USB: don't explicitly reenable root-hub status interrupts

This patch (as1069b) changes the way OHCI root-hub status-change
interrupts are enabled.  Currently a special HCD method,
hub_irq_enable(), is called when the hub driver is finished using a
root hub.  This approach turns out to be subject to races, resulting
in unnecessary polling.

The patch does away with the method entirely.  Instead, the driver
automatically enables the RHSC interrupt when no more status changes
are present.  This scheme is safe with controllers using
level-triggered semantics for their interrupt flags.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

22 files changed, 31 insertions, 70 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index e68fef5361d..bf10e9c4195 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -924,15 +924,6 @@ static int register_root_hub(struct usb_hcd *hcd)
 	return retval;
 }
 
-void usb_enable_root_hub_irq (struct usb_bus *bus)
-{
-	struct usb_hcd *hcd;
-
-	hcd = container_of (bus, struct usb_hcd, self);
-	if (hcd->driver->hub_irq_enable && hcd->state != HC_STATE_HALT)
-		hcd->driver->hub_irq_enable (hcd);
-}
-
 
 /*-------------------------------------------------------------------------*/
 
diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index 3ba258eb05d..1e4b81e9eb5 100644
--- a/drivers/usb/core/hcd.h
+++ b/drivers/usb/core/hcd.h
@@ -210,8 +210,6 @@ struct hc_driver {
 	int	(*bus_suspend)(struct usb_hcd *);
 	int	(*bus_resume)(struct usb_hcd *);
 	int	(*start_port_reset)(struct usb_hcd *, unsigned port_num);
-	void	(*hub_irq_enable)(struct usb_hcd *);
-		/* Needed only if port-change IRQs are level-triggered */
 
 		/* force handover of high-speed port to full-speed companion */
 	void	(*relinquish_port)(struct usb_hcd *, int);
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 1e23e360ea9..5a338a5d4fe 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2001,8 +2001,6 @@ int usb_port_resume(struct usb_device *udev)
 	}
 
 	clear_bit(port1, hub->busy_bits);
-	if (!hub->hdev->parent && !hub->busy_bits[0])
-		usb_enable_root_hub_irq(hub->hdev->bus);
 
 	if (status == 0)
 		status = finish_port_resume(udev);
@@ -2918,11 +2916,6 @@ static void hub_events(void)
 
 		hub->activating = 0;
 
-		/* If this is a root hub, tell the HCD it's okay to
-		 * re-enable port-change interrupts now. */
-		if (!hdev->parent && !hub->busy_bits[0])
-			usb_enable_root_hub_irq(hdev->bus);
-
 loop_autopm:
 		/* Allow autosuspend if we're not going to run again */
 		if (list_empty(&hub->event_list))
@@ -3148,8 +3141,6 @@ int usb_reset_device(struct usb_device *udev)
 			break;
 	}
 	clear_bit(port1, parent_hub->busy_bits);
-	if (!parent_hdev->parent && !parent_hub->busy_bits[0])
-		usb_enable_root_hub_irq(parent_hdev->bus);
 
 	if (ret < 0)
 		goto re_enumerate;
diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
index e534f9de0f0..c96db1153dc 100644
--- a/drivers/usb/host/ohci-at91.c
+++ b/drivers/usb/host/ohci-at91.c
@@ -261,7 +261,6 @@ static const struct hc_driver ohci_at91_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-au1xxx.c b/drivers/usb/host/ohci-au1xxx.c
index f90fe0c7373..1b9abdba920 100644
--- a/drivers/usb/host/ohci-au1xxx.c
+++ b/drivers/usb/host/ohci-au1xxx.c
@@ -288,7 +288,6 @@ static const struct hc_driver ohci_au1xxx_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-ep93xx.c b/drivers/usb/host/ohci-ep93xx.c
index 5adaf36e47d..06aadfb0ec2 100644
--- a/drivers/usb/host/ohci-ep93xx.c
+++ b/drivers/usb/host/ohci-ep93xx.c
@@ -135,7 +135,6 @@ static struct hc_driver ohci_ep93xx_hc_driver = {
 	.get_frame_number	= ohci_get_frame,
 	.hub_status_data	= ohci_hub_status_data,
 	.hub_control		= ohci_hub_control,
-	.hub_irq_enable		= ohci_rhsc_enable,
 #ifdef CONFIG_PM
 	.bus_suspend		= ohci_bus_suspend,
 	.bus_resume		= ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-hub.c b/drivers/usb/host/ohci-hub.c
index 355a82f2527..5be3bb3e6a9 100644
--- a/drivers/usb/host/ohci-hub.c
+++ b/drivers/usb/host/ohci-hub.c
@@ -36,18 +36,6 @@
 
