* Mark SPU memory as sleep-blocking.
* Perform 4-byte accesses only in dma_memset() and dma_memcpy() (32-byte
accesses freeze as one would expect).
This change does *NOT* implement support for SPU's integrated DMAC.
The checks for VRAM access account for image columns intersecting the
longword before the start of a VRAM line, but not the longword after the
start of a VRAM line. This is now fixed.
Known limitation: OpenLibm can't be installed out of the compiler prefix
yet (because of that pesky openlibm/ prefix that it installs to but does
not use when including).
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.
The function was designed with multi-threaded concurrency in mind,
where threads can take over while the lock is held and simply block
trying to acquire it, which allows the lock holder to proceed.
However interrupt handlers are different; they have priority, so once
they start they must complete immediately. The cannot afford to block
on the lock as the program would simply freeze. In exchange, they clean
up before they leave, so there are some guarantees on the execution
state even when interrupted.
The correct protection is therefore not a lock but a temporary block on
interrupts. There is no data race on the value of the saved IMASK
because it is preserved during interrupt handling.
This change introduces new sleep_block() and sleep_unblock() functions
that control whether the sleep() function actually sleeps. This type of
behavior was already implemented in the DMA driver, since DMA access to
on-chip memory is paused when sleeping (on-chip memory being paused
itself), which would make waiting for a DMA transfer a freeze.
Because DMA transfers are now asynchronous, and USB transfers that may
involve on-chip memory are coming, this API change allows the DMA and
USB drivers to block the sleep() function so that user code can sleep()
for interrupts without having to worry about asynchronous tasks
requiring on-chip memory to complete.
