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This patch changes the way ohci-hcd handles the TD done list. In addition to relying on the TD pointers stored by the controller hardware, we need to handle TDs that the hardware has forgotten about. This means the list has to exist even while the dl_done_list() routine isn't running. That function essentially gets split in two: update_done_list() reads the TD pointers stored by the hardware and adds the TDs to the done list, and process_done_list() scans through the list to handle URB completions. When we detect a TD that the hardware forgot about, we will be able to add it to the done list manually and then process it normally. Since the list is really a queue, and because there can be a lot of TDs, keep the existing singly linked implementation. To insure that URBs are given back in order of submission, whenever a TD is added to the done list, all the preceding TDs for the same endpoint must be added as well (going back to the first one that isn't already on the done list). The done list manipulations must all be protected by the private lock. The scope of the lock is expanded in preparation for the watchdog routine to be added in a later patch. We have to be more careful about giving back unlinked URBs. Since TDs may be added to the done list by the watchdog routine and not in response to a controller interrupt, we have to check explicitly to make sure all the URB's TDs that were added to the done list have been processed before giving back the URB. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| 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.