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authorSarah Sharp <sarah.a.sharp@linux.intel.com>2009-04-27 19:54:49 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2009-06-15 21:44:48 -0700
commit7206b00164a1c3ca533e01db285955617e1019f8 (patch)
treed11f6a5a63238110d4b763661a76ca87761a2d02 /drivers/usb/host
parente7b7717247f61e2cf18ec47f91999065c59d1607 (diff)
USB: Add route string to struct usb_device.
This patch adds a hex route string to each USB device. The route string is used by the USB 3.0 host controller to send packets through the device tree. USB 3.0 hubs use this string to route packets to the correct port. This is fundamental bus change from USB 2.0, where all packets were broadcast across the bus. Devices (including hubs) under a root port receive the route string 0x0. Every four bits in the route string represent a port on a hub. This length works because USB 3.0 hubs are limited to 15 ports, and USB 2.0 hubs (with potentially more ports) will never see packets with a route string. A port number of 0 means the packet is destined for that hub. For example, a peripheral device might have a route string of 0x00097. This means the device is connected to port 9 of the hub at depth 1. The hub at depth 1 is connected to port 7 of a hub at depth 0. The hub at depth 0 is connected to a root port. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/host')
0 files changed, 0 insertions, 0 deletions