mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-16 19:29:06 +08:00
4858f06e7d
Fixes mis-use of MUSB's hardware feature where it won't flush FIFOs when TXPKTRDY flag was set before and we are flushing setting both FLUSHFIFO and TXPKTRDY. In other words, we need to ensure that when we try to flush FIFOs, we don't accidentaly set TXPKTRDY bit too due to a read-back of the register. The MUSB Programming Guide says "May be set simultaneously with TxPktRdy to abort the packet that is currently being loaded into the FIFO". This is a situation where TXPKTRDY hasn't been set yet, but some data already loaded into the fifo. It looks, that if TXPKTRDY has been set before, and there is no loading in progress, but we set FLUSHFIFO with the TXPKTRDY, controller tries to use the same logic to abort loading and as the result just does nothing (because there is no packet been loaded currently) Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@nokia.com> [ balbi@ti.com : fixed one whitespace git complained about improved the commit log slightly ] Signed-off-by: Felipe Balbi <balbi@ti.com>
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.