CI20 upstream

This page contains details about the latest kernel branch and any known quirks/special requirements.

It will be periodically updated to keep up to speed with the latest.

The current branch tracking mainline 3.16

https://github.com/MIPS/CI20_linux

Status of Linux Kernel Drivers

Core

Name	State	Path	Notes
Clocks	Works	drivers/clk/jz47xx	Could have common drivers/clk/ingenic for all SoCs with SoC specific binding using common components(?)
CPUfreq			4770 has [1], but clock infrastructure is different. Ingenic kernel had [2] for 4780. Not ported to 3.16 yet.
Device Tree	Mostly		Parsed on boot, but compiled into the kernel. Would be good to allow it to be passed from the bootloader.
DMA	Mostly	drivers/dma/dma-jz4780.c	needs combining into dma-jz4740. Works, just missing priority support
GPIO	Works	drivers/pinctrl/pinctrl-jz4780.c	should perhaps be in drivers/gpio/ (?)
Hotplug
IRQ Controller		drivers/irqchip/irq-jz4780.c	Very similar between SoCs (4740 has one bank, 60,70,80 has two banks)
MXU Context
PinCtrl	Mostly	drivers/pinctrl/pinctrl-jz4780.c	Differs between SoCs. Functional, may need DT binding changes based on feedback from upstream. See also pinctrl-jz4770.c.
Power Controller (LPCR Register)
Power Off & Reset	Works
RTC	Works
SMP	Works
Watchdog	Works

Peripheral drivers

Name	State	Path	Notes
ADC	WIP		Check branches on https://github.com/ZubairLK/CI20_linux
Audio (ALSA)	WIP		Check patches on https://groups.google.com/forum/#!forum/mips-creator-ci20-dev
Camera
Ethernet	Works	drivers/net/ethernet/davicom/dm9000.c	Requires regulator and reset GPIO support, see [3].
GPU
HDMI	WIP		Check patches on https://groups.google.com/forum/#!forum/mips-creator-ci20-dev
I2C	Works	drivers/i2c/busses/i2c-jz4780.c	4740 has HW issue so uses gpio i2c instead. 4770 had [4] but unused so removed (also gave false positives on i2cdetect).
IPU			4770 has driver integrated with fbdev driver, see [5]. Plans to move to DRM+KVM but may take time.
IR	Driver upstream	drivers/media/rc/gpio-ir-recv.c	GPIO, so use upstream GPIO driver
MMC	Works	drivers/mmc/host/jz4740_mmc.c	Various changes needed, see [6]. Should not rename driver. Check whether affected by [7].
NAND	Works
Regulator	Works
SPI (SSI)	None		SPIO GPIO should work, but a dedicated driver for the SSI hardware in drivers/spi/ would be better.
UART	Works		Quirks: see patches [8] [9] need moving to wrapper driver, like 8250_dw and mediatek which can be common between Ingenic SoCs.
USB (EHCI)	Works
USB (OHCI)	Works
USB(OTG)	Works		Upstream driver supports only host mode as of 3.15
VPU			Driver aimed at 4770, see [10]. For samples see [11]. May be insecure (allows userland to do its own cache control and access TCSM banks). RemoteProc driver in progress.
Wifi	WIP		Check patches on https://groups.google.com/forum/#!forum/mips-creator-ci20-dev
BT	WIP		Check branches on https://github.com/ZubairLK/CI20_linux

List of other possible issues

• /etc/init.d/iw8103 is the startup script for the BT/Wifi firmware in the default rootfs.

If using 3.16, the script can cause the boot to hang. Please move the script out of /etc/init.d

Add "root=/dev/mmcblk0p1 rootwait" to bootargs in uboot if you wish to boot a rootfs from mmc.