Add a platform driver to support non-root GICs that require runtime
power-management. Currently, only non-root GICs are supported because
the functions, smp_cross_call() and set_handle_irq(), that need to
be called for a root controller are located in the __init section and
so cannot be called by the platform driver.

The GIC platform driver re-uses many functions from the existing GIC
driver including some functions to save and restore the GIC context
during power transitions. The functions for saving and restoring the
GIC context are currently only defined if CONFIG_CPU_PM is enabled and
to ensure that these functions are always defined when the platform
driver is enabled, a dependency on CONFIG_ARM_GIC_PM (which selects the
platform driver) has been added.

In order to re-use the private GIC initialisation code, a new public
function, gic_of_init_child(), has been added which calls various
private functions to initialise the GIC. This is different from the
existing gic_of_init() because it only supports non-root GICs (ie. does
not call smp_cross_call() is set_handle_irq()) and is not located in
the __init section (so can be used by platform drivers). Furthermore,
gic_of_init_child() dynamically allocates memory for the GIC chip data
which is also different from gic_of_init().

There is no specific suspend handling for GICs registered as platform
devices. Non-wakeup interrupts will be disabled by the kernel during
late suspend, however, this alone will not power down the GIC if
interrupts have been requested and not freed. Therefore, requestors of
non-wakeup interrupts will need to free them on entering suspend in
order to power-down the GIC.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

To support GICs that require runtime power management, it is necessary
to add a platform driver, so that the probing of the chip can be
deferred if resources, such as a power-domain, is not yet available.

To prepare for adding a platform driver:
 1. Drop the __init section from the gic_dist_config() so this can be
    re-used by the platform driver.
 2. Add prototypes for functions required by the platform driver to the
    GIC header file so they can be re-used.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Those three registers are v2 emulation specific, so their implementation
lives entirely in vgic-mmio-v2.c. Also they are handled in one function,
as their implementation is pretty simple.
When the guest enables the distributor, we kick all VCPUs to get
potentially pending interrupts serviced.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

Processing maintenance interrupts and accessing the list registers
are dependent on the host's GIC version.
Introduce vgic-v2.c to contain GICv2 specific functions.
Implement the GICv2 specific code for syncing the emulation state
into the VGIC registers.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

Pull another round of GIC changes from Marc:

 ACPI support for GIV-v2m

This patch introduces gicv2m_acpi_init(), which uses information
in MADT GIC MSI frames structure to initialize GICv2m driver.
It also exposes gicv2m_init() function, which simplifies callers
to a single GICv2m init function.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Duc Dang <dhdang@apm.com>
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

The ARM RealView PB11MPCore reference design has some special
bits in a system controller register to set up the GIC in one
of three modes: legacy, new with DCC, new without DCC. The
register is also used to enable FIQ.

Since the platform will not boot unless this register is set
up to "new with DCC" mode, we need a special quirk to be
compiled-in for the RealView platforms.

If we find the right compatible string on the GIC TestChip,
we enable this quirk by looking up the system controller and
enabling the special bits.

We depend on the CONFIG_REALVIEW_DT Kconfig symbol as the old
boardfile code has the same fix hardcoded, and this is only
needed for the attempts to modernize the RealView code using
device tree.

After fixing this, the PB11MPCore boots with device tree
only.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Since nobody is using gic_init_bases anymore outside of the GIC
driver itself, let's do a bit of housekeeping and remove the now
useless entry point.

Only gic_init() is now exposed to the rest of the kernel for the
benefit of legacy systems.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-and-tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Tomasz Nowicki <tomasz.nowicki@linaro.org>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Cc: Graeme Gregory <graeme@xora.org.uk>
Cc: Jake Oshins <jakeo@microsoft.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Link: http://lkml.kernel.org/r/1444737105-31573-12-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Pull more kvm updates from Paolo Bonzini:
 "ARM:
   - Full debug support for arm64
   - Active state switching for timer interrupts
   - Lazy FP/SIMD save/restore for arm64
   - Generic ARMv8 target

  PPC:
   - Book3S: A few bug fixes
   - Book3S: Allow micro-threading on POWER8

  x86:
   - Compiler warnings

  Generic:
   - Adaptive polling for guest halt"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (49 commits)
  kvm: irqchip: fix memory leak
  kvm: move new trace event outside #ifdef CONFIG_KVM_ASYNC_PF
  KVM: trace kvm_halt_poll_ns grow/shrink
  KVM: dynamic halt-polling
  KVM: make halt_poll_ns per-vCPU
  Silence compiler warning in arch/x86/kvm/emulate.c
  kvm: compile process_smi_save_seg_64() only for x86_64
  KVM: x86: avoid uninitialized variable warning
  KVM: PPC: Book3S: Fix typo in top comment about locking
  KVM: PPC: Book3S: Fix size of the PSPB register
  KVM: PPC: Book3S HV: Exit on H_DOORBELL if HOST_IPI is set
  KVM: PPC: Book3S HV: Fix race in starting secondary threads
  KVM: PPC: Book3S: correct width in XER handling
  KVM: PPC: Book3S HV: Fix preempted vcore stolen time calculation
  KVM: PPC: Book3S HV: Fix preempted vcore list locking
  KVM: PPC: Book3S HV: Implement H_CLEAR_REF and H_CLEAR_MOD
  KVM: PPC: Book3S HV: Fix bug in dirty page tracking
  KVM: PPC: Book3S HV: Fix race in reading change bit when removing HPTE
  KVM: PPC: Book3S HV: Implement dynamic micro-threading on POWER8
  KVM: PPC: Book3S HV: Make use of unused threads when running guests
  ...

So far, GICv2 has been used with EOImode == 0. The effect of this
mode is to perform the priority drop and the deactivation of the
interrupt at the same time.

While this works perfectly for Linux (we only have a single priority),
it causes issues when an interrupt is forwarded to a guest, and when
we want the guest to perform the EOI itself.

For this case, the GIC architecture provides EOImode == 1, where:
- A write to the EOI register drops the priority of the interrupt
  and leaves it active. Other interrupts at the same priority level
  can now be taken, but the active interrupt cannot be taken again
- A write to the DIR marks the interrupt as inactive, meaning it can
  now be taken again.

We only enable this feature when booted in HYP mode and that
the device-tree reported a suitable CPU interface. Observable behaviour
should remain unchanged.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-and-tested-by: Eric Auger <eric.auger@linaro.org>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: kvmarm@lists.cs.columbia.edu
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1440604845-28229-4-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>