Device / Driver PCI / Platform Rust abstractions

This patch series implements the necessary Rust abstractions to implement device drivers in Rust.

This includes some basic generalizations for driver registration, handling of ID tables, MMIO operations and device resource handling.

Those generalizations are used to implement device driver support for two busses, the PCI and platform bus (with OF IDs) in order to provide some evidence that the generalizations work as intended.

The patch series also includes two patches adding two driver samples, one PCI driver and one platform driver.

The PCI bits are motivated by the Nova driver project [1], but are used by at least one more OOT driver (rnvme [2]).

The platform bits, besides adding some more evidence to the base abstractions, are required by a few more OOT drivers aiming at going upstream, i.e. rvkms [3], cpufreq-dt [4], asahi [5] and the i2c work from Fabien [6].

The patches of this series can also be [7], [8] and [9].

Changes in v7:
==============
- Revocable:
- replace compare_exchange with swap

- Driver:
- fix warning when CONFIG_OF=n

- I/O:
- remove unnecessary return statement in rust_helper_iounmap()
- fix cast in doctest for bindings::ioremap

- Devres:
- fix cast in doctest for bindings::ioremap

- PCI:
- remove Deref of pci::DeviceId
- rename DeviceId constructors
- new -> from_id
- with_class -> from_class`

- MISC:
- use kernel::ffi::c_* instead of core::ffi::c_*
- rebase onto latest rust-next (0c5928deada15a8d075516e6e0d9ee19011bb000)

Changes in v6:
==============
- Module:
- remove patch to pass the module name in Module::init
- add a patch adding the ModuleMetadata trait to retreive the module name

- Driver:
- generate module structure within module_driver!, such that we get a unique module type for which ModuleMetadata can be implemented to retreive the module name
- let Adapter::of_id_table return Option<of::IdTable<Self::IdInfo>>

- Platform:
- change type of platform::Driver::OF_ID_TABLE to Option<of::IdTable>

- RCU:
- add RCU abstraction to MAINTAINERS file

- MISC:
- pick up a couple of RBs

Changes in v5:
==============
- Opaque:
- add Opaque::pin_init

- Revocable:
- use const generic instead of bool in revoke_internal
- don't open code things with Opaque::try_ffi_init, use Opaque::pin_init instead

- Driver:
- fix DriverOps -> RegistrationOps in commit message
- fix signature of register and unregister to take an Opaque<T::RegType> instead of a mutable reference
- implement generic driver::Adapter

- ID table:
- fix module_device_table! macro, according to commit 054a9cd395a7 (modpost: rename alias symbol for MODULE_DEVICE_TABLE())

- PCI:
- remove pci::DeviceId argument from probe()
- provide vendor_id and device_id accessor functions
- use addr_of_mut! for the device in probe()

- OF:
- move OF IdTable type alias from platform.rs to of.rs

- Platform:
- use addr_of_mut! for the device in probe()
- move generic OF code to driver::Adapter

- MISC:
- rebase onto latest rust-next (-rc2)

Changes in v4:
==============
- Revocable
- convert Revocable::data to Opaque
- introduce revoke_nosync, which does not wait for an RCU grace period
- fix minor typo

- Device ID
- fix ID table export name to always be unique
- remove #![allow(stable_features)]
- move #![allow(const_refs_to_cell)] to the "stable in 1.83" list

- I/O
- split Io<SIZE> in IoRaw<SIZE> and Io<SIZE>
- add rust helper for ioremap() and iounmap() (needed by doctests)

- Devres
- optimze drop by using revoke_nosync (we're guaranteed there are no more concurrent users, hence no need to wait for a full grace period)

- OF
- rename "Open Firmware" -> "Device Tree / Open Firmware" (Rob)
- remove unused C header reference
- add TODO comment to loop in DeviceId::new
- remove DeviceId::compatible; was only used in sample code
- add missing #[repr(transparent)]
- use #[cfg(CONFIG_OF)] for the relevant functions

- PCI
- let Rust helper for pci_resource_len() return resource_size_t

- PCI Sample
- remove unnecessary from_le

- Platform
- fix example compatible string
- add example for platform::Driver
- rename ID_TABLE to OF_ID_TABLE
- don't allow public use of of_match_table; convert to of_id_info to retrieve the of::DeviceId to gather the corresponding IdInfo
- remove wrong example reference in the documentation of platform::Driver
- remove as_dev, as we already implement AsRef for platform::Device

- Platform Sample
- fix compatible string; add corresponding entry to drivers/of/unittest-data/tests-platform.dtsi
- remove usage of of_match_table

- MISC
- fix a few spelling mistakes
- rebase onto rust-next (v6.13-rc1)

