Comment 0 for bug 1753314

Revision history for this message
Bill Paul (wpaul) wrote : UART in sabrelite machine simulation doesn't work wth VxWorks

The imx_serial.c driver currently implements only partial support for the i.MX6 UART hardware. In particular, it does not implement support for the Transmit Complete Interrupt Enable bit in the UCR4 register. The VxWorks 7 i.MX6 serial driver depends on the behavior of this bit in actual hardware in order to send characters through the UART correctly. The result is that with the current machine model, VxWorks will boot and run in QEMU but it's unable to print any characters to the console serial port.

I have produced a small patch for the imx_serial.c module to make it nominally functional with VxWorks 7. It works well enough to allow the boot banner to appear and for the user to interact with the target shell.

I'm not submitting this as a patch to the development list as I'm not fully certain it complies with the hardware spec and doesn't break any other functionality. I would prefer if the maintainer (or someone) reviewed it for any issues/refinements first.

I'm attaching the patch to this bug report. A copy can also be obtained from:

http://people.freebsd.org/~wpaul/qemu/imx_serial.zip

This patch was generated against QEMU 2.11.0 but also works with QEMU 2.11.1.