mirror of
https://github.com/FEX-Emu/linux.git
synced 2025-01-18 23:59:53 +00:00
c563543784
Introduce the notion of a PCI device that may be associated with more than one USB host controller driver (struct usb_hcd). This patch is the start of the work to separate the xHCI host controller into two roothubs: a USB 3.0 roothub with SuperSpeed-only ports, and a USB 2.0 roothub with HS/FS/LS ports. One usb_hcd structure is designated to be the "primary HCD", and a pointer is added to the usb_hcd structure to keep track of that. A new function call, usb_hcd_is_primary_hcd() is added to check whether the USB hcd is marked as the primary HCD (or if it is not part of a roothub pair). To allow the USB core and xHCI driver to access either roothub in a pair, a "shared_hcd" pointer is added to the usb_hcd structure. Add a new function, usb_create_shared_hcd(), that does roothub allocation for paired roothubs. It will act just like usb_create_hcd() did if the primary_hcd pointer argument is NULL. If it is passed a non-NULL primary_hcd pointer, it sets usb_hcd->shared_hcd and usb_hcd->primary_hcd fields. It will also skip the bandwidth_mutex allocation, and set the secondary hcd's bandwidth_mutex pointer to the primary HCD's mutex. IRQs are only allocated once for the primary roothub. Introduce a new usb_hcd driver flag that indicates the host controller driver wants to create two roothubs. If the HCD_SHARED flag is set, then the USB core PCI probe methods will allocate a second roothub, and make sure that second roothub gets freed during rmmod and in initialization error paths. When usb_hc_died() is called with the primary HCD, make sure that any roothubs that share that host controller are also marked as being dead. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.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.