Wi-Fi adaptation

Start with platform interrupts and DMA. Identify the actual radio, PCI ID, firmware and board-data variant. Read Ath12kWifi and its include/nw_abi.h before implementing callbacks.

Use driver build integration to connect initialization, archive recipes and the OS ABI, then run this page's hardware checks.

Sources and interfaces

These links identify reviewed source revisions. Match interfaces to the selected SoC, component and OS versions. Files in UniXNU-sheng provide board integration examples.

Implementation	Source	What to read and implement
Reusable interface	nw_abi.h	lx_platform, nw_board, nw_wifi_events and station calls
Worker implementation	nw_wifi.c	nw_wifi_start/step/stop and event dispatch
Hardware integration	WifiProbe.cpp	PCIe, MSI, DMA allocation and firmware access callbacks
OS integration	WifiNet.cpp	Network service, Apple80211 requests and receive/transmit ownership

1. Separate the integration layers

Read the board sources. sheng uses WCN7850 on SM8550 PCIe0. The component also contains QCC2072 and QCN9274 definitions. Match the endpoint's hardware revision and firmware support in the driver before selecting a device definition.

2. Bring up the PCIe endpoint

Record controller/PHY windows, lane count, reset sequence, WLAN enable, PERST, reference clock, regulators, interconnect votes, SMMU streams and MSI routing. On sheng these are C++ constants and tables in the board package.

1. Inspect powered and clocked register state.
2. Apply the board's rails, clocks, PHY configuration and reset sequence.
3. Train the link and read the endpoint vendor/device ID.
4. Assign and map the BAR; inspect PCI capabilities and enable the required memory and bus-master operations.
5. Establish the endpoint DMA range and prove that allocated buffers are reachable with the selected cache policy.
6. Attach MSI and confirm delivery before relying on interrupt-driven progress.

Expected result: the correct endpoint, readable BAR, usable DMA and delivered interrupts. sheng's probe stages are selected by sheng-wifi; stage 1 inspects handoff state, stage 2 starts the link and stage 4 inspects the endpoint. The current endpoint path enters the reusable stack at stage 5 or higher; that stack performs its MHI and firmware startup. Read the stage's source before enabling it on a new board.

3. Supply the component callbacks

Implement lx_platform from nw_abi.h: time, sleep, polling, logging, allocation, DMA allocation/mapping/synchronization and fw_get. Implement nw_board: mapped BAR, PCI identity, config-space access and MSI target.

The sheng implementation uses native_ufs_extra_* for its DMA arena and native_ufs_part_* for firmware access. A port with another storage or DMA implementation must supply equivalent board services. Record firmware filenames, board data and calibration provenance in proprietary-files.txt.

Call nw_wifi_start, then service nw_wifi_step from the board worker. Event callbacks run from that worker and must return promptly. Inspect nw_wifi_stats, nw_wifi_where, board MSI counts and the firmware log when progress stops.

Preserve callback ownership from nw_abi.h: dma_alloc returns zeroed CPU memory and an endpoint-reachable bus address; dma_map returns 0 for buffers outside the DMA window; dma_sync handles the transfer direction. fw_get returns data and length by filename and keeps the data valid while consumed. Install nw_wifi_events before starting the worker; continue stepping while nw_wifi_step returns nonzero. Copy receive data into OS-owned storage before returning when delivery continues asynchronously. On shutdown, stop new submissions, stop the worker and component, then release BAR, MSI and DMA resources.

Expected result: firmware and QRTR services start, then scanning reports BSS entries. Firmware startup and successful scanning are separate checkpoints.

4. Connect the OS network interface

Adapt WifiNet.cpp to the selected XNU and wireless-framework ABI. Connect nw_wifi_scan, nw_wifi_connect, nw_wifi_tx and receive/link events to the OS. Provide the device MAC identity, channel/regulatory data and request layouts required by the selected userland.

Select Ath12kWifi in the complete component list. sheng builds its objects through build-ath12k-wifi.py, called by build-gop-legacy-display.py, which also links WifiProbe.cpp and WifiNet.cpp. Inspect the assembled target tree:

rg -n 'struct lx_platform|struct nw_board|nw_wifi_' drivers/Ath12kWifi/include/nw_abi.h
rg -n 'nativewifi|wifi_module_objs|WifiNet|WifiProbe' scripts/build-gop-legacy-display.py

Rebuild the kernel, payload and boot image using Building.

Expected result: scan, authentication, association, address configuration, receive and transmit each succeed. Record access-point settings, firmware, reconnect behavior and sustained traffic separately in the network record.

WCN7850 on sheng

sheng joins WPA2-Personal networks, gets an address by DHCP and loads web pages. sheng-wifi=5 starts Wi-Fi; sheng-wifi-aj=0 leaves the join to Settings.

Area	Finding
Power	Each of the six PMU rails needs RPMh mode, voltage and enable requests. Without the mode request two rails stay off and the link never trains.
PCIe	PCIe0 trains at Gen2 x1; the endpoint reads 17cb:1107.
Interrupts	The chip's MSIs go through PCIe0's own MSI receiver to SPI 141, so the worker sleeps between interrupts.
Firmware	c7-00108 runs; c2-00259 hangs in its demand pager. The firmware reports a zero MAC, so the board makes one from the chip ID.
Scan	6 GHz is left out: its 59 passive channels would take most of the scan time.
Association	The peer entry uses the access point's own HT and VHT capability, not this radio's. Join and the four-way handshake take about 100 ms.
Link	A firmware beacon miss is ignored while frames still arrive within 5 s. Frames at VHT MCS 10 and 11 are dropped.
System	The system cannot store the network password, so it does not treat the network as known.

Next step

Continue with DSP, audio and power, or return to the driver checklist.