Rework "xhci: clear root port wake on bits if controller isn't wake-up capable"

xhci: clear root port wake on bits if controller isn't wake-up capable

When system is being suspended, if host device is not wakeup capable, xhci_suspend() needs to clear all root port wake on bits. Otherwise, some platforms may generate spurious wakeup, even if PCI PME# is dis- abled.

Signed-off-by Lu Baolu <[email protected]>

---
 drivers/usb/host/xhci.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

drivers/usb/host/xhci.c +38 -0

index 2a5d45b..cd57aae 100644
@@ -35,6 +35,8 @@
 #define DRIVER_AUTHOR "Sarah Sharp"
 #define DRIVER_DESC "'eXtensible' Host Controller (xHC) Driver"
 
+#define	PORT_WAKE_BITS	(PORT_WKOC_E | PORT_WKDISC_E | PORT_WKCONN_E)
+
 /* Some 0.95 hardware can't handle the chain bit on a Link TRB being cleared */
 static int link_quirk;
 module_param(link_quirk, int, S_IRUGO | S_IWUSR);

@@ -851,6 +853,42 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci)
 	xhci_set_cmd_ring_deq(xhci);
 }
 
+static void xhci_disable_port_wake_on_bits(struct xhci_hcd *xhci)
+{
+	int port_index;
+	__le32 __iomem **port_array;
+	unsigned long flags;
+	u32 t1, t2;
+
+	spin_lock_irqsave(&xhci->lock, flags);
+
+	/* disble usb3 ports Wake bits*/
+	port_index = xhci->num_usb3_ports;
+	port_array = xhci->usb3_ports;
+	while (port_index--) {
+		t1 = readl(port_array[port_index]);
+		t2 = xhci_port_state_to_neutral(t1);
+		t2 &= ~PORT_WAKE_BITS;
+		t1 = xhci_port_state_to_neutral(t1);
+		if (t1 != t2)
+			writel(t2, port_array[port_index]);
+	}
+
+	/* disble usb2 ports Wake bits*/
+	port_index = xhci->num_usb2_ports;
+	port_array = xhci->usb2_ports;
+	while (port_index--) {
+		t1 = readl(port_array[port_index]);
+		t2 = xhci_port_state_to_neutral(t1);
+		t2 &= ~PORT_WAKE_BITS;
+		t1 = xhci_port_state_to_neutral(t1);
+		if (t1 != t2)
+			writel(t2, port_array[port_index]);
+	}
+
+	spin_unlock_irqrestore(&xhci->lock, flags);
+}
+
 /*
  * Stop HC (not bus-specific)
  *

Quoted 72 lines · Lu Baolu

xhci: clear root port wake on bits if controller isn't wake-up capable

When system is being suspended, if host device is not wakeup capable, xhci_suspend() needs to clear all root port wake on bits. Otherwise, some platforms may generate spurious wakeup, even if PCI PME# is dis- abled.

Signed-off-by Lu Baolu <[email protected]>

---
  drivers/usb/host/xhci.c | 42 ++++++++++++++++++++++++++++++++++++++++++
  1 file changed, 42 insertions(+)

drivers/usb/host/xhci.c +38 -0

index 2a5d45b..cd57aae 100644
@@ -35,6 +35,8 @@
  #define DRIVER_AUTHOR "Sarah Sharp"
  #define DRIVER_DESC "'eXtensible' Host Controller (xHC) Driver"
 
+#define	PORT_WAKE_BITS	(PORT_WKOC_E | PORT_WKDISC_E | PORT_WKCONN_E)
+
  /* Some 0.95 hardware can't handle the chain bit on a Link TRB being cleared */
  static int link_quirk;
  module_param(link_quirk, int, S_IRUGO | S_IWUSR);

@@ -851,6 +853,42 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci)
  	xhci_set_cmd_ring_deq(xhci);
  }
 
+static void xhci_disable_port_wake_on_bits(struct xhci_hcd *xhci)
+{
+	int port_index;
+	__le32 __iomem **port_array;
+	unsigned long flags;
+	u32 t1, t2;
+
+	spin_lock_irqsave(&xhci->lock, flags);
+
+	/* disble usb3 ports Wake bits*/
+	port_index = xhci->num_usb3_ports;
+	port_array = xhci->usb3_ports;
+	while (port_index--) {
+		t1 = readl(port_array[port_index]);
+		t2 = xhci_port_state_to_neutral(t1);
+		t2 &= ~PORT_WAKE_BITS;
+		t1 = xhci_port_state_to_neutral(t1);
+		if (t1 != t2)
+			writel(t2, port_array[port_index]);
+	}
+
+	/* disble usb2 ports Wake bits*/
+	port_index = xhci->num_usb2_ports;
+	port_array = xhci->usb2_ports;
+	while (port_index--) {
+		t1 = readl(port_array[port_index]);
+		t2 = xhci_port_state_to_neutral(t1);
+		t2 &= ~PORT_WAKE_BITS;
+		t1 = xhci_port_state_to_neutral(t1);
+		if (t1 != t2)
+			writel(t2, port_array[port_index]);
+	}
+
+	spin_unlock_irqrestore(&xhci->lock, flags);
+}
+
  /*
   * Stop HC (not bus-specific)
   *

@@ -868,6 +906,10 @@ int xhci_suspend(struct xhci_hcd *xhci)
  			xhci->shared_hcd->state != HC_STATE_SUSPENDED)
  		return -EINVAL;
 

drivers/usb/host/xhci.c int xhci_suspend(struct xhci_hcd *xhci) · line 915

Quoted 7 lines

drivers/usb/host/xhci.c +4 -0

+	/* Clear root port wake on bits if not wakeup capable. */
+	if (!device_may_wakeup(hcd->self.controller))
+		xhci_disable_port_wake_on_bits(xhci);
+
  	/* Don't poll the roothubs on bus suspend. */
  	xhci_dbg(xhci, "%s: stopping port polling.\n", __func__);
  	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);

This is better but still wrong. Remember, this same code gets called for system suspend _and_ for runtime suspend. During runtime suspend, wakeup is always supposed to be turned on, even if device_may_wakeup() is false. That's because device_may_wakeup() refers only to system suspend. What you need to test is the do_wakeup flag, which should be passed into xhci_suspend() by xhci_pci_suspend() and xhci_plat_suspend().

Another problem is in the patch description and the comments. If device_may_wakeup() returns false, it doesn't mean the controller isn't wakeup-capable -- it means the controller isn't _allowed_ to wake up the system. Those are two different things.

Finally, the code in xhci_disable_port_wake_on_bits() looks a little peculiar -- I'm not sure about all those calls to xhci_port_state_to_neutral(). But I'm not an expert on that; Mathias will have to advise on it.

Alan Stern