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usb: dwc3: simplify ZLP handling
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It's much simpler to just add one extra TRB chained to previous TRB to
handle ZLP. This helps us reduce pointless allocations and simplifies
the code a little bit.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
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Felipe Balbi committed Apr 11, 2017
1 parent 4199c5f commit d6e5a54
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Showing 3 changed files with 59 additions and 83 deletions.
4 changes: 1 addition & 3 deletions drivers/usb/dwc3/core.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,6 @@

/* Global constants */
#define DWC3_PULL_UP_TIMEOUT 500 /* ms */
#define DWC3_ZLP_BUF_SIZE 1024 /* size of a superspeed bulk */
#define DWC3_BOUNCE_SIZE 1024 /* size of a superspeed bulk */
#define DWC3_EP0_SETUP_SIZE 512
#define DWC3_ENDPOINTS_NUM 32
Expand Down Expand Up @@ -748,6 +747,7 @@ struct dwc3_request {
unsigned direction:1;
unsigned mapped:1;
unsigned started:1;
unsigned zero:1;
};

/*
Expand All @@ -761,7 +761,6 @@ struct dwc3_scratchpad_array {
/**
* struct dwc3 - representation of our controller
* @ep0_trb: trb which is used for the ctrl_req
* @zlp_buf: used when request->zero is set
* @setup_buf: used while precessing STD USB requests
* @ep0_trb: dma address of ep0_trb
* @ep0_usb_req: dummy req used while handling STD USB requests
Expand Down Expand Up @@ -857,7 +856,6 @@ struct dwc3_scratchpad_array {
struct dwc3 {
struct dwc3_trb *ep0_trb;
void *bounce;
void *zlp_buf;
void *scratchbuf;
u8 *setup_buf;
dma_addr_t ep0_trb_addr;
Expand Down
49 changes: 29 additions & 20 deletions drivers/usb/dwc3/ep0.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -873,34 +873,19 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
transferred = ur->length - length;
ur->actual += transferred;

if (dwc->ep0_bounced) {
if ((IS_ALIGNED(ur->length, ep0->endpoint.maxpacket) &&
ur->length && ur->zero) || dwc->ep0_bounced) {
trb++;
trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
trace_dwc3_complete_trb(ep0, trb);
ep0->trb_enqueue = 0;
dwc->ep0_bounced = false;
}

if ((epnum & 1) && ur->actual < ur->length) {
/* for some reason we did not get everything out */

if ((epnum & 1) && ur->actual < ur->length)
dwc3_ep0_stall_and_restart(dwc);
} else {
else
dwc3_gadget_giveback(ep0, r, 0);

if (IS_ALIGNED(ur->length, ep0->endpoint.maxpacket) &&
ur->length && ur->zero) {
struct dwc3_ep *dep;
int ret;

dwc->ep0_next_event = DWC3_EP0_COMPLETE;

dep = dwc->eps[epnum];
dwc3_ep0_prepare_one_trb(dep, dwc->ep0_trb_addr,
0, DWC3_TRBCTL_CONTROL_DATA, false);
ret = dwc3_ep0_start_trans(dep);
WARN_ON(ret < 0);
}
}
}

static void dwc3_ep0_complete_status(struct dwc3 *dwc,
Expand Down Expand Up @@ -1005,6 +990,30 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
DWC3_TRBCTL_CONTROL_DATA,
false);
ret = dwc3_ep0_start_trans(dep);
} else if (IS_ALIGNED(req->request.length, dep->endpoint.maxpacket) &&
req->request.length && req->request.zero) {
u32 maxpacket;
u32 rem;

ret = usb_gadget_map_request_by_dev(dwc->sysdev,
&req->request, dep->number);
if (ret)
return;

maxpacket = dep->endpoint.maxpacket;
rem = req->request.length % maxpacket;

/* prepare normal TRB */
dwc3_ep0_prepare_one_trb(dep, req->request.dma,
req->request.length,
DWC3_TRBCTL_CONTROL_DATA,
true);

/* Now prepare one extra TRB to align transfer size */
dwc3_ep0_prepare_one_trb(dep, dwc->bounce_addr,
0, DWC3_TRBCTL_CONTROL_DATA,
false);
ret = dwc3_ep0_start_trans(dep);
} else {
ret = usb_gadget_map_request_by_dev(dwc->sysdev,
&req->request, dep->number);
Expand Down
89 changes: 29 additions & 60 deletions drivers/usb/dwc3/gadget.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1044,6 +1044,22 @@ static void dwc3_prepare_one_trb_linear(struct dwc3_ep *dep,
false, 0, req->request.stream_id,
req->request.short_not_ok,
req->request.no_interrupt);
} else if (req->request.zero && req->request.length &&
(IS_ALIGNED(req->request.length,dep->endpoint.maxpacket))) {
struct dwc3 *dwc = dep->dwc;
struct dwc3_trb *trb;

req->zero = true;

