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Interrupt transfers are submitted to the xHCI hardware using the same TRB type as bulk transfers. Re-use the bulk transfer enqueueing code to enqueue interrupt transfers. Interrupt transfers are a bit different than bulk transfers. When the interrupt endpoint is to be serviced, the xHC will consume (at most) one TD. A TD (comprised of sg list entries) can take several service intervals to transmit. The important thing for device drivers to note is that if they use the scatter gather interface to submit interrupt requests, they will not get data sent from two different scatter gather lists in the same service interval. For now, the xHCI driver will use the service interval from the endpoint's descriptor (bInterval). Drivers will need a hook to poll at a more frequent interval. Set urb->interval to the interval that the xHCI hardware will use. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
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| host | ||
| image | ||
| misc | ||
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| otg | ||
| 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.