firmware: arm_sdei: add support for CPU private events

Private SDE events are per-cpu, and need to be registered and enabled
on each CPU.

Hide this detail from the caller by adapting our {,un}regis

firmware: arm_sdei: add support for CPU private events

Private SDE events are per-cpu, and need to be registered and enabled
on each CPU.

Hide this detail from the caller by adapting our {,un}register and
{en,dis}able calls to send an IPI to each CPU if the event is private.

CPU private events are unregistered when the CPU is powered-off, and
re-registered when the CPU is brought back online. This saves bringing
secondary cores back online to call private_reset() on shutdown, kexec
and resume from hibernate.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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firmware: arm_sdei: Add support for CPU and system power states

When a CPU enters an idle lower-power state or is powering off, we
need to mask SDE events so that no events can be delivered while we

firmware: arm_sdei: Add support for CPU and system power states

When a CPU enters an idle lower-power state or is powering off, we
need to mask SDE events so that no events can be delivered while we
are messing with the MMU as the registered entry points won't be valid.

If the system reboots, we want to unregister all events and mask the CPUs.
For kexec this allows us to hand a clean slate to the next kernel
instead of relying on it to call sdei_{private,system}_data_reset().

For hibernate we unregister all events and re-register them on restore,
in case we restored with the SDE code loaded at a different address.
(e.g. KASLR).

Add all the notifiers necessary to do this. We only support shared events
so all events are left registered and enabled over CPU hotplug.

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
[catalin.marinas@arm.com: added CPU_PM_ENTER_FAILED case]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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firmware: arm_sdei: Add driver for Software Delegated Exceptions

The Software Delegated Exception Interface (SDEI) is an ARM standard
for registering callbacks from the platform firmware into the OS

firmware: arm_sdei: Add driver for Software Delegated Exceptions

The Software Delegated Exception Interface (SDEI) is an ARM standard
for registering callbacks from the platform firmware into the OS.
This is typically used to implement firmware notifications (such as
firmware-first RAS) or promote an IRQ that has been promoted to a
firmware-assisted NMI.

Add the code for detecting the SDEI version and the framework for
registering and unregistering events. Subsequent patches will add the
arch-specific backend code and the necessary power management hooks.

Only shared events are supported, power management, private events and
discovery for ACPI systems will be added by later patches.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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