From nobody Thu Feb 6 00:50:00 2025 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DE0091B4156; Thu, 30 Jan 2025 22:14:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738275289; cv=pass; b=NMex5KRWXRgbdHHWQN8k8I+lJleNVk3FqjCSweTmyEOo17jlO01P6JimaMPY5mA1ifO+6s/DvycYlusWZsTgv3T3wSuh1nZiPOf6o2DDRnXk23SXggdF8NRiHoZ7U64sIF/rYyhcEn4ktvN4IWyT1lxobDM4glIZtgoVn/Orres= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738275289; c=relaxed/simple; bh=paaeFJR7IuPnRAC6eLv1SFD9hwof6b/oIsFioNAwtTw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iz98K/Theo16r8b9M8mL3Nwoie4K4mpSeiuXLoP/pztbv1R5j1G5Biku/WivhM6Qep8NszVwqtlqAvq0HBc/4YYfJ8lDe1skLGJtjdwMwbrm0TG9eQw2Z2OXpWAc9Hul2RulawxAczFn27wx4lYVomwUVgkAaL7TAuq34qZ48KY= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=daniel.almeida@collabora.com header.b=WrzKgNmH; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=daniel.almeida@collabora.com header.b="WrzKgNmH" ARC-Seal: i=1; a=rsa-sha256; t=1738275266; cv=none; d=zohomail.com; s=zohoarc; b=ZZXV7dUBQbnu4s8VU9fhJVIuElzttQLlSHClSbV/owWxsC2DySsjRC+5sDGSnIPuUsrT0uN6On68rnJMjxv4C4hTyIPt7t4fwY/2EF12NqLDL99Tf1HVrDI63tlZs+8Bghtb8QP+wdTpD+FnvxyaaS1o9tNwVIk4MEl/t7UOG28= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1738275266; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=S0jt5DNQPlwYJQqb47kjT1wP836ehKjE8roiscU0BeA=; b=FgybcF+Hl7obKA458DE71U5QXOq/rvTghT0hQNIenX+TGIXxerXw9h3cVUoMKIlJBAH0+D+hm8rtRGXgpCdtr8C4u0ME/ZlxO5DHeSRotUhNE77or4DRTECTz5R1batkmoXWWCzrj6v8cv6oudP2WRjrWRFtM6u7pRSPKWFf90I= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=daniel.almeida@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1738275266; s=zohomail; d=collabora.com; i=daniel.almeida@collabora.com; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To; bh=S0jt5DNQPlwYJQqb47kjT1wP836ehKjE8roiscU0BeA=; b=WrzKgNmHfUBqKRzjwVk+WaPy6CPagmCwEw6JmGhZGHvV4sa+AefE4OGwoAscGe/q 3Pt5cCsAWUhapTc913j/hIK+iJSRPvjUS1613oMIlVFfzPic1kAl13NeQTl9/FjnzzT xuA/elT01/k6wS/CC4Q2YXzgfqA4oRYpLn1EGj0c= Received: by mx.zohomail.com with SMTPS id 1738275263083159.469891848398; Thu, 30 Jan 2025 14:14:23 -0800 (PST) From: Daniel Almeida To: ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.mco, benno.lossin@proton.me, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, boris.brezillon@collabora.com, robh@kernel.org Cc: Daniel Almeida , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Fiona Behrens Subject: [PATCH v6 1/3] rust: io: add resource abstraction Date: Thu, 30 Jan 2025 19:05:21 -0300 Message-ID: <20250130220529.665896-2-daniel.almeida@collabora.com> X-Mailer: git-send-email 2.48.0 In-Reply-To: <20250130220529.665896-1-daniel.almeida@collabora.com> References: <20250130220529.665896-1-daniel.almeida@collabora.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMailClient: External Content-Type: text/plain; charset="utf-8" In preparation for ioremap support, add a Rust abstraction for struct resource. A future commit will introduce the Rust API to ioremap a resource from a platform device. The current abstraction, therefore, adds only the minimum API needed to get that done. Co-developed-by: Fiona Behrens Signed-off-by: Fiona Behrens Signed-off-by: Daniel Almeida --- rust/bindings/bindings_helper.h | 1 + rust/helpers/io.c | 36 +++++ rust/kernel/io.rs | 2 + rust/kernel/io/resource.rs | 252 ++++++++++++++++++++++++++++++++ 4 files changed, 291 insertions(+) create mode 100644 rust/kernel/io/resource.rs diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helpe= r.h index e9fdceb568b8..f9c2eedb5b9b 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/helpers/io.c b/rust/helpers/io.c index 4c2401ccd720..939ab38ca61d 100644 --- a/rust/helpers/io.c +++ b/rust/helpers/io.