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Trogdor devices use firmware backed by TF-A instead of Qualcomm's normal TZ. On TF-A we end up mapping memory as cacheable. Specifically, you can see in Trogdor's TF-A code [1] in qti_sip_mem_assign() that we call qti_mmap_add_dynamic_region() with MT_RO_DATA. This translates down to MT_MEMORY instead of MT_NON_CACHEABLE or MT_DEVICE. Apparently Qualcomm's normal TZ implementation maps the memory as non-cacheable. Let's add the "dma-coherent" attribute to the SCM for trogdor. Adding "dma-coherent" like this fixes WiFi on sc7180-trogdor devices. WiFi was broken as of commit7bd6680b47("Revert "Revert "arm64: dma: Drop cache invalidation from arch_dma_prep_coherent()"""). Specifically at bootup we'd get: qcom_scm firmware:scm: Assign memory protection call failed -22 qcom_rmtfs_mem 94600000.memory: assign memory failed qcom_rmtfs_mem: probe of 94600000.memory failed with error -22 From discussion on the mailing lists [2] and over IRC [3], it was determined that we should always have been tagging the SCM as dma-coherent on trogdor but that the old "invalidate" happened to make things work most of the time. Tagging it properly like this is a much more robust solution. [1] https://chromium.googlesource.com/chromiumos/third_party/arm-trusted-firmware/+/refs/heads/firmware-trogdor-13577.B/plat/qti/common/src/qti_syscall.c [2] https://lore.kernel.org/r/20230614165904.1.I279773c37e2c1ed8fbb622ca6d1397aea0023526@changeid [3] https://oftc.irclog.whitequark.org/linux-msm/2023-06-15 Fixes:7bd6680b47("Revert "Revert "arm64: dma: Drop cache invalidation from arch_dma_prep_coherent()""") Fixes:7ec3e67307("arm64: dts: qcom: sc7180-trogdor: add initial trogdor and lazor dt") Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20230616081440.v2.3.Ic62daa649b47b656b313551d646c4de9a7da4bd4@changeid Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.