[PATCH] USB UHCI: Add root hub states

This patch starts making some serious changes to the UHCI driver.
There's a set of private states for the root hub, and the internal
routines for suspending and resuming work completely differently, with
transitions based on the new states.  Now the driver distinguishes
between a privately auto-stopped state and a publicly suspended state,
and it will properly suspend controllers with broken resume-detect
interrupts instead of resetting them.

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

4 files changed, 212 insertions, 156 deletions

diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
index 24c73c5a343..4538a98b6f9 100644
--- a/drivers/usb/host/uhci-debug.c
+++ b/drivers/usb/host/uhci-debug.c
@@ -237,6 +237,37 @@ static int uhci_show_sc(int port, unsigned short status, char *buf, int len)
 	return out - buf;
 }
 
+static int uhci_show_root_hub_state(struct uhci_hcd *uhci, char *buf, int len)
+{
+	char *out = buf;
+	char *rh_state;
+
+	/* Try to make sure there's enough memory */
+	if (len < 60)
+		return 0;
+
+	switch (uhci->rh_state) {
+	    case UHCI_RH_RESET:
+		rh_state = "reset";		break;
+	    case UHCI_RH_SUSPENDED:
+		rh_state = "suspended";		break;
+	    case UHCI_RH_AUTO_STOPPED:
+		rh_state = "auto-stopped";	break;
+	    case UHCI_RH_RESUMING:
+		rh_state = "resuming";		break;
+	    case UHCI_RH_SUSPENDING:
+		rh_state = "suspending";	break;
+	    case UHCI_RH_RUNNING:
+		rh_state = "running";		break;
+	    case UHCI_RH_RUNNING_NODEVS:
+		rh_state = "running, no devs";	break;
+	    default:
+		rh_state = "?";			break;
+	}
+	out += sprintf(out, "Root-hub state: %s\n", rh_state);
+	return out - buf;
+}
+
 static int uhci_show_status(struct uhci_hcd *uhci, char *buf, int len)
 {
 	char *out = buf;
@@ -408,6 +439,7 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len)
 
 	spin_lock_irqsave(&uhci->lock, flags);
 
+	out += uhci_show_root_hub_state(uhci, out, len - (out - buf));
 	out += sprintf(out, "HC status\n");
 	out += uhci_show_status(uhci, out, len - (out - buf));
 
diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
index c17bd7ebc02..57b36dcea5d 100644
--- a/drivers/usb/host/uhci-hcd.c
+++ b/drivers/usb/host/uhci-hcd.c
@@ -64,7 +64,7 @@
 /*
  * Version Information
  */
-#define DRIVER_VERSION "v2.2"
+#define DRIVER_VERSION "v2.3"
 #define DRIVER_AUTHOR "Linus 'Frodo Rabbit' Torvalds, Johannes Erdfelt, \
 Randy Dunlap, Georg Acher, Deti Fliegl, Thomas Sailer, Roman Weissgaerber, \
 Alan Stern"
@@ -109,33 +109,6 @@ static inline void restart_timer(struct uhci_hcd *uhci)
 #include "uhci-debug.c"
 #include "uhci-q.c"
 
-static int suspend_allowed(struct uhci_hcd *uhci)
-{
-	unsigned long io_addr = uhci->io_addr;
-	int i;
-
-	if (to_pci_dev(uhci_dev(uhci))->vendor != PCI_VENDOR_ID_INTEL)
-		return 1;
-
-	/* Some of Intel's USB controllers have a bug that causes false
-	 * resume indications if any port has an over current condition.
-	 * To prevent problems, we will not allow a global suspend if
-	 * any ports are OC.
-	 *
-	 * Some motherboards using Intel's chipsets (but not using all
-	 * the USB ports) appear to hardwire the over current inputs active
-	 * to disable the USB ports.
-	 */
-
-	/* check for over current condition on any port */
-	for (i = 0; i < uhci->rh_numports; i++) {
-		if (inw(io_addr + USBPORTSC1 + i * 2) & USBPORTSC_OC)
-			return 0;
-	}
-
-	return 1;
-}
-
 static void reset_hc(struct uhci_hcd *uhci)
 {
 	unsigned long io_addr = uhci->io_addr;
@@ -147,7 +120,6 @@ static void reset_hc(struct uhci_hcd *uhci)
 	outw(0, uhci->io_addr + USBINTR);
 
