2b99c6fb65
commit 771153fc884f566a89af2d30033b7f3bc6e24e84 upstream. From very vague, ambiguous and incomplete information from Marvell we deduced that the 32-bit Aardvark register at address 0x4 (PCIE_CORE_CMD_STATUS_REG), which is not documented for Root Complex mode in the Functional Specification (only for Endpoint mode), controls two 16-bit PCIe registers: Command Register and Status Registers of PCIe Root Port. This means that bit 2 controls bus mastering and forwarding of memory and I/O requests in the upstream direction. According to PCI specifications bits [0:2] of Command Register, this should be by default disabled on reset. So explicitly disable these bits at early setup of the Aardvark driver. Remove code which unconditionally enables all 3 bits and let kernel code (via pci_set_master() function) to handle bus mastering of Root PCIe Bridge via emulated PCI_COMMAND on emulated bridge. Link: https://lore.kernel.org/r/20211028185659.20329-5-kabel@kernel.org Fixes:8a3ebd8de3("PCI: aardvark: Implement emulated root PCI bridge config space") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org #b2a56469d5("PCI: aardvark: Add FIXME comment for PCIE_CORE_CMD_STATUS_REG access") 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.