It turns out that while the QSEECOM APP_SEND command has specific fields
for request and response buffers, uefisecapp expects them both to be in
a single memory region. Failure to adhere to this has (so far) resulted
in either no response being written to the response buffer (causing an
EIO to be emitted down the line), the SCM call to fail with EINVAL
(i.e., directly from TZ/firmware), or the device to be hard-reset.

While this issue can be triggered deterministically, in the current form
it seems to happen rather sporadically (which is why it has gone
unnoticed during earlier testing). This is likely due to the two
kzalloc() calls (for request and response) being directly after each
other. Which means that those likely return consecutive regions most of
the time, especially when not much else is going on in the system.

Fix this by allocating a single memory region for both request and
response buffers, properly aligning both structs inside it. This
unfortunately also means that the qcom_scm_qseecom_app_send() interface
needs to be restructured, as it should no longer map the DMA regions
separately. Therefore, move the responsibility of DMA allocation (or
mapping) to the caller.

Fixes: 759e7a2b62eb ("firmware: Add support for Qualcomm UEFI Secure Application")
Cc: stable@vger.kernel.org  # 6.7
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Tested-by: Konrad Dybcio <konrad.dybcio@linaro.org> # X13s
Link: https://lore.kernel.org/r/20240406130125.1047436-1-luzmaximilian@gmail.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

The qseecom header does not contain ifdef guards against multiple
inclusion. Add them.

Fixes: 00b1248606ba ("firmware: qcom_scm: Add support for Qualcomm Secure Execution Environment SCM interface")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20231004185732.98621-1-brgl@bgdev.pl
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

The 'extern' specifier in front of a function declaration has no effect.
Remove all of them from the qcom-scm header.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230913192826.36187-1-bartosz.golaszewski@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Add support for SCM calls to Secure OS and the Secure Execution
Environment (SEE) residing in the TrustZone (TZ) via the QSEECOM
interface. This allows communication with Secure/TZ applications, for
example 'uefisecapp' managing access to UEFI variables.

For better separation, make qcom_scm spin up a dedicated child
(platform) device in case QSEECOM support has been detected. The
corresponding driver for this device is then responsible for managing
any QSEECOM clients. Specifically, this driver attempts to automatically
detect known and supported applications, creating a client (auxiliary)
device for each one. The respective client/auxiliary driver is then
responsible for managing and communicating with the application.

While this patch introduces only a very basic interface without the more
advanced features (such as re-entrant and blocking SCM calls and
listeners/callbacks), this is enough to talk to the aforementioned
'uefisecapp'.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20230827211408.689076-3-luzmaximilian@gmail.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Commit 3a99f121fe0b ("firmware: qcom: scm: Introduce pas_metadata
context") left out the `extern` specifier for the API it introduced, so
add it.

Signed-off-by: Guru Das Srinagesh <quic_gurus@quicinc.com>
Link: https://lore.kernel.org/r/bce25c8e215f7cfc7b0780d6965d09f5efe1cc5f.1690503893.git.quic_gurus@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

The maximum VMID for assign_mem is 63. Use a u64 to represent this
bitmap instead of architecture-dependent "unsigned int" which varies in
size on 32-bit and 64-bit platforms.

Acked-by: Kalle Valo <kvalo@kernel.org> (ath10k)
Tested-by: Gokul krishna Krishnakumar <quic_gokukris@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230213181832.3489174-1-quic_eberman@quicinc.com

Move include/linux/qcom_scm.h to include/linux/firmware/qcom/qcom_scm.h.
This removes 1 of a few remaining Qualcomm-specific headers into a more
approciate subdirectory under include/.

Suggested-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Reviewed-by: Guru Das Srinagesh <quic_gurus@quicinc.com>
Acked-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230203210956.3580811-1-quic_eberman@quicinc.com