fsl/usb: Workarourd for USB erratum-A005697

The EHCI specification states the following in the SUSP bit description:
In the Suspend state, the port is sensitive to resume detection.
Note that the bit status does not change until the port is suspended and
that there may be a delay in suspending a port if there is a transaction
currently in progress on the USB.

However, in NXP USBDR controller, the PORTSCx[SUSP] bit changes immediately
when the application sets it and not when the port is actually suspended.

So the application must wait for at least 10 milliseconds after a port
indicates that it is suspended, to make sure this port has entered
suspended state before initiating this port resume using the Force Port
Resume bit. This bit is for NXP controller, not EHCI compatible.

Signed-off-by: Changming Huang <jerry.huang@nxp.com>
Signed-off-by: Ramneek Mehresh <ramneek.mehresh@nxp.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 74f62d68f013..df169c8e7225 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -310,6 +310,14 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
 	}
 	spin_unlock_irq(&ehci->lock);
 
+	if (changed && ehci_has_fsl_susp_errata(ehci))
+		/*
+		 * Wait for at least 10 millisecondes to ensure the controller
+		 * enter the suspend status before initiating a port resume
+		 * using the Force Port Resume bit (Not-EHCI compatible).
+		 */
+		usleep_range(10000, 20000);
+
 	if ((changed && ehci->has_tdi_phy_lpm) || fs_idle_delay) {
 		/*
 		 * Wait for HCD to enter low-power mode or for the bus
@@ -1200,6 +1208,12 @@ int ehci_hub_control(
 					wIndex, (temp1 & HOSTPC_PHCD) ?
 					"succeeded" : "failed");
 			}
+			if (ehci_has_fsl_susp_errata(ehci)) {
+				/* 10ms for HCD enter suspend */
+				spin_unlock_irqrestore(&ehci->lock, flags);
+				usleep_range(10000, 20000);
+				spin_lock_irqsave(&ehci->lock, flags);
+			}
 			set_bit(wIndex, &ehci->suspended_ports);
 			break;
 		case USB_PORT_FEAT_POWER: