| Message ID | 20241022213221.2383-14-dakr@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | Device / Driver PCI / Platform Rust abstractions | expand |
On Tue, Oct 22, 2024 at 11:31:50PM +0200, Danilo Krummrich wrote: > This commit adds a sample Rust PCI driver for QEMU's "pci-testdev" > device. To enable this device QEMU has to be called with > `-device pci-testdev`. Note that the DT unittests also use this device. So this means we have 2 drivers that bind to the device. Probably it's okay, but does make them somewhat mutually-exclusive. > The same driver shows how to use the PCI device / driver abstractions, > as well as how to request and map PCI BARs, including a short sequence of > MMIO operations. > > Signed-off-by: Danilo Krummrich <dakr@kernel.org> > --- > MAINTAINERS | 1 + > samples/rust/Kconfig | 11 ++++ > samples/rust/Makefile | 1 + > samples/rust/rust_driver_pci.rs | 109 ++++++++++++++++++++++++++++++++ > 4 files changed, 122 insertions(+) > create mode 100644 samples/rust/rust_driver_pci.rs > > diff --git a/MAINTAINERS b/MAINTAINERS > index 2d00d3845b4a..d9c512a3e72b 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -17940,6 +17940,7 @@ F: include/linux/of_pci.h > F: include/linux/pci* > F: include/uapi/linux/pci* > F: rust/kernel/pci.rs > +F: samples/rust/rust_driver_pci.rs > > PCIE DRIVER FOR AMAZON ANNAPURNA LABS > M: Jonathan Chocron <jonnyc@amazon.com> > diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig > index b0f74a81c8f9..6d468193cdd8 100644 > --- a/samples/rust/Kconfig > +++ b/samples/rust/Kconfig > @@ -30,6 +30,17 @@ config SAMPLE_RUST_PRINT > > If unsure, say N. > > +config SAMPLE_RUST_DRIVER_PCI > + tristate "PCI Driver" > + depends on PCI > + help > + This option builds the Rust PCI driver sample. > + > + To compile this as a module, choose M here: > + the module will be called driver_pci. > + > + If unsure, say N. > + > config SAMPLE_RUST_HOSTPROGS > bool "Host programs" > help > diff --git a/samples/rust/Makefile b/samples/rust/Makefile > index 03086dabbea4..b66767f4a62a 100644 > --- a/samples/rust/Makefile > +++ b/samples/rust/Makefile > @@ -2,5 +2,6 @@ > > obj-$(CONFIG_SAMPLE_RUST_MINIMAL) += rust_minimal.o > obj-$(CONFIG_SAMPLE_RUST_PRINT) += rust_print.o > +obj-$(CONFIG_SAMPLE_RUST_DRIVER_PCI) += rust_driver_pci.o > > subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS) += hostprogs > diff --git a/samples/rust/rust_driver_pci.rs b/samples/rust/rust_driver_pci.rs > new file mode 100644 > index 000000000000..d24dc1fde9e8 > --- /dev/null > +++ b/samples/rust/rust_driver_pci.rs > @@ -0,0 +1,109 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +//! Rust PCI driver sample (based on QEMU's `pci-testdev`). > +//! > +//! To make this driver probe, QEMU must be run with `-device pci-testdev`. > + > +use kernel::{bindings, c_str, devres::Devres, pci, prelude::*}; > + > +struct Regs; > + > +impl Regs { > + const TEST: usize = 0x0; > + const OFFSET: usize = 0x4; > + const DATA: usize = 0x8; > + const COUNT: usize = 0xC; > + const END: usize = 0x10; > +} > + > +type Bar0 = pci::Bar<{ Regs::END }>; > + > +#[derive(Debug)] > +struct TestIndex(u8); > + > +impl TestIndex { > + const NO_EVENTFD: Self = Self(0); > +} > + > +struct SampleDriver { > + pdev: pci::Device, > + bar: Devres<Bar0>, > +} > + > +kernel::pci_device_table!