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21da84a893
This patch refactors some shutdown code so it can be shared between ehci_stop() and ehci_shutdown(). This also fixes a couple potential bugs: - ehci_shutdown() was not locking ehci->lock before halting the HC. - ehci_shutdown() didn't disable the watchdog and IAA timers. - ehci_stop() was resetting the host controller when it may have been running, which the EHCI spec says "may result in undefined behavior". ehci_stop() was calling port_power() to turn off the ports, which waited 20ms after applying the port change. The msleep was for the case where the HC might take 20ms to turn the ports on; since we're shutting them off, we can avoid the msleep and just use ehci_turn_off_ports(). ehci_stop() doesn't need to clear the intr_enable register or revert ownership of the companion controllers to the BIOS, because the host controller reset should have done that. There might be a buggy host controller that doesn't follow the reset rules, but for now we assume it's redundant code and remove it. [ A subsequent patch will cancel the timers later ... this version carries forward existing bugs where timers could get re-armed after they're canceled. ] Signed-off-by: Sarah Sharp <sarah.a.sharp@intel.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
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| 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.