On 2019-02-21 23:23, Bjorn Helgaas wrote:
On Wed, Feb 20, 2019 at 10:48:39AM +0100, Thomas Petazzoni wrote:
Hello,
This set of two patches aim at fixing some regression reported by two
users (Luis and Leigh), that were introduced by the conversion of the
pci-mvebu driver to the common PCI bridge emulation code shared
between pci-aardvark and pci-mvebu.
Due to this conversion, some registers of the PCI configuration that
used to be read-only are now read-write, making the Linux PCI core
believe that some features are implemented by the PCI bridge. Namely
in the case of pci-mvebu, the prefetchable memory base/limit registers
were read-only, while they are now read-write. Due to this, the Linux
PCI core now believes it can configure a prefetchable memory area, but
this is not supported by pci-mvebu, which does not have the logic to
create the appropriate MBUs windows.
This set of two commits allow PCI controller code to tell the PCI
bridge emulation logic about their capabilities. Because we envision
that other capabilities than prefetchable memory support might need to
be communicated from the PCI controller code to the PCI bridge
emulation code in the future, we introduce a "flags" argument, even if
for now only one flag is supported.
Lorenzo, let me know what you think about this approach. I am open to
suggestions if the proposed approach is not satisfying.
Both patches have been confirmed by Luis and Leigh to fix the
regression, but I'll let them give a formal Tested-by.
Best regards,
Thomas Petazzoni
Thomas Petazzoni (2):
PCI: pci-bridge-emul: Create per-bridge copy of register behavior
PCI: pci-bridge-emul: Extend pci_bridge_emul_init() with flags
drivers/pci/controller/pci-aardvark.c | 2 +-
drivers/pci/controller/pci-mvebu.c | 2 +-
drivers/pci/pci-bridge-emul.c | 86
++++++++++++++++++---------
drivers/pci/pci-bridge-emul.h | 13 +++-
4 files changed, 73 insertions(+), 30 deletions(-)
Lorenzo, I assume you'll take both of these, so for both patches,
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Maybe we should add a stable tag (v4.20+)?
That would be great, as it would get that kernel version working again.
Regards,
Leigh.