( > + PCI_TABLE, > + MODULE_PCI_TABLE, > + <SampleDriver as pci::Driver>::IdInfo, > + [( > + pci::DeviceId::new(bindings::PCI_VENDOR_ID_REDHAT, 0x5), > + TestIndex::NO_EVENTFD > + )] > +); > + > +impl SampleDriver { > + fn testdev(index: &TestIndex, bar: &Bar0) -> Result<u32> { > + // Select the test. > + bar.writeb(index.0, Regs::TEST); > + > + let offset = u32::from_le(bar.readl(Regs::OFFSET)) as usize; The C version of readl takes care of from_le for you. Why not here? Also, can't we do better with rust and make this a generic: let offset = bar.read::<u32>(Regs::OFFSET)) as usize; > + let data = bar.readb(Regs::DATA); > + > + // Write `data` to `offset` to increase `count` by one. > + // > + // Note that we need `try_writeb`, since `offset` can't be checked at compile-time. > + bar.try_writeb(data, offset)?; > + > + Ok(u32::from_le(bar.readl(Regs::COUNT))) > + } > +}
On Wed, Oct 23, 2024 at 10:57:37AM -0500, Rob Herring wrote: > On Tue, Oct 22, 2024 at 11:31:50PM +0200, Danilo Krummrich wrote: > > This commit adds a sample Rust PCI driver for QEMU's "pci-testdev" > > device. To enable this device QEMU has to be called with > > `-device pci-testdev`. > > Note that the DT unittests also use this device. So this means we have 2 > drivers that bind to the device. Probably it's okay, but does make > them somewhat mutually-exclusive. > > > The same driver shows how to use the PCI device / driver abstractions, > > as well as how to request and map PCI BARs, including a short sequence of > > MMIO operations. > > > > Signed-off-by: Danilo Krummrich <dakr@kernel.org> > > --- > > MAINTAINERS | 1 + > > samples/rust/Kconfig | 11 ++++ > > samples/rust/Makefile | 1 + > > samples/rust/rust_driver_pci.rs | 109 ++++++++++++++++++++++++++++++++ > > 4 files changed, 122 insertions(+) > > create mode 100644 samples/rust/rust_driver_pci.rs > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > index 2d00d3845b4a..d9c512a3e72b 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -17940,6 +17940,7 @@ F: include/linux/of_pci.h > > F: include/linux/pci* > > F: include/uapi/linux/pci* > > F: rust/kernel/pci.rs > > +F: samples/rust/rust_driver_pci.rs > > > > PCIE DRIVER FOR AMAZON ANNAPURNA LABS > > M: Jonathan Chocron <jonnyc@amazon.com> > > diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig > > index b0f74a81c8f9..6d468193cdd8 100644 > > --- a/samples/rust/Kconfig > > +++ b/samples/rust/Kconfig > > @@ -30,6 +30,17 @@ config SAMPLE_RUST_PRINT > > > > If unsure, say N. > > > > +config SAMPLE_RUST_DRIVER_PCI > > + tristate "PCI Driver" > > + depends on PCI > > + help > > + This option builds the Rust PCI driver sample. > > + > > + To compile this as a module, choose M here: > > + the module will be called driver_pci. > > + > > + If unsure, say N. > > + > > config SAMPLE_RUST_HOSTPROGS > > bool "Host programs" > > help > > diff --git a/samples/rust/Makefile b/samples/rust/Makefile > > index 03086dabbea4..b66767f4a62a 100644 > > --- a/samples/rust/Makefile > > +++ b/samples/rust/Makefile > > @@ -2,5 +2,6 @@ > > > > obj-$(CONFIG_SAMPLE_RUST_MINIMAL) += rust_minimal.o > > obj-$(CONFIG_SAMPLE_RUST_PRINT) += rust_print.o > > +obj-$(CONFIG_SAMPLE_RUST_DRIVER_PCI) += rust_driver_pci.o > > > > subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS) += hostprogs > > diff --git a/samples/rust/rust_driver_pci.rs b/samples/rust/rust_driver_pci.rs > > new file mode 100644 > > index 000000000000..d24dc1fde9e8 > > --- /dev/null > > +++ b/samples/rust/rust_driver_pci.rs > > @@ -0,0 +1,109 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > + > > +//! Rust PCI driver sample (based on QEMU's `pci-testdev`). > > +//! > > +//! To make this driver probe, QEMU must be run with `-device pci-testdev`. > > + > > +use kernel::{bindings, c_str, devres::Devres, pci, prelude::*}; > > + > > +struct Regs; > > + > > +impl Regs { > > + const TEST: usize = 0x0; > > + const OFFSET: usize = 0x4; > > + const DATA: usize = 0x8; > > + const COUNT: usize = 0xC; > > + const END: usize = 0x10; > > +} > > + > > +type Bar0 = pci::Bar<{ Regs::END }>; > > + > > +#[derive(Debug)] > > +struct TestIndex(u8); > > + > > +impl TestIndex { > > + const NO_EVENTFD: Self = Self(0); > > +} > > + > > +struct SampleDriver { > > + pdev: pci::Device, > > + bar: Devres<Bar0>, > > +} > > + > > +kernel::pci_device_table!( > > + PCI_TABLE, > > + MODULE_PCI_TABLE, > > + <SampleDriver as pci::Driver>::IdInfo, > > + [( > > + pci::DeviceId::new(bindings::PCI_VENDOR_ID_REDHAT, 0x5), > > + TestIndex::NO_EVENTFD > > + )] > > +); > > + > > +impl SampleDriver { > > + fn testdev(index: &TestIndex, bar: &Bar0) -> Result<u32> { > > + // Select the test. > > + bar.writeb(index.0, Regs::TEST); > > + > > + let offset = u32::from_le(bar.readl(Regs::OFFSET)) as usize; > > The C version of readl takes care of from_le for you. Why not here? It's just an abstraction around the C readl(), so it does -- good catch. > > Also, can't we do better with rust and make this a generic: > > let offset = bar.read::<u32>(Regs::OFFSET)) as usize; I think we probably could, but we'd still need to handle the special cases for 1 to 8 bytes type size (always using memcopy_{to,from}io() would lead to unnecessary overhead). Hence, there's probably not much benefit in that. Also, what would be the logic for a generic `{read, write}::<T>` in terms of memory barriers? I think memcopy_{to,from}io() is always "relaxed", isn't it? I think it's probably best to keep the two separate, the b,w,l,q variants and a generic one that maps to memcopy_{to,from}io(). > > > > + let data = bar.readb(Regs::DATA); > > + > > + // Write `data` to `offset` to increase `count` by one. > > + // > > + // Note that we need `try_writeb`, since `offset` can't be checked at compile-time. > > + bar.try_writeb(data, offset)?; > > + > > + Ok(u32::from_le(bar.readl(Regs::COUNT))) > > + } > > +} >
diff --git a/MAINTAINERS b/MAINTAINERS index 2d00d3845b4a..d9c512a3e72b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17940,6 +17940,7 @@ F: include/linux/of_pci.h F: include/linux/pci* F: include/uapi/linux/pci* F: rust/kernel/pci.rs +F: samples/rust/rust_driver_pci.rs PCIE DRIVER FOR AMAZON ANNAPURNA LABS M: Jonathan Chocron <jonnyc@amazon.com> diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig index b0f74a81c8f9..6d468193cdd8 100644 --- a/samples/rust/Kconfig +++ b/samples/rust/Kconfig @@ -30,6 +30,17 @@ config SAMPLE_RUST_PRINT If unsure, say N. +config SAMPLE_RUST_DRIVER_PCI + tristate "PCI Driver" + depends on PCI + help + This option builds the Rust PCI driver sample. + + To compile this as a module, choose M here: + the module will be called driver_pci. + + If unsure, say N. + config SAMPLE_RUST_HOSTPROGS bool "Host programs" help diff --git a/samples/rust/Makefile b/samples/rust/Makefile index 03086dabbea4..b66767f4a62a 100644 --- a/samples/rust/Makefile +++ b/samples/rust/Makefile @@ -2,5 +2,6 @@ obj-$(CONFIG_SAMPLE_RUST_MINIMAL) += rust_minimal.o obj-$(CONFIG_SAMPLE_RUST_PRINT) += rust_print.o +obj-$(CONFIG_SAMPLE_RUST_DRIVER_PCI) += rust_driver_pci.o subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS) += hostprogs diff --git a/samples/rust/rust_driver_pci.rs b/samples/rust/rust_driver_pci.rs new file mode 100644 index 000000000000..d24dc1fde9e8 --- /dev/null +++ b/samples/rust/rust_driver_pci.rs @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Rust PCI driver sample (based on QEMU's `pci-testdev`). +//! +//! To make this driver probe, QEMU must be run with `-device pci-testdev`. + +use kernel::{bindings, c_str, devres::Devres, pci, prelude::*}; + +struct Regs; + +impl Regs { + const TEST: usize = 0x0; + const OFFSET: usize = 0x4; + const DATA: usize = 0x8; + const COUNT: usize = 0xC; + const END: usize = 0x10; +} + +type Bar0 = pci::Bar<{ Regs::END }>; + +#[derive(Debug)] +struct TestIndex(u8); + +impl TestIndex { + const NO_EVENTFD: Self = Self(0); +} + +struct SampleDriver { + pdev: pci::Device, + bar: Devres<Bar0>, +} + +kernel::pci_device_table!( + PCI_TABLE, + MODULE_PCI_TABLE, + <SampleDriver as pci::Driver>::IdInfo, + [( + pci::DeviceId::new(bindings::PCI_VENDOR_ID_REDHAT, 0x5), + TestIndex::NO_EVENTFD + )] +); + +impl SampleDriver { + fn testdev(index: &TestIndex, bar: &Bar0) -> Result<u32> { + // Select the test. + bar.writeb(index.0, Regs::TEST); + + let offset = u32::from_le(bar.readl(Regs::OFFSET)) as usize; + let data = bar.readb(Regs::DATA); + + // Write `data` to `offset` to increase `count` by one. + // + // Note that we need `try_writeb`, since `offset` can't be checked at compile-time. + bar.try_writeb(data, offset)?; + + Ok(u32::from_le(bar.readl(Regs::COUNT))) + } +} + +impl pci::Driver for SampleDriver { + type IdInfo = TestIndex; + + const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE; + + fn probe( + pdev: &mut pci::Device, + _id: &pci::DeviceId, + info: &Self::IdInfo, + ) -> Result<Pin<KBox<Self>>> { + dev_dbg!(pdev.as_ref(), "Probe Rust PCI driver sample.\n"); + + pdev.enable_device_mem()?; + pdev.set_master(); + + let bar = pdev.iomap_region_sized::<{ Regs::END }>(0, c_str!("rust_driver_pci"))?; + + let drvdata = KBox::new( + Self { + pdev: pdev.clone(), + bar, + }, + GFP_KERNEL, + )?; + + let bar = drvdata.bar.try_access().ok_or(ENXIO)?; + + dev_info!( + pdev.as_ref(), + "pci-testdev data-match count: {}\n", + Self::testdev(info, &bar)? + ); + + Ok(drvdata.into()) + } +} + +impl Drop for SampleDriver { + fn drop(&mut self) { + dev_dbg!(self.pdev.as_ref(), "Remove Rust PCI driver sample.\n"); + } +} + +kernel::module_pci_driver! { + type: SampleDriver, + name: "rust_driver_pci", + author: "Danilo Krummrich", + description: "Rust PCI driver", + license: "GPL v2", +}
This commit adds a sample Rust PCI driver for QEMU's "pci-testdev" device. To enable this device QEMU has to be called with `-device pci-testdev`. The same driver shows how to use the PCI device / driver abstractions, as well as how to request and map PCI BARs, including a short sequence of MMIO operations. Signed-off-by: Danilo Krummrich <dakr@kernel.org> --- MAINTAINERS | 1 + samples/rust/Kconfig | 11 ++++ samples/rust/Makefile | 1 + samples/rust/rust_driver_pci.rs | 109 ++++++++++++++++++++++++++++++++ 4 files changed, 122 insertions(+) create mode 100644 samples/rust/rust_driver_pci.rs