[PATCH] USB UHCI: Add root-hub suspend/resume support

This patch implements (finally!) separate suspend and resume routines
for the root hub and the controller in the UHCI driver.  It also
changes the sequence used to reset the controller during initial
probing, so as to preserve the existing state during a Resume-From-Disk.
(This new sequence is what should be used in the PCI Quirks code for
early USB handoffs, incidentally.)  Lastly it adds a notion of the
controller being "inaccessible" while in a PCI low-power state, when
normal I/O operations shouldn't be allowed.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/uhci-hcd.h

@@ -41,6 +41,7 @@
 #define USBFRNUM	6
 #define USBFLBASEADD	8
 #define USBSOF		12
+#define   USBSOF_DEFAULT	64	/* Frame length is exactly 1 ms */
 
 /* USB port status and control registers */
 #define USBPORTSC1	16
@@ -66,6 +67,8 @@
 /* Legacy support register */
 #define USBLEGSUP		0xc0
 #define   USBLEGSUP_DEFAULT	0x2000	/* only PIRQ enable set */
+#define   USBLEGSUP_RWC		0x8f00	/* the R/WC bits */
+#define   USBLEGSUP_RO		0x5040	/* R/O and reserved bits */
 
 #define UHCI_NULL_DATA_SIZE	0x7FF	/* for UHCI controller TD */
 
@@ -325,8 +328,9 @@ static inline int __interval_to_skel(int interval)
  */
 enum uhci_rh_state {
 	/* In the next 4 states the HC must be halted */
-	UHCI_RH_RESET,
+	UHCI_RH_RESET,			/* These two must come first */
 	UHCI_RH_SUSPENDED,
+
 	UHCI_RH_AUTO_STOPPED,
 	UHCI_RH_RESUMING,
 
@@ -334,7 +338,8 @@ enum uhci_rh_state {
 	 * can legally appear either way */
 	UHCI_RH_SUSPENDING,
 
-	/* In the next two states it's an error if the HC is halted */
+	/* In the next two states it's an error if the HC is halted.
+	 * These two must come last */
 	UHCI_RH_RUNNING,		/* The normal state */
 	UHCI_RH_RUNNING_NODEVS,		/* Running with no devices attached */
 };
@@ -376,6 +381,7 @@ struct uhci_hcd {
 	unsigned int scan_in_progress:1;	/* Schedule scan is running */
 	unsigned int need_rescan:1;		/* Redo the schedule scan */
 	unsigned int resume_detect:1;		/* Need a Global Resume */
+	unsigned int hc_inaccessible:1;		/* HC is suspended or dead */
 
 	/* Support for port suspend/resume/reset */
 	unsigned long port_c_suspend;		/* Bit-arrays of ports */

drivers/usb/host/uhci-hub.c

@@ -54,6 +54,9 @@ static int uhci_hub_status_data(struct usb_hcd *hcd, char *buf)
 	struct uhci_hcd *uhci = hcd_to_uhci(hcd);
 	int port;
 
+	if (uhci->hc_inaccessible)
+		return 0;
+
 	*buf = 0;
 	for (port = 0; port < uhci->rh_numports; ++port) {
 		if ((inw(uhci->io_addr + USBPORTSC1 + port * 2) & RWC_BITS) ||
@@ -150,6 +153,9 @@ static int uhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 	u16 wPortChange, wPortStatus;
 	unsigned long flags;
 
+	if (uhci->hc_inaccessible)
+		return -ETIMEDOUT;
+
 	spin_lock_irqsave(&uhci->lock, flags);
 	switch (typeReq) {