SoC (System on a Chip)
The perpetual effort to make the Linux kernel work on any piece of hardware available is ongoing. This work takes place within projects like OpenWrt and also within companies that design, manufacture, or sell hardware and products based on Linux. Much of this work eventually gets mainlined, meaning the code becomes part of the mainline Linux kernel.
Today, we take wireless functionality for granted, but in the beginning, it was a real challenge. The IEEE 802.11 family of standards inspired what could be achieved, but the available Linux kernel drivers were poorly written, lacked features, or didn't exist. This is still true for some of the wireless hardware on the market today. No matter how fantastic or powerful a device may be, its Linux drivers offer limited functionality.
Since its founding, OpenWrt has focused on customer premise equipment (CPE) hardware such as routers and NAS devices, dedicating much effort to supporting IEEE 802.11 as extensively as possible. Given that the initial hardware, the Linksys WRT54G, sold over 400,000 units in its first months, it's safe to say that the work done by the OpenWrt project has had an impact.
Companies
Most SoC manufacturers license a (soft or hard) IP core for a certain CPU design from a licensor like MIPS or ARM, then combine this with other (self-developed or licensed) (soft or hard) IP cores for DSP-, wireless-, VoIP-, Sound-, Switch-, etc-functionality and commission the manufacturing of Chips at some semiconductor foundry. These Chips, SoCs, are acquired by different manufacturers of Routers. The latter design PCBs for whatever purpose and solder the purchased chips (SoC, RAM, Flash) onto them.
Company | CPU | IP for Mixed-signal integrated circuit | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Intruction set license for | own IP | wired | optical | wireless | |||||||
MIPS | ARM | Power Architecture | other | Ethernet | DSL | DOCSIS | GPON | 802.11 | WiMAX | LTE | |
Broadcom | MIPS32, MIPS64 | ARMv6, ARMv7, ARMv8 | ✔ | ✔ | ✔ | ✔ | |||||
Marvell (Intel) | ARMv5 (XScale, Sheeva), ARMv6, ARMv7 | ✔ | ✔ | ||||||||
Qualcomm (Atheros, ZyDAS) | MIPS32 | ARMv5, ARMv6, ARMv7 | Ubicom32, Ubicom64 | ✔ | ✔ | ||||||
MediaTek (Ralink) | MIPS32 | ARMv5, ARMv6, ARMv7 | ✔ | ✔ | ✔ | ||||||
Lantiq (Infineon, Texas Instruments) | MIPS32 | ✔ | ✔ | ✔ | |||||||
Samsung | ARMv4, ARMv5, ARMv6, ARMv7 | ||||||||||
Texas Instuments | ARMv5, ARMv6, ARMv7 | TMS320 | ✔ | ||||||||
Ikanos (Conexant, Analog Devices) | MIPS32, Lexra | ARMv5, ARMv6 | ✔ | ||||||||
Realtek | Lexra, MIPS32 | ✔ | ✔ | ✔ | |||||||
Intel (Digital Equipment Corporation) (Texas Instruments) | ARMv4 (StrongARM), ARMv5 (XScale), ARMv6 | x86, x86-64, IA-64 | ✔ | ✔ | ✔ | ||||||
AMD | MIPS32, MIPS64 | ARMv8? | x86, x86-64 | ||||||||
Apple | ARMv7 | ||||||||||
Hisilicon | ARMv? | ||||||||||
Cavium Networks | MIPS32, MIPS64 | ARMv4 | |||||||||
Vitesse Semiconductor | |||||||||||
Applied Micro Circuits Corporation | ARMv8 | ✔ | |||||||||
Maxim Integrated | |||||||||||
Freescale Semiconductor | ARMv5, ARMv6, ARMv7 | ✔ | Motorola 68000 | ||||||||
Allwinner Technology | ARMv5, ARMv7, ARMv8 | ||||||||||
Renesas Electronics | MIPS64 | ARMv7 | SuperH ,M32R | ||||||||
Sony | MIPS? | ✔ | |||||||||
Toshiba | MIPS? | ||||||||||
SiFive | RISC-V |
Examples of devices with an exotic SoC
- Cavium CNS1202: Cisco RVS4000 v2
- Mindspeed Comcerto-SoC: ZyXEL NBG5715
- Qualcomm Ubicom32: D-Link DIR-657 HD Media Router 1000
- Conexant/Ikanos CX94610-11Z: Xavi 7968
- Freescale MPC85xx PowerQUICC III P1014@800MHz TP-Link TL-WDR4900 v1, v1.3
Linux support
Now that we have an overview over the companies that own/license semiconductor IP, let's have a look of the available support of their products in the mainline Linux kernel or in the OpenWrt Linux kernel. We don't much care about the Android Linux kernel or about heavily modified (and outdated) Linux kernels.
