[PATCH v6 0/5] powerpc/powernv/pci: Make hotplug self-sufficient, independent of FW and DT

[Sergey Miroshnichenko <s.miroshnichenko@yadro.com>]

Allow switching from the pnv_php module to the standard pciehp driver for
PowerNV, if the platform supports it: it can be a server working on top of
the skiboot with the [1] patchset applied.

Add the ability to discover hot-added devices which weren't added to the
Device Tree (by the pnv_php via an explicit OPAL call when a hotplug event
was intercepted) by direct access to the bus.

Sync the changes in PCIe topology (bus numbers and PEs) with the skiboot.

Tested on POWER8 PowerNV+PHB3 ppc64le (our Vesnin server) with:
 - the pciehp driver active;
 - the pnv_php driver disabled;
 - the "pci=pcie_bus_peer2peer,realloc" kernel command line argument;
 - controlled hotplug of a network card with SR-IOV works;
 - activating of SR-IOV on a network card works;
 - [with extra patches for movable BARs and bus numbers] manually initiated
   (via sysfs) rescan has found and turned on a hotplugged bridge.

[1] https://lists.ozlabs.org/pipermail/skiboot/2019-August/015140.html
    [Skiboot] [PATCH v3 0/5] core/pci: Track changes of topology by an OS

Change since v5:
 - Activates on "ibm,supported-movable-bdfs" property in DT from skiboot
   instead of the "pci=realloc" flag;
 - Removed the code refactoring patches - will send them separately.

Changes since v4:
 - Fixed failing build when EEH is disabled in a kernel config;
 - Unfreeze the bus on EEH_IO_ERROR_VALUE(size), not only 0xffffffff;
 - Replaced the 0xff magic constant with phb->ioda.reserved_pe_idx;
 - Renamed create_pdn() -> pci_create_pdn_from_dev();
 - Renamed add_one_dev_pci_data(..., vf_index, ...) -> pci_alloc_pdn();
 - Renamed add_dev_pci_data() -> pci_create_vf_pdns();
 - Renamed remove_dev_pci_data() -> pci_destroy_vf_pdns();
 - Removed the patch fixing uninitialized IOMMU group - now it is fixed in
   commit 8f5b27347e88 ("powerpc/powernv/sriov: Register IOMMU groups for
   VFs")

Changes since v3:
 - 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.

Sergey Miroshnichenko (5):
  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/powernv/pci: Hook up the writes to PCI_SECONDARY_BUS register
  powerpc/pci: Enable assigning bus numbers instead of reading them from
    DT

 arch/powerpc/include/asm/ppc-pci.h           |   1 +
 arch/powerpc/kernel/pci_dn.c                 |  95 +++++++--
 arch/powerpc/kernel/rtas_pci.c               |  97 ++++++---
 arch/powerpc/platforms/powernv/eeh-powernv.c |   2 +-
 arch/powerpc/platforms/powernv/pci.c         | 205 +++++++++++++++++--
 5 files changed, 331 insertions(+), 69 deletions(-)

-- 
2.21.0