Broadcom Kona

Kona was Broadcom's mobile SoC platform. Most notably, Kona chips were used in multiple budget Samsung devices, as well as the Sony SmartWatch 3 (sony-tetra) and the Amazon Fire TV Stick 1st gen (amazon-montoya).

The Broadcom chips used in Raspberry Pi devices (BCM2837, etc.) are actually completely different from the Kona chips, the only thing they share is the GPU (Videocore IV).

= Mainline status =

Development for the Samsung Galaxy Grand Neo (samsung-baffinlite) (BCM23550), as well as the Samsung Galaxy Trend Plus (samsung-kylepro) and the Samsung Galaxy Core Plus (samsung-cs02) (BCM21664), is currently (slowly) happening in the bcm-kona-mainline organization on GitHub.

There is no active work being done on the BCM28155 or BCM21654-based devices yet.

BCM21664/BCM23550
The BCM21664 and BCM23550 share some components, so most drivers can be reused between the two. They're often paired with the BCM59054 PMU and the BCM2093 modem.

Currently, the 3 devices being worked on can boot into the initramfs. The BCM59054 PMU used in these devices works with the BCM59056 driver - some modifications have been made to add proper support for the different regulators in the bcm-kona-mainline repository.

On at least the BCM23550, SMP does not work. Some peripherals are slowly being enabled, but the general support is still quite bare-bones.

Progress can be tracked in this issue in the bcm-kona-mainline/linux repository.

History
The initial work for Kona mainlining was started around 2012, when the board_bcm generic device and some extra drivers were added to the kernel (commit). Proper board development, as well as the addition of board files for the BCM21664 started around 2013, and ended around 2014, with a few commits to some devices later on (see: BCM21664 bringup). Support for the BCM23550 was added around 2016 (see: BCM23550 bringup).

Many Kona platform devices also make use of BCM590XX PMUs; initial support for one of them - the BCM59056 - was added in early 2014. According to a message on the Linux mailing list, support was planned for the similar BCM59054, however it has not been merged into upstream.

In 2014 Broadcom stopped its Mobile SoC activities, which also stopped further developments from Linaro (see this mail on the mailing list).

See also: Broadcom's old website with a list of their mobile chips (archive)

= Chipsets =

Specifications

 * Dual-core 1.2 GHz ARM Cortex-A9 CPU
 * VideoCore IV GPU

Mainline status
There's a dtsi available for the 1.2Ghz variant of this chipset in the mainline kernel. The weaker variant is not supported, but it's most likely as easy as changing the BCM21664 DTSI (as they both share the same source code in downstream).

Some mainlining progress was made by Deata (see deata/kylepro-mainlining on GitLab), and it is being continued in the bcm-kona-mainline/linux repo on GitHub.

More information

 * phonedb.net
 * Broadcom's website (archive)

Broadcom BCM23550 (Java)
Shares a lot of common platform code with Hawaii chips, and has a lot of similar drivers.

Specifications

 * Quad-core 1.2 GHz ARM Cortex-A7 CPU
 * VideoCore IV GPU

Mainline status
There's a dtsi available for this chipset in the mainline kernel.

Some mainlining progress was made by knuxify (see bcm-kona-mainline/linux on GitHub).

More information

 * phonedb.net
 * Broadcom's website (archive)

Specifications

 * Single-core 850 MHz ARM Cortex-A9 CPU
 * VideoCore IV GPU

Mainline status
No DTSI. May be similar to the BCM28155, but this hasn't been researched yet.

More information

 * phonedb.net
 * Broadcom's website (archive)

Specifications

 * Dual-core 1.2 GHz ARM Cortex-A9 CPU
 * VideoCore IV GPU

Mainline status
There's a DTSI available for this chipset in the mainline kernel.

More information

 * phonedb.net
 * Broadcom's website (archive)