Changes in v3:
==============
- add commits for Opaque::try_ffi_init and InPlaceModule
- rename DriverOps to RegistrationOps
- rework device ID abstractions to get rid of almost all macro magic (thanks to Gary Guo for working this out!)
- this is possible due to recently stabilized language features
- add modpost alias generation for device ID tables
- unfortunately, this is the part that still requires some macro magic in the device ID abstractions
- PCI
- represent the driver private data with the driver specific Driver instance and bind it's lifetime to the time of the driver being bound to a device
- this allows us to handle class / subsystem registrations in a cleaner way
- get rid of Driver::remove
- Rust drivers should bind cleanup code to the Drop implementation of the corresponding structure instead and put it into their driver structure for automatic cleanup
- add a sample PCI driver
- add abstractions for struct of_device_id
- add abstractions for the platform bus, including a sample driver
- update the MAINTAINERS file accordingly
- currently this turns out a bit messy, but it should become better once the build system supports a treewide distribution of the kernel crate
- I didn't add myself as maintainer, but (if requested) I'm willing to do so and help with maintenance

Changes in v2:
==============
- statically initialize driver structures (Greg)
- move base device ID abstractions to a separate source file (Greg)
- remove DeviceRemoval trait in favor of using a Devres callback to unregister drivers
- remove device::Data, we don't need this abstraction anymore now that we Devres to revoke resources and registrations
- pass the module name to Module::init and InPlaceModule::init in a separate patch
- rework of Io including compile time boundary checks (Miguel, Wedson)
- adjust PCI abstractions accordingly and implement a module_pci_driver! macro
- rework pci::Bar to support a const SIZE
- increase the total amount of Documentation, rephrase some safety comments and commit messages for less ambiguity
- fix compilation issues with some documentation examples

Danilo Krummrich (14):
rust: module: add trait ModuleMetadata
rust: implement generic driver registration
rust: implement IdArray, IdTable and RawDeviceId
rust: types: add Opaque::pin_init
rust: add io::{Io, IoRaw} base types
rust: add devres abstraction
rust: pci: add basic PCI device / driver abstractions
rust: pci: implement I/O mappable pci::Bar
samples: rust: add Rust PCI sample driver
rust: of: add of::DeviceId abstraction
rust: driver: implement Adapter
rust: platform: add basic platform device / driver abstractions
samples: rust: add Rust platform sample driver
MAINTAINERS: add Danilo to DRIVER CORE

Wedson Almeida Filho (2):
rust: add rcu abstraction
rust: add Revocable type

 MAINTAINERS                                  |  10 +
 drivers/of/unittest-data/tests-platform.dtsi |   5 +
 rust/bindings/bindings_helper.h              |   3 +
 rust/helpers/device.c                        |  10 +
 rust/helpers/helpers.c                       |   5 +
 rust/helpers/io.c                            | 101 +++++
 rust/helpers/pci.c                           |  18 +
 rust/helpers/platform.c                      |  13 +
 rust/helpers/rcu.c                           |  13 +
 rust/kernel/device_id.rs                     | 165 +++++++
 rust/kernel/devres.rs                        | 178 ++++++++
 rust/kernel/driver.rs                        | 173 ++++++++
 rust/kernel/io.rs                            | 260 +++++++++++
 rust/kernel/lib.rs                           |  20 +
 rust/kernel/of.rs                            |  60 +++
 rust/kernel/pci.rs                           | 432 +++++++++++++++++++
 rust/kernel/platform.rs                      | 198 +++++++++
 rust/kernel/revocable.rs                     | 219 ++++++++++
 rust/kernel/sync.rs                          |   1 +
 rust/kernel/sync/rcu.rs                      |  47 ++
 rust/kernel/types.rs                         |  11 +
 rust/macros/module.rs                        |   4 +
 samples/rust/Kconfig                         |  21 +
 samples/rust/Makefile                        |   2 +
 samples/rust/rust_driver_pci.rs              | 110 +++++
 samples/rust/rust_driver_platform.rs         |  49 +++
 26 files changed, 2128 insertions(+)
 create mode 100644 rust/helpers/device.c
 create mode 100644 rust/helpers/io.c
 create mode 100644 rust/helpers/pci.c
 create mode 100644 rust/helpers/platform.c
 create mode 100644 rust/helpers/rcu.c
 create mode 100644 rust/kernel/device_id.rs
 create mode 100644 rust/kernel/devres.rs
 create mode 100644 rust/kernel/driver.rs
 create mode 100644 rust/kernel/io.rs
 create mode 100644 rust/kernel/of.rs
 create mode 100644 rust/kernel/pci.rs
 create mode 100644 rust/kernel/platform.rs
 create mode 100644 rust/kernel/revocable.rs
 create mode 100644 rust/kernel/sync/rcu.rs
 create mode 100644 samples/rust/rust_driver_pci.rs
 create mode 100644 samples/rust/rust_driver_platform.rs

base-commit: 0c5928deada15a8d075516e6e0d9ee19011bb000

2.47.1