usb: dwc_otg_310: fix bad unlock balance issue

There is a bad unlock balance issue in the following case:
1. Use micro USB 2.0 interface;
2. Vbus 5v is always powered on;
3. Wait until DWC2 completes initialization, and then plug
   in OTG to Host cable;
4. Plug out the OTG cable, and then we will reproduce this
   issue, and we'll get the following log if we enable the
   kernel lock debugging.

=====================================
[ BUG: bad unlock balance detected! ]
4.4.71 torvalds#303 Not tainted
-------------------------------------
swapper/0/0 is trying to release lock (&(sl)->rlock) at:
[<c0795848>] dwc_otg_pcd_suspend_cb+0x20/0x48
but there are no more locks to release!

other info that might help us debug this:
1 lock held by swapper/0/0:

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.71 torvalds#303
Hardware name: Rockchip (Device Tree)
[<c0110018>] (unwind_backtrace) from [<c010c04c>] (show_stack+0x10/0x14)
[<c010c04c>] (show_stack) from [<c0423e28>] (dump_stack+0x9c/0xd4)
[<c0423e28>] (dump_stack) from [<c021803c>] (print_unlock_imbalance_bug.part.7+0x8c/0xb8)
[<c021803c>] (print_unlock_imbalance_bug.part.7) from [<c018ce74>] (lock_release+0x284/0x54c)
[<c018ce74>] (lock_release) from [<c0c0e03c>] (_raw_spin_unlock+0x18/0x54)
[<c0c0e03c>] (_raw_spin_unlock) from [<c0795848>] (dwc_otg_pcd_suspend_cb+0x20/0x48)
[<c0795848>] (dwc_otg_pcd_suspend_cb) from [<c0792cc4>] (dwc_otg_handle_usb_suspend_intr+0x68/0x37c)
[<c0792cc4>] (dwc_otg_handle_usb_suspend_intr) from [<c079329c>] (dwc_otg_handle_common_intr+0x2c4/0xd58)
[<c079329c>] (dwc_otg_handle_common_intr) from [<c0786a18>] (dwc_otg_common_irq+0xc/0x18)
[<c0786a18>] (dwc_otg_common_irq) from [<c0199e48>] (handle_irq_event_percpu+0x188/0x4d4)
[<c0199e48>] (handle_irq_event_percpu) from [<c019a1cc>] (handle_irq_event+0x38/0x5c)
[<c019a1cc>] (handle_irq_event) from [<c019d654>] (handle_fasteoi_irq+0xa8/0x124)
[<c019d654>] (handle_fasteoi_irq) from [<c0199454>] (generic_handle_irq+0x18/0x28)
[<c0199454>] (generic_handle_irq) from [<c0199754>] (__handle_domain_irq+0x88/0xb0)
[<c0199754>] (__handle_domain_irq) from [<c01014b4>] (gic_handle_irq+0x4c/0x94)
[<c01014b4>] (gic_handle_irq) from [<c010cbb8>] (__irq_svc+0x58/0x98)

It's because that when plug in OTG to host cable, the
core_if->lock will be initialized to hcd->lock (check_id()->
id_status_change()->cil_hcd_start()->dwc_otg_hcd_reinit()),
so we should release core_if->lock before call cil_pcd_suspend()
rather than release the pcd->lock inside of callback function.

Change-Id: I1e32f37c701d1a8d741947b6bf385c1bbcb6da78
Signed-off-by: William Wu <[email protected]>

drivers/usb/dwc_otg_310/dwc_otg_cil_intr.c

@@ -1202,8 +1202,11 @@ int32_t dwc_otg_handle_usb_suspend_intr(dwc_otg_core_if_t *core_if)
 			DWC_DEBUGPL(DBG_ANY, "disconnect?\n");
 		}
 #endif
-		/* PCD callback for suspend. Release the lock inside of callback function */
+		/* PCD callback for suspend */
+		DWC_SPINUNLOCK(core_if->lock);
 		cil_pcd_suspend(core_if);
+		DWC_SPINLOCK(core_if->lock);
+
 		if (core_if->power_down == 2) {
 			dcfg.d32 =
 			    DWC_READ_REG32(&core_if->dev_if->dev_global_regs->

drivers/usb/dwc_otg_310/dwc_otg_pcd.c

@@ -198,11 +198,8 @@ static int32_t dwc_otg_pcd_suspend_cb(void *p)
 {
 	dwc_otg_pcd_t *pcd = (dwc_otg_pcd_t *) p;
 
-	if (pcd->fops->suspend) {
-		DWC_SPINUNLOCK(pcd->lock);
+	if (pcd->fops->suspend)
 		pcd->fops->suspend(pcd);
-		DWC_SPINLOCK(pcd->lock);
-	}
 
 	return 1;
 }