchronously, start
with a small delay between two polls and increase it each round.
Signed-off-by: NAlexander Steffen <Alexander.Steffen@infineon.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

tpm2_do_selftest is only used during initialization of the TPM to ensure
that the device functions correctly. Therefore, it is sufficient to request
only missing self tests (parameter full_test=0), not a reexecution of all
self tests, as was done before. This allows for a faster execution of this
command.
Signed-off-by: NAlexander Steffen <Alexander.Steffen@infineon.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

The patch simply replaces all msleep function calls with usleep_range calls
in the generic drivers.

Tested with an Infineon TPM 1.2, using the generic tpm-tis module, for a
thousand PCR extends, we see results going from 1m57s unpatched to 40s
with the new patch. We obtain similar results when using the original and
patched tpm_infineon driver, which is also part of the patch.
Similarly with a STM TPM 2.0, using the CRB driver, it takes about 20ms per
extend unpatched and around 7ms with the new patch.

Note that the PCR consistency is untouched with this patch, each TPM has
been tested with 10 million extends and the aggregated PCR value is
continuously verified to be correct.

As an extension of this work, this could potentially and easily be applied
to other vendor's drivers. Still, these changes are not included in the
proposed patch as they are untested.
Signed-off-by: NHamza Attak <hamza@hpe.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

tpm2_do_selftest() performs a PCR read during the TPM initialization phase.
This patch replaces the PCR read code with a call to tpm2_pcr_read().
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

tpm2_pcr_read() now builds the PCR read command buffer with tpm_buf
functions. This solution is preferred to using a tpm2_cmd structure,
as tpm_buf functions provide protection against buffer overflow.
Signed-off-by: NRoberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Consolidated all the "manual" TPM startup code to a single function
in order to make code flows a bit cleaner and migrate to tpm_buf.
Tested-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Suppress the error logging when the core TPM driver sends commands
to the VTPM proxy driver and -EPIPE is returned in case the VTPM
proxy driver is 'closed' (closed anonymous file descriptor).  This
error code is only returned by the send function and by tpm_transmit
when the VTPM proxy driver is being used.
Signed-off-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Added an ability to virtualize TPM commands into an isolated context
that we call a TPM space because the word context is already heavily
used in the TPM specification. Both the handle areas and bodies (where
necessary) are virtualized.

The mechanism works by adding a new parameter struct tpm_space to the
tpm_transmit() function. This new structure contains the list of virtual
handles and a buffer of page size (currently) for backing storage.

When tpm_transmit() is called with a struct tpm_space instance it will
execute the following sequence:

1. Take locks.
2. Load transient objects from the backing storage by using ContextLoad
   and map virtual handles to physical handles.
3. Perform the transaction.
4. Save transient objects to backing storage by using ContextSave and
   map resulting physical handle to virtual handle if there is such.

This commit does not implement virtualization support for hmac and
policy sessions.
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Check for every TPM 2.0 command that the command code is supported and
the command buffer has at least the length that can contain the header
and the handle area.

For ContextSave and FlushContext we mark the body to be part of the
handle area. This gives validation for these commands at zero
cost, including the body of the command.

The more important reason for this is that we can virtualize these
commands in the same way as you would virtualize the handle area of a
command.
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

There's no need to export tpm2_get_pcr_alloation() because it is only
a helper function for tpm2_auto_startup(). For the same reason it does
not make much sense to maintain documentation for it.
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

The current TPM 2.0 device driver extends only the SHA1 PCR bank
but the TCG Specification[1] recommends extending all active PCR
banks, to prevent malicious users from setting unused PCR banks with
fake measurements and quoting them.

The existing in-kernel interface(tpm_pcr_extend()) expects only a
SHA1 digest.  To extend all active PCR banks with differing
digest sizes, the SHA1 digest is padded with trailing 0's as needed.

This patch reuses the defined digest sizes from the crypto subsystem,
adding a dependency on CRYPTO_HASH_INFO module.

[1] TPM 2.0 Specification referred here is "TCG PC Client Specific
Platform Firmware Profile for TPM 2.0"
Signed-off-by: NNayna Jain <nayna@linux.vnet.ibm.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NKenneth Goldman <kgold@linux.vnet.ibm.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

This patch implements the TPM 2.0 capability TPM_CAP_PCRS to
retrieve the active PCR banks from the TPM. This is needed
to enable extending all active banks as recommended by TPM 2.0
TCG Specification.
Signed-off-by: NNayna Jain <nayna@linux.vnet.ibm.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NKenneth Goldman <kgold@linux.vnet.ibm.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

The error code handling is broken as any error code that has the same
bits set as TPM_RC_HASH passes. Implemented tpm2_rc_value() helper to
parse the error value from FMT0 and FMT1 error codes so that these types
of mistakes are prevented in the future.

Fixes: 5ca4c20c ("keys, trusted: select hash algorithm for TPM2 chips")
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>

Make sure that we have not received less bytes than what is indicated
in the header of the TPM response. Also, check the number of bytes in
the response before accessing its data.
Signed-off-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkine@linux.intel.com>

Use correct kdoc format, describe correct parameters and return values.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Signed-off-by: NBaruch Siach <baruch@tkos.co.il>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

It is better to tpm_transmit_cmd() in tpm2_probe() in order to get
consistent command handling throughout the subsystem.
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>

Since tpm_gen_interrupt() is only used in tpm_tis_core.c this commit
replaces it with an internal tpm_tis_gen_interrupt(). The semantics
also changed in a way that on a system error the driver initialization
is failed.
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>

Unseal and load operations should be done as an atomic operation. This
commit introduces unlocked tpm_transmit() so that tpm2_unseal_trusted()
can do the locking by itself.

