From nobody Mon Feb 9 09:15:10 2026 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 BB63022A813; Tue, 3 Jun 2025 15:06:52 +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=1748963214; cv=pass; b=qU5mlWIQtiKHjciblQDIoWSqUwrw1rP3kfTRc3rdKgczIZ55wPX58W2cZiy7gSn22VzcgNxA1LPo0/atVliPBl+66DxnxMUQo2nYi4XfGxaeo3E8UguJdrF5ouU5PYfhbT8s1lkg+RerSUonBVjSsYALMYJefZGjPnSlONnezUg= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748963214; c=relaxed/simple; bh=v4ziDmllNN5oslWZek5DsUSjkwSbX8XxPrYpCpja5sg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=NCgY0x3EputvBQBdkRuDRH20eMWFBLXHKutcyx5SKt4jbo6bp1R+75k9S9o3ZiZT9LHg3sdc6UmH7rA17qih0J7p7T3QLoIM8sh3fI3IL6BfVrt286h/QwUualVULAmjrH0cw1ZGGHUv7WSAjNqNCZGXmzbXev/hZdaiq3olKZw= 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=ITd7K75G; 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="ITd7K75G" ARC-Seal: i=1; a=rsa-sha256; t=1748963176; cv=none; d=zohomail.com; s=zohoarc; b=mKjJpfUjeVRONKtR8VyIWti0Lj/iAyCRcvOP2++nkPoAnWhOxB7Bgxdd38gNJL5fNxRB7E5B63eNO2f45UtBFjIC/WyG76xAHpjQdFHWjXHadcCvUYbFFt8WNCu6yrFAXwyXuOUUPTn59yFsqZsiT0lPp7BXBTGYNBGCCCSz0ao= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1748963176; h=Content-Type: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=LHWgIBa/roB7wo0SLBs0h20uA9BUWvk4i+3aWwc+e/c=; b=Gzt4e2m8llbORzp5XjI8B13BLEn5cKmEf4Vq9swLiqv5n+f/ENCrAj40sWnpUkV3InWLLWrshPEANFcdmeeU0D1Mj2DgVo7B3felE+/8BGx5GT2hJzCZcz1Uix8OJdH2EX/opFc74/vXuPcvTb1zl/ngsPcizi3xu/Pkn05X+/A= 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=1748963176; s=zohomail; d=collabora.com; i=daniel.almeida@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=LHWgIBa/roB7wo0SLBs0h20uA9BUWvk4i+3aWwc+e/c=; b=ITd7K75GzYSsVtLntRm9wcHoXxUUfNq4qPpDZZJfQtHMIGi8eIGzo94her5HzP95 bz+OiI35oKJgV7ZReQ2zWWXekiLjThTpqlZSc97QDGgZc1weK75+RKmooMLuBl1ZMFK 6rusf1wvmuWsyMBffWw8EOa/DR2oCyPhbEnWNVjQ= Received: by mx.zohomail.com with SMTPS id 1748963175662371.6194504307243; Tue, 3 Jun 2025 08:06:15 -0700 (PDT) From: Daniel Almeida Date: Tue, 03 Jun 2025 12:05:27 -0300 Subject: [PATCH v9 1/4] rust: io: add resource abstraction Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250603-topics-tyr-platform_iomem-v9-1-a27e04157e3e@collabora.com> References: <20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com> In-Reply-To: <20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Andrew Morton , Andy Shevchenko , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Bjorn Helgaas , Mika Westerberg , Ying Huang Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Fiona Behrens , Daniel Almeida X-Mailer: b4 0.14.2 X-ZohoMailClient: External 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 | 222 ++++++++++++++++++++++++++++++++++++= ++++ 4 files changed, 261 insertions(+) diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helpe= r.h index e0676ba99d372afe197e1866d291570012519a2b..a8d619e8df31d04bd48c1bb2d4f= b90105f161c91 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/helpers/io.c b/rust/helpers/io.c index 4c2401ccd72078af4e6901f4cd95f9070522f396..939ab38ca61dac4cf884677a20e= dc760094d5812 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 72d80a6f131e3e826ecd9d2c3bcf54e89aa60cc3..1da447078633e058000953a581b= 59d3ed5eb0e69 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 0000000000000000000000000000000000000000..611eca8cc693d83bccc2c384db2= ff22d11e7ac46 --- /dev/null +++ b/rust/kernel/io/resource.rs @@ -0,0 +1,222 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Abstractions 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; + +#[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::as_ref(&raw mut