wusb: teach choose_address() about wireless devices

Modify choose_address() so it knows about our special scheme of
addressing WUSB devices (1:1 w/ port number).

Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 31 insertions, 9 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 06c3acb161ee..baae2aa0dbf6 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1195,21 +1195,42 @@ void usb_set_device_state(struct usb_device *udev,
         spin_unlock_irqrestore(&device_state_lock, flags);
 }
 
+/*
+ * WUSB devices are simple: they have no hubs behind, so the mapping
+ * device <-> virtual port number becomes 1:1. Why? to simplify the
+ * life of the device connection logic in
+ * drivers/usb/wusbcore/devconnect.c. When we do the initial secret
+ * handshake we need to assign a temporary address in the unauthorized
+ * space. For simplicity we use the first virtual port number found to
+ * be free [drivers/usb/wusbcore/devconnect.c:wusbhc_devconnect_ack()]
+ * and that becomes it's address [X < 128] or its unauthorized address
+ * [X | 0x80].
+ *
+ * We add 1 as an offset to the one-based USB-stack port number
+ * (zero-based wusb virtual port index) for two reasons: (a) dev addr
+ * 0 is reserved by USB for default address; (b) Linux's USB stack
+ * uses always #1 for the root hub of the controller. So USB stack's
+ * port #1, which is wusb virtual-port #0 has address #2.
+ */
 static void choose_address(struct usb_device *udev)
 {
         int             devnum;
         struct usb_bus  *bus = udev->bus;
 
         /* If khubd ever becomes multithreaded, this will need a lock */
-
-        /* Try to allocate the next devnum beginning at bus->devnum_next. */
-        devnum = find_next_zero_bit(bus->devmap.devicemap, 128,
-                        bus->devnum_next);
-        if (devnum >= 128)
-                devnum = find_next_zero_bit(bus->devmap.devicemap, 128, 1);
-
-        bus->devnum_next = ( devnum >= 127 ? 1 : devnum + 1);
-
+        if (udev->wusb) {
+                devnum = udev->portnum + 1;
+                BUG_ON(test_bit(devnum, bus->devmap.devicemap));
+        } else {
+                /* Try to allocate the next devnum beginning at
+                 * bus->devnum_next. */
+                devnum = find_next_zero_bit(bus->devmap.devicemap, 128,
+                                            bus->devnum_next);
+                if (devnum >= 128)
+                        devnum = find_next_zero_bit(bus->devmap.devicemap,
+                                                    128, 1);
+                bus->devnum_next = ( devnum >= 127 ? 1 : devnum + 1);
+        }
         if (devnum < 128) {
                 set_bit(devnum, bus->devmap.devicemap);
                 udev->devnum = devnum;
@@ -2611,6 +2632,7 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
                 udev->speed = USB_SPEED_UNKNOWN;
                 udev->bus_mA = hub->mA_per_port;
                 udev->level = hdev->level + 1;
+                udev->wusb = hub_is_wusb(hub);
 
                 /* set the address */
                 choose_address(udev);