arm: Use little endian packet accessors.

We know data is little endian, so we can use those accessors
explicitly.

Change-Id: Iee337109fcda134e1ac5a700e5141fd7060f9c45
Reviewed-on: https://gem5-review.googlesource.com/c/13457
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arm: ignore writes to the reset_ctl register

Change-Id: I953521572e6ace475b656369c9f07ddfa50d731a
Signed-off-by: Gedare Bloom <gedare@rtems.org>
Reviewed-on: https://gem5-review.googlesource.com/3263
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

sim: Thermal support for Linux

This patch enables Linux to read the temperature using hwmon infrastructure.
In order to use this in your gem5 you need to compile the kernel using the
following configs:

CONFIG_HWMON=y
CONFIG_SENSORS_VEXPRESS=y

And a proper dts file (containing an entry such as):

dcc {
compatible = "arm,vexpress,config-bus";
arm,vexpress,config-bridge = <&v2m_sysreg>;

temp@0 {
compatible = "arm,vexpress-temp";
arm,vexpress-sysreg,func = <4 0>;
label = "DCC";
};
};

arm: Add support for programmable oscillators

Add support for oscillators that can be programmed using the RealView
/ Versatile Express configuration interface. These oscillators are
typically used for things like the pixel clock in the display
controller.

The default configurations support the oscillators from a Versatile
Express motherboard (V2M-P1) with a CoreTile Express A15x2.

sim: Refactor the serialization base class

Objects that are can be serialized are supposed to inherit from the
Serializable class. This class is meant to provide a unified API for
such objects. However, so far it has mainly been used by SimObjects
due to some fundamental design limitations. This changeset redesigns
to the serialization interface to make it more generic and hide the
underlying checkpoint storage. Specifically:

* Add a set of APIs to serialize into a subsection of the current
object. Previously, objects that needed this functionality would
use ad-hoc solutions using nameOut() and section name
generation. In the new world, an object that implements the
interface has the methods serializeSection() and
unserializeSection() that serialize into a named /subsection/ of
the current object. Calling serialize() serializes an object into
the current section.

* Move the name() method from Serializable to SimObject as it is no
longer needed for serialization. The fully qualified section name
is generated by the main serialization code on the fly as objects
serialize sub-objects.

* Add a scoped ScopedCheckpointSection helper class. Some objects
need to serialize data structures, that are not deriving from
Serializable, into subsections. Previously, this was done using
nameOut() and manual section name generation. To simplify this,
this changeset introduces a ScopedCheckpointSection() helper
class. When this class is instantiated, it adds a new /subsection/
and subsequent serialization calls during the lifetime of this
helper class happen inside this section (or a subsection in case
of nested sections).

* The serialize() call is now const which prevents accidental state
manipulation during serialization. Objects that rely on modifying
state can use the serializeOld() call instead. The default
implementation simply calls serialize(). Note: The old-style calls
need to be explicitly called using the
serializeOld()/serializeSectionOld() style APIs. These are used by
default when serializing SimObjects.

* Both the input and output checkpoints now use their own named
types. This hides underlying checkpoint implementation from
objects that need checkpointing and makes it easier to change the
underlying checkpoint storage code.

mem: Remove redundant Packet::allocate calls

This patch cleans up the packet memory allocation confusion. The data
is always allocated at the requesting side, when a packet is created
(or copied), and there is never a need for any device to allocate any
space if it is merely responding to a paket. This behaviour is in line
with how SystemC and TLM works as well, thus increasing
interoperability, and matching established conventions.

The redundant calls to Packet::allocate are removed, and the checks in
the function are tightened up to make sure data is only ever allocated
once. There are still some oddities in the packet copy constructor
where we copy the data pointer if it is static (without ownership),
and allocate new space if the data is dynamic (with ownership). The
latter is being worked on further in a follow-on patch.

dev: Add 'OSC' oscillator sys control reg support to VersatileExpress

The VE motherboard provides a set of system control registers through which
various motherboard and coretile registers are accessed. Voltage regulators and
oscillator (DLL/PLL) config are examples. These registers must be impleted to
boot Linux 3.9+ kernels.

dev: make BasicPioDevice take size in constructor

Instead of relying on derived classes explicitly assigning
to the BasicPioDevice pioSize field, require them to pass
a size value in to the constructor.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

ARM: fix the calculation of the values in the RV clocks

This clock is used by the linux scheduler.

gem5: Fix a number of incorrect case statements

ARM: Add support for Versatile Express extended memory map

Also clean up how we create boot loader memory a bit.

ARM: Add support for Versatile Express boards

ARM: Better RealView/Versatile EB platform support.

Add registers and components to better support the VersatileEB board.
Made the MIDR and SYS_ID register parameters to ArmSystem and RealviewCtrl
respectively.

ARM: Add support for some more registers in the real view controller.

RealView: Fix the 24 and 100MHz clocks which were providing incorrect values.

ARM: Add support for read of 100MHz clock in system controller.

VNC/ARM: Use VNC server and add support to boot into X11

Replace curTick global variable with accessor functions.
This step makes it easy to replace the accessor functions
(which still access a global variable) with ones that access
per-thread curTick values.

ARM: Add checkpointing support

ARM: Add I/O devices for booting linux