TODO
For mainlined Linux kernel-drivers for the
- IEEE 802.3 (Ethernet) cf. ?
- E.g. BCM63xx codebase with GPL'd Ethernet and USB support proves, that sometimes FOSS drivers for Ethernet NICs are not available.
- DSL is a Layer1 protocol; as Layer2 protocol usually ATM is employed. Cf. PPPoEoA vs. PPPoE to PPPoA. Long story short, we require support for ATM in the Linux kernel:
- For the Lantiq xDSL support cf. soc.lantiq. Any better sources?
- FOSS support for the Broadcom DSL-IP does not exist.
- FOSS support for the Ikanos/Conexant DSL-IP does not exist.
Platforms
Each different OpenWrt platform represents a set of hardware that share certain common features, such as being part of the same family of SoCs. Depending on the semiconductor company that designs the SoC, a SoC-family can consist entirely of IP blocks that are all well-supported, maybe already mainlined. But it can also contain IP blocks, for that only raggedly written, feature-poor code exists, that would never be mainlined. Or IP blocks that are completely unsupported by the Linux kernel.
Qualcomm Atheros
ar5xxx
Qualcomm Atheros AR5xxx boards (Atheros brand)
ar71xx
Qualcomm Atheros AR7xxx, AR9xxx and QCA9xxx boards
ipq40xx
ipq806x
msm
- not supported / removed from Linux in March 2015
Lantiq / Infineon
adm5120
Infineon/ADMtek ADM5120
adm8668
Infineon WildPass ADM8668
AR7
TNETV1050, TNETD7200, TNETD73XX SoCs with ADSL2+ support.
- → soc.ar7
Lantiq
XWAY, XRX200 SoCs with ADSL2+ and VDLS2 support in OpenWrt.
MediaTek / Ralink
- In OpenWrt, all MediaTek/Ralink SoCs are merged under the target
ramips
, see MediaTek-Ralink ramips
Broadcom
brcm47xx
Broadcom 47xx boards
bcm63xx
Broadcom 6338, 6345, 6348, 6358, 6361, 6368, 63168 among other SoCs. Working with no driver for the on-board DSL/VoIP
bcm33xx
Minimal support for some of these SoCs.
brcm2708 (= Raspberry Pi)
- OpenWrt support is WIP
- no, there are NO FOSS Linux drivers for the GPU. There is merely an open source wrapper for the closed source GPU driver
bcm53xx
ARM-based bcm53xx and ARM-based bcm47xx SoCs:
Hisilicon
hi35xx
Ikanos
Conexant/Ikanos Solos-W
Boards based on the CX94610 SoCs.
- → wag54g2
Marvell
orion
Marvell MV88F518x/MV88F528x
kirkwood
Marvell MV88F61xx/MV88F62xx
mvebu
Marvell Armada XP/370
Moschip
mcs814x
Only 2 known devices (supported). Devolo dLAN USB Extender
Realtek
- → Realtek
Rockchip
- → Rockchip
Freescale
mpc52xx
Freescale MPC52xx
mpc83xx
Freescale MPC83xx
mpc85xx
Freescale MPC8xx
imx21
imx23
Freescale i.MX23 series
imx6
Freescale i.MX6 series
Oxford / PLXTECH / Avago
oxnas
Oxford Semi OX82x / PLXTECH NAS782x
SiFive
- → SiFive
Allwinner
sunxi
A10/A10s/A13/A20/A23/A31/A33/A64/A80/H3/H5/H8
d1
D1 RISC-V
Unsupported SoCs
- Realtek RTL8196C is unsupported, see Lexra
- Ubicom is not supported
- QCA msm arch was removed from Linux mainline and is unsupported.