On Mon, Mar 18, 2013 at 03:28:26PM +0100, Michael Grzeschik wrote:
> On Fri, Mar 08, 2013 at 05:54:37PM +0200, Alexander Shishkin wrote:
> > Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> writes:
> >
> > > A static count of transfer descriptors was used everywhere in the driver
> > > with the fixed number 4. This patch adds a define, named TD_COUNT, and
> > > replaces all users of this value. This way its possible to have only one
> > > parameter to change and limit the amount of tds per transfer.
> >
> > I think Svetoslav made exactly the same patch in his patchset, but I
> > think this patchset will go first.
>
> I did not find any patch comparable by Svetoslav. But, that patch
> is superseeded by that hunk in my current branch anyway, as every TD can
> maintain five DMA buffers:
>
> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> index 09bc6ea..c961e3b 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -688,8 +688,8 @@ static int _ep_queue(struct usb_ep *ep, struct usb_request *req)
> goto done;
> }
>
> - if (req->length > 4 * CI13XXX_PAGE_SIZE) {
> - req->length = 4 * CI13XXX_PAGE_SIZE;
> + if (req->length > 5 * CI13XXX_PAGE_SIZE) {
> + req->length = 5 * CI13XXX_PAGE_SIZE;
> retval = -EMSGSIZE;
> dev_warn(mEp->ci->dev, "request length truncated\n");
> }
No, 4 is ok. There are 5 buffer Pointers are dTD, but the Buffer Point 0
may not 4K aligned. Eg, if the reg->length is 18KB, and the buf DMA address
is 1K aligned, it needs two dTDs.
The first dTD only uses: 1KB, 4KB, 4KB, 4KB, 4KB as 5 buffers space.
>
> I will resend that series with some additional fixes.
>
> Regards,
> Michael
>
> --
> Pengutronix e.K. | |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
> Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
>
--
Best Regards,
Peter Chen
--
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
