[U-Boot-Users] MPC8315E-RDB kernel serial console baudrate

Leon Woestenberg leon.woestenberg at gmail.com
Wed May 28 21:33:33 CEST 2008


Hello,

I have tried to run the vanilla upstream 2.6.25.4 kernel on my
MPC8315E-RDB board, but the serial console seems not to respect the
bitrate I give it in u-boot.
(nor does it default to the well-known often used values 9600 ... 230400).

Some findings so far:
- The on-board u-boot comes up properly on the serial console.
- The on-flash Linux 2.6.23 that comes from the on-board flash runs
fine and gives me a 115200 bps serial console.

- Both 2.6.25.4 and 2.6.26-rc4 using the default config and default
device tree that comes with the kernel gives me garbled output.
- 2.6.25.4, but this time using the on-flash device tree (also) gives
me garbled output.
- The u-boot command line ("setenv bootargs console=ttyS0,115200") is
interpreted by the kernel, because different baudrates give me
reproducable but different garbage at each speed.

This is what is on the board's FlashROM:

U-Boot 1.3.0-rc2 (Nov 19 2007 - 16:37:36) MPC83XX

CPU:   e300c3, MPC8315E, Rev: 10 at 400 MHz, CSB:  133 MHz
Board: Freescale MPC8315ERDB Rev 0.0

Is this u-boot too old, i.e. might there be a compatibility issue
involved between u-boot / dtb / kernel?

What would be the best approach from here?
(I plan to measure the actual bitrate using a scope tomorrow).

Regards,
-- 
Leon




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