On Mon, 19 Dec 2011, Felipe Balbi wrote:
> > > + if (dma_mapping_error(&gadget->dev, req->dma)) {
> > > + dev_err(&gadget->dev, "failed to map buffer\n");
> > > + return -EFAULT;
> > > + }
> > > + }
> > > +
> > > + return 0;
> >
> > You forgot to set req->mapped.
>
> actually there's no 'mapped' field on struct usb_request. That's a
Whoops, you're right. It's part of the UDC-private structure.
> nonsense added to all struct my_controller_request just because of that
> DMA_ADDR_INVALID hackery. I'm dropping that completely. There were no
> gadget drivers allocating memory from coherent or mapping requests
> themselves, so req->mapped becomes useless.
There's more to it than that. A controller might support DMA on some
endpoints but not others, or for certain request lengths but not
others. Hence when a request finishes, the driver needs to know
whether the request was mapped for DMA.
For example, your net2280 patch needs to be fixed. Here's how it looks
now:
> --- a/drivers/usb/gadget/net2280.c
> +++ b/drivers/usb/gadget/net2280.c
> @@ -806,12 +806,8 @@ done (struct net2280_ep *ep, struct net2280_request
> *req, int status)
> status = req->req.status;
>
> dev = ep->dev;
> - if (req->mapped) {
> - pci_unmap_single (dev->pdev, req->req.dma, req->req.length,
> - ep->is_in ? PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);
> - req->req.dma = DMA_ADDR_INVALID;
> - req->mapped = 0;
> - }
> + if (req->mapped)
> + usb_gadget_unmap_request(&dev->gadget, &req->req, ep->is_in);
This code will never be executed because you never set req->mapped.
And after that's fixed, when the unmapping occurs, req->mapped has to
be set back to 0.
> @@ -857,10 +853,13 @@ net2280_queue (struct usb_ep *_ep, struct usb_request
> *_req, gfp_t gfp_flags)
> return -EOPNOTSUPP;
>
> /* set up dma mapping in case the caller didn't */
> - if (ep->dma && _req->dma == DMA_ADDR_INVALID) {
> - _req->dma = pci_map_single (dev->pdev, _req->buf, _req->length,
> - ep->is_in ? PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);
> - req->mapped = 1;
> + if (ep->dma) {
> + int ret;
> +
> + ret = usb_gadget_map_request(&dev->gadget, &req->req,
> + ep->is_in);
> + if (ret)
> + return ret;
You probably need to set req->mapped right here. Or rather, avoid
removing the line that sets it.
> }
Alan Stern
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