soc: apple: mailbox: Rename config symbol to APPLE_MAILBOX

With the original owner of APPLE_MAILBOX removed, let's rename the new
APPLE_MBOX to the old name. This avoids .config churn for downstream
users, and leaves us with an identical config symbol and module name as
before.

Acked-by: Eric Curtin <ecurtin@redhat.com>
Acked-by: Neal Gompa <neal@gompa.dev>
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Hector Martin <marcan@marcan.st>

soc: apple: mailbox: Add ASC/M3 mailbox driver

This new driver is based on the existing apple-mailbox driver, but
replaces the usage of the mailbox subsystem with directly exported
symbols.

As part of this refactor, this adds support for using the hardware FIFOs
(not supported in mailbox) and implicitly fixes a bunch of bugs caused
by bad interactions with the mailbox subsystem. It also adds runtime-PM
support.

The new config symbol is APPLE_MBOX, while the module name remains
identical ("apple-mailbox"). The configs are mutually exclusive in
Kconfig, to avoid conflicts.

Acked-by: Eric Curtin <ecurtin@redhat.com>
Acked-by: Neal Gompa <neal@gompa.dev>
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Hector Martin <marcan@marcan.st>

soc: apple: Move power-domain driver to the genpd dir

To simplify with maintenance let's move the apple power-domain driver to
the new genpd directory. Going forward, patches are intended to be managed
through a separate git tree, according to MAINTAINERS.

Cc: Hector Martin <marcan@marcan.st>
Cc: Sven Peter <sven@svenpeter.dev>
Cc: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Cc: <asahi@lists.linux.dev>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

soc: apple: Add SART driver

The NVMe co-processor on the Apple M1 uses a DMA address filter called
SART for some DMA transactions. This adds a simple driver used to
configure the memory regions from which DMA transactions are allowed.

Unlike a real IOMMU, SART does not support any pagetables and can't be
implemented inside the IOMMU subsystem using iommu_ops.

It also can't be implemented using dma_map_ops since not all DMA
transactions of the NVMe controller are filtered by SART.
Instead, most buffers have to be registered using the integrated NVMe
IOMMU and we can't have two separate dma_map_ops implementations for a
single device.

Co-developed-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Sven Peter <sven@svenpeter.dev>

soc: apple: Add RTKit IPC library

Apple SoCs such as the M1 come with multiple embedded co-processors
running proprietary firmware. Communication with those is established
over a simple mailbox using the RTKit IPC protocol.

This cannot be implemented inside the mailbox subsystem since on top
of communication over channels we also need support for starting,
hibernating and resetting these co-processors. We also need to
handle shared memory allocations differently depending on the
co-processor and don't want to split that across multiple drivers.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sven Peter <sven@svenpeter.dev>

soc: apple: Add driver for Apple PMGR power state controls

Implements genpd and reset providers for downstream devices. Each
instance of the driver binds to a single register and represents a
single SoC power domain.

The driver does not currently implement all features (clockgate-only
state, misc flags), but we declare the respective registers for
documentation purposes. These features will be added as they become
useful for downstream devices.

This also creates the apple/soc tree and Kconfig submenu.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Hector Martin <marcan@marcan.st>