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89931cb463
Adding a "secure" version of STM32 boards (DK1/DK2/ED1/EV1), SCMI (clock/
reset) protocol and OP-TEE node have been added in SoC dtsi file
(stm32mp151.dtsi). They have been added with a status disabled in order to
keep our legacy unchanged. It is actually not enough to keep our legacy
unchanged.
First, just a reminder about our use case: TF-A (BL2) loads and starts
OP-TEE, then loads and runs U-Boot. U-Boot code checks if an OP-TEE is
running, if yes it searches in Kernel device tree if an OP-TEE node is
present:
-If the OP-TEE node is not present then U-Boot copies OP-TEE node and its
reserved memory region from U-Boot device tree to the kernel device tree.
-If the OP-TEE node is present then it does nothing (this OP-TEE node will
be used by Linux). So U-Boot lets the kernel device tree unchanged thinking
it is correct for an OP-TEE usage. It is the case for our legacy boards,
the OP-TEE node is present (although disabled) but the reserved memory
region is not declared. As no memory region has been reserved for OP-TEE,
the end of DDR is seen by the kernel as free and then used for CMA. But as
OP-TEE is running, this end of DDR is already used by OP-TEE. So as soon as
kernel tries to access to the CMA region OP-TEE raises an error.
To fix it, all OP-TEE node and SCMI is moved in a dedicated file.
Fixes: 40b4157dbd ("ARM: dts: stm32: enable optee firmware and SCMI support on STM32MP15")
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Link: https://lore.kernel.org/r/20220613071920.5463-1-alexandre.torgue@foss.st.com'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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.