Subsystems

Cellular

The modem: what the trees say, and why it is not in release 1.

Hardware

The modem is MediaTek’s (the realme tree’s CCCI stack): a separate processor that Android’s ccci_mdinit and ccci_rpcd start with firmware and nvram data, reached through the CCIF mailboxes (ap_ccif0 to ap_ccif4 and the modem’s side) and DPMAIF for packet data. The modem’s memory (md_mem_usage, 256 MiB at 0xae000000) is one of LK’s reservations, so it is a hole in the memory map. The firmware, the nvram and the SIM data are the vendor’s and the owner’s, and never go into a repository or a log.

Driver

None on the main branch of the kernel at 76b737c: the tree has no modem code, and the device tree carries no modem node. The bring-up (power-on and reset release, the CCIF handshake, the ports, an AT dialect, the file-system and RPC services) is developed on branches.

Device tree

None.

Boot-arguments

None.

User space

None on the main branches.

Status

device.conf: missing. Planned for release 2.

Seen on a branch: the modem starting, with no second handshake (run 45).

Known issues

• No SIM, signal, calls, SMS or mobile data.

Source files

None on the pinned main branches.