Normal baudrate for Rockchip boards

[t4_4t]

>> the "console=ttyS1,115200n8" is setting the serial port speed.

I actually tried it, it's all right with only above addition.
(However, unless the "u-boot" freezes due to garbled characters on boot-up ....)

Code:

label kernel-4.4.167-1163-rockchip-ayufan-g3d2c5b33817a
   kernel /boot/vmlinuz-4.4.167-1163-rockchip-ayufan-g3d2c5b33817a
   initrd /boot/initrd.img-4.4.167-1163-rockchip-ayufan-g3d2c5b33817a
   devicetreedir /boot/dtbs/4.4.167-1163-rockchip-ayufan-g3d2c5b33817a
   append console=ttyS2,115200n8 rw panic=10 init=/sbin/init coherent_pool=1M ethaddr=${ethaddr} eth1addr=${eth1addr} serial=${serial#} cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory swapaccount=1 root=LABEL=linux-root_sd1 rootwait rootfstype=ext4

Confirmed that Linux:ttyS2 is running at "baudrate=115200".

Code:

~# stty -a
speed 115200 baud; rows 35; columns 132; line = 0;
...

~# uname -a
Linux Rock64 4.4.167-1163-rockchip-ayufan-g3d2c5b33817a #1 SMP Tue Mar 26 15:06:19 UTC 2019 aarch64 aarch64 aarch64 GNU/Linux

*** CAUTION ***
If you execute "saveenv" on "u-boot", you can not restore it. (See below.)

Code:

=> setenv baudrate 115200
## Switch baudrate to 115200 bps and press ENTER ...

=> setenv baudrate 1500000
## Baudrate 1500000 bps not supported
## Error inserting "baudrate" variable, errno=22

----
>> I wonder if that "{serial#}" is something being passed to the kernel by u-boot?

"u-boot" passes "{serial#}", but which is a HASH value of "cpuid#".
So it has nothing to do with this issue.