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<TITLE>Re: UCC UART</TITLE>
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<P><FONT SIZE=2>Gary Thomas wrote:<BR>
> I'm still trying to get UCC UART to work on my MPC8358 with<BR>
> the 2.6.33.3 kernel.<BR>
><BR>
> When I try to send data to the port, there is no output, not<BR>
> even any interrupts on the device. What I see is that the UART<BR>
> driver seems to initialize fine and pushes characters into<BR>
> the output buffers & descriptors. However, there are no<BR>
> interrupts hence it just sits there...<BR>
><BR>
> My device tree entry for this device now looks like this:<BR>
> /* ttyQE0 (UCC3) */<BR>
> serial_qe0: serial@4000 {<BR>
> device_type = "serial";<BR>
> compatible = "ucc_uart";<BR>
> cell-index = <3>;<BR>
> reg = <0x2200 0x200>;<BR>
> interrupts = <34>;<BR>
> interrupt-parent = <&qeic>;<BR>
> port-number = <0>;<BR>
> rx-clock-name = "brg1";<BR>
> tx-clock-name = "brg1";<BR>
> };<BR>
<BR>
You might try assigning different BRGs to TX and RX.<BR>
<BR>
><BR>
> * Are there any known issues with this driver?<BR>
<BR>
Heh. :-)<BR>
<BR>
I'd say that there are plenty of unknown issues with this driver/hardware.<BR>
For some reason, QE UART is just unreliable. I've had several people try to<BR>
use the QE for UART, and almost everyone has problems with it.<BR>
<BR>
> * Is there any way to get a handle on why no data is moving?<BR>
<BR>
The QE is a black box. If you're programming it correctly but it doesn't do<BR>
what it's supposed to, there's almost no way to debug it.<BR>
<BR>
> * Is there some way to tell if the QE even sees the descriptors?<BR>
<BR>
Not to my knowledge.<BR>
<BR>
> * The driver and documentation mention a "soft UART" mode for<BR>
> chips with broken UART hardware. How do I know if my board<BR>
> has functioning UART hardware?<BR>
<BR>
I believe only the 8323 and the 8360 have broken UARTs. Those are the only<BR>
ones that have the microcode update that enable soft-UART, anyway.<BR>
<BR>
><BR>
> Note: I have UCC1+UCC2 working great with ethernet.<BR>
><BR>
> Thanks for any pointers or ideas<BR>
<BR>
You should contact Freescale support and ask them for help. Even though I<BR>
wrote the Linux driver, I have no "inside" connection to the QE team here at<BR>
Freescale.<BR>
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