[RESEND,v3,2/2] usb: dwc3: Wait for control tranfer completed when stopping gadget

Message ID 0e1e7e00e3e2aacf0fe0ee91854e6a0ee81cc320.1475570367.git.baolin.wang@linaro.org
State New
Headers show

Commit Message

Baolin Wang Oct. 4, 2016, 8:42 a.m.
When we change the USB function with configfs dynamically, we possibly met this
situation: one core is doing the control transfer, another core is trying to
unregister the USB gadget from userspace, we must wait for completing this
control tranfer, or it will hang the controller to set the DEVCTRLHLT flag.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

---
 drivers/usb/dwc3/core.h   |    2 ++
 drivers/usb/dwc3/ep0.c    |    2 ++
 drivers/usb/dwc3/gadget.c |   23 +++++++++++++++++++++++
 3 files changed, 27 insertions(+)

-- 
1.7.9.5

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Comments

Baolin Wang Oct. 13, 2016, 7:51 a.m. | #1
Hi,

On 13 October 2016 at 15:08, Felipe Balbi <balbi@kernel.org> wrote:
>

> Hi,

>

> Baolin Wang <baolin.wang@linaro.org> writes:

>> @@ -1487,10 +1496,22 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)

>>

>>       is_on = !!is_on;

>>

>> +try_again:

>>       spin_lock_irqsave(&dwc->lock, flags);

>>       ret = dwc3_gadget_run_stop(dwc, is_on, false);

>>       spin_unlock_irqrestore(&dwc->lock, flags);

>>

>> +     if (ret == -EBUSY) {

>> +             ret = wait_for_completion_timeout(&dwc->ep0_in_setup,

>> +                                               msecs_to_jiffies(500));

>> +             if (ret == 0) {

>> +                     dev_err(dwc->dev, "timeout to stop gadget.\n");

>> +                     ret = -ETIMEDOUT;

>> +             } else {

>> +                     goto try_again;

>

> you are not really reading my comments. It's the third time I tell you

> there's no need for try_again. If you can't complete a control transfer

> in 500ms, you already have other issues. Take this thing out of here.


I think you misunderstood the code. If there is 500ms timeout, we will
return '-ETIMEDOUT' error. If the control transfer is completed before
timeout, we can not just return and we need try again to stop the
gadget, right? Any other good suggestion? Thanks.


-- 
Baolin.wang
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Baolin Wang Oct. 13, 2016, 8:01 a.m. | #2
On 13 October 2016 at 15:54, Felipe Balbi <balbi@kernel.org> wrote:
>

> Hi,

>

> Baolin Wang <baolin.wang@linaro.org> writes:

>> Hi,

>>

>> On 13 October 2016 at 15:08, Felipe Balbi <balbi@kernel.org> wrote:

>>>

>>> Hi,

>>>

>>> Baolin Wang <baolin.wang@linaro.org> writes:

>>>> @@ -1487,10 +1496,22 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)

>>>>

>>>>       is_on = !!is_on;

>>>>

>>>> +try_again:

>>>>       spin_lock_irqsave(&dwc->lock, flags);

>>>>       ret = dwc3_gadget_run_stop(dwc, is_on, false);

>>>>       spin_unlock_irqrestore(&dwc->lock, flags);

>>>>

>>>> +     if (ret == -EBUSY) {

>>>> +             ret = wait_for_completion_timeout(&dwc->ep0_in_setup,

>>>> +                                               msecs_to_jiffies(500));

>>>> +             if (ret == 0) {

>>>> +                     dev_err(dwc->dev, "timeout to stop gadget.\n");

>>>> +                     ret = -ETIMEDOUT;

>>>> +             } else {

>>>> +                     goto try_again;

>>>

>>> you are not really reading my comments. It's the third time I tell you

>>> there's no need for try_again. If you can't complete a control transfer

>>> in 500ms, you already have other issues. Take this thing out of here.

>>

>> I think you misunderstood the code. If there is 500ms timeout, we will

>> return '-ETIMEDOUT' error. If the control transfer is completed before

>> timeout, we can not just return and we need try again to stop the

>> gadget, right? Any other good suggestion? Thanks.

>

> Yeah, change the patch a bit so you wait for completion before calling

> dwc3_gadget_runt_stop()? I mean, move the !is_on && ep0_state check

> before calling dwc3_gadget_run_stop() and wait_for_completion_timeout()

> there.


OK. I will refactor the patch. Thanks.

>

> --

> balbi




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Patch hide | download patch | download mbox

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index b2317e7..9128725 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -745,6 +745,7 @@  struct dwc3_scratchpad_array {
  * @ep0_usb_req: dummy req used while handling STD USB requests
  * @ep0_bounce_addr: dma address of ep0_bounce
  * @scratch_addr: dma address of scratchbuf
+ * @ep0_in_setup: One control transfer is completed and enter setup phase
  * @lock: for synchronizing
  * @dev: pointer to our struct device
  * @xhci: pointer to our xHCI child
@@ -843,6 +844,7 @@  struct dwc3 {
 	dma_addr_t		ep0_bounce_addr;
 	dma_addr_t		scratch_addr;
 	struct dwc3_request	ep0_usb_req;
+	struct completion	ep0_in_setup;
 
 	/* device lock */
 	spinlock_t		lock;
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index fe79d77..06c167a 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -311,6 +311,8 @@  void dwc3_ep0_out_start(struct dwc3 *dwc)
 	ret = dwc3_ep0_start_trans(dwc, 0, dwc->ctrl_req_addr, 8,
 			DWC3_TRBCTL_CONTROL_SETUP, false);
 	WARN_ON(ret < 0);
+
+	complete(&dwc->ep0_in_setup);
 }
 
 static struct dwc3_ep *dwc3_wIndex_to_dep(struct dwc3 *dwc, __le16 wIndex_le)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index ca2ae5b..fef023a 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1437,6 +1437,15 @@  static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
 	if (pm_runtime_suspended(dwc->dev))
 		return 0;
 
+	/*
+	 * Per databook, when we want to stop the gadget, if a control transfer
+	 * is still in process, complete it and get the core into setup phase.
+	 */
+	if (!is_on && dwc->ep0state != EP0_SETUP_PHASE) {
+		reinit_completion(&dwc->ep0_in_setup);
+		return -EBUSY;
+	}
+
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 	if (is_on) {
 		if (dwc->revision <= DWC3_REVISION_187A) {
@@ -1487,10 +1496,22 @@  static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
 
 	is_on = !!is_on;
 
+try_again:
 	spin_lock_irqsave(&dwc->lock, flags);
 	ret = dwc3_gadget_run_stop(dwc, is_on, false);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	if (ret == -EBUSY) {
+		ret = wait_for_completion_timeout(&dwc->ep0_in_setup,
+						  msecs_to_jiffies(500));
+		if (ret == 0) {
+			dev_err(dwc->dev, "timeout to stop gadget.\n");
+			ret = -ETIMEDOUT;
+		} else {
+			goto try_again;
+		}
+	}
+
 	return ret;
 }
 
@@ -2914,6 +2935,8 @@  int dwc3_gadget_init(struct dwc3 *dwc)
 		goto err4;
 	}
 
+	init_completion(&dwc->ep0_in_setup);
+
 	dwc->gadget.ops			= &dwc3_gadget_ops;
 	dwc->gadget.speed		= USB_SPEED_UNKNOWN;
 	dwc->gadget.sg_supported	= true;