[PATCHv2,0/3] PCI: emulated PCI bridge config space

Message

Thomas Petazzoni Sept. 12, 2018, 3:48 p.m. UTC

Hello,

The pci-mvebu driver already contains some logic to emulate a root
port PCI bridge configuration space. It turns out that we have a
similar need for the pci-aardvark driver. Instead of duplicating the
same logic in two drivers, this patch series starts by adding a small
common infrastructure that helps emulate a root port PCI bridge config
space, converts pci-mvebu to use it, and finally extends pci-aardvark
to use it as well.

Thanks to this, Marvell Armada 3720 based systems, which use the
Aarkvark PCI controller, will have better PCI support, by having a
root port PCI bridge exposed.

The emulated PCI bridge common logic is a proposal, I very much
welcome comments and suggestions. Also, if you feel that adding a
common logic for only two drivers is too early, I'm fine with
duplicating a bit of code betwen pci-mvebu and pci-aardvark.

In this version 2, I have (hopefully) taken into account the comments
from Bjorn Helgaas and Russell King. Here are the changes:

 - Rebased to 4.19-rc1

 - The functions implementing the config space read/write emulation
   now have the knowledge of which registers/bits are read-only,
   read-write, reserved and write-1-to-clear, and behave according to
   this information.

 - I have renamed the function to use conf_read() and conf_write()
   suffixes, as suggested by Bjorn.

 - The whole thing is now named pci-bridge-emul instead of
   pci-sw-bridge (and of course all functions, types and macros were
   changed accordingly), as Bjorn wasn't happy about pci-sw-bridge.

 - The header file was moved into drivers/pci (instead of being in
   include/linux).

Thanks a lot in advance for your review and feedback.

Best regards,

Thomas Petazzoni

Thomas Petazzoni (2):
  PCI: Introduce PCI bridge emulated config space common logic
  PCI: mvebu: Convert to PCI emulated bridge config space

Zachary Zhang (1):
  PCI: aardvark: Implement emulated root PCI bridge config space

 drivers/pci/Kconfig                   |   3 +
 drivers/pci/Makefile                  |   1 +
 drivers/pci/controller/Kconfig        |   2 +
 drivers/pci/controller/pci-aardvark.c | 129 ++++++++++-
 drivers/pci/controller/pci-mvebu.c    | 375 +++++++++----------------------
 drivers/pci/pci-bridge-emul.c         | 408 ++++++++++++++++++++++++++++++++++
 drivers/pci/pci-bridge-emul.h         | 124 +++++++++++
 7 files changed, 770 insertions(+), 272 deletions(-)
 create mode 100644 drivers/pci/pci-bridge-emul.c
 create mode 100644 drivers/pci/pci-bridge-emul.h