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 =20 #include +#include =20 void __iomem *rust_helper_ioremap(phys_addr_t offset, size_t size) { @@ -99,3 +100,38 @@ void rust_helper_writeq_relaxed(u64 value, volatile voi= d __iomem *addr) writeq_relaxed(value, addr); } #endif + +resource_size_t rust_helper_resource_size(struct resource *res) +{ + return resource_size(res); +} + +struct resource *rust_helper_request_mem_region(resource_size_t start, + resource_size_t n, + const char *name) +{ + return request_mem_region(start, n, name); +} + +void rust_helper_release_mem_region(resource_size_t start, resource_size_t= n) +{ + release_mem_region(start, n); +} + +struct resource *rust_helper_request_region(resource_size_t start, + resource_size_t n, const char *name) +{ + return request_region(start, n, name); +} + +struct resource *rust_helper_request_muxed_region(resource_size_t start, + resource_size_t n, + const char *name) +{ + return request_muxed_region(start, n, name); +} + +void rust_helper_release_region(resource_size_t start, resource_size_t n) +{ + release_region(start, n); +} diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs index d4a73e52e3ee..566d8b177e01 100644 --- a/rust/kernel/io.rs +++ b/rust/kernel/io.rs @@ -7,6 +7,8 @@ use crate::error::{code::EINVAL, Result}; use crate::{bindings, build_assert}; =20 +pub mod resource; + /// Raw representation of an MMIO region. /// /// By itself, the existence of an instance of this structure does not pro= vide any guarantees that diff --git a/rust/kernel/io/resource.rs b/rust/kernel/io/resource.rs new file mode 100644 index 000000000000..64244a00786a --- /dev/null +++ b/rust/kernel/io/resource.rs @@ -0,0 +1,252 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Abstraction for system resources. +//! +//! C header: [`include/linux/ioport.h`](srctree/include/linux/ioport.h) + +use core::ops::Deref; +use core::ptr::NonNull; + +use crate::str::CStr; +use crate::types::Opaque; + +type RequestFn =3D unsafe extern "C" fn( + ResourceSize, + ResourceSize, + *const kernel::ffi::c_char, +) -> *mut bindings::resource; + +#[cfg(CONFIG_HAS_IOPORT)] +/// Returns a reference to the global `ioport_resource` variable. +pub fn ioport_resource() -> &'static Resource { + // SAFETY: `bindings::ioport_resoure` has global lifetime and is of ty= pe Resource. + unsafe { Resource::from_ptr(core::ptr::addr_of_mut!(bindings::ioport_r= esource)) } +} + +/// Returns a reference to the global `iomem_resource` variable. +pub fn iomem_resource() -> &'static Resource { + // SAFETY: `bindings::iomem_resoure` has global lifetime and is of typ= e Resource. + unsafe { Resource::from_ptr(core::ptr::addr_of_mut!(bindings::iomem_re= source)) } +} + +/// Resource Size type. +/// This is a type alias to `u64` +/// depending on the config option `CONFIG_PHYS_ADDR_T_64BIT`. +#[cfg(CONFIG_PHYS_ADDR_T_64BIT)] +pub type ResourceSize =3D u64; + +/// Resource Size type. +/// This is a type alias to `u32` +/// depending on the config option `CONFIG_PHYS_ADDR_T_64BIT`. +#[cfg(not(CONFIG_PHYS_ADDR_T_64BIT))] +pub type ResourceSize =3D u32; + +/// A region allocated from a parent resource. +/// +/// # Invariants +/// - `self.0` points to a valid `bindings::resource` that was obtained th= rough +/// `__request_region`. +pub struct Region(NonNull); + +impl Deref for Region { + type Target =3D Resource; + + fn deref(&self) -> &Self::Target { + // SAFETY: Safe as per the invariant of `Region` + unsafe { Resource::from_ptr(self.0.as_ptr()) } + } +} + +impl Drop for Region { + fn drop(&mut self) { + // SAFETY: Safe as per the invariant of `Region` + let res =3D unsafe { Resource::from_ptr(self.0.as_ptr()) }; + let flags =3D res.flags(); + + let release_fn =3D if flags.contains(flags::IORESOURCE_MEM) { + bindings::release_mem_region + } else { + bindings::release_region + }; + + // SAFETY: Safe as per the invariant of `Region` + unsafe { release_fn(res.start(), res.size()) }; + } +} + +// SAFETY: `Region` only holds a pointer to a C `struct resource`, which i= s safe to be used from +// any thead. +unsafe impl Send for Region {} + +// SAFETY: `Region` only holds a pointer to a C `struct resource`, referen= ces to which are +// safe to be used from any thead. +unsafe impl Sync for Region {} + +/// A resource abstraction. +/// +/// # Invariants +/// +/// `Resource` is a transparent wrapper around a valid `bindings::resource= `. +#[repr(transparent)] +pub struct Resource(Opaque); + +impl Resource { + /// Creates a reference to a [`Resource`] from a valid pointer. + /// + /// # Safety + /// + /// The caller must ensure that for the duration of 'a, the pointer wi= ll + /// point at a valid `bindings::resource` + /// + /// The caller must also ensure that the `Resource` is only accessed v= ia the + /// returned reference for the duration of 'a. + pub(crate) const unsafe fn from_ptr<'a>(ptr: *mut bindings::resource) = -> &'a Self { + // SAFETY: Self is a transparent wrapper around `Opaque`. + unsafe { &*ptr.cast() } + } + + /// A helper to abstract the common pattern of requesting a region. + fn request_region_checked( + &self, + start: ResourceSize, + size: ResourceSize, + name: &CStr, + request_fn: RequestFn, + ) -> Option { + // SAFETY: Safe as per the invariant of `Resource` + let region =3D unsafe { request_fn(start, size, name.as_char_ptr()= ) }; + + Some(Region(NonNull::new(region)?)) + } + + /// Requests a resource region. + /// + /// Exclusive access will be given and the region will be marked as bu= sy. + /// Further calls to `request_region` will return `None` if the region= , or a + /// part of it, is already in use. + pub fn request_region( + &self, + start: ResourceSize, + size: ResourceSize, + name: &CStr, + ) -> Option { + self.request_region_checked(start, size, name, bindings::request_r= egion) + } + + /// Requests a resource region with the IORESOURCE_MUXED flag. + /// + /// Exclusive access will be given and the region will be marked as bu= sy. + /// Further calls to `request_region` will return `None` if the region= , or a + /// part of it, is already in use. + pub fn request_muxed_region( + &self, + start: ResourceSize, + size: ResourceSize, + name: &CStr, + ) -> Option { + self.request_region_checked(start, size, name, bindings::request_m= uxed_region) + } + + /// Requests a memory resource region, i.e.: a resource of type + /// IORESOURCE_MEM. + /// + /// Exclusive access will be given and the region will be marked as bu= sy. + /// Further calls to `request_region` will return `None` if the region= , or a + /// part of it, is already in use. + pub fn request_mem_region( + &self, + start: ResourceSize, + size: ResourceSize, + name: &CStr, + ) -> Option { + self.request_region_checked(start, size, name, bindings::request_m= em_region) + } + + /// Returns the size of the resource. + pub fn size(&self) -> ResourceSize { + let inner =3D self.0.get(); + // SAFETY: safe as per the invariants of `Resource` + unsafe { bindings::resource_size(inner) } + } + + /// Returns the start address of the resource. + pub fn start(&self) -> u64 { + let inner =3D self.0.get(); + // SAFETY: safe as per the invariants of `Resource` + unsafe { *inner }.start + } + + /// Returns the name of the resource. + pub fn name(&self) -> &CStr { + let inner =3D self.0.get(); + // SAFETY: safe as per the invariants of `Resource` + unsafe { CStr::from_char_ptr((*inner).name) } + } + + /// Returns the flags associated with the resource. + pub fn flags(&self) -> Flags { + let inner =3D self.0.get(); + // SAFETY: safe as per the invariants of `Resource` + let flags =3D unsafe { *inner }.flags; + + Flags(flags) + } +} + +// SAFETY: `Resource` only holds a pointer to a C `struct resource`, which= is safe to be used from +// any thead. +unsafe impl Send for Resource {} + +// SAFETY: `Resource` only holds a pointer to a C `struct resource`, refer= ences to which are +// safe to be used from any thead. +unsafe impl Sync for Resource {} + +/// Resource flags as stored in the C `struct resource::flags` field. +/// +/// They can be combined with the operators `|`, `&`, and `!`. +/// +/// Values can be used from the [`flags`] module. +#[derive(Clone, Copy, PartialEq)] +pub struct Flags(u64); + +impl Flags { + /// Check whether `flags` is contained in `self`. + pub fn contains(self, flags: Flags) -> bool { + (self & flags) =3D=3D flags + } +} + +impl core::ops::BitOr for Flags { + type Output =3D Self; + fn bitor(self, rhs: Self) -> Self::Output { + Self(self.0 | rhs.0) + } +} + +impl core::ops::BitAnd for Flags { + type Output =3D Self; + fn bitand(self, rhs: Self) -> Self::Output { + Self(self.0 & rhs.0) + } +} + +impl core::ops::Not for Flags { + type Output =3D Self; + fn not(self) -> Self::Output { + Self(!self.0) + } +} + +/// Resource flags as stored in the `struct resource::flags` field. +pub mod flags { + use super::Flags; + + /// PCI/ISA I/O ports + pub const IORESOURCE_IO: Flags =3D Flags(bindings::IORESOURCE_IO as u6= 4); + + /// Resource is software muxed. + pub const IORESOURCE_MUXED: Flags =3D Flags(bindings::IORESOURCE_MUXED= as u64); + + /// Resource represents a memory region. + pub const IORESOURCE_MEM: Flags =3D Flags(bindings::IORESOURCE_MEM as = u64); +} --=20 2.48.0