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Assume that the peer of a superspeed port is the port with the same id on the shared_hcd root hub. This identification scheme is required of external hubs by the USB3 spec [1]. However, for root hubs, tier mismatch may be in effect [2]. Tier mismatch can only be enumerated via platform firmware. For now, simply perform the nominal association. A new lock 'usb_port_peer_mutex' is introduced to synchronize port device add/remove with peer lookups. It protects peering against changes to hcd->shared_hcd, hcd->self.root_hub, hdev->maxchild, and port_dev->child pointers. [1]: usb 3.1 section 10.3.3 [2]: xhci 1.1 appendix D Cc: Alan Stern <stern@rowland.harvard.edu> [alan: usb_port_peer_mutex locking scheme] Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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atm | ||
c67x00 | ||
chipidea | ||
class | ||
common | ||
core | ||
dwc2 | ||
dwc3 | ||
early | ||
gadget | ||
host | ||
image | ||
misc | ||
mon | ||
musb | ||
phy | ||
renesas_usbhs | ||
serial | ||
storage | ||
wusbcore | ||
Kconfig | ||
Makefile | ||
README | ||
usb-skeleton.c |
To understand all the Linux-USB framework, you'll use these resources: * This source code. This is necessarily an evolving work, and includes kerneldoc that should help you get a current overview. ("make pdfdocs", and then look at "usb.pdf" for host side and "gadget.pdf" for peripheral side.) Also, Documentation/usb has more information. * The USB 2.0 specification (from www.usb.org), with supplements such as those for USB OTG and the various device classes. The USB specification has a good overview chapter, and USB peripherals conform to the widely known "Chapter 9". * Chip specifications for USB controllers. Examples include host controllers (on PCs, servers, and more); peripheral controllers (in devices with Linux firmware, like printers or cell phones); and hard-wired peripherals like Ethernet adapters. * Specifications for other protocols implemented by USB peripheral functions. Some are vendor-specific; others are vendor-neutral but just standardized outside of the www.usb.org team. Here is a list of what each subdirectory here is, and what is contained in them. core/ - This is for the core USB host code, including the usbfs files and the hub class driver ("khubd"). host/ - This is for USB host controller drivers. This includes UHCI, OHCI, EHCI, and others that might be used with more specialized "embedded" systems. gadget/ - This is for USB peripheral controller drivers and the various gadget drivers which talk to them. Individual USB driver directories. A new driver should be added to the first subdirectory in the list below that it fits into. image/ - This is for still image drivers, like scanners or digital cameras. ../input/ - This is for any driver that uses the input subsystem, like keyboard, mice, touchscreens, tablets, etc. ../media/ - This is for multimedia drivers, like video cameras, radios, and any other drivers that talk to the v4l subsystem. ../net/ - This is for network drivers. serial/ - This is for USB to serial drivers. storage/ - This is for USB mass-storage drivers. class/ - This is for all USB device drivers that do not fit into any of the above categories, and work for a range of USB Class specified devices. misc/ - This is for all USB device drivers that do not fit into any of the above categories.