ath79: add support for ZTE MF281

Add support for the ZTE MF281 battery-powered WiFi router.

Hardware
--------
SoC:    Qualcomm Atheros QCA9563
RAM:    128M DDR2
FLASH:  2M SPI-NOR (GigaDevice GD25Q16)
        128M SPI-NAND (GigaDevice)
WLAN:   QCA9563 2T2R 802.11 abgn
        QCA9886 2T2R 802.11 nac
WWAN:   ASRMicro ASR1826
ETH:    Qualcomm Atheros QCA8337
UART:   115200 8n1
        Unpopulated connector next to SIM slot
        (SIM) GND - RX - TX - 3V3
        Don't connect 3V3
BUTTON: Reset - WPS
LED:    1x debug-LED (internal)
        LEDs on front of the device are controlled
        using the modem CPU and can not be controlled
        by OpenWrt

Installation
------------

1. Connect to the serial console. Power up the device and interrupt
   autoboot when prompted

2. Connect a TFTP server reachable at 192.168.1.66 to the ethernet port.
   Serve the OpenWrt initramfs image as "speedbox-2.bin"

3. Boot the initramfs image using U-Boot

   $ setenv serverip 192.168.1.66
   $ setenv ipaddr 192.168.1.154
   $ tftpboot 0x84000000 speedbox-2.bin
   $ bootm

4. Copy the OpenWrt factory image to the device using scp and write to
   the NAND flash

   $ mtd write /path/to/openwrt/factory.bin firmware

WWAN
----

The WWAN card can be used with OpenWrt. Example configuration for
connection with a unauthenticated dual-stack APN:

network.lte=interface
network.lte.proto='ncm'
network.lte.device='/dev/ttyACM0'
network.lte.pdptype='IPV4V6'
network.lte.apn='internet.telekom'
network.lte.ipv6='auto'
network.lte.delay='10'

The WWAN card is running a modified version of OpenWrt and handles
power-management as well as the LED controller (AW9523). A root shell
can be acquired by installing adb using opkg and executing "adb shell".

Signed-off-by: David Bauer <mail@david-bauer.net>
(cherry picked from commit 1e1695f959e678868bb7911d059b847f38fc9cf4)

1 files changed, 17 insertions, 4 deletions

diff --git a/target/linux/ath79/image/nand.mk b/target/linux/ath79/image/nand.mk
index 726fab068f..1d086b1918 100644
--- a/target/linux/ath79/image/nand.mk
+++ b/target/linux/ath79/image/nand.mk
@@ -305,7 +305,7 @@ define Device/netgear_wndr4500-v3
 endef
 TARGET_DEVICES += netgear_wndr4500-v3
 
-define Device/zte_mf286_common
+define Device/zte_mf28x_common
   SOC := qca9563
   DEVICE_VENDOR := ZTE
   DEVICE_PACKAGES := kmod-usb2 kmod-ath10k-ct
@@ -315,8 +315,21 @@ define Device/zte_mf286_common
   IMAGE/sysupgrade.bin := sysupgrade-tar | append-metadata
 endef
 
+define Device/zte_mf281
+  $(Device/zte_mf28x_common)
+  DEVICE_MODEL := MF281
+  KERNEL_SIZE := 6144k
+  IMAGE_SIZE := 29696k
+  IMAGES += factory.bin
+  IMAGE/factory.bin := append-kernel | pad-to $$$$(KERNEL_SIZE) | append-ubi | \
+	check-size
+  DEVICE_PACKAGES += ath10k-firmware-qca9888-ct kmod-usb-net-rndis \
+	kmod-usb-acm comgt-ncm
+endef
+TARGET_DEVICES += zte_mf281
+
 define Device/zte_mf286
-  $(Device/zte_mf286_common)
+  $(Device/zte_mf28x_common)
   DEVICE_MODEL := MF286
   DEVICE_PACKAGES += ath10k-firmware-qca988x-ct kmod-usb-net-qmi-wwan \
 	kmod-usb-serial-option uqmi
@@ -324,7 +337,7 @@ endef
 TARGET_DEVICES += zte_mf286
 
 define Device/zte_mf286a
-  $(Device/zte_mf286_common)
+  $(Device/zte_mf28x_common)
   DEVICE_MODEL := MF286A
   DEVICE_PACKAGES += ath10k-firmware-qca9888-ct kmod-usb-net-qmi-wwan \
 	kmod-usb-serial-option uqmi
@@ -332,7 +345,7 @@ endef
 TARGET_DEVICES += zte_mf286a
 
 define Device/zte_mf286r
-  $(Device/zte_mf286_common)
+  $(Device/zte_mf28x_common)
   DEVICE_MODEL := MF286R
   DEVICE_PACKAGES += ath10k-firmware-qca9888-ct kmod-usb-net-rndis kmod-usb-acm \
 	comgt-ncm