LX2160a linux UART configuration

[Takarth]

I noticed, that linux is not able to configure the UART interface. (arm,pl011 driver) using LSDK 21.08

I'm able to configure the interface in bootloader environment (u-boot 2021-04)

For example:

Bootlader is using UART1 (0x21c0000) with baudrate 115200

If I configure the linux boot commands to console=ttyAMA0,57600 it does not change during linux boot and the login prompt will still be disabled (With a baudrate of 115200)

I'm also not able to modify the settings on other UART (2-4) interfaces if i do not set them up during bootloader.

[ 0.000000] earlycon: pl11 at MMIO32 0x00000000021c0000 (options '9600n8')
[ 0.000000] printk: bootconsole [pl11] enabled

(earlycon settings are also not applied)

stty -F /dev/ttyAMA0 57600
stty: /dev/ttyAMA0: cannot perform all requested operations

stty fails to change baud rate

Does anybody else have the same issue? 

Exists there a bugfix for the pl011 driver)

[yipingwang]

The SBSA UART has a fixed baud rate and flow control setting which cannot be changed by user space software.

Changes to be done in firmware for changing baud rate.

In atf source code plat/nxp/soc-lx2160a/lx2160ardb/plat_def.h, please do the following modification.

#define NXP_CONSOLE_BAUDRATE 115200

=>

#define NXP_CONSOLE_BAUDRATE 57600

=> printenv bootargs

bootargs=console=ttyAMA0,115200 root=/dev/ram0 rw rootdelay=10 earlycon=pl011,mmio32,0x21c0000 ramdisk_size=0x2000000 default_hugepagesz=1024m hugepagesz=1024m hugepages=2 pci=pcie_bus_perf iommu.passthrough=1

=> editenv bootargs

edit: console=ttyAMA0,57600 root=/dev/ram0 rw rootdelay=10 earlycon=pl011,mmio32,0x21c0000 ramdisk_size=0x2000000 default_hugepagesz=1024m hugepagesz=1024