[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>

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));
 

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

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;
 }