Hi,
John Youn <John.Youn@xxxxxxxxxxxx> writes:
> On 12/3/2015 7:18 AM, Felipe Balbi wrote:
>> So far, dwc3 has always missed request->zero
>> handling for every endpoint. Let's implement
>> that so we can handle cases where transfer must
>> be finished with a ZLP.
>>
>> Note that dwc3 is a little special. Even though
>> we're dealing with a ZLP, we still need a buffer
>> of wMaxPacketSize bytes; to hide that detail from
>> every gadget driver, we have a preallocated buffer
>> of 1024 bytes (biggest bulk size) to use (and
>> share) among all endpoints.
>>
>> Reported-by: Ravi B <ravibabu@xxxxxx>
>> Signed-off-by: Felipe Balbi <balbi@xxxxxx>
>> ---
>>
>> since v1:
>> - remove unnecessary 'free_on_complete' flag
>>
>> since v2:
>> - remove unnecessary 'out' label
>>
>> drivers/usb/dwc3/core.h | 3 +++
>> drivers/usb/dwc3/gadget.c | 50 +++++++++++++++++++++++++++++++++++++++++++++--
>> 2 files changed, 51 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
>> index 36f1cb74588c..29130682e547 100644
>> --- a/drivers/usb/dwc3/core.h
>> +++ b/drivers/usb/dwc3/core.h
>> @@ -37,6 +37,7 @@
>> #define DWC3_MSG_MAX 500
>>
>> /* Global constants */
>> +#define DWC3_ZLP_BUF_SIZE 1024 /* size of a superspeed bulk */
>> #define DWC3_EP0_BOUNCE_SIZE 512
>> #define DWC3_ENDPOINTS_NUM 32
>> #define DWC3_XHCI_RESOURCES_NUM 2
>> @@ -647,6 +648,7 @@ struct dwc3_scratchpad_array {
>> * @ctrl_req: usb control request which is used for ep0
>> * @ep0_trb: trb which is used for the ctrl_req
>> * @ep0_bounce: bounce buffer for ep0
>> + * @zlp_buf: used when request->zero is set
>> * @setup_buf: used while precessing STD USB requests
>> * @ctrl_req_addr: dma address of ctrl_req
>> * @ep0_trb: dma address of ep0_trb
>> @@ -734,6 +736,7 @@ struct dwc3 {
>> struct usb_ctrlrequest *ctrl_req;
>> struct dwc3_trb *ep0_trb;
>> void *ep0_bounce;
>> + void *zlp_buf;
>> void *scratchbuf;
>> u8 *setup_buf;
>> dma_addr_t ctrl_req_addr;
>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
>> index e341f034296f..e916c11ded59 100644
>> --- a/drivers/usb/dwc3/gadget.c
>> +++ b/drivers/usb/dwc3/gadget.c
>> @@ -1158,6 +1158,32 @@ out:
>> return ret;
>> }
>>
>> +static void __dwc3_gadget_ep_zlp_complete(struct usb_ep *ep,
>> + struct usb_request *request)
>> +{
>> + dwc3_gadget_ep_free_request(ep, request);
>> +}
>> +
>> +static int __dwc3_gadget_ep_queue_zlp(struct dwc3 *dwc, struct dwc3_ep *dep)
>> +{
>> + struct dwc3_request *req;
>> + struct usb_request *request;
>> + struct usb_ep *ep = &dep->endpoint;
>> +
>> + dwc3_trace(trace_dwc3_gadget, "queueing ZLP\n");
>> + request = dwc3_gadget_ep_alloc_request(ep, GFP_ATOMIC);
>> + if (!request)
>> + return -ENOMEM;
>> +
>> + request->length = 0;
>> + request->buf = dwc->zlp_buf;
>> + request->complete = __dwc3_gadget_ep_zlp_complete;
>> +
>> + req = to_dwc3_request(request);
>> +
>> + return __dwc3_gadget_ep_queue(dep, req);
>> +}
>> +
>> static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request,
>> gfp_t gfp_flags)
>> {
>> @@ -1171,6 +1197,16 @@ static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request,
>>
>> spin_lock_irqsave(&dwc->lock, flags);
>> ret = __dwc3_gadget_ep_queue(dep, req);
>> +
>> + /*
>> + * Okay, here's the thing, if gadget driver has requested for a ZLP by
>> + * setting request->zero, instead of doing magic, we will just queue an
>> + * extra usb_request ourselves so that it gets handled the same way as
>> + * any other request.
>> + */
>> + if (ret == 0 && request->zero && (request->length % ep->maxpacket == 0))
>> + ret = __dwc3_gadget_ep_queue_zlp(dwc, dep);
>
> Hi Felipe,
>
> This causes regression with at least mass storage + Windows host.
>
> When the gadget queues a ZLP, we end up sending two ZLPs which leads
> to violating the MSC protocol.
heh, no idea why mass storage would set Zero flag in this case :-p
> The following fixes it:
>
> - if (ret == 0 && request->zero && (request->length % ep->maxpacket == 0))
> + if (ret == 0 && request->zero && (request->length % ep->maxpacket == 0) &&
> + (request->length != 0))
Can you send this as a proper patch ? And also patch g_mass_storage to
_not_ set Zero flag in this case ?
thanks
--
balbi
Attachment:
signature.asc
Description: PGP signature
