Hi, On Fri, Nov 17, 2017 at 05:51:31PM +0530, dev jad wrote: > Thanks Balbi adding 'Bin Liu' MUSB maintainer. > > Hi Liu, > Can you help me enabling PIO ONLY mode in USB HCD ? > the ASIC I am using doesn't support dma. so to enable USB WiFi dongle I > need to disable DMA usage of USB subsystem in kernel. which is causing > kernel panic(usb_hcd_map_urb_for_dma). > which is caused by > > usb_hcd_map_urb_for_dma -> dma_map_single > -> BUG_ON(!virt_addr_valid(cpu_addr)); > > > 1. so how to make his driver PIO Only like we have in MUSB ? This is a usb core driver question, I don't have the answer on top of my head. But I am currently tied to a high priority work and don't have time to review the core driver to give you an answer, sorry. > > 2. Is there any other way to enable PIO only mode in USB HCD other than > adding it in MUSB sub sytem glue driver ? Not sure if I understand your question. You cannot make the USB HCD driver (assuming you meant the core driver) as an MUSB glue, which is for MUSB controllers. HCD core is an abstract layer. > > 3. Is it possible to enable PIO only mode from MUSB for non ti /mentor > graphics SoC ? Only if the SoC uses MUSB controller, and it has a glue driver in MUSB subsystem. Regards, -Bin. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
