new repo: https://github.com/newluhux/qemu-hui

I’m try add mt7628 support into qemu.

You can boot from flash, but need skip ‘ddr_calibrate’:

Disassemble uboot.bin, find the location of the ddr_calibrate function, and then use hexedit to modify it so that it can skip ddr initialization (because qemu does not emulate it).

If you not skip ddr_calibrate, you will take a lot of time at memory test,

but uboot still can bootup, test on mainline uboot.

I can’t found it on real board.

I am going to write a simple bootrom to initialize the device, only use for qemu.

1. use buildroot build firmware: https://github.com/newluhux/vocore2/tree/master/buildroot

why use vocore2’s buildroot?:

I found ‘mt7628_evb’ in uboot source code, but I can’t found this board on taobao or ebay.

1. get qemu source tree and apply patch

git clone https://gitlab.com/qemu-project/qemu /path/to/qemu
cd /path/to/qemu/
git am < xxxx.patch

1. build qemu

cd /path/to/qemu/
./configure --cc=gcc --cxx=g   \
		--target-list=mipsel-softmmu \
		--enable-debug --enable-debug-tcg --enable-debug-info
make -j$(nproc)
make check

1. run qemu:

because use ‘uboot.elf’.

you must select ‘CONFIG_REMAKE_ELF=y’ in uboot config file.

cd /path/to/qemu/
./qemu-system-mipsel -M mt7628 -m 128 \
               -nographic \
		-serial telnet:127.0.0.1:4000,server \
		-serial telnet:127.0.0.1:4001,server \
		-serial telnet:127.0.0.1:4002,server \
		-drive if=mtd,index=0,file=/path/to/buildroot/output/images/flash_16M.bin,format=raw \
		-object filter-dump,id=f1,netdev=hub0port0,file=dump.dat \
		-kernel /path/to/buildroot/output/build/u-boot-VERSION/uboot.elf \
		-s -S

connect to serial port:

telnet 127.0.0.1 4000 # UART0
telnet 127.0.0.1 4001 # UART1
telnet 127.0.0.1 4002 # UART2

look network traffic:

use wireshark open ‘dump.dat’

same with qemu

2022/01/06: UART output is working, input is not working, need impl irq.

2022/01/09: add unimp memory region mapping.

2022/01/14: add mt7628-intc, UART input is working. can use shell.

2022/01/15: upload missing code, fix intc, add mt7628 reset control, usb host is working.

2022/01/16: add flash direct access support. try add boot from flash support, but uboot is not working, need fix qemu to run unmodify uboot.

2022/01/18: try send patch to qemu upstream.

2022/01/21: uboot is wip, I need emulate a mt7628 DDR controler.

2022/01/23: write a ddr controler is boring, try impl spi master.

2022/01/25: spi master is ok, default attach a w25q128 flash, next is ethernet or pcie.

2022/01/28: spi master have bug, rewrite it, add chip select.

2022/01/30: uboot is working, you can use uboot to boot from flash.

2022/02/04: rewrite system control, merge vocore2 device to mt7628 device.

2022/02/13: write a ethernet emulate, uboot bootp can working.

2022/02/14: fix ethernet recive missing some packet, add ohci.

2022/02/15: spi control support two cs line.

2022/02/16: flash direct access is provide by spi controller.

2022/02/19: now, you can boot from flash, but need skip ddr_calibrate, please read source code, support bootrom.

2022/03/17: rewrite ethernet emulation, add interrupt support, network is pass on NetBSD 9.0

2023/03/30: my job is busy, haven’t time to test it, now mt7628’s ethernet can work on mainline openwrt.

2023/03/31: study i2c :), try impl i2c controller.