 	/* Global reset for 50ms */
-	uhci->state = UHCI_RESET;
 	outw(USBCMD_GRESET, io_addr + USBCMD);
 	msleep(50);
 	outw(0, io_addr + USBCMD);
@@ -156,63 +128,130 @@ static void reset_hc(struct uhci_hcd *uhci)
 	msleep(10);
 	uhci->resume_detect = 0;
 	uhci->is_stopped = UHCI_IS_STOPPED;
+	uhci->rh_state = UHCI_RH_RESET;
 }
 
-static void suspend_hc(struct uhci_hcd *uhci)
+static int resume_detect_interrupts_are_broken(struct uhci_hcd *uhci)
 {
-	unsigned long io_addr = uhci->io_addr;
+	int port;
 
-	dev_dbg(uhci_dev(uhci), "%s\n", __FUNCTION__);
-	uhci->state = UHCI_SUSPENDED;
-	uhci->resume_detect = 0;
-	outw(USBCMD_EGSM, io_addr + USBCMD);
+	switch (to_pci_dev(uhci_dev(uhci))->vendor) {
+	    default:
+		break;
+
+	    case PCI_VENDOR_ID_GENESYS:
+		/* Genesys Logic's GL880S controllers don't generate
+		 * resume-detect interrupts.
+		 */
+		return 1;
+
+	    case PCI_VENDOR_ID_INTEL:
+		/* Some of Intel's USB controllers have a bug that causes
+		 * resume-detect interrupts if any port has an over-current
+		 * condition.  To make matters worse, some motherboards
+		 * hardwire unused USB ports' over-current inputs active!
+		 * To prevent problems, we will not enable resume-detect
+		 * interrupts if any ports are OC.
+		 */
+		for (port = 0; port < uhci->rh_numports; ++port) {
+			if (inw(uhci->io_addr + USBPORTSC1 + port * 2) &
+					USBPORTSC_OC)
+				return 1;
+		}
+		break;
+	}
+	return 0;
+}
+
+static void suspend_hc(struct uhci_hcd *uhci, enum uhci_rh_state new_state)
+__releases(uhci->lock)
+__acquires(uhci->lock)
+{
+	int auto_stop;
+	int int_enable;
+
+	auto_stop = (new_state == UHCI_RH_AUTO_STOPPED);
+	dev_dbg(uhci_dev(uhci), "%s%s\n", __FUNCTION__,
+			(auto_stop ? " (auto-stop)" : ""));
+
+	/* If we get a suspend request when we're already auto-stopped
+	 * then there's nothing to do.
+	 */
+	if (uhci->rh_state == UHCI_RH_AUTO_STOPPED) {
+		uhci->rh_state = new_state;
+		return;
+	}
+
+	/* Enable resume-detect interrupts if they work.
+	 * Then enter Global Suspend mode, still configured.
+	 */
+	int_enable = (resume_detect_interrupts_are_broken(uhci) ?
+			0 : USBINTR_RESUME);
+	outw(int_enable, uhci->io_addr + USBINTR);
+	outw(USBCMD_EGSM | USBCMD_CF, uhci->io_addr + USBCMD);
+	udelay(5);
+
+	/* If we're auto-stopping then no devices have been attached
+	 * for a while, so there shouldn't be any active URBs and the
+	 * controller should stop after a few microseconds.  Otherwise
+	 * we will give the controller one frame to stop.
+	 */
+	if (!auto_stop && !(inw(uhci->io_addr + USBSTS) & USBSTS_HCH)) {
+		uhci->rh_state = UHCI_RH_SUSPENDING;
+		spin_unlock_irq(&uhci->lock);
+		msleep(1);
+		spin_lock_irq(&uhci->lock);
+	}
+	if (!(inw(uhci->io_addr + USBSTS) & USBSTS_HCH))
+		dev_warn(uhci_dev(uhci), "Controller not stopped yet!\n");
 
-	/* FIXME: Wait for the controller to actually stop */
 	uhci_get_current_frame_number(uhci);
+	smp_wmb();
+
+	uhci->rh_state = new_state;
 	uhci->is_stopped = UHCI_IS_STOPPED;
+	uhci->resume_detect = 0;
 
 	uhci_scan_schedule(uhci, NULL);
 }
 
 static void wakeup_hc(struct uhci_hcd *uhci)
+__releases(uhci->lock)
+__acquires(uhci->lock)
 {
-	unsigned long io_addr = uhci->io_addr;
+	dev_dbg(uhci_dev(uhci), "%s%s\n", __FUNCTION__,
+			uhci->rh_state == UHCI_RH_AUTO_STOPPED ?
+				" (auto-start)" : "");
 
