USB: fix up suspend and resume for PCI host controllers

This patch (as1192) rearranges the USB PCI host controller suspend and
resume and resume routines:

	Use pci_wake_from_d3() for enabling and disabling wakeup,
	instead of pci_enable_wake().

	Carry out the actual state change while interrupts are
	disabled.

	Change the order of the preparations to agree with the
	general recommendation for PCI devices, instead of
	messing around with the wakeup settings while the device
	is in D3.

		In .suspend:
			Call the underlying driver to disable IRQ
				generation;
			pci_wake_from_d3(device_may_wakeup());
			pci_disable_device();

		In .suspend_late:
			pci_save_state();
			pci_set_power_state(D3hot);
			(for PPC_PMAC) Disable ASIC clocks

		In .resume_early:
			(for PPC_PMAC) Enable ASIC clocks
			pci_set_power_state(D0);
			pci_restore_state();

		In .resume:
			pci_enable_device();
			pci_set_master();
			pci_wake_from_d3(0);
			Call the underlying driver to reenable IRQ
				generation

	Add the necessary .suspend_late and .resume_early method
	pointers to the PCI host controller drivers.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 106 insertions, 94 deletions

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index 5b87ae7f0a6a..99432785f438 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -191,17 +191,15 @@ EXPORT_SYMBOL_GPL(usb_hcd_pci_remove);
 /**
  * usb_hcd_pci_suspend - power management suspend of a PCI-based HCD
  * @dev: USB Host Controller being suspended
- * @message: semantics in flux
+ * @message: Power Management message describing this state transition
  *
- * Store this function in the HCD's struct pci_driver as suspend().
+ * Store this function in the HCD's struct pci_driver as .suspend.
  */
 int usb_hcd_pci_suspend(struct pci_dev *dev, pm_message_t message)
 {
-	struct usb_hcd		*hcd;
+	struct usb_hcd		*hcd = pci_get_drvdata(dev);
 	int			retval = 0;
-	int			has_pci_pm;
-
-	hcd = pci_get_drvdata(dev);
+	int			wake, w;
 
 	/* Root hub suspend should have stopped all downstream traffic,
 	 * and all bus master traffic.  And done so for both the interface
@@ -212,8 +210,15 @@ int usb_hcd_pci_suspend(struct pci_dev *dev, pm_message_t message)
 	 * otherwise the swsusp will save (and restore) garbage state.
 	 */
 	if (!(hcd->state == HC_STATE_SUSPENDED ||
-			hcd->state == HC_STATE_HALT))
-		return -EBUSY;
+			hcd->state == HC_STATE_HALT)) {
+		dev_warn(&dev->dev, "Root hub is not suspended\n");
+		retval = -EBUSY;
+		goto done;
+	}
+
+	/* We might already be suspended (runtime PM -- not yet written) */
+	if (dev->current_state != PCI_D0)
+		goto done;
 
 	if (hcd->driver->pci_suspend) {
 		retval = hcd->driver->pci_suspend(hcd, message);
@@ -221,49 +226,60 @@ int usb_hcd_pci_suspend(struct pci_dev *dev, pm_message_t message)
 		if (retval)
 			goto done;
 	}
-	synchronize_irq(dev->irq);
 
-	/* FIXME until the generic PM interfaces change a lot more, this
-	 * can't use PCI D1 and D2 states.  For example, the confusion
-	 * between messages and states will need to vanish, and messages
-	 * will need to provide a target system state again.
-	 *
-	 * It'll be important to learn characteristics of the target state,
-	 * especially on embedded hardware where the HCD will often be in
-	 * charge of an external VBUS power supply and one or more clocks.
-	 * Some target system states will leave them active; others won't.
-	 * (With PCI, that's often handled by platform BIOS code.)
-	 */
+	synchronize_irq(dev->irq);
 
-	/* even when the PCI layer rejects some of the PCI calls
-	 * below, HCs can try global suspend and reduce DMA traffic.
-	 * PM-sensitive HCDs may already have done this.
+	/* Don't fail on error to enable wakeup.  We rely on pci code
+	 * to reject requests the hardware can't implement, rather
+	 * than coding the same thing.
 	 */
-	has_pci_pm = pci_find_capability(dev, PCI_CAP_ID_PM);
+	wake = (hcd->state == HC_STATE_SUSPENDED &&
+			device_may_wakeup(&dev->dev));
+	w = pci_wake_from_d3(dev, wake);
+	if (w < 0)
+		wake = w;
+	dev_dbg(&dev->dev, "wakeup: %d\n", wake);
 
