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LS1021A-PB: Early UART Debugging on ttyS0 (Bank-0)

Question asked by srikanth krishnakar on Jun 27, 2016
Latest reply on Aug 24, 2016 by Jason Hendrix

Hi,

I am trying to get the EARLY_DEBUG working for LS1021A-PB on BANK-0 i.e via. standard 8250/16550 UART and it seems the kernel hangs after "Starting Kernel..." without proceeding further, as shown below:

 

Bootargs appended: earlycon=uart8250,mmio,0x21c0500

-----------------------------------------------------------------------------

## Booting kernel from Legacy Image at 81000000 ...

   Image Name:   Linux-4.1.8-rt8+

   Image Type:   ARM Linux Kernel Image (uncompressed)

   Data Size:    4352576 Bytes = 4.2 MiB

   Load Address: 80008000

   Entry Point:  80008000

   Verifying Checksum ... OK

## Flattened Device Tree blob at 81f00000

   Booting using the fdt blob at 0x81f00000

   Loading Kernel Image ... OK

   Loading Device Tree to bef11000, end bef19469 ... OK

 

Starting kernel ...

 

   <<<< --- HANGS HERE ----->>>>>

-----------------------------------------------------------------------------

 

Kernel config options enabled:

---------------------------------------

CONFIG_DEBUG_LL=y

CONFIG_DEBUG_LL_UART_8250=y

CONFIG_DEBUG_LL_INCLUDE="debug/8250.S"

# CONFIG_DEBUG_UART_8250 is not set

CONFIG_DEBUG_UART_PHYS=0x21c0500

CONFIG_DEBUG_UART_VIRT=0xf21c0500

CONFIG_DEBUG_UART_8250_SHIFT=2

CONFIG_SERIAL_EARLYCON=y

CONFIG_EARLY_PRINTK=y

---------------------------------------

Any inputs are highly appreciated If I am missing anything or doing something wrong in configuration.

 

Thanks,

SK

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