[1/7] usb: mtu3: give back request when rx error happens

When the Rx enconnter errors, currently, only print error logs, that
may cause class driver's RX halt, shall give back the request with
error status meanwhile.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
---
 drivers/usb/mtu3/mtu3_qmu.c | 39 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

On Mon, 2023-04-03 at 14:34 +0200, AngeloGioacchino Del Regno wrote:
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> 
> 
> Il 03/04/23 04:52, Chunfeng Yun ha scritto:
> > Add optional clock 'xhci_ck' which is usually the same as sys_ck,
> > but
> > some SoC use two separated clocks when the controller supports dual
> > role mode;
> > Add optional clock 'frmcnt_ck' used on 4nm or advanced process SoC.
> 
> This needs more details, because from what it seems, `xhci_ck` could
> be
> a children of `sys_ck`,
No, it's not child of 'sys_ck', they are all the 125Mhz clocks.

> in which case there would be no need to add that
> to this driver, as it'd be handled by the clock API instead.
> 
> What SoC is this for?
encounter the issue on mt8195

> 
> Regards,
> Angelo
>

On Mon, 2023-04-03 at 14:31 +0200, AngeloGioacchino Del Regno wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> Il 03/04/23 04:52, Chunfeng Yun ha scritto:
> > When the Rx enconnter errors, currently, only print error logs,
> > that
> > may cause class driver's RX halt, shall give back the request with
> > error status meanwhile.
> > 
> > Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
> 
>  From what I understand, this is not a new feature, but a fix for a
> unwanted QMU
> halt.
> This means that this commit needs a Fixes tag.
I did not take into account this cases when write this driver, it
caused the issue by the bug of host driver.

> 
> > ---
> >   drivers/usb/mtu3/mtu3_qmu.c | 39
> > ++++++++++++++++++++++++++++++++++++-
> >   1 file changed, 38 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/usb/mtu3/mtu3_qmu.c
> > b/drivers/usb/mtu3/mtu3_qmu.c
> > index a2fdab8b63b2..7be4e4be1a6a 100644
> > --- a/drivers/usb/mtu3/mtu3_qmu.c
> > +++ b/drivers/usb/mtu3/mtu3_qmu.c
> > @@ -466,6 +466,39 @@ static void qmu_tx_zlp_error_handler(struct
> > mtu3 *mtu, u8 epnum)
> >       mtu3_qmu_resume(mep);
> >   }
> > 
> > +/*
> > + * when rx error happens (except zlperr), QMU will stop, and RQCPR
> > saves
> > + * the GPD encountered error, Done irq will arise after resuming
> > QMU again.
> > + */
> > +static void qmu_error_rx(struct mtu3 *mtu, u8 epnum)
> > +{
> > +     struct mtu3_ep *mep = mtu->out_eps + epnum;
> > +     struct mtu3_gpd_ring *ring = &mep->gpd_ring;
> > +     struct qmu_gpd *gpd_current = NULL;
> > +     struct usb_request *req = NULL;
> > +     struct mtu3_request *mreq;
> > +     dma_addr_t cur_gpd_dma;
> > +
> > +     cur_gpd_dma = read_rxq_cur_addr(mtu->mac_base, epnum);
> > +     gpd_current = gpd_dma_to_virt(ring, cur_gpd_dma);
> > +
> > +     mreq = next_request(mep);
> > +     if (!mreq || mreq->gpd != gpd_current) {
> > +             dev_err(mtu->dev, "no correct RX req is found\n");
> > +             return;
> > +     }
> > +
> > +     req = &mreq->request;
> > +     req->status = -EAGAIN;
> 
> You don't need a *req pointer for just one simple assignment.
> 
>         mreq->request.status = -EAGAIN;
> 
> that'll do.
That's good, I'll modify it, thanks
> 
> > +
> > +     /* by pass the current GDP */
> > +     gpd_current->dw0_info |= cpu_to_le32(GPD_FLAGS_BPS |
> > GPD_FLAGS_HWO);
> > +     mtu3_qmu_resume(mep);
> > +
> > +     dev_dbg(mtu->dev, "%s EP%d, current=%p, req=%p\n",
> > +             __func__, epnum, gpd_current, mreq);
> > +}
> > +
> >   /*
> >    * NOTE: request list maybe is already empty as following case:
> >    * queue_tx --> qmu_interrupt(clear interrupt pending, schedule
> > tasklet)-->
> > @@ -571,14 +604,18 @@ static void qmu_exception_isr(struct mtu3
> > *mtu, u32 qmu_status)
> > 
> >       if ((qmu_status & RXQ_CSERR_INT) || (qmu_status &
> > RXQ_LENERR_INT)) {
> >               errval = mtu3_readl(mbase, U3D_RQERRIR0);
> > +             mtu3_writel(mbase, U3D_RQERRIR0, errval);
> 
> Please mention in the commit description the reason why you're moving
> this register
> write here.
It clears irq status before handling the error;

> 
> Regards,
> Angelo