Re: [PATCH v3 fwctl 4/5] fwctl/bnxt_fwctl: Add bnxt fwctl device

From: Jason Gunthorpe

Date: Thu Feb 05 2026 - 12:33:51 EST


On Thu, Feb 05, 2026 at 09:55:08AM +0530, Pavan Chebbi wrote:
> >
> > I find it a bit weird that the user needs to provide dma information and
> > structure ! this is supposed to be completely hidden by the driver to
> > simplify user space, the driver handles dma and access to HW, user space
> > just provides the commands and payloads and driver carries the input/output
> > for that user space.
>
> This is so because our FW commands require optional DMA-able buffers.
> The application is only giving us the information that the driver
> should encapsulate in additional DMA-able buffers.
> There is a defined format for exchange of this information, because
> every command has a different number of additional buffers. Also the
> majority of the commands don't need any additional buffers.
> I hope this answers your next comments also.

Now I have questions, who allocates these buffers, how do they get DMA
mapped, who does all the copying??

Jason