 	/* Downstream ports from this root hub should already be quiesced, so
 	 * there will be no DMA activity.  Now we can shut down the upstream
 	 * link (except maybe for PME# resume signaling) and enter some PCI
 	 * low power state, if the hardware allows.
 	 */
-	if (hcd->state == HC_STATE_SUSPENDED) {
+	pci_disable_device(dev);
+ done:
+	return retval;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_pci_suspend);
 
-		/* no DMA or IRQs except when HC is active */
-		if (dev->current_state == PCI_D0) {
-			pci_save_state(dev);
-			pci_disable_device(dev);
-		}
+/**
+ * usb_hcd_pci_suspend_late - suspend a PCI-based HCD after IRQs are disabled
+ * @dev: USB Host Controller being suspended
+ * @message: Power Management message describing this state transition
+ *
+ * Store this function in the HCD's struct pci_driver as .suspend_late.
+ */
+int usb_hcd_pci_suspend_late(struct pci_dev *dev, pm_message_t message)
+{
+	int			retval = 0;
+	int			has_pci_pm;
 
-		if (message.event == PM_EVENT_FREEZE ||
-				message.event == PM_EVENT_PRETHAW) {
-			dev_dbg(hcd->self.controller, "--> no state change\n");
-			goto done;
-		}
+	/* We might already be suspended (runtime PM -- not yet written) */
+	if (dev->current_state != PCI_D0)
+		goto done;
 
-		if (!has_pci_pm) {
-			dev_dbg(hcd->self.controller, "--> PCI D0/legacy\n");
-			goto done;
-		}
+	pci_save_state(dev);
+
+	/* Don't change state if we don't need to */
+	if (message.event == PM_EVENT_FREEZE ||
+			message.event == PM_EVENT_PRETHAW) {
+		dev_dbg(&dev->dev, "--> no state change\n");
+		goto done;
+	}
+
+	has_pci_pm = pci_find_capability(dev, PCI_CAP_ID_PM);
+	if (!has_pci_pm) {
+		dev_dbg(&dev->dev, "--> PCI D0 legacy\n");
+	} else {
 
 		/* NOTE:  dev->current_state becomes nonzero only here, and
 		 * only for devices that support PCI PM.  Also, exiting
@@ -273,35 +289,16 @@ int usb_hcd_pci_suspend(struct pci_dev *dev, pm_message_t message)
 		retval = pci_set_power_state(dev, PCI_D3hot);
 		suspend_report_result(pci_set_power_state, retval);
 		if (retval == 0) {
-			int wake = device_can_wakeup(&hcd->self.root_hub->dev);
-
-			wake = wake && device_may_wakeup(hcd->self.controller);
-
-			dev_dbg(hcd->self.controller, "--> PCI D3%s\n",
-					wake ? "/wakeup" : "");
-
-			/* Ignore these return values.  We rely on pci code to
-			 * reject requests the hardware can't implement, rather
-			 * than coding the same thing.
-			 */
-			(void) pci_enable_wake(dev, PCI_D3hot, wake);
-			(void) pci_enable_wake(dev, PCI_D3cold, wake);
+			dev_dbg(&dev->dev, "--> PCI D3\n");
 		} else {
 			dev_dbg(&dev->dev, "PCI D3 suspend fail, %d\n",
 					retval);
-			(void) usb_hcd_pci_resume(dev);
+			pci_restore_state(dev);
 		}
-
-	} else if (hcd->state != HC_STATE_HALT) {
-		dev_dbg(hcd->self.controller, "hcd state %d; not suspended\n",
-			hcd->state);
-		WARN_ON(1);
-		retval = -EINVAL;
 	}
 
-done:
-	if (retval == 0) {
 #ifdef CONFIG_PPC_PMAC
+	if (retval == 0) {
 		/* Disable ASIC clocks for USB */
 		if (machine_is(powermac)) {
 			struct device_node	*of_node;
@@ -311,30 +308,24 @@ done:
 				pmac_call_feature(PMAC_FTR_USB_ENABLE,
 							of_node, 0, 0);
 		}
-#endif
 	}
+#endif
 
+ done:
 	return retval;
 }
-EXPORT_SYMBOL_GPL(usb_hcd_pci_suspend);
+EXPORT_SYMBOL_GPL(usb_hcd_pci_suspend_late);
 
