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Message-ID: <CAMz4ku+vs-cGTur--6+vhc50zewDZbsP1YMSgcD6vOLn+d0x-w@mail.gmail.com>
Date:   Tue, 1 Nov 2016 19:46:43 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     Felipe Balbi <balbi@...nel.org>
Cc:     Greg KH <gregkh@...uxfoundation.org>,
        Mark Brown <broonie@...nel.org>,
        USB <linux-usb@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] usb: dwc3: gadget: wait for End Transfer to complete

Hi,

On 1 November 2016 at 19:36, Felipe Balbi <balbi@...nel.org> wrote:
>
> Hi,
>
> Baolin Wang <baolin.wang@...aro.org> writes:
>> Hi,
>>
>> On 1 November 2016 at 19:01, Felipe Balbi <balbi@...nel.org> wrote:
>>>
>>> Hi,
>>>
>>> Baolin Wang <baolin.wang@...aro.org> writes:
>>>> Changes since v1:
>>>>  - Move the suspend checking to right place to avoid checking twice.
>>>
>>> there is still one problem
>>>
>>>> @@ -1736,12 +1739,38 @@ static int dwc3_gadget_stop(struct usb_gadget *g)
>>>>  {
>>>>       struct dwc3             *dwc = gadget_to_dwc(g);
>>>>       unsigned long           flags;
>>>> +     int                     epnum;
>>>>
>>>>       spin_lock_irqsave(&dwc->lock, flags);
>>>>       __dwc3_gadget_stop(dwc);
>>>
>>> this tries to access registers. If __dwc3_gadget_stop() runs while
>>> clocks are gated, we will get Data Abort exception.
>>
>> We have suspend checking in __dwc3_gadget_stop(), thus it will not
>> access registers if clocks are disabled.
>>
>>>
>>> How about this version, instead?
>>
>> I think it is OK except we missed set 'dwc->gadget_driver = NULL'.
>
> argh. Man, next time we meet in a conference, I owe you a beer :-)

Okay:) Now it looks good to me. Thanks.