bindings::ioport_resource) } +} + +#[cfg(CONFIG_HAS_IOMEM)] +/// 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::as_ref(&raw mut bindings::iomem_resource) } +} + +/// 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 +/// `bindings::__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::as_ref(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::as_ref(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 thread. +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 thread. +unsafe impl Sync for Region {} + +/// A resource abstraction. +/// +/// # Invariants +/// +/// [`Resource`] is a transparent wrapper around a valid `bindings::resour= ce`. +#[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= via the + /// returned reference for the duration of 'a. + pub(crate) const unsafe fn as_ref<'a>(ptr: *mut bindings::resource) ->= &'a Self { + // SAFETY: Self is a transparent wrapper around `Opaque`. + unsafe { &*ptr.cast() } + } + + /// Requests a resource region. + /// + /// Exclusive access will be given and the region will be marked as bu= sy. + /// Further calls to [`Self::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: &'static CStr, + flags: Flags, + ) -> Option { + // SAFETY: Safe as per the invariant of `Resource` + let region =3D unsafe { + bindings::__request_region( + self.0.get(), + start, + size, + name.as_char_ptr(), + flags.0 as i32, + ) + }; + + Some(Region(NonNull::new(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) -> &'static 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(usize); + +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 us= ize); + + /// Resource is software muxed. + pub const IORESOURCE_MUXED: Flags =3D Flags(bindings::IORESOURCE_MUXED= as usize); + + /// Resource represents a memory region. + pub const IORESOURCE_MEM: Flags =3D Flags(bindings::IORESOURCE_MEM as = usize); + + /// Resource represents a memory region that must be ioremaped using `= ioremap_np`. + pub const IORESOURCE_MEM_NONPOSTED: Flags =3D Flags(bindings::IORESOUR= CE_MEM_NONPOSTED as usize); +} --=20 2.49.0 From nobody Mon Feb 9 09:15:10 2026 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 1E87A22A813; Tue, 3 Jun 2025 15:06:45 +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=1748963207; cv=pass; b=W/gcyIKKeifw1oXOcdgG7DdWzQgHxMezQPz/vgx3ecilN68r45G0n6yjp9BKM+elFbcglzLtRrP5dNqNM7B3ICEyulefTjSFZ9398VAIBjn4RZd5C6r/8T6x0h40+FL7/3sqchTEORG412mlyDgQWvRmDqcvfq8WjDTURxb2gAQ= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748963207; c=relaxed/simple; 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bh=2uyj7NIVcWkTF2iRk/SFYpp1aLvAuNsvuv8ite9SmzE=; b=hqUAMUFfmb2fyw7JRyinCUlELSfOOSxF6fl4SGEDUQsQ4LCuR4i0dKcPMpqiiVdu dsc9Ae/U8k4K9YoFoxnu1jXK4H7ghLJDwoqQaNg03GwK7FxPMH+AzOSRijV5pevIYRE r4+rSCVu9fhmVIw3Ko4lpxhSPCCMEl3GGv3crCHo= Received: by mx.zohomail.com with SMTPS id 1748963180462299.34861723796234; Tue, 3 Jun 2025 08:06:20 -0700 (PDT) From: Daniel Almeida Date: Tue, 03 Jun 2025 12:05:28 -0300 Subject: [PATCH v9 2/4] rust: io: mem: add a generic iomem abstraction Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250603-topics-tyr-platform_iomem-v9-2-a27e04157e3e@collabora.com> References: <20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com> In-Reply-To: <20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Andrew Morton , Andy Shevchenko , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Bjorn Helgaas , Mika Westerberg , Ying Huang Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Daniel Almeida X-Mailer: b4 0.14.2 X-ZohoMailClient: External Add a generic iomem abstraction to safely read and write