Fixes: 0fe54803 ("keys, trusted: seal/unseal with TPM 2.0 chips")
Cc: stable@vger.kernel.org
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>

The driver emits invalid self test error message even though the init
succeeds.
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Fixes: cae8b441 ("tpm: Factor out common startup code")
Reviewed-by: NJames Morris <james.l.morris@oracle.com>

The driver emits invalid self test error message even though the init
succeeds.
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Fixes: cae8b441 ("tpm: Factor out common startup code")
Reviewed-by: NJames Morris <james.l.morris@oracle.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

The TCG standard startup sequence (get timeouts, tpm startup, etc) for
TPM and TPM2 chips is being open coded in many drivers, move it into
the core code.

tpm_tis and tpm_crb are used as the basis for the core code
implementation and the easy drivers are converted. In the process
several small drivers bugs relating to error handling this flow
are fixed.

For now the flag TPM_OPS_AUTO_STARTUP is optional to allow a staged
driver roll out, but ultimately all drivers should use this flow and
the flag removed. Some drivers still do not implement the startup
sequence at all and will need to be tested with it enabled.
Signed-off-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Tested-by: NAndrew Zamansky <andrew.zamansky@nuvoton.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

The result must be converted from BE byte order, which is used by the
TPM2 protocol. This has not popped out because tpm2_get_tpm_pt() has
been only used for probing.

Fixes: 7a1d7e6d ("tpm: TPM 2.0 baseline support")
Change-Id: I7d71cd379b1a3b7659d20a1b6008216762596590
Signed-off-by: NAndrey Pronin <apronin@chromium.org>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Move tpm_vendor_specific data related to TCG PTP specification to tpm_chip.

Move all fields directly linked with well known TCG concepts and used in
TPM drivers (tpm_i2c_atmel, tpm_i2c_infineon, tpm_i2c_nuvoton, tpm_tis
and xen-tpmfront) as well as in TPM core files (tpm-sysfs, tpm-interface
and tpm2-cmd) in tpm_chip.
Signed-off-by: NChristophe Ricard <christophe-h.ricard@st.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

rmmod crashes the driver because tpm_chip_unregister() already sets ops
to NULL. This commit fixes the issue by moving tpm2_shutdown() to
tpm_chip_unregister(). This commit is also cleanup because it removes
duplicate code from tpm_crb and tpm_tis to the core.

Fixes: 4d3eac5e156a ("tpm: Provide strong locking for device removal")
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>

This is a hold over from before the struct device conversion.

- All prints should be using &chip->dev, which is the Linux
  standard. This changes prints to use tpm0 as the device name,
  not the PnP/etc ID.
- The few places involving sysfs/modules that really do need the
  parent just use chip->dev.parent instead
- We no longer need to get_device(pdev) in any places since it is no
  longer used by any of the code. The kref on the parent is held
  by the device core during device_add and dropped in device_del
Signed-off-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Tested-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

It's better to set the continueSession attribute for the unseal
operation so that the session object is not removed as a side-effect
when the operation is successful. Since a user process created the
session, it should be also decide when the session is destroyed.
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Fixes: 5beb0c43 ("keys, trusted: seal with a TPM2 authorization policy")

In my original patch sealing with policy was done with dynamically
allocated buffer that I changed later into an array so the checks in
tpm2-cmd.c became invalid. This patch fixes the issue.

Fixes: 5beb0c43 ("keys, trusted: seal with a TPM2 authorization policy")
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: NPeter Huewe <peterhuewe@gmx.de>

TPM2 supports authorization policies, which are essentially
combinational logic statements repsenting the conditions where the data
can be unsealed based on the TPM state. This patch enables to use
authorization policies to seal trusted keys.

Two following new options have been added for trusted keys:

* 'policydigest=': provide an auth policy digest for sealing.
* 'policyhandle=': provide a policy session handle for unsealing.

If 'hash=' option is supplied after 'policydigest=' option, this
will result an error because the state of the option would become
mixed.
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NPeter Huewe <peterhuewe@gmx.de>

Added 'hash=' option for selecting the hash algorithm for add_key()
syscall and documentation for it.

Added entry for sm3-256 to the following tables in order to support
TPM_ALG_SM3_256:

* hash_algo_name
* hash_digest_size

Includes support for the following hash algorithms:

* sha1
* sha256
* sha384
* sha512
* sm3-256
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NJames Morris <james.l.morris@oracle.com>
Reviewed-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NPeter Huewe <peterhuewe@gmx.de>

The 'migratable' flag was not added to the key payload. This patch
fixes the problem.

Fixes: 0fe54803 ("keys, trusted: seal/unseal with TPM 2.0 chips")
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: NPeter Huewe <PeterHuewe@gmx.de>

Added tpm_trusted_seal() and tpm_trusted_unseal() API for sealing
trusted keys.

This patch implements basic sealing and unsealing functionality for
TPM 2.0:

* Seal with a parent key using a 20 byte auth value.
* Unseal with a parent key using a 20 byte auth value.
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NPeter Huewe <peterhuewe@gmx.de>

If during transmission system error was returned, the logic was to
incorrectly deduce that chip is a TPM 1.x chip. This patch fixes this
issue. Also, this patch changes probing so that message tag is used as the
measure for TPM 2.x, which should be much more stable. A separate function
called tpm2_probe() is encapsulated because it can be used with any
chipset.

Fixes: aec04cbd ("tpm: TPM 2.0 FIFO Interface")
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: NPeter Huewe <peterhuewe@gmx.de>
Signed-off-by: NPeter Huewe <peterhuewe@gmx.de>