6f3710f1f6
Accessing the NOR flash memory from the kernel will disrupt CPU sleep/
idles states and CPU hotplugging. We need to disable this DT node by
default. Setups that want to access the flash can modify this entry to
enable the flash again but also ensuring to disable CPU idle states and
CPU hotplug.
The platform firmware assumes the flash is always in read mode while
Linux kernel driver leaves NOR flash in "read id" mode after
initialization. If it gets used actively, it can be in some other state.
So far we had not seen this issue as the NOR flash drivers in kernel
were not enabled by default. However it was enable in multi_v7 config by
Commit 5f068190cc10 ("ARM: multi_v7_defconfig: Enable support for CFI NOR FLASH")
So, let's mark the NOR flash disabled so that the platform can boot
again. This based on:
Commit 980bbff018f6 ("ARM64: juno: disable NOR flash node by default")
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
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.