-	switch (uhci->state) {
-		case UHCI_SUSPENDED:		/* Start the resume */
-			dev_dbg(uhci_dev(uhci), "%s\n", __FUNCTION__);
-
-			/* Global resume for >= 20ms */
-			outw(USBCMD_FGR | USBCMD_EGSM, io_addr + USBCMD);
-			uhci->state = UHCI_RESUMING_1;
-			uhci->state_end = jiffies + msecs_to_jiffies(20);
-			uhci->is_stopped = 0;
-			break;
+	/* If we are auto-stopped then no devices are attached so there's
+	 * no need for wakeup signals.  Otherwise we send Global Resume
+	 * for 20 ms.
+	 */
+	if (uhci->rh_state == UHCI_RH_SUSPENDED) {
+		uhci->rh_state = UHCI_RH_RESUMING;
+		outw(USBCMD_FGR | USBCMD_EGSM | USBCMD_CF,
+				uhci->io_addr + USBCMD);
+		spin_unlock_irq(&uhci->lock);
+		msleep(20);
+		spin_lock_irq(&uhci->lock);
 
-		case UHCI_RESUMING_1:		/* End global resume */
-			uhci->state = UHCI_RESUMING_2;
-			outw(0, io_addr + USBCMD);
-			/* Falls through */
-
-		case UHCI_RESUMING_2:		/* Wait for EOP to be sent */
-			if (inw(io_addr + USBCMD) & USBCMD_FGR)
-				break;
-
-			/* Run for at least 1 second, and
-			 * mark it configured with a 64-byte max packet */
-			uhci->state = UHCI_RUNNING_GRACE;
-			uhci->state_end = jiffies + HZ;
-			outw(USBCMD_RS | USBCMD_CF | USBCMD_MAXP,
-					io_addr + USBCMD);
-			break;
+		/* End Global Resume and wait for EOP to be sent */
+		outw(USBCMD_CF, uhci->io_addr + USBCMD);
+		udelay(4);
+		if (inw(uhci->io_addr + USBCMD) & USBCMD_FGR)
+			dev_warn(uhci_dev(uhci), "FGR not stopped yet!\n");
+	}
 
-		case UHCI_RUNNING_GRACE:	/* Now allowed to suspend */
-			uhci->state = UHCI_RUNNING;
-			break;
+	uhci->rh_state = UHCI_RH_RUNNING;
+	uhci->is_stopped = 0;
+	smp_wmb();
 
-		default:
-			break;
-	}
+	/* Mark it configured and running with a 64-byte max packet.
+	 * All interrupts are enabled, even though RD won't do anything.
+	 */
+	outw(USBCMD_RS | USBCMD_CF | USBCMD_MAXP, uhci->io_addr + USBCMD);
+	outw(USBINTR_TIMEOUT | USBINTR_RESUME | USBINTR_IOC | USBINTR_SP,
+			uhci->io_addr + USBINTR);
 }
 
 static int start_hc(struct uhci_hcd *uhci)
@@ -249,49 +288,40 @@ static int start_hc(struct uhci_hcd *uhci)
 	outl(uhci->fl->dma_handle, io_addr + USBFLBASEADD);
 
 	/* Run and mark it configured with a 64-byte max packet */
-	uhci->state = UHCI_RUNNING_GRACE;
-	uhci->state_end = jiffies + HZ;
+	uhci->rh_state = UHCI_RH_RUNNING;
 	outw(USBCMD_RS | USBCMD_CF | USBCMD_MAXP, io_addr + USBCMD);
 	uhci->is_stopped = 0;
 
 	return 0;
 }
 
-static void hc_state_transitions(struct uhci_hcd *uhci)
+static void rh_state_transitions(struct uhci_hcd *uhci)
 {
-	switch (uhci->state) {
-		case UHCI_RUNNING:
-
-			/* global suspend if nothing connected for 1 second */
-			if (!any_ports_active(uhci) && suspend_allowed(uhci)) {
-				uhci->state = UHCI_SUSPENDING_GRACE;
-				uhci->state_end = jiffies + HZ;
-			}
-			break;
-
-		case UHCI_SUSPENDING_GRACE:
-			if (any_ports_active(uhci))
-				uhci->state = UHCI_RUNNING;
-			else if (time_after_eq(jiffies, uhci->state_end))
-				suspend_hc(uhci);
-			break;
-
-		case UHCI_SUSPENDED:
-
-			/* wakeup if requested by a device */
-			if (uhci->resume_detect)
-				wakeup_hc(uhci);
-			break;
-
-		case UHCI_RESUMING_1:
-		case UHCI_RESUMING_2:
-		case UHCI_RUNNING_GRACE:
-			if (time_after_eq(jiffies, uhci->state_end))
-				wakeup_hc(uhci);
-			break;
-
-		default:
-			break;
+	switch (uhci->rh_state) {
+	    case UHCI_RH_RUNNING:
+		/* are any devices attached? */
+		if (!any_ports_active(uhci)) {
+			uhci->rh_state = UHCI_RH_RUNNING_NODEVS;
+			uhci->auto_stop_time = jiffies + HZ;
+		}
+		break;
+
+	    case UHCI_RH_RUNNING_NODEVS:
+		/* auto-stop if nothing connected for 1 second */
+		if (any_ports_active(uhci))
+			uhci->rh_state = UHCI_RH_RUNNING;
+		else if (time_after_eq(jiffies, uhci->auto_stop_time))
+			suspend_hc(uhci, UHCI_RH_AUTO_STOPPED);
+		break;
+
+	    case UHCI_RH_AUTO_STOPPED:
+		/* wakeup if requested by a device */
+		if (uhci->resume_detect)
+			wakeup_hc(uhci);
+		break;
+
+	    default:
+		break;
 	}
 }
 
