usb: musb: Fix host mode error -71 regression

Commit 467d5c98 ("usb: musb: Implement session bit based runtime PM for
musb-core") started implementing musb generic runtime PM support by
introducing devctl register session bit based state control.

This caused a regression where if a USB mass storage device is connected
to a USB hub, we can get:

usb 1-1: reset high-speed USB device number 2 using musb-hdrc
usb 1-1: device descriptor read/64, error -71
usb 1-1.1: new high-speed USB device number 4 using musb-hdrc

This is because before the USB storage device is connected, musb is
in OTG_STATE_A_SUSPEND. And we currently only set need_finish_resume
in musb_stage0_irq() and the related code calling finish_resume_work
in musb_resume() and musb_runtime_resume() never gets called.

To fix the issue, we can call schedule_delayed_work() directly in
musb_stage0_irq() to have finish_resume_work run.

And we should no longer never get interrupts when when suspended.
We have changed musb to no longer need pm_runtime_irqsafe().
The need_finish_resume flag was added in commit 9298b4aa ("usb:
musb: fix device hotplug behind hub") and no longer applies as far
as I can tell. So let's just remove the earlier code that no longer
is needed.

Fixes: 467d5c98 ("usb: musb: Implement session bit based runtime PM for musb-core")
Reported-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/musb_core.c

@@ -594,11 +594,11 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 						| MUSB_PORT_STAT_RESUME;
 				musb->rh_timer = jiffies
 					+ msecs_to_jiffies(USB_RESUME_TIMEOUT);
-				musb->need_finish_resume = 1;
-
 				musb->xceiv->otg->state = OTG_STATE_A_HOST;
 				musb->is_active = 1;
 				musb_host_resume_root_hub(musb);
+				schedule_delayed_work(&musb->finish_resume_work,
+					msecs_to_jiffies(USB_RESUME_TIMEOUT));
 				break;
 			case OTG_STATE_B_WAIT_ACON:
 				musb->xceiv->otg->state = OTG_STATE_B_PERIPHERAL;
@@ -2710,11 +2710,6 @@ static int musb_resume(struct device *dev)
 	mask = MUSB_DEVCTL_BDEVICE | MUSB_DEVCTL_FSDEV | MUSB_DEVCTL_LSDEV;
 	if ((devctl & mask) != (musb->context.devctl & mask))
 		musb->port1_status = 0;
-	if (musb->need_finish_resume) {
-		musb->need_finish_resume = 0;
-		schedule_delayed_work(&musb->finish_resume_work,
-				      msecs_to_jiffies(USB_RESUME_TIMEOUT));
-	}
 
 	/*
 	 * The USB HUB code expects the device to be in RPM_ACTIVE once it came
@@ -2766,12 +2761,6 @@ static int musb_runtime_resume(struct device *dev)
 
 	musb_restore_context(musb);
 
-	if (musb->need_finish_resume) {
-		musb->need_finish_resume = 0;
-		schedule_delayed_work(&musb->finish_resume_work,
-				msecs_to_jiffies(USB_RESUME_TIMEOUT));
-	}
-
 	spin_lock_irqsave(&musb->lock, flags);
 	error = musb_run_resume_work(musb);
 	if (error)

drivers/usb/musb/musb_core.h

@@ -410,7 +410,6 @@ struct musb {
 
 	/* is_suspended means USB B_PERIPHERAL suspend */
 	unsigned		is_suspended:1;
-	unsigned		need_finish_resume :1;
 
 	/* may_wakeup means remote wakeup is enabled */
 	unsigned		may_wakeup:1;