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