 /**
- * usb_hcd_pci_resume - power management resume of a PCI-based HCD
+ * usb_hcd_pci_resume_early - resume a PCI-based HCD before IRQs are enabled
  * @dev: USB Host Controller being resumed
  *
- * Store this function in the HCD's struct pci_driver as resume().
+ * Store this function in the HCD's struct pci_driver as .resume_early.
  */
-int usb_hcd_pci_resume(struct pci_dev *dev)
+int usb_hcd_pci_resume_early(struct pci_dev *dev)
 {
-	struct usb_hcd		*hcd;
-	int			retval;
-
-	hcd = pci_get_drvdata(dev);
-	if (hcd->state != HC_STATE_SUSPENDED) {
-		dev_dbg(hcd->self.controller,
-				"can't resume, not suspended!\n");
-		return 0;
-	}
+	int		retval = 0;
+	pci_power_t	state = dev->current_state;
 
 #ifdef CONFIG_PPC_PMAC
 	/* Reenable ASIC clocks for USB */
@@ -352,7 +343,7 @@ int usb_hcd_pci_resume(struct pci_dev *dev)
 	 * calls "standby", "suspend to RAM", and so on).  There are also
 	 * dirty cases when swsusp fakes a suspend in "shutdown" mode.
 	 */
-	if (dev->current_state != PCI_D0) {
+	if (state != PCI_D0) {
 #ifdef	DEBUG
 		int	pci_pm;
 		u16	pmcr;
@@ -364,8 +355,7 @@ int usb_hcd_pci_resume(struct pci_dev *dev)
 			/* Clean case:  power to USB and to HC registers was
 			 * maintained; remote wakeup is easy.
 			 */
-			dev_dbg(hcd->self.controller, "resume from PCI D%d\n",
-					pmcr);
+			dev_dbg(&dev->dev, "resume from PCI D%d\n", pmcr);
 		} else {
 			/* Clean:  HC lost Vcc power, D0 uninitialized
 			 *   + Vaux may have preserved port and transceiver
@@ -376,32 +366,55 @@ int usb_hcd_pci_resume(struct pci_dev *dev)
 			 *   + after BIOS init
 			 *   + after Linux init (HCD statically linked)
 			 */
-			dev_dbg(hcd->self.controller,
-				"PCI D0, from previous PCI D%d\n",
-				dev->current_state);
+			dev_dbg(&dev->dev, "resume from previous PCI D%d\n",
+					state);
 		}
 #endif
-		/* yes, ignore these results too... */
-		(void) pci_enable_wake(dev, dev->current_state, 0);
-		(void) pci_enable_wake(dev, PCI_D3cold, 0);
+
+		retval = pci_set_power_state(dev, PCI_D0);
 	} else {
 		/* Same basic cases: clean (powered/not), dirty */
-		dev_dbg(hcd->self.controller, "PCI legacy resume\n");
+		dev_dbg(&dev->dev, "PCI legacy resume\n");
+	}
+
+	if (retval < 0)
+		dev_err(&dev->dev, "can't resume: %d\n", retval);
+	else
+		pci_restore_state(dev);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_pci_resume_early);
+
+/**
+ * usb_hcd_pci_resume - power management resume of a PCI-based HCD
+ * @dev: USB Host Controller being resumed
+ *
+ * Store this function in the HCD's struct pci_driver as .resume.
+ */
+int usb_hcd_pci_resume(struct pci_dev *dev)
+{
+	struct usb_hcd		*hcd;
+	int			retval;
+
+	hcd = pci_get_drvdata(dev);
+	if (hcd->state != HC_STATE_SUSPENDED) {
+		dev_dbg(hcd->self.controller,
+				"can't resume, not suspended!\n");
+		return 0;
 	}
 
-	/* NOTE:  the PCI API itself is asymmetric here.  We don't need to
-	 * pci_set_power_state(PCI_D0) since that's part of re-enabling;
-	 * but that won't re-enable bus mastering.  Yet pci_disable_device()
-	 * explicitly disables bus mastering...
-	 */
 	retval = pci_enable_device(dev);
 	if (retval < 0) {
-		dev_err(hcd->self.controller,
-			"can't re-enable after resume, %d!\n", retval);
+		dev_err(&dev->dev, "can't re-enable after resume, %d!\n",
+				retval);
 		return retval;
 	}
+
 	pci_set_master(dev);
-	pci_restore_state(dev);
+
+	/* yes, ignore this result too... */
+	(void) pci_wake_from_d3(dev, 0);
 
 	clear_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
 
@@ -413,7 +426,6 @@ int usb_hcd_pci_resume(struct pci_dev *dev)
 			usb_hc_died(hcd);
 		}
 	}
-
 	return retval;
 }
 EXPORT_SYMBOL_GPL(usb_hcd_pci_resume);