[PATCH v2 00/25] Apple M1 SoC platform bring-up

Hector Martin
2021-02-15T12:19:29Z

This series brings up initial support for the Apple M1 SoC, used in the
2020 Mac Mini, MacBook Pro, and MacBook Air models.

The following features are supported in this initial port:

- UART (samsung-style) with earlycon support
- Interrupts, including affinity and IPIs (Apple Interrupt Controller)
- SMP (through standard spin-table support)
- simplefb-based framebuffer
- Devicetree for the Mac Mini (should work for the others too at this
stage)

See below for an overview of changes since v1.

== Patch overview ==

- 01-02 Core platform DT bindings
- 03-04 CPU DT bindings and MIDR defines
- 05-06 Add interrupt-names support to the ARM timer driver
This is used to cleanly express the lack of a secure timer;
platforms in the past have used various hacks like dummy
IRQs here.
- 07-09 FIQ support
These platforms require FIQ support, as some interrupt sources
are hard-wired to FIQ. We settled on always keeping the FIQ/IRQ
mask state synced, and only redirecting the vectors using
alternatives on these CPUs. Other platforms retain the existing
panic-on-FIQ behavior.
- 10-12 ioremap_np() (nGnRnE) support
The fabric in these SoCs only supports nGnRnE accesses for
standard MMIO, except for PCI ranges which use nGnRE. Linux
currently defaults to the latter on ARM64, so this adds a new
ioremap type and DT properties to automatically select it for
drivers using OF and devm abstractions, under buses specified
in DT.
- 13-15 AIC (Apple Interrupt Controller) driver and support defines
This also embeds FIQ handling for this platform.
- 16 Introduce CONFIG_ARCH_APPLE & add it to defconfig
- 17-23 Add Apple SoC support to the samsung_tty driver
This includes several refactoring patches to be able to more
cleanly introduce this, as well as a switch to
devm_ioremap_resource to be able to use the nGnRnE support
introduced above. Earlycon support is included with a
special-case nGnRnE hack, as earlycon is too early to use the
generic infrastructure.
- 24 simple-framebuffer bindings for Apple (trivial)
- 25 Add the initial M1 Mac Mini (j274) devicetree

== About the hardware ==

These machines officially support booting unsigned/user-provided
XNU-like kernels, with a very different boot protocol and devicetree
format. We are developing an initial bootloader, m1n1 [1], to take care
of as many hardware peculiarities as possible and present a standard
Linux arm64 boot protocol and device tree. In the future, I expect that
production setups will add U-Boot and perhaps GRUB into the boot chain,
to make the boot process similar to other ARM64 platforms.

The machines expose their debug UART over USB Type C, triggered with
vendor-specific USB-PD commands. Currently, the easiest way to get a
serial console on these machines is to use a second M1 box and a simple
USB C cable [2]. You can also build a DIY interface using an Arduino, a
FUSB302 chip or board, and a 1.2V UART-TTL adapter [3]. In the coming
weeks we will be designing an open hardware project to provide
serial/debug connectivity to these machines (and, hopefully, also
support other UART-over-Type C setups from other vendors). Please
contact me privately if you are interested in getting an early prototype
version of one of these devices.

A quickstart guide to booting Linux kernels on these machines is
available at [4], and we are documenting the hardware at [5].

[1] https://github.com/AsahiLinux/m1n1/
[2] https://github.com/AsahiLinux/macvdmtool/
[3] https://github.com/AsahiLinux/vdmtool/
[4] https://github.com/AsahiLinux/docs/wiki/Developer-Quickstart
[5] https://github.com/AsahiLinux/docs/wiki

== Project Blurb ==

Asahi Linux is an open community project dedicated to developing and
maintaining mainline support for Apple Silicon on Linux. Feel free to
drop by #asahi and #asahi-dev on freenode to chat with us, or check
our website for more information on the project:

https://asahilinux.org/

== Changes since v1 ==

* DT vendor prefix AAPL -> apple
* Added interrupt-names support to the ARMv8 timer driver, to better
represent the lack of secure timer
* Added sysreg_apple.h to define Apple vendor specific CPU system
registers
* No longer gating the DAIF.F bit handling via alternatives; now we
always keep it in sync with DAIF.I on all platforms.
* ARCH_APPLE selects APPLE_AIC
* Fixed copyright of DT (GPL-2.0+ OR MIT)
* Made all the copyright lines for new files
`Copyright The Asahi Linux Contributors`
* Split DT into apple-m1.dtsi and apple-j274.dts
* Cleaner solution for FIQ alternatives in entry.S from Marc
* Implemented proper nGnRnE solution using the `[non]posted-mmio`
DT properties and ioremap_np()
* Added (tentative) support for guest timer FIQs in AIC
* Added masked initialization and basic fallback handling for other FIQs
* Reworked AIC to not use chained IRQ domains, and split up FIQ irqchip
* More refactoring of the samsung_tty driver to cleanly introduce Apple
support
* Fixed many style issues, bugs, and other nits

Note: this keeps the `apple,arm-platform` compatible, which is now used
to gate the OF nonposted-mmio logic to Apple platforms only.

