BHND Wi-Fi chipsets and SoCs share a common DMA engine, operating within
backplane address space. To support host DMA on Wi-Fi chipsets, the bridge
core maps host address space onto the backplane; any host addresses must
be translated to their corresponding backplane address.
- Defines a new bhnd_get_dma_translation(9) API to support querying DMA
address translation parameters from the bhnd(4) bus.
- Extends bhndb(4) to provide DMA translation descriptors from a DMA
address translation table defined in the host bridge-specific
bhndb_hwcfg.
- Defines bhndb(4) DMA address translation tables for all supported host
bridge cores.
- Extends mips/broadcom's bhnd_nexus driver to return an identity (no-op)
DMA translation descriptor; no translation is required when addressing
the SoC backplane.
Approved by: adrian (mentor)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D12582
9ed453245b