 /*-------------------------------------------------------------------------*/
 
-/* hcd->hub_irq_enable() */
-static void ohci_rhsc_enable (struct usb_hcd *hcd)
-{
-	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
-
-	spin_lock_irq(&ohci->lock);
-	if (!ohci->autostop)
-		del_timer(&hcd->rh_timer);	/* Prevent next poll */
-	ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrenable);
-	spin_unlock_irq(&ohci->lock);
-}
-
 #define OHCI_SCHED_ENABLES \
 	(OHCI_CTRL_CLE|OHCI_CTRL_BLE|OHCI_CTRL_PLE|OHCI_CTRL_IE)
 
@@ -374,18 +362,28 @@ static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
 		int any_connected)
 {
 	int	poll_rh = 1;
+	int	rhsc;
 
+	rhsc = ohci_readl(ohci, &ohci->regs->intrenable) & OHCI_INTR_RHSC;
 	switch (ohci->hc_control & OHCI_CTRL_HCFS) {
 
 	case OHCI_USB_OPER:
-		/* keep on polling until we know a device is connected
-		 * and RHSC is enabled */
+		/* If no status changes are pending, enable status-change
+		 * interrupts.
+		 */
+		if (!rhsc && !changed) {
+			rhsc = OHCI_INTR_RHSC;
+			ohci_writel(ohci, rhsc, &ohci->regs->intrenable);
+		}
+
+		/* Keep on polling until we know a device is connected
+		 * and RHSC is enabled, or until we autostop.
+		 */
 		if (!ohci->autostop) {
 			if (any_connected ||
 					!device_may_wakeup(&ohci_to_hcd(ohci)
 						->self.root_hub->dev)) {
-				if (ohci_readl(ohci, &ohci->regs->intrenable) &
-						OHCI_INTR_RHSC)
+				if (rhsc)
 					poll_rh = 0;
 			} else {
 				ohci->autostop = 1;
@@ -398,12 +396,13 @@ static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
 				ohci->autostop = 0;
 				ohci->next_statechange = jiffies +
 						STATECHANGE_DELAY;
-			} else if (time_after_eq(jiffies,
+			} else if (rhsc && time_after_eq(jiffies,
 						ohci->next_statechange)
 					&& !ohci->ed_rm_list
 					&& !(ohci->hc_control &
 						OHCI_SCHED_ENABLES)) {
 				ohci_rh_suspend(ohci, 1);
+				poll_rh = 0;
 			}
 		}
 		break;
@@ -417,6 +416,12 @@ static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
 			else
 				usb_hcd_resume_root_hub(ohci_to_hcd(ohci));
 		} else {
+			if (!rhsc && (ohci->autostop ||
+					ohci_to_hcd(ohci)->self.root_hub->
+						do_remote_wakeup))
+				ohci_writel(ohci, OHCI_INTR_RHSC,
+						&ohci->regs->intrenable);
+
 			/* everything is idle, no need for polling */
 			poll_rh = 0;
 		}
@@ -438,12 +443,16 @@ static inline int ohci_rh_resume(struct ohci_hcd *ohci)
 static int ohci_root_hub_state_changes(struct ohci_hcd *ohci, int changed,
 		int any_connected)
 {
-	int	poll_rh = 1;
-
-	/* keep on polling until RHSC is enabled */
+	/* If RHSC is enabled, don't poll */
 	if (ohci_readl(ohci, &ohci->regs->intrenable) & OHCI_INTR_RHSC)
-		poll_rh = 0;
-	return poll_rh;
+		return 0;
+
+	/* If no status changes are pending, enable status-change interrupts */
+	if (!changed) {
+		ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrenable);
+		return 0;
+	}
+	return 1;
 }
 
