dev-arm: Cleanup GICv3 initialization

This patch is removing the unnecessary initState() / reset() methods
from GICv3 classes, since we can initialize everything at
construction/init time

Change-Id: Ia70edcc4ca4f11878fac0024342e4f2cd81883a0
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20636
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

dev-arm: Rewrite GICv3 update

The GICv3 update methods are method which are invoked anytime the model
needs to evaluate a change in its state, which most of the time means
managing the state of an interrupt (forwarding it to a PE, deasserting
it, etc).
The way it is currently done is a little bit obscure and doesn't
handle correctly IRQ prioritization.
Example:
An IRQ which is handled by the redistributor (PPI or LPI) was not
competing with any pending interrupts coming from the distributor (SPIs)
once raised by a peripheral.

Also the way the pending state of an interrupt was removed at the
cpu interface level wasn't happening in place where this was actually
happening (E.g. when activating it), but happened with a weird
fullUpdate semantic, where if there was a pending interrupt in a
cpu interface, all cpu interfaces had their pending interrupt (if any)
been disabled.

With this patch, state update always starts at the distributor, and
it goes down until the cpu interface where a Gicv3CPUInterface::update
method selects the winning interrupt coming from distributor/redistributor
to be forwarded to the PE.

Change-Id: I1c517cbc4bf107cc2d7ae7beb2692e3cf5187a40
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20614
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

dev-arm: Provide a GICv3 ITS Implementation

This patch introduces the GICv3 ITS module, which is in charge of
translating MSIs into physical (GICv3) and virtual (GICv4) LPIs. The
patch is only GICv3 compliant, which means that there is no direct
virtual LPI injection (this also means V* commands are unimplemented)
Other missing features are:

* No 2level ITS tables (only flat table supported)

* Command errors: when there is an error in the ITS, it is
IMPLEMENTATION DEFINED on how the ITS behaves. There are three possible
scenarios (see GICv3 TRM) and this implementation only supports one of
these (which is, aborting the command and jumping to the next one).
Furter patches could make it possible to select different reactions

* Invalidation commands (INV, INVALL) are only doing the memory table
walks, assuming the current Gicv3Redistributor is not caching any
configuration table entry.

Change-Id: If4ae9267ac1de7b20a04986a2af3ca3109743211
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18601
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

dev-arm: Store a PhysProxy port in Gicv3Redist

This spares us from retrieving the TC pointer every time we want to
write/read to memory (LPIs)

Change-Id: Iad76b5e69188fa0ac5c6777a3b2664b0fc66b12f
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18600
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

dev-arm: Add several LPI methods in Gicv3Redistributor

Refactoring the existing in code in smaller methods will be crucial when
adding the ITS module, which is a client for the redistributor class and
which will require it to take different actions depending on the command
it receives from software.

List of methods:

* read/writeEntryLPI
Reading/Writing a byte from the LPI pending table

* isPendingLPI
Checks if the pINTID LPI is set. Knowing if an LPI is set is needed by
the MOVI command, which is transfering the pending state from one
redistributor to the other only if the LPI is pending.

Change-Id: If14b1c28ff7f2aa20b12dcd822bf6a490cbe0270
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18596
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

dev-arm: Disable LPI Configuration Table caching

This is done since caching is not done correctly, and we don't care for
now about performance degradations since the redistributor is using
PhysProxy ports.
Caching will make sense once the magical accesses will be replaced by
real atomic/timing transactions.

Change-Id: Iafe2a7843210111efc82c265bd0d5ec3cd9abb5a
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18593
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

dev-arm: Add GICv4 extension switch in GICv3

This is currently used only for determining which is the correct
size of redistributors in memory (256KB in GICv4 and 128KB in GICv3)

Change-Id: I2c07005e97167fde03548313c9927176788f31dd
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18391
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

dev-arm: cleanup of gicv3 code

Change-Id: I9aba90022f6408838c4ab87c6b90bba438752e53
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/16222
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>

dev-arm: LPI support for GICv3. This doesn't include an ITS model.

Change-Id: Ia2c02cca4f95672d6361fba16201a56e2047ddb7
Reviewed-on: https://gem5-review.googlesource.com/c/16142
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

dev-arm: Add a GICv3 model

Change-Id: Ib0067fc743f84ff7be9f12d2fc33ddf63736bdd1
Reviewed-on: https://gem5-review.googlesource.com/c/13436
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>