From mboxrd@z Thu Jan 1 00:00:00 1970 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 1C4A42D3A6C; Mon, 23 Jun 2025 18:01:53 +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=1750701717; cv=pass; b=gwV0WW0KlGJAHxrCFhyXD4TzoWV74KFWVH3lsN9xl2tigypQXOgnkPL0XPK50yM78/Gtr8gJwb4dLaZShy7qCDioFds3O+oR0zeeE6fDPYVroCntAaNvRuo8grICB7/miAypQhW+YouKN5luu8QhT/JrYFGyHpZ+LSSbUlO9qm8= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750701717; c=relaxed/simple; bh=2qwMN6lN8/x/WoX6+eNWfhRLRYqxNp8PNR13U7u3pig=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=oLlS/YxeIqS7bY+FbYXmD5nJ1DR8VI9jHY6KDJFqfXMcP/KZaUo739Cuorhbx8bteNA3rL1FLJvmnfNVeOX0fmrE1u47xV5OCHmAGafo5rrZt3t8CaXPX7aeDHfkgu+A6thRyu00k/6fGMKgSAYQG+JLwNDdSIlA4mx2eRPyBj0= 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=MSidSuKt; 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="MSidSuKt" ARC-Seal: i=1; a=rsa-sha256; t=1750701687; cv=none; d=zohomail.com; s=zohoarc; b=MV65MM+NemfThrZ1zziW7nNgJkmDuDZCb7xdjOQ7VNx94EI3NtklO4ot/1LVp1gTF9LeF0n3wJ1GS/WRQJheUAJ0RUnHnYhwAx10CabFsc5x32gtI+WopqE7VRF9uuHSlwx1carunw9l6oMsShEhLkKQb7V/z76JXb4Ze/B4h58= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1750701687; 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=5FpfJ0CqUASp3pNcpfXNd9kKLY1o6Cwk8Nt966cf4OM=; b=Gf5V1zqiBrSni9hT3uaTKxKVRPBC2r51vATVJwxwtvqteLXMnuVDb2j1H01VMUEdRmTohZgsuoB4dClkiQhvAXdhZ8rH2ZGwI1a/LCbnRQeuTSpqJuNsKlyaw0dKbJPtQwWuF/sNMhLHBQgE6IkPa0bL4UYhP5E6+KUNU6H3hbk= 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=1750701687; 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=5FpfJ0CqUASp3pNcpfXNd9kKLY1o6Cwk8Nt966cf4OM=; b=MSidSuKtm3QMOBrXZ2nOY/UBlclyqhE+0ItNCuf1QyujyLnSB1194dp/be+icCZy 3GzEWW6zFH0pfHhFjOpQ/9TRc3pW2vR6gb6B78113QiUtUoATJJiwEyRjzvXc1/d92T 9uAgmVAFZeiho+cL7Sw1uHHfTINy4baffrYZ7Hms= Received: by mx.zohomail.com with SMTPS id 1750701683906348.3665812969841; Mon, 23 Jun 2025 11:01:23 -0700 (PDT) From: Daniel Almeida Date: Mon, 23 Jun 2025 15:00:58 -0300 Subject: [PATCH v10 1/4] rust: io: add resource abstraction Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250623-topics-tyr-platform_iomem-v10-1-ed860a562940@collabora.com> References: <20250623-topics-tyr-platform_iomem-v10-0-ed860a562940@collabora.com> In-Reply-To: <20250623-topics-tyr-platform_iomem-v10-0-ed860a562940@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 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 | 4 + rust/kernel/io/resource.rs | 222 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 263 insertions(+) diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 8cbb660e2ec218021d16e6e0144acf6f4d7cca13..38992cb4b2fc33c51c6894cf2a0b8a1366c338a3 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -52,6 +52,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/helpers/io.c b/rust/helpers/io.c index 15ea187c5466256effd07efe6f6995a1dd95a967..404776cf6717c8570c7600a24712ce6e4623d3c6 100644 --- a/rust/helpers/io.c +++ b/rust/helpers/io.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 #include +#include void __iomem *rust_helper_ioremap(phys_addr_t offset, size_t size) { @@ -99,3 +100,38 @@ void rust_helper_writeq_relaxed(u64 value, void __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..7b70d5b5477e57d6d0f24bcd26bd8b0071721bc0 100644 --- a/rust/kernel/io.rs +++ b/rust/kernel/io.rs @@ -7,6 +7,10 @@ use crate::error::{code::EINVAL, Result}; use crate::{bindings, build_assert}; +pub mod resource; + +pub use resource::Resource; + /// Raw representation of an MMIO region. /// /// By itself, the existence of an instance of this structure does not provide any guarantees that diff --git a/rust/kernel/io/resource.rs b/rust/kernel/io/resource.rs new file mode 100644 index 0000000000000000000000000000000000000000..611eca8cc693d83bccc2c384db2ff22d11e7ac46 --- /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 type 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 type 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 = 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 = u32; + +/// A region allocated from a parent [`Resource`]. +/// +/// # Invariants +/// +/// - `self.0` points to a valid `bindings::resource` that was obtained through +/// `bindings::__request_region`. +pub struct Region(NonNull); + +impl Deref for Region { + type Target = 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 = unsafe { Resource::as_ref(self.0.as_ptr()) }; + let flags = res.flags(); + + let release_fn = 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 is safe to be used from +// any thread. +unsafe impl Send for Region {} + +// SAFETY: `Region` only holds a pointer to a C `struct resource`, references 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::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 will + /// 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 busy. + /// 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 = 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 = 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 = 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 = 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 = self.0.get(); + // SAFETY: safe as per the invariants of `Resource` + let flags = 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`, references 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) == flags + } +} + +impl core::ops::BitOr for Flags { + type Output = Self; + fn bitor(self, rhs: Self) -> Self::Output { + Self(self.0 | rhs.0) + } +} + +impl core::ops::BitAnd for Flags { + type Output = Self; + fn bitand(self, rhs: Self) -> Self::Output { + Self(self.0 & rhs.0) + } +} + +impl core::ops::Not for Flags { + type Output = 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 = Flags(bindings::IORESOURCE_IO as usize); + + /// Resource is software muxed. + pub const IORESOURCE_MUXED: Flags = Flags(bindings::IORESOURCE_MUXED as usize); + + /// Resource represents a memory region. + pub const IORESOURCE_MEM: Flags = Flags(bindings::IORESOURCE_MEM as usize); + + /// Resource represents a memory region that must be ioremaped using `ioremap_np`. + pub const IORESOURCE_MEM_NONPOSTED: Flags = Flags(bindings::IORESOURCE_MEM_NONPOSTED as usize); +} -- 2.50.0