Hi,
On Thu, 2015-10-01 at 12:44 +0100, Daniel Thompson wrote:
> On 29/09/15 04:01, Chunfeng Yun wrote:
> > There some vendor quirks for MTK xhci host controller:
> > 1. It defines some extra SW scheduling parameters for HW
> > to minimize the scheduling effort for synchronous and
> > interrupt endpoints. The parameters are put into reseved
> > DWs of slot context and endpoint context.
> > 2. Its IMODI unit for Interrupter Moderation register is
> > 8 times as much as that defined in xHCI spec.
> > 3. Its TDS in Normal TRB defines a number of packets that
> > remains to be transferred for a TD after processing all
> > Max packets in all previous TRBs.
> >
> > Signed-off-by: Chunfeng Yun <chunfeng....@mediatek.com>
>
> I've done some basic soak tests, both with a directly attached USB3 HDD
> and, given the extra code to manage isochronous xfer, also with a hub,
> disc and two audio interfaces.
>
> Tested-by: Daniel Thompson <daniel.thomp...@linaro.org>
>
>
> > diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> > index 57f40a1..243f696 100644
> > --- a/drivers/usb/host/xhci-ring.c
> > +++ b/drivers/usb/host/xhci-ring.c
> > @@ -68,6 +68,7 @@
> > #include <linux/slab.h>
> > #include "xhci.h"
> > #include "xhci-trace.h"
> > +#include "xhci-mtk.h"
> >
> > /*
> > * Returns zero if the TRB isn't in this segment, otherwise it returns
> > the DMA
> > @@ -3044,18 +3045,27 @@ static u32 xhci_td_remainder(struct xhci_hcd *xhci,
> > int transferred,
> > struct urb *urb, unsigned int num_trbs_left)
> > {
> > u32 maxp, total_packet_count;
> > + u32 skip_current_trb = 0;
>
> A bit of a nitpick but why do we need skip_current_trb? Testing
> (xhci->quirks & XHCI_MTK_HOST) twice would make what the code does, and
> why, more obvious.
>
I am not sure which way it is better, so add variable of
skip_current_trb to reduce test times.
> Anyhow with that looked at, and the caveat that I'm not much of USB
> expert, you're welcome to add my Reviewed-by: to v10.
>
Thanks a lot
> >
> > - if (xhci->hci_version < 0x100)
> > - return ((td_total_len - transferred) >> 10);
> > -
> > - maxp = GET_MAX_PACKET(usb_endpoint_maxp(&urb->ep->desc));
> > - total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
> > + if (xhci->hci_version < 0x100) {
> > + /* for MTK xHCI, TD size doesn't include this TRB */
> > + if (xhci->quirks & XHCI_MTK_HOST)
> > + skip_current_trb = 1;
> > + else
> > + return ((td_total_len - transferred) >> 10);
> > + }
> >
> > /* One TRB with a zero-length data packet. */
> > if (num_trbs_left == 0 || (transferred == 0 && trb_buff_len == 0) ||
> > trb_buff_len == td_total_len)
> > return 0;
> >
> > + if (skip_current_trb)
> > + trb_buff_len = 0;
> > +
> > + maxp = GET_MAX_PACKET(usb_endpoint_maxp(&urb->ep->desc));
> > + total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
> > +
> > /* Queueing functions don't count the current TRB into transferred */
> > return (total_packet_count - ((transferred + trb_buff_len) / maxp));
> > }
>
>
> Daniel.
>
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