 #endif	/* CONFIG_PM */
diff --git a/drivers/usb/host/ohci-lh7a404.c b/drivers/usb/host/ohci-lh7a404.c
index 13c12ed2225..96d14fa1d83 100644
--- a/drivers/usb/host/ohci-lh7a404.c
+++ b/drivers/usb/host/ohci-lh7a404.c
@@ -193,7 +193,6 @@ static const struct hc_driver ohci_lh7a404_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-omap.c b/drivers/usb/host/ohci-omap.c
index 3a7c24c0367..6859fb5f1d6 100644
--- a/drivers/usb/host/ohci-omap.c
+++ b/drivers/usb/host/ohci-omap.c
@@ -466,7 +466,6 @@ static const struct hc_driver ohci_omap_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-pci.c b/drivers/usb/host/ohci-pci.c
index 4696cc912e1..3bf175d95a2 100644
--- a/drivers/usb/host/ohci-pci.c
+++ b/drivers/usb/host/ohci-pci.c
@@ -327,7 +327,6 @@ static const struct hc_driver ohci_pci_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-pnx4008.c b/drivers/usb/host/ohci-pnx4008.c
index 28b458f20cc..664f07ee873 100644
--- a/drivers/usb/host/ohci-pnx4008.c
+++ b/drivers/usb/host/ohci-pnx4008.c
@@ -280,7 +280,6 @@ static const struct hc_driver ohci_pnx4008_hc_driver = {
 	 */
 	.hub_status_data = ohci_hub_status_data,
 	.hub_control = ohci_hub_control,
-	.hub_irq_enable = ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend = ohci_bus_suspend,
 	.bus_resume = ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-pnx8550.c b/drivers/usb/host/ohci-pnx8550.c
index 605d59cba28..28467e288a9 100644
--- a/drivers/usb/host/ohci-pnx8550.c
+++ b/drivers/usb/host/ohci-pnx8550.c
@@ -201,7 +201,6 @@ static const struct hc_driver ohci_pnx8550_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-ppc-of.c b/drivers/usb/host/ohci-ppc-of.c
index a6725279122..50e55db1363 100644
--- a/drivers/usb/host/ohci-ppc-of.c
+++ b/drivers/usb/host/ohci-ppc-of.c
@@ -72,7 +72,6 @@ static const struct hc_driver ohci_ppc_of_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-ppc-soc.c b/drivers/usb/host/ohci-ppc-soc.c
index 523c3012557..cd3398b675b 100644
--- a/drivers/usb/host/ohci-ppc-soc.c
+++ b/drivers/usb/host/ohci-ppc-soc.c
@@ -172,7 +172,6 @@ static const struct hc_driver ohci_ppc_soc_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-ps3.c b/drivers/usb/host/ohci-ps3.c
index c1935ae537f..bfdeb0d22d0 100644
--- a/drivers/usb/host/ohci-ps3.c
+++ b/drivers/usb/host/ohci-ps3.c
@@ -68,7 +68,6 @@ static const struct hc_driver ps3_ohci_hc_driver = {
 	.get_frame_number	= ohci_get_frame,
 	.hub_status_data	= ohci_hub_status_data,
 	.hub_control		= ohci_hub_control,
-	.hub_irq_enable		= ohci_rhsc_enable,
 	.start_port_reset	= ohci_start_port_reset,
 #if defined(CONFIG_PM)
 	.bus_suspend 		= ohci_bus_suspend,
diff --git a/drivers/usb/host/ohci-pxa27x.c b/drivers/usb/host/ohci-pxa27x.c
index d4ee27d92be..70b0d4b459e 100644
--- a/drivers/usb/host/ohci-pxa27x.c
+++ b/drivers/usb/host/ohci-pxa27x.c
@@ -298,7 +298,6 @@ static const struct hc_driver ohci_pxa27x_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef  CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-s3c2410.c b/drivers/usb/host/ohci-s3c2410.c
index ead4772f0f2..a73d2ff322e 100644
--- a/drivers/usb/host/ohci-s3c2410.c
+++ b/drivers/usb/host/ohci-s3c2410.c
@@ -466,7 +466,6 @@ static const struct hc_driver ohci_s3c2410_hc_driver = {
 	 */
 	.hub_status_data =	ohci_s3c2410_hub_status_data,
 	.hub_control =		ohci_s3c2410_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-sa1111.c b/drivers/usb/host/ohci-sa1111.c
index 0f48f2d9922..99438c65981 100644
--- a/drivers/usb/host/ohci-sa1111.c
+++ b/drivers/usb/host/ohci-sa1111.c
@@ -231,7 +231,6 @@ static const struct hc_driver ohci_sa1111_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-sh.c b/drivers/usb/host/ohci-sh.c
index e7ee607278f..60f03cc7ec4 100644
--- a/drivers/usb/host/ohci-sh.c
+++ b/drivers/usb/host/ohci-sh.c
@@ -68,7 +68,6 @@ static const struct hc_driver ohci_sh_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-sm501.c b/drivers/usb/host/ohci-sm501.c
index 4a11e181601..77204f001b9 100644
--- a/drivers/usb/host/ohci-sm501.c
+++ b/drivers/usb/host/ohci-sm501.c
@@ -75,7 +75,6 @@ static const struct hc_driver ohci_sm501_hc_driver = {
 	 */
 	.hub_status_data =	ohci_hub_status_data,
 	.hub_control =		ohci_hub_control,
-	.hub_irq_enable =	ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend =		ohci_bus_suspend,
 	.bus_resume =		ohci_bus_resume,
diff --git a/drivers/usb/host/ohci-ssb.c b/drivers/usb/host/ohci-ssb.c
index 7275186db31..c4265caec78 100644
--- a/drivers/usb/host/ohci-ssb.c
+++ b/drivers/usb/host/ohci-ssb.c
@@ -81,7 +81,6 @@ static const struct hc_driver ssb_ohci_hc_driver = {
 
