linux-kernel - Re: [PATCH] usb: chipidea: udc: clear vbus_active flag in udc

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Date:	Tue, 20 Oct 2015 14:28:12 +0800
From:	Peter Chen <peter.chen@...escale.com>
To:	Jiada Wang <jiada_wang@...tor.com>
CC:	<gregkh@...uxfoundation.org>, <linux-usb@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] usb: chipidea: udc: clear vbus_active flag in udc_stop

On Tue, Oct 20, 2015 at 03:09:02PM +0900, Jiada Wang wrote:
> Hi
> 
> On 10/20/2015 03:01 PM, Peter Chen wrote:
> >On Tue, Oct 20, 2015 at 11:29:18AM +0900, Jiada Wang wrote:
> >>Currently in udc_stop, if vbus_active flag is true, all USB activities
> >>will be stopped, but vbus_active flag is still left to be true,
> >>this causes issue, when afterwards driver tries to connect gadget
> >>device to host, But due to the uncleared vbus_active, some necessary
> >>setup steps are skipped.
> >>
> >>This patch clears vbus_active flag in udc_stop callback.
> >>
> >>Signed-off-by: Jiada Wang <jiada_wang@...tor.com>
> >>---
> >>  drivers/usb/chipidea/udc.c | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >>diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> >>index 8223fe7..b9ac228 100644
> >>--- a/drivers/usb/chipidea/udc.c
> >>+++ b/drivers/usb/chipidea/udc.c
> >>@@ -1762,6 +1762,7 @@ static int ci_udc_stop(struct usb_gadget *gadget)
> >>  	spin_lock_irqsave(&ci->lock, flags);
> >>
> >>  	if (ci->vbus_active) {
> >>+		ci->vbus_active = 0;
> >>  		hw_device_state(ci, 0);
> >>  		if (ci->platdata->notify_event)
> >>  			ci->platdata->notify_event(ci,
> >>--
> >>2.4.5
> >>
> >
> >This flag will be handled by vbus interrupt, would you please explain
> >more what problem you have met?
> the actual issue I had is,
> build kernel with USB_OTG_FSM enabled,
> keep usb cable plugged,
> load/unload USB gadget module (for example I tried g_zero or g_serial),
> after unload gadget module once, then the status of vbus_active is not
> correct,
> this causes host machine failed to detect gadget device when later
> gadget device module is loaded again.
> 
> 

ci->vbus_active is only used at non-fsm mode, would you please try below
fix?

usb: chipidea: otg: gadget module load and unload support

This patch is to support load and unload gadget driver in full OTG mode.

Acked-by: Peter Chen <peter.chen@...escale.com>
Signed-off-by: Li Jun <jun.li@...escale.com>
---
 drivers/usb/chipidea/udc.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index e19d8b8..67cfa04 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -1755,6 +1755,22 @@ static int ci_udc_start(struct usb_gadget *gadget,
 	return retval;
 }
 
+static void ci_udc_stop_for_otg_fsm(struct ci_hdrc *ci)
+{
+	if (!ci_otg_is_fsm_mode(ci))
+		return;
+
+	mutex_lock(&ci->fsm.lock);
+	if (ci->fsm.otg->state == OTG_STATE_A_PERIPHERAL) {
+		ci->fsm.a_bidl_adis_tmout = 1;
+		ci_hdrc_otg_fsm_start(ci);
+	} else if (ci->fsm.otg->state == OTG_STATE_B_PERIPHERAL) {
+		ci->fsm.protocol = PROTO_UNDEF;
+		ci->fsm.otg->state = OTG_STATE_UNDEFINED;
+	}
+	mutex_unlock(&ci->fsm.lock);
+}
+
 /**
  * ci_udc_stop: unregister a gadget driver
  */
@@ -1779,6 +1795,7 @@ static int ci_udc_stop(struct usb_gadget *gadget)
 	ci->driver = NULL;
 	spin_unlock_irqrestore(&ci->lock, flags);
 
+	ci_udc_stop_for_otg_fsm(ci);
 	return 0;
 }
 
-- 
1.9.1

-- 

Best Regards,
Peter Chen
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