From nobody Wed Oct 8 07:31:27 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 D63EB277C9E; Tue, 1 Jul 2025 14:35:36 +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=1751380540; cv=pass; b=TkjLo5bhdkldtvFGGYIUn/jX6tUqugKMc6Ic9oa3SZuR8rXfB4bdOQbAydDHw0kmCDO4jBjqBWVhLkCK061sceNs1J6YecNPOuWwZUumfEdh7+UIhZStFVGYPLPq2OMWV8f+ne2MJhK2yFiDCZKJQO0yn0vvYCAbHEpTS0OwbYA= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751380540; c=relaxed/simple; bh=Rptf+sv1VX4B/+C2B9gdhZFGhVXXCxTi1EyWHPPzAvo=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Uc2Pt3a4LbaX3Pmj3ZHU7MhN7EdLgwv80xefaeNqNFpAv1sDlPgpeKJJpE5k2SfsVZlzH6BfgJZfxR2HZ/QT0oDfFU9aoWhfUfGwp8uF7L9Bjq19I181iOG7qnySRO3wHDublFAB97d8M35ZiWemyBIgokqCOX58lYGQGWBR4Pc= 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=LlQgoUTw; 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="LlQgoUTw" ARC-Seal: i=1; a=rsa-sha256; t=1751380519; cv=none; d=zohomail.com; s=zohoarc; b=KDlfEKqYhWYlN62pN2CZjM/UAZZxUVdrnVa+tEuFkLXfuxWX9+Qn4BJ7a6p2C26tLU4nv7/ynWcwXWEjkX8iMuOBWR8u74rDA7S9sG5gLhMpsrk3Hrbpy3ujjpnugT4WY86CZMK53l8iUatb4BUb7sU78LmZS/Jvpdym0XSJOgU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1751380519; 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=EYrBsQi1TC80wEIpdSJrvb4LqOzrOeOmKctTnpjzleQ=; b=mxUnC1nVHrjC3yOcbsNRlBZ/2JQdNAVNBJb97tH1PIySNyMuyu/lDQYyTaf2c/tbh61ySSwsx6bu0SBj1b+h6vq14uCHG2UPs4UZE8Gjg8aM6RL/aw+aazgcG1eOdUSodwTxq9Nc3EmlPaw8uHmsodzGu4Oib6hdzEfE97W86WI= 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=1751380519; 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=EYrBsQi1TC80wEIpdSJrvb4LqOzrOeOmKctTnpjzleQ=; b=LlQgoUTwP272M41QYJdMtEsqKUtOJtXr3DLow2Sb0oZsKiOazB/QtbdkD9IeyuJ1 lHUakjE3qEDs19TmWK6YYini7J6Jgv1UHg2piNw+OLdW+STKjJ2p1bvfj1niaxI9yBQ MC/aTBXkwqxx1aAyEW5VE8VTU3kKndS1tPW/Hmc8= Received: by mx.zohomail.com with SMTPS id 1751380515131699.1691349237082; Tue, 1 Jul 2025 07:35:15 -0700 (PDT) From: Daniel Almeida Date: Tue, 01 Jul 2025 11:34:40 -0300 Subject: [PATCH v11 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: <20250701-topics-tyr-platform_iomem-v11-2-6cd5d5061151@collabora.com> References: <20250701-topics-tyr-platform_iomem-v11-0-6cd5d5061151@collabora.com> In-Reply-To: <20250701-topics-tyr-platform_iomem-v11-0-6cd5d5061151@collabora.com> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , 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 , Benno Lossin , Benno Lossin 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 | 147 ++++++++++++++++++++++++++++++++++++++++++++++= ++++ 3 files changed, 153 insertions(+) diff --git a/rust/helpers/io.c b/rust/helpers/io.c index 404776cf6717c8570c7600a24712ce6e4623d3c6..c475913c69e647b1042e8e7d66b= 9148d892947a1 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(void __iomem *addr) { iounmap(addr); diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs index 7b70d5b5477e57d6d0f24bcd26bd8b0071721bc0..b7fc759f8b5d3c3ac6f33f5a66e= 9f619c58b7405 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 pub use resource::Resource; diff --git a/rust/kernel/io/mem.rs b/rust/kernel/io/mem.rs new file mode 100644 index 0000000000000000000000000000000000000000..16bd2d6752ff720cb791eaff633= adbc1c0964f03 --- /dev/null +++ b/rust/kernel/io/mem.rs @@ -0,0 +1,147 @@ +// 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`]. +#[pin_data] +pub struct ExclusiveIoMem { + /// The underlying `IoMem` instance. + iomem: IoMem, + + /// The region abstraction. This represents exclusive access to the + /// range represented by the underlying `iomem`. + /// + /// This field is needed for ownership of the region. + _region: Region, +} + +impl ExclusiveIoMem { + /// Creates a new `ExclusiveIoMem` instance. + pub(crate) fn ioremap(resource: &Resource) -> Result { + 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 IoMem::ioremap(resource)?; + + let iomem =3D ExclusiveIoMem { + iomem, + _region: region, + }; + + Ok(iomem) + } + + pub(crate) fn new<'a>( + resource: &Resource, + device: &'a Device, + ) -> Result, Error> + 'a> { + let iomem =3D Self::ioremap(resource)?; + let devres =3D Devres::new(device, iomem); + + 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<'a>( + resource: &Resource, + device: &'a Device, + ) -> Result, Error> + 'a> { + let io =3D Self::ioremap(resource)?; + let devres =3D Devres::new(device, io); + + 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 2.50.0