@@ -305,8 +335,8 @@ static void stall_callback(unsigned long _uhci)
 	check_fsbr(uhci);
 
 	/* Poll for and perform state transitions */
-	hc_state_transitions(uhci);
-	if (unlikely(uhci->suspended_ports && uhci->state != UHCI_SUSPENDED))
+	rh_state_transitions(uhci);
+	if (unlikely(uhci->suspended_ports))
 		uhci_check_ports(uhci);
 
 	restart_timer(uhci);
@@ -336,7 +366,8 @@ static irqreturn_t uhci_irq(struct usb_hcd *hcd, struct pt_regs *regs)
 		if (status & USBSTS_HCPE)
 			dev_err(uhci_dev(uhci), "host controller process "
 					"error, something bad happened!\n");
-		if ((status & USBSTS_HCH) && uhci->state > 0) {
+		if ((status & USBSTS_HCH) &&
+				uhci->rh_state >= UHCI_RH_RUNNING) {
 			dev_err(uhci_dev(uhci), "host controller halted, "
 					"very bad!\n");
 			/* FIXME: Reset the controller, fix the offending TD */
@@ -683,17 +714,7 @@ static int uhci_suspend(struct usb_hcd *hcd, pm_message_t message)
 	struct uhci_hcd *uhci = hcd_to_uhci(hcd);
 
 	spin_lock_irq(&uhci->lock);
-
-	/* Don't try to suspend broken motherboards, reset instead */
-	if (suspend_allowed(uhci))
-		suspend_hc(uhci);
-	else {
-		spin_unlock_irq(&uhci->lock);
-		reset_hc(uhci);
-		spin_lock_irq(&uhci->lock);
-		uhci_scan_schedule(uhci, NULL);
-	}
-
+	suspend_hc(uhci, UHCI_RH_SUSPENDED);
 	spin_unlock_irq(&uhci->lock);
 	return 0;
 }
@@ -701,13 +722,9 @@ static int uhci_suspend(struct usb_hcd *hcd, pm_message_t message)
 static int uhci_resume(struct usb_hcd *hcd)
 {
 	struct uhci_hcd *uhci = hcd_to_uhci(hcd);
-	int rc;
-
-	pci_set_master(to_pci_dev(uhci_dev(uhci)));
 
 	spin_lock_irq(&uhci->lock);
-
-	if (uhci->state == UHCI_SUSPENDED) {
+	if (uhci->rh_state == UHCI_RH_SUSPENDED) {
 
 		/*
 		 * Some systems don't maintain the UHCI register values
@@ -721,19 +738,13 @@ static int uhci_resume(struct usb_hcd *hcd)
 		outl(uhci->fl->dma_handle, uhci->io_addr + USBFLBASEADD);
 		outw(USBINTR_TIMEOUT | USBINTR_RESUME | USBINTR_IOC |
 				USBINTR_SP, uhci->io_addr + USBINTR);
-		uhci->resume_detect = 1;
 		pci_write_config_word(to_pci_dev(uhci_dev(uhci)), USBLEGSUP,
 				USBLEGSUP_DEFAULT);
-	} else {
-		spin_unlock_irq(&uhci->lock);
-		reset_hc(uhci);
-		if ((rc = start_hc(uhci)) != 0)
-			return rc;
-		spin_lock_irq(&uhci->lock);
+		wakeup_hc(uhci);
 	}
-	hcd->state = HC_STATE_RUNNING;
-
 	spin_unlock_irq(&uhci->lock);
+
+	hcd->state = HC_STATE_RUNNING;
 	return 0;
 }
 #endif
@@ -750,13 +761,15 @@ static void uhci_hcd_endpoint_disable(struct usb_hcd *hcd,
 static int uhci_hcd_get_frame_number(struct usb_hcd *hcd)
 {
 	struct uhci_hcd *uhci = hcd_to_uhci(hcd);
-	int frame_number;
 	unsigned long flags;
+	int is_stopped;
+	int frame_number;
 