Hector Martin (24):
dt-bindings: vendor-prefixes: Add apple prefix
dt-bindings: arm: apple: Add bindings for Apple ARM platforms
dt-bindings: arm: cpus: Add apple,firestorm & icestorm compatibles
arm64: cputype: Add CPU implementor & types for the Apple M1 cores
dt-bindings: timer: arm,arch_timer: Add interrupt-names support
arm64: arch_timer: implement support for interrupt-names
arm64: cpufeature: Add a feature for FIQ support
arm64: Always keep DAIF.[IF] in sync
asm-generic/io.h: Add a non-posted variant of ioremap()
arm64: Implement ioremap_np() to map MMIO as nGnRnE
of/address: Add infrastructure to declare MMIO as non-posted
arm64: Add Apple vendor-specific system registers
dt-bindings: interrupt-controller: Add DT bindings for apple-aic
irqchip/apple-aic: Add support for the Apple Interrupt Controller
arm64: Kconfig: Introduce CONFIG_ARCH_APPLE
tty: serial: samsung_tty: Separate S3C64XX ops structure
tty: serial: samsung_tty: add s3c24xx_port_type
tty: serial: samsung_tty: IRQ rework
tty: serial: samsung_tty: Use devm_ioremap_resource
dt-bindings: serial: samsung: Add apple,s5l-uart compatible
tty: serial: samsung_tty: Add support for Apple UARTs
tty: serial: samsung_tty: Add earlycon support for Apple UARTs
dt-bindings: display: Add apple,simple-framebuffer
arm64: apple: Add initial Mac Mini 2020 (M1) devicetree

Marc Zyngier (1):
arm64: entry: Map the FIQ vector to IRQ on NEEDS_FIQ platforms

.../devicetree/bindings/arm/apple.yaml | 36 +
.../devicetree/bindings/arm/cpus.yaml | 2 +
.../bindings/display/simple-framebuffer.yaml | 5 +
.../interrupt-controller/apple,aic.yaml | 88 +++
.../bindings/serial/samsung_uart.yaml | 4 +-
.../bindings/timer/arm,arch_timer.yaml | 14 +
.../devicetree/bindings/vendor-prefixes.yaml | 2 +
MAINTAINERS | 15 +
arch/arm64/Kconfig | 11 +
arch/arm64/Kconfig.platforms | 8 +
arch/arm64/boot/dts/Makefile | 1 +
arch/arm64/boot/dts/apple/Makefile | 2 +
arch/arm64/boot/dts/apple/apple-j274.dts | 41 ++
arch/arm64/boot/dts/apple/apple-m1.dtsi | 124 ++++
arch/arm64/configs/defconfig | 1 +
arch/arm64/include/asm/assembler.h | 6 +-
arch/arm64/include/asm/cpucaps.h | 3 +-
arch/arm64/include/asm/cputype.h | 6 +
arch/arm64/include/asm/daifflags.h | 4 +-
arch/arm64/include/asm/io.h | 1 +
arch/arm64/include/asm/irqflags.h | 19 +-
arch/arm64/include/asm/sysreg_apple.h | 69 ++
arch/arm64/kernel/cpufeature.c | 14 +
arch/arm64/kernel/entry.S | 27 +-
drivers/clocksource/arm_arch_timer.c | 25 +-
drivers/irqchip/Kconfig | 10 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-apple-aic.c | 647 ++++++++++++++++++
drivers/of/address.c | 72 +-
drivers/tty/serial/Kconfig | 2 +-
drivers/tty/serial/samsung_tty.c | 499 +++++++++++---
include/asm-generic/io.h | 8 +-
include/clocksource/arm_arch_timer.h | 1 +
.../interrupt-controller/apple-aic.h | 15 +
include/linux/cpuhotplug.h | 1 +
include/linux/io.h | 2 +
include/linux/ioport.h | 1 +
include/linux/of_address.h | 1 +
include/linux/serial_s3c.h | 16 +
lib/devres.c | 22 +
40 files changed, 1685 insertions(+), 141 deletions(-)
create mode 100644 Documentation/devicetree/bindings/arm/apple.yaml
create mode 100644 Documentation/devicetree/bindings/interrupt-controller/apple,aic.yaml
create mode 100644 arch/arm64/boot/dts/apple/Makefile
create mode 100644 arch/arm64/boot/dts/apple/apple-j274.dts
create mode 100644 arch/arm64/boot/dts/apple/apple-m1.dtsi
create mode 100644 arch/arm64/include/asm/sysreg_apple.h
create mode 100644 drivers/irqchip/irq-apple-aic.c
create mode 100644 include/dt-bindings/interrupt-controller/apple-aic.h

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2.30.0