>
> 8<------------------------------------------------------------------------------
> From 06a204f1c2276ca1ffe68d8d59ef2e2ead337bba Mon Sep 17 00:00:00 2001
> From: Baolin Wang <baolin.wang@...aro.org>
> Date: Mon, 31 Oct 2016 19:38:36 +0800
> Subject: [PATCH] usb: dwc3: gadget: wait for End Transfer to complete
>
> Instead of just delaying for 100us, we should
> actually wait for End Transfer Command Complete
> interrupt before moving on. Note that this should
> only be done if we're dealing with one of the core
> revisions that actually require the interrupt before
> moving on.
>
> [ felipe.balbi@...ux.intel.com: minor improvements ]
>
> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
> Signed-off-by: Felipe Balbi <felipe.balbi@...ux.intel.com>
> ---
>  drivers/usb/dwc3/core.h   |  8 ++++++++
>  drivers/usb/dwc3/gadget.c | 49 +++++++++++++++++++++++++++++++++++++++--------
>  2 files changed, 49 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 5fc437021ac7..c2b86856e85d 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -26,6 +26,7 @@
>  #include <linux/dma-mapping.h>
>  #include <linux/mm.h>
>  #include <linux/debugfs.h>
> +#include <linux/wait.h>
>
>  #include <linux/usb/ch9.h>
>  #include <linux/usb/gadget.h>
> @@ -505,6 +506,7 @@ struct dwc3_event_buffer {
>   * @endpoint: usb endpoint
>   * @pending_list: list of pending requests for this endpoint
>   * @started_list: list of started requests on this endpoint
> + * @wait_end_transfer: wait_queue_head_t for waiting on End Transfer complete
>   * @lock: spinlock for endpoint request queue traversal
>   * @regs: pointer to first endpoint register
>   * @trb_pool: array of transaction buffers
> @@ -530,6 +532,8 @@ struct dwc3_ep {
>         struct list_head        pending_list;
>         struct list_head        started_list;
>
> +       wait_queue_head_t       wait_end_transfer;
> +
>         spinlock_t              lock;
>         void __iomem            *regs;
>
> @@ -546,6 +550,7 @@ struct dwc3_ep {
>  #define DWC3_EP_BUSY           (1 << 4)
>  #define DWC3_EP_PENDING_REQUEST        (1 << 5)
>  #define DWC3_EP_MISSED_ISOC    (1 << 6)
> +#define DWC3_EP_END_TRANSFER_PENDING   (1 << 7)
>
>         /* This last one is specific to EP0 */
>  #define DWC3_EP0_DIR_IN                (1 << 31)
> @@ -1050,6 +1055,9 @@ struct dwc3_event_depevt {
>  #define DEPEVT_TRANSFER_BUS_EXPIRY     2
>
>         u32     parameters:16;
> +
> +/* For Command Complete Events */
> +#define DEPEVT_PARAMETER_CMD(n)        (((n) & (0xf << 8)) >> 8)
>  } __packed;
>
>  /**
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 4743e53cc295..64d01ff8c119 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -593,11 +593,14 @@ static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep,
>                 dep->comp_desc = comp_desc;
>                 dep->type = usb_endpoint_type(desc);
>                 dep->flags |= DWC3_EP_ENABLED;
> +               dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
>
>                 reg = dwc3_readl(dwc->regs, DWC3_DALEPENA);
>                 reg |= DWC3_DALEPENA_EP(dep->number);
>                 dwc3_writel(dwc->regs, DWC3_DALEPENA, reg);
>
> +               init_waitqueue_head(&dep->wait_end_transfer);
> +
>                 if (usb_endpoint_xfer_control(desc))
>                         return 0;
>
> @@ -699,7 +702,7 @@ static int __dwc3_gadget_ep_disable(struct dwc3_ep *dep)
>         dep->endpoint.desc = NULL;
>         dep->comp_desc = NULL;
>         dep->type = 0;
> -       dep->flags = 0;
> +       dep->flags &= DWC3_EP_END_TRANSFER_PENDING;
>
>         return 0;
>  }
> @@ -1783,9 +1786,6 @@ static int dwc3_gadget_start(struct usb_gadget *g,
>
>  static void __dwc3_gadget_stop(struct dwc3 *dwc)
>  {
> -       if (pm_runtime_suspended(dwc->dev))
> -               return;
> -
>         dwc3_gadget_disable_irq(dwc);
>         __dwc3_gadget_ep_disable(dwc->eps[0]);
>         __dwc3_gadget_ep_disable(dwc->eps[1]);
> @@ -1795,9 +1795,30 @@ static int dwc3_gadget_stop(struct usb_gadget *g)
>  {
>         struct dwc3             *dwc = gadget_to_dwc(g);
>         unsigned long           flags;
> +       int                     epnum;
>
>         spin_lock_irqsave(&dwc->lock, flags);
> +
> +       if (pm_runtime_suspended(dwc->dev))
> +               goto out;
> +
>         __dwc3_gadget_stop(dwc);
> +
> +       for (epnum = 2; epnum < DWC3_ENDPOINTS_NUM; epnum++) {
> +               struct dwc3_ep  *dep = dwc->eps[epnum];
> +
> +               if (!dep)
> +                       continue;
> +
> +               if (!(dep->flags & DWC3_EP_END_TRANSFER_PENDING))
> +                       continue;
> +
> +               wait_event_lock_irq(dep->wait_end_transfer,
> +                                   !(dep->flags & DWC3_EP_END_TRANSFER_PENDING),
> +                                   dwc->lock);
> +       }
> +
> +out:
>         dwc->gadget_driver      = NULL;
>         spin_unlock_irqrestore(&dwc->lock, flags);
>
> @@ -2171,10 +2192,12 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
>  {
>         struct dwc3_ep          *dep;
>         u8                      epnum = event->endpoint_number;
> +       u8                      cmd;
>
>         dep = dwc->eps[epnum];
>
> -       if (!(dep->flags & DWC3_EP_ENABLED))
> +       if (!(dep->flags & DWC3_EP_ENABLED) &&
> +           !(dep->flags & DWC3_EP_END_TRANSFER_PENDING))
>                 return;
>
>         if (epnum == 0 || epnum == 1) {
> @@ -2215,8 +2238,15 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
>                         return;
>                 }
>                 break;
> -       case DWC3_DEPEVT_RXTXFIFOEVT:
>         case DWC3_DEPEVT_EPCMDCMPLT:
> +               cmd = DEPEVT_PARAMETER_CMD(event->parameters);
> +
> +               if (cmd == DWC3_DEPCMD_ENDTRANSFER) {
> +                       dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
> +                       wake_up(&dep->wait_end_transfer);
> +               }
> +               break;
> +       case DWC3_DEPEVT_RXTXFIFOEVT:
>                 break;
>         }
>  }
> @@ -2269,7 +2299,8 @@ static void dwc3_stop_active_transfer(struct dwc3 *dwc, u32 epnum, bool force)
>
>         dep = dwc->eps[epnum];
>
> -       if (!dep->resource_index)
> +       if ((dep->flags & DWC3_EP_END_TRANSFER_PENDING) ||
> +           !dep->resource_index)
>                 return;
>
>         /*
> @@ -2313,8 +2344,10 @@ static void dwc3_stop_active_transfer(struct dwc3 *dwc, u32 epnum, bool force)
>         dep->resource_index = 0;
>         dep->flags &= ~DWC3_EP_BUSY;
>
> -       if (dwc3_is_usb31(dwc) || dwc->revision < DWC3_REVISION_310A)
> +       if (dwc3_is_usb31(dwc) || dwc->revision < DWC3_REVISION_310A) {
> +               dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
>                 udelay(100);
> +       }
>  }
>
>  static void dwc3_clear_stall_all_ep(struct dwc3 *dwc)
> --
> 2.10.1
>
>
>
> --
> balbi



-- 
Baolin.wang
Best Regards

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