EHCI: keep track of ports being resumed and indicate in hub_status_data

This patch (as1537) adds a bit-array to ehci-hcd for keeping track of
which ports are undergoing a resume transition.  If any of the bits
are set when ehci_hub_status_data() is called, the routine will return
a nonzero value even if no ports have any status changes pending.
This will allow usbcore to handle races between root-hub suspend and
port wakeup.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Sarah Sharp <sarah.a.sharp@linux.intel.com>
CC: Chen Peter-B29397 <B29397@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 16 insertions, 15 deletions

diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 256fbd42e48c..38fe07623152 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -223,15 +223,10 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
          * remote wakeup, we must fail the suspend.
          */
         if (hcd->self.root_hub->do_remote_wakeup) {
-                port = HCS_N_PORTS(ehci->hcs_params);
-                while (port--) {
-                        if (ehci->reset_done[port] != 0) {
-                                spin_unlock_irq(&ehci->lock);
-                                ehci_dbg(ehci, "suspend failed because "
-                                                "port %d is resuming\n",
-                                                port + 1);
-                                return -EBUSY;
-                        }
+                if (ehci->resuming_ports) {
+                        spin_unlock_irq(&ehci->lock);
+                        ehci_dbg(ehci, "suspend failed because a port is resuming\n");
+                        return -EBUSY;
                 }
         }
 
@@ -554,16 +549,12 @@ static int
 ehci_hub_status_data (struct usb_hcd *hcd, char *buf)
 {
         struct ehci_hcd *ehci = hcd_to_ehci (hcd);
-        u32             temp, status = 0;
+        u32             temp, status;
         u32             mask;
         int             ports, i, retval = 1;
         unsigned long   flags;
         u32             ppcd = 0;
 
-        /* if !USB_SUSPEND, root hub timers won't get shut down ... */
-        if (ehci->rh_state != EHCI_RH_RUNNING)
-                return 0;
-
         /* init status to no-changes */
         buf [0] = 0;
         ports = HCS_N_PORTS (ehci->hcs_params);
@@ -572,6 +563,11 @@ ehci_hub_status_data (struct usb_hcd *hcd, char *buf)
                 retval++;
         }
 
+        /* Inform the core about resumes-in-progress by returning
+         * a non-zero value even if there are no status changes.
+         */
+        status = ehci->resuming_ports;
+
         /* Some boards (mostly VIA?) report bogus overcurrent indications,
          * causing massive log spam unless we completely ignore them.  It
          * may be relevant that VIA VT8235 controllers, where PORT_POWER is
@@ -846,6 +842,7 @@ static int ehci_hub_control (
                                 ehci_writel(ehci,
                                         temp & ~(PORT_RWC_BITS | PORT_RESUME),
                                         status_reg);
+                                clear_bit(wIndex, &ehci->resuming_ports);
                                 retval = handshake(ehci, status_reg,
                                            PORT_RESUME, 0, 2000 /* 2msec */);
                                 if (retval != 0) {
@@ -864,6 +861,7 @@ static int ehci_hub_control (
                                         ehci->reset_done[wIndex])) {
                         status |= USB_PORT_STAT_C_RESET << 16;
                         ehci->reset_done [wIndex] = 0;
+                        clear_bit(wIndex, &ehci->resuming_ports);
 
                         /* force reset to complete */
                         ehci_writel(ehci, temp & ~(PORT_RWC_BITS | PORT_RESET),
@@ -884,8 +882,10 @@ static int ehci_hub_control (
                                         ehci_readl(ehci, status_reg));
                 }
 
-                if (!(temp & (PORT_RESUME|PORT_RESET)))
+                if (!(temp & (PORT_RESUME|PORT_RESET))) {
                         ehci->reset_done[wIndex] = 0;
+                        clear_bit(wIndex, &ehci->resuming_ports);
+                }
 
                 /* transfer dedicated ports to the companion hc */
                 if ((temp & PORT_CONNECT) &&
@@ -920,6 +920,7 @@ static int ehci_hub_control (
                         status |= USB_PORT_STAT_SUSPEND;
                 } else if (test_bit(wIndex, &ehci->suspended_ports)) {
                         clear_bit(wIndex, &ehci->suspended_ports);
+                        clear_bit(wIndex, &ehci->resuming_ports);
                         ehci->reset_done[wIndex] = 0;
                         if (temp & PORT_PE)
                                 set_bit(wIndex, &ehci->port_c_suspend);