ioremapped regions. The reads and writes are done through IoRaw, and are thus checked either at compile-time, if the size of the region is known at that point, or at runtime otherwise. Non-exclusive access to the underlying memory region is made possible to cater to cases where overlapped regions are unavoidable. Signed-off-by: Daniel Almeida --- rust/helpers/io.c | 5 ++ rust/kernel/io.rs | 1 + rust/kernel/io/mem.rs | 142 ++++++++++++++++++++++++++++++++++++++++++++++= ++++ 3 files changed, 148 insertions(+) diff --git a/rust/helpers/io.c b/rust/helpers/io.c index 939ab38ca61dac4cf884677a20edc760094d5812..4fbd70ab60f64155bef835a43b3= c64d441aee7bf 100644 --- a/rust/helpers/io.c +++ b/rust/helpers/io.c @@ -8,6 +8,11 @@ void __iomem *rust_helper_ioremap(phys_addr_t offset, size= _t size) return ioremap(offset, size); } =20 +void __iomem *rust_helper_ioremap_np(phys_addr_t offset, size_t size) +{ + return ioremap_np(offset, size); +} + void rust_helper_iounmap(volatile void __iomem *addr) { iounmap(addr); diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs index 1da447078633e058000953a581b59d3ed5eb0e69..0249aedd8c6ce435b6b00137be0= 895a206956bca 100644 --- a/rust/kernel/io.rs +++ b/rust/kernel/io.rs @@ -7,6 +7,7 @@ use crate::error::{code::EINVAL, Result}; use crate::{bindings, build_assert}; =20 +pub mod mem; pub mod resource; =20 /// Raw representation of an MMIO region. diff --git a/rust/kernel/io/mem.rs b/rust/kernel/io/mem.rs new file mode 100644 index 0000000000000000000000000000000000000000..2bd9cf4c4f1a59f027999a6e9a2= 03dc99ad6c003 --- /dev/null +++ b/rust/kernel/io/mem.rs @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Generic memory-mapped IO. + +use core::ops::Deref; + +use crate::device::Bound; +use crate::device::Device; +use crate::devres::Devres; +use crate::io; +use crate::io::resource::Region; +use crate::io::resource::Resource; +use crate::io::Io; +use crate::io::IoRaw; +use crate::prelude::*; + +/// An exclusive memory-mapped IO region. +/// +/// # Invariants +/// +/// - [`ExclusiveIoMem`] has exclusive access to the underlying [`IoMem`]. +pub struct ExclusiveIoMem { + /// The region abstraction. This represents exclusive access to the + /// range represented by the underlying `iomem`. + /// + /// It's placed first to ensure that the region is released before it = is + /// unmapped as a result of the drop order. + /// + /// This field is needed for ownership of the region. + _region: Region, + /// The underlying `IoMem` instance. + iomem: IoMem, +} + +impl ExclusiveIoMem { + /// Creates a new `ExclusiveIoMem` instance. + pub(crate) fn ioremap(resource: &Resource) -> Result { + let iomem =3D IoMem::ioremap(resource)?; + + let start =3D resource.start(); + let size =3D resource.size(); + let name =3D resource.name(); + + let region =3D resource + .request_region(start, size, name, io::resource::flags::IORESO= URCE_MEM) + .ok_or(EBUSY)?; + + let iomem =3D ExclusiveIoMem { + iomem, + _region: region, + }; + + Ok(iomem) + } + + pub(crate) fn new(resource: &Resource, device: &Device) -> Resu= lt> { + let iomem =3D Self::ioremap(resource)?; + let devres =3D Devres::new(device, iomem, GFP_KERNEL)?; + + Ok(devres) + } +} + +impl Deref for ExclusiveIoMem { + type Target =3D Io; + + fn deref(&self) -> &Self::Target { + &self.iomem + } +} + +/// A generic memory-mapped IO region. +/// +/// Accesses to the underlying region is checked either at compile time, i= f the +/// region's size is known at that point, or at runtime otherwise. +/// +/// # Invariants +/// +/// [`IoMem`] always holds an [`IoRaw`] instance that holds a valid pointe= r to the +/// start of the I/O memory mapped region. +pub struct IoMem { + io: IoRaw, +} + +impl IoMem { + fn ioremap(resource: &Resource) -> Result { + let size =3D resource.size(); + if size =3D=3D 0 { + return Err(EINVAL); + } + + let res_start =3D resource.start(); + + let addr =3D if resource + .flags() + .contains(io::resource::flags::IORESOURCE_MEM_NONPOSTED) + { + // SAFETY: + // - `res_start` and `size` are read from a presumably valid `= struct resource`. + // - `size` is known not to be zero at this point. + unsafe { bindings::ioremap_np(res_start, size as usize) } + } else { + // SAFETY: + // - `res_start` and `size` are read from a presumably valid `= struct resource`. + // - `size` is known not to be zero at this point. + unsafe { bindings::ioremap(res_start, size as usize) } + }; + + if addr.is_null() { + return Err(ENOMEM); + } + + let io =3D IoRaw::new(addr as usize, size as usize)?; + let io =3D IoMem { io }; + + Ok(io) + } + + /// Creates a new `IoMem` instance. + pub(crate) fn new(resource: &Resource, device: &Device) -> Resu= lt> { + let io =3D Self::ioremap(resource)?; + let devres =3D Devres::new(device, io, GFP_KERNEL)?; + + Ok(devres) + } +} + +impl Drop for IoMem { + fn drop(&mut self) { + // SAFETY: Safe as by the invariant of `Io`. + unsafe { bindings::iounmap(self.io.addr() as *mut core::ffi::c_voi= d) } + } +} + +impl Deref for IoMem { + type Target =3D Io; + + fn deref(&self) -> &Self::Target { + // SAFETY: Safe as by the invariant of `IoMem`. + unsafe { Io::from_raw(&self.io) } + } +} --=20 2.49.0 From nobody Mon Feb 9 09:15:10 2026 Received: from sender4-op-o15.zoho.com (sender4-op-o15.zoho.com [136.143.188.15]) (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 8F3BB23BD1F; 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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250603-topics-tyr-platform_iomem-v9-3-a27e04157e3e@collabora.com> References: <20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com> In-Reply-To: <20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Andrew Morton , Andy Shevchenko , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Bjorn Helgaas , Mika Westerberg , Ying Huang Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Daniel Almeida X-Mailer: b4 0.14.2 X-ZohoMailClient: External A previous patch has exposed the abstractions struct resource. Now make it possible to retrieve retrieve resources from platform devices in Rust using either a name or an index. Signed-off-by: Daniel Almeida --- rust/kernel/platform.rs | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs index 08849d92c07418d6390803bb8cc51516368bca84..427bc706f4349083b6bab81a02c= b8ed803903590 100644 --- a/rust/kernel/platform.rs +++ b/rust/kernel/platform.rs @@ -7,6 +7,7 @@ use crate::{ bindings, container_of, device, driver, error::{to_result, Result}, + io::resource::Resource, of, prelude::*, str::CStr, @@ -187,6 +188,43 @@ impl Device { fn as_raw(&self) -> *mut bindings::platform_device { self.0.get() } + + /// Returns the resource at `index`, if any. + pub fn resource_by_index(&self, index: u32) -> Option<&Resource> { + // SAFETY: `self.as_raw()` returns a valid pointer to a `struct pl= atform_device`. + let resource =3D unsafe { + bindings::platform_get_resource(self.as_raw(), bindings::IORES= OURCE_MEM, index) + }; + + if resource.is_null() { + return None; + } + + // SAFETY: `resource` is a valid pointer to a `struct resource` as + // returned by `platform_get_resource`. + Some(unsafe { Resource::as_ref(resource) }) + } + + /// Returns the resource with a given `name`, if any. + pub fn resource_by_name(&self, name: &CStr) -> Option<&Resource> { + // SAFETY: `self.as_raw()` returns a valid pointer to a `struct + // platform_device` and `name` points to a valid C string. + let resource =3D unsafe { + bindings::platform_get_resource_byname( + self.as_raw(), + bindings::IORESOURCE_MEM, + name.as_char_ptr(), + ) + }; + + if resource.is_null() { + return None; + } + + // SAFETY: `resource` is a valid pointer to a `struct resource` as + // returned by `platform_get_resource`. + Some(unsafe { Resource::as_ref(resource) }) + } } =20 // SAFETY: `Device` is a transparent wrapper of a type that doesn't depend= on `Device`'s generic --=20 2.49.0 From nobody Mon Feb 9 09:15:10 2026 Received: from sender4-op-o15.zoho.com (sender4-op-o15.zoho.com [136.143.188.15]) (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 6640823C8D3; Tue, 3 Jun 2025 15:06:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.15 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748963218; cv=pass; b=e1BZQYXTawpnDBz8TGwdCbJaKwdtPPqOgJirO56rw1qvwDSIRTkgUukhIbx4aKvkA2ohKSt3kfFr5rxpZ2W1eSplJHn0/8AkvO1c5r0ncG+iWvSI/2g3sgi8/bRhs5P2L2BCC0aAWon+rY3GbO2xVucXGPF3q7PYzs3g09G/5vk= ARC-Message-Signature: i=2; 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h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=T3yU8CXxTLuipg5JsHWMG+be2YfylB3fwzElXc1ikec=; b=Fe+Kfbb4i0ZUbWJ9rTpWm5jw8+yqPDJqwENjFvs6Hu5QNqUk1MA5tXmbvfXb88Gz nVzh8WA/5WbtV+qy8bruwKWOtDgFOk3ymDs3GzjWp99fCqoxpz3l1n8r8k+tyygOHCz Tx8Jv0euHmdXbEMMmDWmU8iSx8lvmyHlt7o52Xaw= Received: by mx.zohomail.com with SMTPS id 1748963189882603.10385779974; Tue, 3 Jun 2025 08:06:29 -0700 (PDT) From: Daniel Almeida Date: Tue, 03 Jun 2025 12:05:30 -0300 Subject: [PATCH v9 4/4] rust: platform: allow ioremap of platform resources Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250603-topics-tyr-platform_iomem-v9-4-a27e04157e3e@collabora.com> References: <20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com> In-Reply-To: <20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Andrew Morton , Andy Shevchenko , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Bjorn Helgaas , Mika Westerberg , Ying Huang Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Daniel Almeida X-Mailer: b4 0.14.2 X-ZohoMailClient: External The preceding patches added support for resources, and for a general IoMem abstraction, but thus far there is no way to access said IoMem from drivers, as its creation is unsafe and depends on a resource that must be acquired from some device first. Now, allow the ioremap of platform resources themselves, thereby making the IoMem available to platform drivers. Signed-off-by: Daniel Almeida --- rust/kernel/platform.rs | 123 ++++++++++++++++++++++++++++++++++++++++++++= +++- 1 file changed, 121 insertions(+), 2 deletions(-) diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs index 427bc706f4349083b6bab81a02cb8ed803903590..57414fd0db296e412f45fbefd77= 07b338b37332a 100644 --- a/rust/kernel/platform.rs +++ b/rust/kernel/platform.rs @@ -5,9 +5,14 @@ //! C header: [`include/linux/platform_device.h`](srctree/include/linux/pl= atform_device.h) =20 use crate::{ - bindings, container_of, device, driver, + bindings, container_of, device, + devres::Devres, + driver, error::{to_result, Result}, - io::resource::Resource, + io::{ + mem::{ExclusiveIoMem, IoMem}, + resource::Resource, + }, of, prelude::*, str::CStr, @@ -227,6 +232,120 @@ pub fn resource_by_name(&self, name: &CStr) -> Option= <&Resource> { } } =20 +impl Device { + /// Maps a platform resource where the size is known at compile time. + /// + /// This uses the + /// [`ioremap()`](https://docs.kernel.org/driver-api/device-io.html#ge= tting-access-to-the-device) + /// C API. + /// + /// # Examples + /// + /// ```no_run + /// # use kernel::{bindings, c_str, platform, of, device::Core}; + /// # struct SampleDriver; + /// + /// impl platform::Driver for SampleDriver { + /// # type IdInfo =3D (); + /// # const OF_ID_TABLE: Option> =3D None; + /// + /// fn probe( + /// pdev: &platform::Device, + /// info: Option<&Self::IdInfo>, + /// ) -> Result>> { + /// let offset =3D 0; // Some offset. + /// + /// // If the size is known at compile time, use [`Self::iomap_r= esource_sized`]. + /// // + /// // No runtime checks will apply when reading and writing. + /// let resource =3D pdev.resource_by_index(0).ok_or(ENODEV)?; + /// let iomem =3D pdev.iomap_resource_sized::<42>(&resource)?; + /// let io =3D iomem.access(pdev.as_ref())?; + /// + /// // Read and write a 32-bit value at `offset`. Calling `try_a= ccess()` on + /// // the `Devres` makes sure that the resource is still valid. + /// let data =3D io.read32_relaxed(offset); + /// + /// iomem.try_access().ok_or(ENODEV)?.write32_relaxed(data, offs= et); + /// + /// # let sample_driver =3D KBox::new(SampleDriver, GFP_KERNEL).= map_err(|_| ENOMEM)?; + /// # Ok(sample_driver.into()) + /// } + /// } + /// ``` + pub fn iomap_resource_sized( + &self, + resource: &Resource, + ) -> Result>> { + IoMem::new(resource, self.as_ref()) + } + + /// Same as [`Self::iomap_resource_sized`] but with exclusive access t= o the + /// underlying region. + /// + /// This uses the + /// [`ioremap()`](https://docs.kernel.org/driver-api/device-io.html#ge= tting-access-to-the-device) + /// C API. + pub fn iomap_resource_exclusive_sized( + &self, + resource: &Resource, + ) -> Result>> { + ExclusiveIoMem::new(resource, self.as_ref()) + } + + /// Maps a platform resource through iomap(). + /// + /// This uses the + /// [`ioremap()`](https://docs.kernel.org/driver-api/device-io.html#ge= tting-access-to-the-device) + /// C API. + /// + /// # Examples + /// + /// ```no_run + /// # use kernel::{bindings, c_str, platform, of, device::Core}; + /// # struct SampleDriver; + /// + /// impl platform::Driver for SampleDriver { + /// # type IdInfo =3D (); + /// # const OF_ID_TABLE: Option> =3D None; + /// + /// fn probe( + /// pdev: &platform::Device, + /// info: Option<&Self::IdInfo>, + /// ) -> Result>> { + /// let offset =3D 0; // Some offset. + /// + /// // Unlike [`Self::iomap_resource_sized`], here the size of t= he memory region + /// // is not known at compile time, so only the `try_read*` and= `try_write*` + /// // family of functions should be used, leading to runtime ch= ecks on every + /// // access. + /// let resource =3D pdev.resource_by_index(0).ok_or(ENODEV)?; + /// let iomem =3D pdev.iomap_resource(&resource)?; + /// let io =3D iomem.access(pdev.as_ref())?; + /// + /// let data =3D io.try_read32_relaxed(offset)?; + /// + /// io.try_write32_relaxed(data, offset)?; + /// + /// # let sample_driver =3D KBox::new(SampleDriver, GFP_KERNEL).= map_err(|_| ENOMEM)?; + /// # Ok(sample_driver.into()) + /// } + /// } + /// ``` + pub fn iomap_resource(&self, resource: &Resource) -> Result>> { + self.iomap_resource_sized::<0>(resource) + } + + /// Same as [`Self::iomap_resource`] but with exclusive access to the = underlying + /// region. + pub fn iomap_resource_exclusive( + &self, + resource: &Resource, + ) -> Result>> { + self.iomap_resource_exclusive_sized::<0>(resource) + } +} + // SAFETY: `Device` is a transparent wrapper of a type that doesn't depend= on `Device`'s generic // argument. kernel::impl_device_context_deref!(unsafe { Device }); --=20 2.49.0