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c4860af88d
On Qualcomm platforms like SC8280XP and SA8540P, interconnect bandwidth
must be requested before enabling interconnect clocks.
Add basic support for managing an optional "pcie-mem" interconnect path
by setting a low constraint before enabling clocks and updating it after
the link is up.
Note that it is not possible for a controller driver to set anything but
a maximum peak bandwidth as expected average bandwidth will vary with
use case and actual use (and power policy?). This very much remains an
unresolved problem with the interconnect framework.
Also note that no constraint is set for the SC8280XP/SA8540P "cpu-pcie"
path for now as it is not clear what an appropriate constraint would be
(and the system does not crash when left unspecified).
Link: https://lore.kernel.org/r/20221102090705.23634-3-johan+linaro@kernel.org
Fixes: 70574511f3 ("PCI: qcom: Add support for SC8280XP")
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Brian Masney <bmasney@redhat.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Acked-by: Georgi Djakov <djakov@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.