In theory USB3 ports do not require a reset to enable the port.
Experimentation shows that this is sometimes required, particularly
when rerouting ports from EHCI to xHCI and switching speeds.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[xhci] Support USB1 devices attached via transaction translators
xHCI provides a somewhat convoluted mechanism for specifying details
of a transaction translator. Hubs must be marked as such in the
device slot context. The only opportunity to do so is as part of a
Configure Endpoint command, which can be executed only when opening
the hub's interrupt endpoint.
We add a mechanism for host controllers to intercept the opening of
hub devices, providing xHCI with an opportunity to update the internal
device slot structure for the corresponding USB device to indicate
that the device is a hub. We then include the hub-specific details in
the input context whenever any Configure Endpoint command is issued.
When a device is opened, we record the device slot and port for its
transaction translator (if any), and supply these as part of the
Address Device command.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[ehci] Support USB1 devices attached via transaction translators
Support low-speed and full-speed devices attached to a USB2 hub. Such
devices use a transaction translator (TT) within the USB2 hub, which
asynchronously initiates transactions on the lower-speed bus and
returns the result via a split completion on the high-speed bus.
We make the simplifying assumption that there will never be more than
sixteen active interrupt endpoints behind a single transaction
translator; this assumption allows us to schedule all periodic start
splits in microframe 0 and all periodic split completions in
microframes 2 and 3. (We do not handle isochronous endpoints.)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The endpoint may already have enqueued TRBs at the time that
xhci_endpoint_reset() is called. Ring the doorbell to resume
processing these TRBs immediately, rather than waiting until the next
call to xhci_endpoint_message() or xhci_endpoint_stream().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Several of the USB timeouts were chosen on the principle of "pick an
arbitrary but ridiculously large value, just to be safe". It turns
out that some of the timeouts permitted by the USB specification are
even larger: for example, control transactions are allowed to take up
to five seconds to complete.
Fix up these USB timeout values to match those found in the USB2
specification.
Debugged-by: Robin Smidsrød <robin@smidsrod.no>
Tested-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[xhci] Do not release ownership back to BIOS when booting an OS
xHCI (and EHCI) nominally provide a mechanism for releasing ownership
of the host controller back to the BIOS, which can then potentially
restore legacy USB keyboard functionality.
This is a rarely used code path, since most operating systems claim
ownership and never attempt to later return to the BIOS. On some
systems (observed with a Lenovo X1 Carbon), this code path leads to
obscure and interesting bugs: if the xHCI and EHCI controllers are
both claimed and later released back to the BIOS, then a subsequent
call to INT 16,0305 to set the keyboard repeat rate to a non-default
value will lock the system.
Obscure though this sequence of operations may sound, it is exactly
what happens when using iPXE to boot a Linux kernel via a USB network
card. There is old and probably unwanted code in Linux's
arch/x86/boot/main.c which sets the keyboard repeat rate (with the
accompanying comment "Set keyboard repeat rate (why?)"). When booting
Linux via a USB network card on a Lenovo X1 Carbon, the system
therefore locks up immediately after jumping to the kernel's entry
point.
Work around this problem by preventing the release of ownership back
to the BIOS if it is known that we are shutting down to boot an OS.
This should allow legacy USB keyboard functionality to be restored if
the user chooses to exit iPXE, while avoiding the rarely used code
paths (and corresponding BIOS bugs) if the user chooses instead to
boot an OS.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[xhci] Forcibly disable SMIs if BIOS fails to release ownership
If the BIOS fails to gracefully release ownership of the xHCI
controller, we can forcibly claim it by disabling all SMIs via the
USB legacy support control/status register.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[xhci] Undo PCH-specific quirk fixes when removing device
Restore the original values of XUSB2PR and USB3PSSEN, in case we are
booting an OS with no support for xHCI.
Suggested-by: Dan Ellis <Dan.Ellis@displaylink.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[xhci] Enable USB3 ports on Intel PCH8/PCH9 controllers
Intel PCH controllers default to routing USB2 ports to EHCI rather
than xHCI, and default to disabling SuperSpeed connections.
Manipulate the PCI configuration space registers as necessary to
reroute ports and enable SuperSpeed.
Originally-fixed-by: Dan Ellis <Dan.Ellis@displaylink.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When a command times out, abort it (via the Command Abort bit in the
Command Ring Control Register) so that subsequent commands may execute
as expected.
This improves robustness when a device fails to respond to the Set
Address command, since the subsequent Disable Slot command will now
succeed.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[xhci] Leak memory if controller fails to disable slot
If the Disable Slot command fails then the hardware may continue to
write to the slot context. Leak the memory used by the slot context
to avoid future memory corruption.
This situation has been observed in practice when a Set Address
command fails, causing the command ring to become temporarily
unresponsive.
Note that there is no need to similarly leak memory on the failure
path in xhci_device_open(), since in the event of a failure the
hardware is never informed of the slot context address.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[xhci] Delay after (possibly) forcing port link state to RxDetect
Some xHCI controllers (observed with a Renesas Electronics PCIe USB3
card) seem to require a delay after forcing the link state of USB3
ports to RxDetect. Omitting this delay causes strange behaviour
including system lockups.
Add an unconditional 20ms delay after writing the port link states.
This seems to be sufficient to avoid the problem.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[usb] Allow usb_stream() to enforce a terminating short packet
Some USB endpoints require that a short packet be used to terminate
transfers, since they have no other way to determine message
boundaries. If the message length happens to be an exact multiple of
the USB packet size, then this requires the use of an additional
zero-length packet.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown