qualcommax: ipq807x: add support for Linksys MX5300

Hardware specification:
========
SoC: Qualcomm IPQ8072A
Flash: 512MB (Winbond W29N04GZBIBA)
RAM: 1GB (2x Nanya DDR3L NT5CC256M16ER-EK)
Ethernet: 5x 10/100/1000Mbps (Qualcomm QCA8075)
WiFi1: 5GHz ac 4x4 (Qualcomm QCA9984 + Skyworks SKY85746-11) - channels 100-169
WiFi2: 5GHz ax 4x4 (Qualcomm QCN5054 + Skyworks SKY85755-11) - channels 36-64
WiFi3: 2.4GHz ax 4x4 (Qualcomm QCN5024 + Skyworks SKY8340-11)
IoT: Bluetooth 5, Zigbee and Thread (Qualcomm QCA4024 + Skyworks SE2433T-R)
IoT Flash: 4MB (Macronix MX25R3235F)
RTC: ST M41T00S
LED: 1x RGB status (NXP PCA9633)
USB: 1x USB 3.0
Button: WPS, Reset

Flash instructions:
========
1. Manually upgrade firmware using openwrt-qualcommax-ipq807x-linksys_mx5300-squashfs-factory.bin image.
More details can be found here: https://www.linksys.com/hk/support-article?articleNum=274497
After first boot check actual partition:
- fw_printenv -n boot_part
and install firmware on second partition using command in case of 2:
- mtd -r -e kernel -n write openwrt-qualcommax-ipq807x-linksys_mx5300-squashfs-factory.bin kernel
and in case of 1:
- mtd -r -e alt_kernel -n write openwrt-qualcommax-ipq807x-linksys_mx5300-squashfs-factory.bin alt_kernel

2. Installation using serial connection from OEM firmware (default login: root, password: admin):
- fw_printenv -n boot_part
In case of 2:
- flash_erase /dev/mtd21 0 0
  nandwrite -p /dev/mtd21 openwrt-qualcommax-ipq807x-linksys_mx5300-squashfs-factory.bin
or in case of 1:
- flash_erase /dev/mtd23 0 0
  nandwrite -p /dev/mtd23 openwrt-qualcommax-ipq807x-linksys_mx5300-squashfs-factory.bin
After first boot install firmware on second partition:
- mtd -r -e kernel -n write openwrt-qualcommax-ipq807x-linksys_mx5300-squashfs-factory.bin kernel
or:
- mtd -r -e alt_kernel -n write openwrt-qualcommax-ipq807x-linksys_mx5300-squashfs-factory.bin alt_kernel

3. Installation from initramfs image using USB FAT32 formatted drive:
Stop u-boot and run:
- usb start && fatload usb 0:1 $loadaddr openwrt-qualcommax-ipq807x-linksys_mx5300-initramfs-uImage.itb && bootm $loadaddr
Write firmware to the flash from initramfs:
- mtd -e kernel -n write openwrt-qualcommax-ipq807x-linksys_mx5300-squashfs-factory.bin kernel
and:
- mtd -r -e alt_kernel -n write openwrt-qualcommax-ipq807x-linksys_mx5300-squashfs-factory.bin alt_kernel

4. Back to the OEM firmware:
- mtd -e kernel -n write FW_MX5300_1.1.9.200251_prod.img kernel
and:
- mtd -r -e alt_kernel -n write FW_MX5300_1.1.9.200251_prod.img alt_kernel

5. USB recovery:
- fw_setenv usbimage 'openwrt-qualcommax-ipq807x-linksys_mx5300-initramfs-uImage.itb'
  fw_setenv bootusb 'usb start && fatload usb 0:1 $loadaddr $usbimage && bootm $loadaddr'
  fw_setenv bootcmd 'run bootusb; aq_load_fw && if test $auto_recovery = no; then bootipq; elif test $boot_part = 1; then run bootpart1; else run bootpart2; fi'

Notes:
========
IoT device is accesible over spi. Not yet supported.

Signed-off-by: Paweł Owoc <frut3k7@gmail.com>
Reviewed-by: Robert Marko <robimarko@gmail.com>

package/boot/uboot-envtools/files/qualcommax_ipq807x

@@ -30,7 +30,8 @@ edimax,cax1800)
 		ubootenv_add_uci_config "/dev/mtd$idx" "0x0" "0x10000" "0x20000"
 	;;
 linksys,mx4200v1|\
-linksys,mx4200v2)
+linksys,mx4200v2|\
+linksys,mx5300)
 	idx="$(find_mtd_index u_env)"
 	[ -n "$idx" ] && \
 		ubootenv_add_uci_config "/dev/mtd$idx" "0x0" "0x40000" "0x20000" "2"