Serial 8250 DMA Broken on OMAP3630

From: Adam Ford
Date: Sun Oct 06 2019 - 13:08:34 EST


Has anyone else had any issues using the CONFIG_SERIAL_8250_DMA on the OMAP?

I can use the DMA on the legacy, omap-serial driver, but when I enable
the DMA on the 8250-omap driver, I get missing frames in Bluetooth.

The older driver seems to have an ISR that seems to address a variety
of items compared to the very tiny ISR for 8250-omap.c.

I am not exactly sure where to start, but if someone has any
suggestions on how I can troubleshoot, please let me know. As of now,
I have to disable CONFIG_SERIAL_8250_DMA to get the Bluetooth
connected to UART2 operational on a DM3730 at 3,000,000 baud, but it
appears to work just fine after some patches I just submitted for
handling RTS/CTS. The legacy omap-serial driver works fine with DMA.

adam