[PATCH RFC v4 0/9] powerpc/powernv/pci: Make hotplug self-sufficient, independent of FW and DT

[Sergey Miroshnichenko]

This patchset allows switching from the pnv_php module to the standard
pciehp driver for PCIe hotplug functionality, if the platform supports it:
PowerNV working on on top of the skiboot with the "core/pci: Sync VFs and
the changes of bdfns between the firmware and the OS" patch serie applied.

The feature is activated by the "pci=realloc" command line argument.

The goal is ability to hotplug bridges full of devices in the future. The
"Movable BARs" [1] is a platform-independent part of our work in this. The
final part will be movable bus numbers to support inserting a bridge in the
middle of an existing PCIe tree.

Tested on POWER8 PowerNV+PHB3 ppc64le (our Vesnin server) with:
 - the pciehp driver active;
 - the pnv_php driver disabled;
 - The "pci=realloc" argument is passed;
 - surprise hotplug of an NVME disk works;
 - controlled hotplug of a network card with SR-IOV works;
 - activating of SR-IOV on a network card works;
 - [with extra patches] manually initiated (via sysfs) rescan has found
   and turned on a hotplugged bridge;
 - Without "pci=realloc" works just as before.

Changes since v3 [2]:
 - Subject changed;
 - Don't disable EEH during rescan anymore - instead just unfreeze the
   target buses deliberately;
 - Add synchronization with the firmware when changing the PCIe topology;
 - Fixed for VFs;
 - Code cleanup.

Changes since v2:
 - Don't reassign bus numbers on PowerNV by default (to retain the default
   behavior), but only when pci=realloc is passed;
 - Less code affected;
 - pci_add_device_node_info is refactored with add_one_dev_pci_data;
 - Minor code cleanup.

Changes since v1:
 - Fixed build for ppc64le and ppc64be when CONFIG_PCI_IOV is disabled;
 - Fixed build for ppc64e when CONFIG_EEH is disabled;
 - Fixed code style warnings.

[1] https://www.spinics.net/lists/linux-pci/msg79995.html
[2] https://lists.ozlabs.org/pipermail/linuxppc-dev/2018-September/178053.html

Sergey Miroshnichenko (9):
  powerpc/pci: Access PCI config space directly w/o pci_dn
  powerpc/powernv/pci: Suppress an EEH error when reading an empty slot
  powerpc/pci: Create pci_dn on demand
  powerpc/pci: Reduce code duplication in pci_add_device_node_info
  powerpc/powernv/ioda: Fix using uninitialized IOMMU group
  powerpc/pci/IOV: Add support for runtime enabling the VFs
  powerpc/pci: Don't rely on DT is the PCI_REASSIGN_ALL_BUS is set
  powerpc/powernv/pci: Hook up the writes to PCI_SECONDARY_BUS register
  powerpc/powernv/pci: Enable reassigning the bus numbers

 arch/powerpc/include/asm/pci-bridge.h        |   2 +-
 arch/powerpc/include/asm/ppc-pci.h           |   1 +
 arch/powerpc/kernel/pci_dn.c                 | 164 +++++++++++----
 arch/powerpc/kernel/rtas_pci.c               |  97 ++++++---
 arch/powerpc/platforms/powernv/eeh-powernv.c |   2 +-
 arch/powerpc/platforms/powernv/pci-ioda.c    |   5 +-
 arch/powerpc/platforms/powernv/pci.c         | 208 +++++++++++++++++--
 arch/powerpc/platforms/pseries/pci.c         |   2 +-
 8 files changed, 381 insertions(+), 100 deletions(-)

-- 
2.20.1