/* prepare normal TRB */
dwc3_prepare_one_trb(dep, req, true, 0);

/* Now prepare one extra TRB to handle ZLP */
trb = &dep->trb_pool[dep->trb_enqueue];
__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, 0,
false, 0, req->request.stream_id,
req->request.short_not_ok,
req->request.no_interrupt);
} else {
dwc3_prepare_one_trb(dep, req, false, 0);
}
Expand Down Expand Up @@ -1259,31 +1275,6 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
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;

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)
{
Expand All @@ -1297,17 +1288,6 @@ 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 &&
(request->length % ep->maxpacket == 0))
ret = __dwc3_gadget_ep_queue_zlp(dwc, dep);

spin_unlock_irqrestore(&dwc->lock, flags);

return ret;
Expand Down Expand Up @@ -1387,7 +1367,7 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
dwc3_ep_inc_deq(dep);
}

if (r->unaligned) {
if (r->unaligned || r->zero) {
trb = r->trb + r->num_pending_sgs + 1;
trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
dwc3_ep_inc_deq(dep);
Expand All @@ -1398,7 +1378,7 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
dwc3_ep_inc_deq(dep);

if (r->unaligned) {
if (r->unaligned || r->zero) {
trb = r->trb + 1;
trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
dwc3_ep_inc_deq(dep);
Expand Down Expand Up @@ -2164,7 +2144,7 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
* with one TRB pending in the ring. We need to manually clear HWO bit
* from that TRB.
*/
if (req->unaligned && (trb->ctrl & DWC3_TRB_CTRL_HWO)) {
if ((req->zero || req->unaligned) && (trb->ctrl & DWC3_TRB_CTRL_HWO)) {
trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
return 1;
}
Expand Down Expand Up @@ -2258,11 +2238,12 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
event, status, chain);
}

if (req->unaligned) {
if (req->unaligned || req->zero) {
trb = &dep->trb_pool[dep->trb_dequeue];
ret = __dwc3_cleanup_done_trbs(dwc, dep, req, trb,
event, status, false);
req->unaligned = false;
req->zero = false;
}

req->request.actual = length - req->remaining;
Expand Down Expand Up @@ -3143,17 +3124,11 @@ int dwc3_gadget_init(struct dwc3 *dwc)
goto err1;
}

dwc->zlp_buf = kzalloc(DWC3_ZLP_BUF_SIZE, GFP_KERNEL);
if (!dwc->zlp_buf) {
ret = -ENOMEM;
goto err2;
}

dwc->bounce = dma_alloc_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE,
&dwc->bounce_addr, GFP_KERNEL);
if (!dwc->bounce) {
ret = -ENOMEM;
goto err3;
goto err2;
}

init_completion(&dwc->ep0_in_setup);
Expand Down Expand Up @@ -3193,24 +3168,22 @@ int dwc3_gadget_init(struct dwc3 *dwc)

ret = dwc3_gadget_init_endpoints(dwc, dwc->num_eps);
if (ret)
goto err4;
goto err3;

ret = usb_add_gadget_udc(dwc->dev, &dwc->gadget);
if (ret) {
dev_err(dwc->dev, "failed to register udc\n");
goto err5;
goto err4;
}

return 0;
err5:
dwc3_gadget_free_endpoints(dwc);

err4:
dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
dwc->bounce_addr);
dwc3_gadget_free_endpoints(dwc);

err3:
kfree(dwc->zlp_buf);
dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
dwc->bounce_addr);

err2:
kfree(dwc->setup_buf);
Expand All @@ -3228,16 +3201,12 @@ int dwc3_gadget_init(struct dwc3 *dwc)
void dwc3_gadget_exit(struct dwc3 *dwc)
{
usb_del_gadget_udc(&dwc->gadget);

dwc3_gadget_free_endpoints(dwc);

dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
dwc->bounce_addr);
dwc->bounce_addr);
kfree(dwc->setup_buf);
kfree(dwc->zlp_buf);

dma_free_coherent(dwc->sysdev, sizeof(*dwc->ep0_trb) * 2,
dwc->ep0_trb, dwc->ep0_trb_addr);
dwc->ep0_trb, dwc->ep0_trb_addr);
}

int dwc3_gadget_suspend(struct dwc3 *dwc)
Expand Down

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