SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
Instead of polling if the device ended the operation, we can just use
interrupts for signalling about end of IO operation.
In similar way, we use interrupts during device detection.
Also, we use the new Work Queue mechanism introduced by @tomuta to allow
better performance and stability :)
These errors are classed as fatal, so we need to recover from them.
Found while trying to debug AHCI boot on VMware Player,
where I got TFES.
From the spec: "Fatal errors (signified by the setting of PxIS.HBFS,
PxIS.HBDS, PxIS.IFS, or PxIS.TFES) will cause the HBA to enter
the ERR:Fatal state"
We were already recovering from IFS.
Instead of blindly resetting every AHCI port, let's just reset only the
controller by default. The user can still request to reset everything
with a new kernel boot argument called ahci_reset_mode which is set
by default to "controller", so the code will only invoke an HBA reset.
This kernel boot argument can be set to 3 different values:
1. "controller" - reset the HBA and skip resetting AHCI ports
2. "none" - don't reset anything, so we rely on the firmware to
initialize the AHCI HBA and ports for us.
3. "complete" - reset the AHCI HBA and ports.
Instead of waiting for the AHCI HBA to reset the signature after SATA
reset sequence, let's just check if the Port x Serial ATA Status
register was set to value 3, indicating that device was detected
and phy communication was established.
The intention is to make the boot to be faster, therefore we should
decrease the time deltas in timeout loops to allow earlier break
from these.
Also, there's no need to wait 10 milliseconds before setting
the interface state to "no action request" during the reset sequence.
This class is used in the AHCI code to handle a big request of
read/write to the disk. If we happen to encounter such request,
we will get the needed amount of physical pages from the
already-allocated physical pages in AHCIPort, and with that we
will create a ScatterList that will create a Region that maps
all of these pages in a contiguous virtual memory range.
Then, we could easily copy to/from this range, before and after
calling the operation on the StorageDevice as needed with
read or write operations.
The hierarchy is AHCIController, AHCIPortHandler, AHCIPort and
SATADiskDevice. Each AHCIController has at least one AHCIPortHandler.
An AHCIPortHandler is an interrupt handler that takes care of
enumeration of handled AHCI ports when an interrupt occurs. Each
AHCIPort takes care of one SATADiskDevice, and later on we can add
support for Port multiplier.
When we implement support of Message signalled interrupts, we can spawn
many AHCIPortHandlers, and allow each one of them to be responsible for
a set of AHCIPorts.
