We do that to increase clarity of the major and secondary components in
the subsystem. To ensure it's even more understandable, we rename the
files to better represent the class within them and to remove redundancy
in the name.
Also, some includes are removed from the general components of the ATA
components' classes.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
Instead of doing this in a parent class like the AHCIController, let's
do that directly in the AHCIPort class as that class is the only user of
these sort of physical pages. While it seems like we waste an entire 4KB
of physical RAM for each allocation, this could serve us later on if we
want to fetch other types of logs from the ATA device.
The way AHCIPortHandler held AHCIPorts and even provided them with
physical pages for the ATA identify buffer just felt wrong.
To fix this, AHCIPortHandler is not a ref-counted object anymore. This
solves the big part of the problem, because AHCIPorts can't hold a
reference to this object anymore, only the AHCIController can do that.
Then, most of the responsibilities are shifted to the AHCIController,
making the AHCIPortHandler a handler of port interrupts only.
The AHCI code is not very good at OOM conditions, so this is a first
step towards OOM correctness. We should not allocate things inside C++
constructors because we can't catch OOM failures, so most allocation
code inside constructors is exported to a different function.
Also, don't use a HashMap for holding RefPtr of AHCIPort objects in
AHCIPortHandler because this structure is not very OOM-friendly. Instead
use a fixed Array of 32 RefPtrs, as at most we can have 32 AHCI ports
per AHCI controller.
Instead of repeating ourselves with the pattern of waiting for some
condition to be met, we can have a general method for this task,
and then we can provide the retry count, the required delay and a lambda
function for the checked condition.
Don't use interrupts when trying to reset a device that is connected to
a port on the AHCI controller, and instead poll for changes in status to
break out from the loop. At the worst case scenario we can wait 0.01
seconds for each SATA reset.
Don't use interrupts when trying to identify a device that is connected
to a port on the AHCI controller, and instead poll for changes in status
to end the transaction.
Not only this simplifies the initialization sequence, it ensures that
for whatever reason the controller doesn't send an IRQ, we are never
getting stuck at this point.
Like what happened with the PCI and USB code, this feels like the right
thing to do because we can improve on the ATA capabilities and keep it
distinguished from the rest of the subsystem.
