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To create a global command queue we require that each command put on the command ring is submitted with a command structure. Functions that queue commands and wait for completion need to allocate a command before submitting it, and free it once completed. The following command queuing functions need to be modified. xhci_configure_endpoint() xhci_address_device() xhci_queue_slot_control() xhci_queue_stop_endpoint() xhci_queue_new_dequeue_state() xhci_queue_reset_ep() xhci_configure_endpoint() xhci_configure_endpoint() could already be called with a command structure, and only xhci_check_maxpacket and xhci_check_bandwidth did not do so. These are changed and a command structure is now required. This change also simplifies the configure endpoint command completion handling and the "goto bandwidth_change" handling code can be removed. In some cases the command queuing function is called in interrupt context. These commands needs to be allocated atomically, and they can't wait for completion. These commands will in this patch be freed directly after queuing, but freeing will be moved to the command completion event handler in a later patch once we get the global command queue up.(Just so that we won't leak memory in the middle of the patch set) Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.