cpm_uart_console_write() stuck in waiting for transmitter fifo ready

Shawn Jin shawnxjin at gmail.com
Fri Jul 16 17:12:21 EST 2010

>> Why would the TxBD be filled with all 0xF? Would it be possible that
>> the bdbase actually points somewhere else other than the TxBD?
> The virtual address 0xfddfa000 is mapped to 0xfa202000. I suspect that
> the TxBD of my MPC870 may not start at 0xfa202020.
> I notice that for adder875, ep88xc and mpc885ads, the muram data's reg
> = <0 0x1c00> but for mgsuvd, its reg = <0x800 0x1800>. How does the
> kernel use muram for 885 family SoCs? How much muram should be
> reserved for data?
> My RCCR=0x1, meaning the first 512B is for microcode. So the data and
> the TxBD should really be starting at 0xfa202200? Then my muram data's
> reg should be <0x200 ?>? What size shall I specify?

After the muram data's reg is changed to <0x200 0x1a00>, the cpm_uart
driver works properly and the kernel messages are printed on the
serial port.


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