 	.hub_status_data	= ohci_hub_status_data,
 	.hub_control		= ohci_hub_control,
-	.hub_irq_enable		= ohci_rhsc_enable,
 #ifdef	CONFIG_PM
 	.bus_suspend		= ohci_bus_suspend,
 	.bus_resume		= ohci_bus_resume,
diff --git a/drivers/usb/host/u132-hcd.c b/drivers/usb/host/u132-hcd.c
index 9b6323f768b..f29307405bb 100644
--- a/drivers/usb/host/u132-hcd.c
+++ b/drivers/usb/host/u132-hcd.c
@@ -2934,16 +2934,6 @@ static int u132_start_port_reset(struct usb_hcd *hcd, unsigned port_num)
 		return 0;
 }
 
-static void u132_hub_irq_enable(struct usb_hcd *hcd)
-{
-	struct u132 *u132 = hcd_to_u132(hcd);
-	if (u132->going > 1) {
-		dev_err(&u132->platform_dev->dev, "device has been removed %d\n"
-			, u132->going);
-	} else if (u132->going > 0)
-		dev_err(&u132->platform_dev->dev, "device is being removed\n");
-}
-
 
 #ifdef CONFIG_PM
 static int u132_bus_suspend(struct usb_hcd *hcd)
@@ -2995,7 +2985,6 @@ static struct hc_driver u132_hc_driver = {
 	.bus_suspend = u132_bus_suspend,
 	.bus_resume = u132_bus_resume,
 	.start_port_reset = u132_start_port_reset,
-	.hub_irq_enable = u132_hub_irq_enable,
 };
 
 /*