* Clear pipes and FIFOs during world switches to avoid interference
with the OS. LINK uses pipes 3 and 4, and attempts to add a second
pipe to the fxlink interface (thus using pipe 4) would interfere with
LINK and somehow prevent the pipe from being used (Wireshark captures
showed no responses on that pipe). Forcing a blank state is a valid
move because that state occurs naturally after a RESET, thus LINK and
other add-ins must support it as well.
* Delay the application of configuration to the USB configuration stage
(specifically, the DVST configured interrupt, even though technically
we should do that in SET_CONFIGURATION 0). This is because we
previously relied on world switches preserving pipe settings (by not
changing them) to reconnect the gint driver after a world switch.
This is no longer possible as the world switch now clears the pipes.
The new timing makes the driver automatically re-configure as the
connection restarts.
* Move logic around tracking transfers to asyncio.c.
* Add a "short buffer" holding 0-3 bytes between writes, so that the
driver performs only 4-byte writes in the FIFO and a short write in
the commit, if needed.
- This is partially due to me thinking at some point that degrading
writing size was impossible, but it might actually be possible by
writing to FIFO/FIFO+2 or FIFO/FIFO+1/FIFO+2/FIFO+3.
- In any case I think this new approach wins on performance.
* Get rid of unit_size since we now always use 4 bytes.
* Add a waiting function which is used in usb_close() (and once tested
should be used in world switches too).
* Eliminate some of the special cases for the DCP, though not all (in
particular I can't get the commit to rely on the BEMP interrupt yet,
nor can I properly clear PID to NAK when unbinding).
* Finish updating the register list
* Use RTC-based timeouts to not involve more interrupts
* Be a lot more conservative about PID=BUF
* Start setting up parameters and checking invariants for future
bidirectional communications
We're not using them yet (specifically in fxlink) because timeouts
leave the pipes in undesirable states that currently end up crashing.
Some reset mechanism is needed, plus support from the protocol for
canceling messages, etc.
When the driver goes through a world switch a reconnection with the host
is needed before operations can resume. This requires usb_open_status to
be reset.
Also: bind a FIFO before a commit that involves data transfer, mirroring
what happens in writes. This ensures that PID is set to BUF, mainly.
Performing an asynchronous commit on an inactive pipe would yield
USB_COMMIT_INACTVE and *not* invoke the callback (as intended),
which usb_commit_sync() ignored, causing a freeze.
This issue appeared after a world switch, which (for reasons not yet
known) appear to fail the first writes until a commit, and that commit
would then hit an inactive pipe.
Nothing particular to change, simply make sure that the DMA channels
have higher priority than the USB module, otherwise the BEMP interrupt
might be executed before the DMA frees the channel, resulting in the
transfer failing because the channel is still busy.
Also reduce BUSWAIT since it works even on high overclock levels, and
keeping it high won't help increase performance.
This changes fixes the way gint uses the FIFO controllers D0F and D1F
to access the FIFO. It previously used D0F in the main thread and D1F
during interrupt handling, but this is incorrect for several reasons,
mainly the possible change of controllers between a write and a commit,
and numerous instances of two FIFOs managing the same pipe caused by
the constant switching.
gint now treats FIFO controllers as resources allocated to pipes for
the duration of a commit-terminated sequence of writes. The same
controller is used for a single pipe in both normal and interrupt
modes, and released when the pipe is committed. If no controller is
available, asynchronous writes fail and synchronous ones wait.
The fxlink API is also added with a small amount of functions, namely
to transfer screenshots and raw text. Currently these are synchronous
and do not use the DMA, this will be improved later.
Finally:
* Removed pipe logic from src/usb/setup.c, instead letting pipes.c
handle the special case of the DCP (which might be regularized later)
* Removed the usb_pipe_mode_{read,write} functions as they're actually
about FIFo controllers and it's not clear yet how a pipe with both
read and write should be handled. This is left for the future.
* Clarified end-of-sequence semantics after a successful commit.
* Properly define the callback time of a write/commit as the time when
the pipe is available again for further writing.
* Refuse commits when writes are pending; instead, enforce a strict
order of finishing writes before committing, which makes sense since
consecutive writes are ordered this way already.
* Properly support callbacks for writes and for commits.
* Define the synchronous APIs in terms of waiting until the callbacks
for equivalent asynchronous functions are invoked (plus initial
waiting for pipes to be ready).
* Add the power management functions (mostly stable even under
overclock; requires some testing, but no known issue)
* Add a dynamic configuration system where interfaces can declare
descriptors with arbitrary endpoint numbers and additional
parameters, and the driver allocates USB resources (endpoints, pipes
and FIFO memory) between interfaces at startup. This allows
implementations of different classes to be independent from each
other.
* Add responses to common SETUP requests.
* Add pipe logic that allows programs to write data synchronously or
asynchronously to pipes, in a single or several fragments, regardless
of the buffer size (still WIP with a few details to polish and the
API is not public yet).
* Add a WIP bulk IN interface that allows sending data to the host.
This will eventually support the fxlink protocol.
Lephe