pci: Expose a VF's owning PF to bus subclasses
ofw_pcibus now uses pci_iov_get_pf() to inherit PF locality for
VFs, but the accessor was inadvertently left in an uncommited ACPI
change. This breaks powerpc builds.
Expose the accessor from the PCI core and provide a stub when PCI_IOV
is omitted. Record VF ownership before pci_add_child() so child added
callbacks can safely query it, and remove the later redundant
assignment.
Sponsored by: BBOX.io
(cherry picked from commit 3481a9cdc4dc26ef583bb0f46a04d5d059cde466)
e1000: Limit the TSO sentinel to lem(4) controllers
The TSO workaround splits the final DMA segment to create a four byte
sentinel descriptor. Intel documents the premature descriptor writeback
erratum and this workaround in the 82540EP and 82545GM specification
updates (erratum 3) and the 82546GB specification update (erratum 1).
Limit the workaround and its preceding TSO state to the legacy PCI and
PCI-X controllers so PCIe controllers retain their natural descriptor
layout using one fewer descriptor per TSO packet, no split of the final
segment, and one less four byte DMA.
Sponsored by: BBOX.io
(cherry picked from commit 2a7af8ebcf90af83f01f9523b25bfc6e58c7b809)
ofw_pcibus: Honor device proximity for DMA tags
BUS_GET_DOMAIN can report a PCI function's firmware locality, including
an SR-IOV VF's inherited PF locality, but ordinary OFW PCI functions
still use the shared bus DMA tag. Consequently, busdma metadata and
coherent memory can be allocated from the bus's domain instead of the
function's domain.
Create and cache a child tag for each function that requests a DMA tag
and apply its reported domain without modifying the shared parent tag.
Apply the same domain to the private IOMMU tag already created by the
pSeries PCI bus. Destroy cached tags when PCI children are removed so
VF create and destroy cycles do not leak them.
Reviewed by: PowerPC (jhibbits)
Sponsored by: BBOX.io
Differential Revision: https://reviews.freebsd.org/D59065
(cherry picked from commit df6bbc9b17dcb75e220b9ab44f5a6483b47c562e)
