265883d1d8
commit 216f8e95aacc8e9690d8e2286c472671b65f4128 upstream.
According to the Armada XP datasheet, section 10.2.6: "in order for
the device to do a write to the MSI doorbell address, it needs to write
to a register in the internal registers space".
As a result of the requirement above, without this patch, MSI won't
function and therefore some devices won't operate properly without
pci=nomsi.
This requirement was not present at the time of writing this driver
since the vendor u-boot always initializes all PCIe controllers
(incl. BAR0 initialization) and for some time, the vendor u-boot was
the only available bootloader for this driver's SoCs (e.g. A38x,A37x,
etc).
Tested on an Armada 385 board on mainline u-boot (2020.4), without
u-boot PCI initialization and the following PCIe devices:
- Wilocity Wil6200 rev 2 (wil6210)
- Qualcomm Atheros QCA6174 (ath10k_pci)
Both failed to get a response from the device after loading the
firmware and seem to operate properly with this patch.
Link: https://lore.kernel.org/r/20200623060334.108444-1-sh@tkos.co.il
Signed-off-by: Shmuel Hazan <sh@tkos.co.il>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.