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Message-Id: <20241024-topic-panthor-rs-platform_io_support-v1-1-3d1addd96e30@collabora.com>
Date: Thu, 24 Oct 2024 11:20:28 -0300
From: Daniel Almeida <daniel.almeida@...labora.com>
To: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>,
Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>,
Björn Roy Baron <bjorn3_gh@...tonmail.com>,
Benno Lossin <benno.lossin@...ton.me>,
Andreas Hindborg <a.hindborg@...nel.org>, Alice Ryhl <aliceryhl@...gle.com>,
Trevor Gross <tmgross@...ch.edu>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J. Wysocki" <rafael@...nel.org>
Cc: rust-for-linux@...r.kernel.org, linux-kernel@...r.kernel.org,
Daniel Almeida <daniel.almeida@...labora.com>
Subject: [PATCH] rust: platform: add Io support
The IoMem is backed by ioremap_resource()
Signed-off-by: Daniel Almeida <daniel.almeida@...labora.com>
---
The PCI/Platform abstractions are in-flight and can be found at:
https://lore.kernel.org/rust-for-linux/Zxili5yze1l5p5GN@pollux/T/#t
---
rust/bindings/bindings_helper.h | 1 +
rust/helpers/io.c | 11 ++++++
rust/kernel/platform.rs | 88 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 100 insertions(+)
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 217c776615b9593a2fa921dee130c357dbd96761..90b2d29e7b99f33ceb313b4cc7f8232fef5eed17 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -13,6 +13,7 @@
#include <linux/errname.h>
#include <linux/ethtool.h>
#include <linux/firmware.h>
+#include <linux/ioport.h>
#include <linux/jiffies.h>
#include <linux/mdio.h>
#include <linux/of_device.h>
diff --git a/rust/helpers/io.c b/rust/helpers/io.c
index f9bb1bbf1fd5daedc970fc342eeacd8777a8d8ed..f708c09c4c87634c56af29ef22ebaa2bf51d82a9 100644
--- a/rust/helpers/io.c
+++ b/rust/helpers/io.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/io.h>
+#include <linux/ioport.h>
u8 rust_helper_readb(const volatile void __iomem *addr)
{
@@ -89,3 +90,13 @@ void rust_helper_writeq_relaxed(u64 value, volatile void __iomem *addr)
writeq_relaxed(value, addr);
}
#endif
+
+resource_size_t rust_helper_resource_size(struct resource *res)
+{
+ return resource_size(res);
+}
+
+void __iomem *rust_helper_ioremap(resource_size_t addr, unsigned long size)
+{
+ return ioremap(addr, size);
+}
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index addf5356f44f3cf233503aed97f1aa0d32f4f062..d152432c80a4499ead30ddaebe8d87a9679bfa97 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -4,11 +4,15 @@
//!
//! C header: [`include/linux/platform_device.h`](srctree/include/linux/platform_device.h)
+use core::ops::Deref;
+
use crate::{
bindings, container_of, device,
device_id::RawDeviceId,
+ devres::Devres,
driver,
error::{to_result, Result},
+ io::Io,
of,
prelude::*,
str::CStr,
@@ -208,6 +212,49 @@ fn as_raw(&self) -> *mut bindings::platform_device {
// embedded in `struct platform_device`.
unsafe { container_of!(self.0.as_raw(), bindings::platform_device, dev) }.cast_mut()
}
+
+ /// Maps a platform resource through ioremap() where the size is known at
+ /// compile time.
+ pub fn ioremap_resource_sized<const SIZE: usize>(
+ &self,
+ resource: u32,
+ ) -> Result<Devres<IoMem<SIZE>>> {
+ let res = self.resource(resource)?;
+ let size = self.resource_len(resource)? as usize;
+
+ // SAFETY: `res` is guaranteed to be a valid MMIO address and the size
+ // is given by the kernel as per `self.resource_len()`.
+ let io = unsafe { IoMem::new(res as _, size) }?;
+ let devres = Devres::new(self.as_ref(), io, GFP_KERNEL)?;
+
+ Ok(devres)
+ }
+
+ /// Maps a platform resource through ioremap().
+ pub fn ioremap_resource(&self, resource: u32) -> Result<Devres<IoMem>> {
+ self.ioremap_resource_sized::<0>(resource)
+ }
+
+ /// Returns the resource len for `resource`, if it exists.
+ pub fn resource_len(&self, resource: u32) -> Result<bindings::resource_size_t> {
+ match self.resource(resource) {
+ // SAFETY: if a struct resource* is returned by the kernel, it is valid.
+ Ok(resource) => Ok(unsafe { bindings::resource_size(resource) }),
+ Err(e) => Err(e),
+ }
+ }
+
+ fn resource(&self, resource: u32) -> Result<*mut bindings::resource> {
+ // SAFETY: By the type invariants, we know that `self.ptr` is non-null and valid.
+ let resource = unsafe {
+ bindings::platform_get_resource(self.as_raw(), bindings::IORESOURCE_MEM, resource)
+ };
+ if !resource.is_null() {
+ Ok(resource)
+ } else {
+ Err(EINVAL)
+ }
+ }
}
impl AsRef<device::Device> for Device {
@@ -215,3 +262,44 @@ fn as_ref(&self) -> &device::Device {
&self.0
}
}
+
+/// A I/O-mapped memory region for platform devices.
+///
+/// See also [`kernel::pci::Bar`].
+pub struct IoMem<const SIZE: usize = 0>(Io<SIZE>);
+
+impl<const SIZE: usize> IoMem<SIZE> {
+ /// Creates a new `IoMem` instance.
+ ///
+ /// # Safety
+ ///
+ /// The caller must make sure that `paddr` is a valid MMIO address.
+ unsafe fn new(paddr: usize, size: usize) -> Result<Self> {
+ // SAFETY: the safety requirements assert that `paddr` is a valid MMIO address.
+ let addr = unsafe { bindings::ioremap(paddr as _, size as u64) };
+ if addr.is_null() {
+ return Err(ENOMEM);
+ }
+
+ // SAFETY: `addr` is guaranteed to be the start of a valid I/O mapped memory region of
+ // size `size`.
+ let io = unsafe { Io::new(addr as _, size)? };
+
+ Ok(IoMem(io))
+ }
+}
+
+impl<const SIZE: usize> Drop for IoMem<SIZE> {
+ fn drop(&mut self) {
+ // SAFETY: Safe as by the invariant of `Io`.
+ unsafe { bindings::iounmap(self.0.base_addr() as _) };
+ }
+}
+
+impl<const SIZE: usize> Deref for IoMem<SIZE> {
+ type Target = Io<SIZE>;
+
+ fn deref(&self) -> &Self::Target {
+ &self.0
+ }
+}
---
base-commit: 2a5c159f49a5801603af03510c7cef89ff4c9850
change-id: 20241023-topic-panthor-rs-platform_io_support-f97aeb2ea887
Best regards,
--
Daniel Almeida <daniel.almeida@...labora.com>
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