* 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).
* Create a heap arena over the OS stack, large enough to hold two VRAMs
as was previously done, unless GINT_NO_OS_STACK is set at compile
time. (This replaces GINT_USER_VRAM.)
* Allocate a single VRAM in the heap at startup.
* Use double buffering by default as triple buffering is almost entirely
useless. dudpate() waits if both VRAMs are identical to prevent
corruption, but this can be bypassed with R61524 functions as usual.
This adds about 180 kB of heap data to any add-in using default
settings.
* Stop trying to be smart and generate repeats on the fly; this breaks
time consistency. Also if repeats are not handled in time this causes
infinite loops.
* Move rarely-used functions to external files, simplify stuff, get rid
of internal driver events; saves ~1 kB per add-in overall.
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.
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.
* Change gint_inth_callback()
* Add intc_handler_function() to use C functions as handlers instead of
writing assembler, and use it in the RTC and USB
* Revisit the TMU handlers, which after moving out the callbacks, now
fit into 3 gates (great!), and adapt the ETMU handler
* Improve the timer driver (less code = better code, removed magic
constants assuming the VBR layout on SH3/SH4, etc.)
* Remove 2 gates and a gap from the compact scheme on SH3
* Define timer_configure() to replace timer_setup(), which could not be
cleanly updated to support GINT_CALL()
* Replace rtc_start/stop_timer with rtc_periodic_enable/disable, which
is less confusing because of ETMU being "RTC timers"
Changes in the driver and world system:
* Rewrite driver logic to include more advanced concepts. The notion of
binding a driver to a device is introduced to formalize wait(); power
management is now built-in instead of being handled by the drivers
(for instance DMA). The new driver model is described in great detail
in <gint/drivers.h>
* Formalized the concept of "world switch" where the hardware state is
saved and later restored. As a tool, the world switch turns out to be
very stable, and allows a lot of hardware manipulation that would be
edgy at best when running in the OS world.
* Added a GINT_DRV_SHARED flag for drivers to specify that their state
is shared between worlds and not saved/restored. This has a couple of
uses.
* Exposed a lot more of the internal driver/world system as their is no
particular downside to it. This includes stuff in <gint/drivers.h>
and the driver's state structures in <gint/drivers/states.h>. This is
useful for debugging and for cracked concepts, but there is no
API stability guarantee.
* Added a more flexible driver level system that allows any 2-digit
level to be used.
Feature changes:
* Added a CPU driver that provides the VBR change as its state save.
Because the whole context switch relied on interrupts being disabled
anyway, there is no longer an inversion of control when setting the
VBR; this is just part of the CPU driver's configuration. The CPU
driver may also support other features such as XYRAM block transfer
in the future.
* Moved gint_inthandler() to the INTC driver under the name
intc_handler(), pairing up again with intc_priority().
* Added a reentrant atomic lock based on the test-and-set primitive.
Interrupts are disabled with IMASK=15 for the duration of atomic
operations.
* Enabled the DMA driver on SH7305-based fx-9860G. The DMA provides
little benefit on this platform because the RAM is generally faster
and buffers are ultimately small. The DMA is still not available on
SH3-based fx-9860G models.
* Solved an extremely obnoxious bug in timer_spin_wait() where the
timer is not freed, causing the callback to be called when interrupts
are re-enabled. This increments a random value on the stack. As a
consequence of the change, removed the long delays in the USB driver
since they are not actually needed.
Minor changes:
* Deprecated some of the elements in <gint/hardware.h>. There really is
no good way to "enumerate" devices yet.
* Deprecated gint_switch() in favor of a new function
gint_world_switch() which uses the GINT_CALL abstraction.
* Made the fx-9860G VRAM 32-aligned so that it can be used for tests
with the DMA.
Some features of the driver and world systems have not been implemented
yet, but may be in the future:
* Some driver flags should be per-world in order to create multiple
gint worlds. This would be useful in Yatis' hypervisor.
* A GINT_DRV_LAZY flag would be useful for drivers that don't want to
be started up automatically during a world switch. This is relevant
for drivers that have a slow start/stop sequence. However, this is
tricky to do correctly as it requires dynamic start/stop and also
tracking which world the current hardware state belongs to.