 	/* Minimize latency by avoiding the spinlock */
 	local_irq_save(flags);
-	rmb();
-	frame_number = (uhci->is_stopped ? uhci->frame_number :
+	is_stopped = uhci->is_stopped;
+	smp_rmb();
+	frame_number = (is_stopped ? uhci->frame_number :
 			inw(uhci->io_addr + USBFRNUM));
 	local_irq_restore(flags);
 	return frame_number;
diff --git a/drivers/usb/host/uhci-hcd.h b/drivers/usb/host/uhci-hcd.h
index 02255d69e1f..4bac57c74ec 100644
--- a/drivers/usb/host/uhci-hcd.h
+++ b/drivers/usb/host/uhci-hcd.h
@@ -314,26 +314,29 @@ static inline int __interval_to_skel(int interval)
 }
 
 /*
- * Device states for the host controller.
+ * States for the root hub.
  *
  * To prevent "bouncing" in the presence of electrical noise,
- * we insist on a 1-second "grace" period, before switching to
- * the RUNNING or SUSPENDED states, during which the state is
- * not allowed to change.
- *
- * The resume process is divided into substates in order to avoid
- * potentially length delays during the timer handler.
- *
- * States in which the host controller is halted must have values <= 0.
+ * when there are no devices attached we delay for 1 second in the
+ * RUNNING_NODEVS state before switching to the AUTO_STOPPED state.
+ * 
+ * (Note that the AUTO_STOPPED state won't be necessary once the hub
+ * driver learns to autosuspend.)
  */
-enum uhci_state {
-	UHCI_RESET,
-	UHCI_RUNNING_GRACE,		/* Before RUNNING */
-	UHCI_RUNNING,			/* The normal state */
-	UHCI_SUSPENDING_GRACE,		/* Before SUSPENDED */
-	UHCI_SUSPENDED = -10,		/* When no devices are attached */
-	UHCI_RESUMING_1,
-	UHCI_RESUMING_2
+enum uhci_rh_state {
+	/* In the next 4 states the HC must be halted */
+	UHCI_RH_RESET,
+	UHCI_RH_SUSPENDED,
+	UHCI_RH_AUTO_STOPPED,
+	UHCI_RH_RESUMING,
+
+	/* In the next state the HC changes from running to halted, so it
+	 * can legally appear either way */
+	UHCI_RH_SUSPENDING,
+
+	/* In the next two states it's an error if the HC is halted */
+	UHCI_RH_RUNNING,		/* The normal state */
+	UHCI_RH_RUNNING_NODEVS,		/* Running with no devices attached */
 };
 
 /*
@@ -363,8 +366,9 @@ struct uhci_hcd {
 	int fsbr;				/* Full-speed bandwidth reclamation */
 	unsigned long fsbrtimeout;		/* FSBR delay */
 
-	enum uhci_state state;			/* FIXME: needs a spinlock */
-	unsigned long state_end;		/* Time of next transition */
+	enum uhci_rh_state rh_state;
+	unsigned long auto_stop_time;		/* When to AUTO_STOP */
+
 	unsigned int frame_number;		/* As of last check */
 	unsigned int is_stopped;
 #define UHCI_IS_STOPPED		9999		/* Larger than a frame # */
@@ -451,4 +455,11 @@ struct urb_priv {
  * #2 urb->lock
  */
 
+
+/* Some special IDs */
+
+#define PCI_VENDOR_ID_GENESYS		0x17a0
+#define PCI_DEVICE_ID_GL880S_UHCI	0x8083
+#define PCI_DEVICE_ID_GL880S_EHCI	0x8084
+
 #endif
diff --git a/drivers/usb/host/uhci-hub.c b/drivers/usb/host/uhci-hub.c
index ddb19cbf4b7..fc34fee2ab0 100644
--- a/drivers/usb/host/uhci-hub.c
+++ b/drivers/usb/host/uhci-hub.c
@@ -60,7 +60,7 @@ static int uhci_hub_status_data(struct usb_hcd *hcd, char *buf)
 				test_bit(port, &uhci->port_c_suspend))
 			*buf |= (1 << (port + 1));
 	}
-	if (*buf && uhci->state == UHCI_SUSPENDED)
+	if (*buf && uhci->is_stopped)
 		uhci->resume_detect = 1;
 	return !!*buf;
 }