Add a lifetime parameter to IoMem<'bound, SIZE> and ExclusiveIoMem<'bound, SIZE>, storing a &'bound Device<Bound> reference to tie the mapping to the device's lifetime.
This mirrors the pci::Bar<'bound, SIZE> design and enables drivers to hold I/O memory mappings directly in their HRT private data, tied to the device lifetime. IoRequest::iomap_* methods now return the mapping directly instead of wrapping it in Devres. Callers that need device-managed revocation can call the new into_devres() method. Acked-by: Uwe Kleine-König <[email protected]> Signed-off-by: Danilo Krummrich <[email protected]> --- drivers/gpu/drm/tyr/driver.rs | 4 +- drivers/pwm/pwm_th1520.rs | 4 +- rust/kernel/io/mem.rs | 115 +++++++++++++++++----------------- 3 files changed, 62 insertions(+), 61 deletions(-) diff --git a/drivers/gpu/drm/tyr/driver.rs b/drivers/gpu/drm/tyr/driver.rs index 96d83605e4b9..295a627de2b2 100644 --- a/drivers/gpu/drm/tyr/driver.rs +++ b/drivers/gpu/drm/tyr/driver.rs @@ -37,7 +37,7 @@ regs, // }; -pub(crate) type IoMem = kernel::io::mem::IoMem<SZ_2M>; +pub(crate) type IoMem = kernel::io::mem::IoMem<'static, SZ_2M>; pub(crate) struct TyrDrmDriver; @@ -109,7 +109,7 @@ fn probe( let sram_regulator = Regulator::<regulator::Enabled>::get(pdev.as_ref(), c"sram")?; let request = pdev.io_request_by_index(0).ok_or(ENODEV)?; - let iomem = Arc::pin_init(request.iomap_sized::<SZ_2M>(), GFP_KERNEL)?; + let iomem = Arc::new(request.iomap_sized::<SZ_2M>()?.into_devres()?, GFP_KERNEL)?; issue_soft_reset(pdev.as_ref(), &iomem)?; gpu::l2_power_on(pdev.as_ref(), &iomem)?; diff --git a/drivers/pwm/pwm_th1520.rs b/drivers/pwm/pwm_th1520.rs index a7831b4ebe00..3deb39d8e0fc 100644 --- a/drivers/pwm/pwm_th1520.rs +++ b/drivers/pwm/pwm_th1520.rs @@ -92,7 +92,7 @@ struct Th1520WfHw { #[pin_data(PinnedDrop)] struct Th1520PwmDriverData { #[pin] - iomem: devres::Devres<IoMem<TH1520_PWM_REG_SIZE>>, + iomem: devres::Devres<IoMem<'static, TH1520_PWM_REG_SIZE>>, clk: Clk, } @@ -351,7 +351,7 @@ fn probe( dev, TH1520_MAX_PWM_NUM, try_pin_init!(Th1520PwmDriverData { - iomem <- request.iomap_sized::<TH1520_PWM_REG_SIZE>(), + iomem <- request.iomap_sized::<TH1520_PWM_REG_SIZE>()?.into_devres(), clk <- clk, }), )?; diff --git a/rust/kernel/io/mem.rs b/rust/kernel/io/mem.rs index fd5292df5870..a4cb12ee70d3 100644 --- a/rust/kernel/io/mem.rs +++ b/rust/kernel/io/mem.rs @@ -23,19 +23,19 @@ }; /// An IO request for a specific device and resource. -pub struct IoRequest<'a> { - device: &'a Device<Bound>, - resource: &'a Resource, +pub struct IoRequest<'bound> { + device: &'bound Device<Bound>, + resource: &'bound Resource, } -impl<'a> IoRequest<'a> { +impl<'bound> IoRequest<'bound> { /// Creates a new [`IoRequest`] instance. /// /// # Safety /// /// Callers must ensure that `resource` is valid for `device` during the - /// lifetime `'a`. - pub(crate) unsafe fn new(device: &'a Device<Bound>, resource: &'a Resource) -> Self { + /// lifetime `'bound`. + pub(crate) unsafe fn new(device: &'bound Device<Bound>, resource: &'bound Resource) -> Self { IoRequest { device, resource } } @@ -73,22 +73,19 @@ pub(crate) unsafe fn new(device: &'a Device<Bound>, resource: &'a Resource) -> S /// // /// // No runtime checks will apply when reading and writing. /// let request = pdev.io_request_by_index(0).ok_or(ENODEV)?; - /// let iomem = request.iomap_sized::<42>(); - /// let iomem = KBox::pin_init(iomem, GFP_KERNEL)?; - /// - /// let io = iomem.access(pdev.as_ref())?; + /// let iomem = request.iomap_sized::<42>()?; /// /// // Read and write a 32-bit value at `offset`. - /// let data = io.read32(offset); + /// let data = iomem.read32(offset); /// - /// io.write32(data, offset); + /// iomem.write32(data, offset); /// /// # Ok(SampleDriver) /// } /// } /// ``` - pub fn iomap_sized<const SIZE: usize>(self) -> impl PinInit<Devres<IoMem<SIZE>>, Error> + 'a { - IoMem::new(self) + pub fn iomap_sized<const SIZE: usize>(self) -> Result<IoMem<'bound, SIZE>> { + IoMem::ioremap(self.device, self.resource) } /// Same as [`Self::iomap_sized`] but with exclusive access to the @@ -97,10 +94,8 @@ pub fn iomap_sized<const SIZE: usize>(self) -> impl PinInit<Devres<IoMem<SIZE>>, /// This uses the [`ioremap()`] C API. /// /// [`ioremap()`]: https://docs.kernel.org/driver-api/device-io.html#getting-access-to-the-device - pub fn iomap_exclusive_sized<const SIZE: usize>( - self, - ) -> impl PinInit<Devres<ExclusiveIoMem<SIZE>>, Error> + 'a { - ExclusiveIoMem::new(self) + pub fn iomap_exclusive_sized<const SIZE: usize>(self) -> Result<ExclusiveIoMem<'bound, SIZE>> { + ExclusiveIoMem::ioremap(self.device, self.resource) } /// Maps an [`IoRequest`] where the size is not known at compile time, @@ -138,27 +133,24 @@ pub fn iomap_exclusive_sized<const SIZE: usize>( /// // family of functions should be used, leading to runtime checks on every /// // access. /// let request = pdev.io_request_by_index(0).ok_or(ENODEV)?; - /// let iomem = request.iomap(); - /// let iomem = KBox::pin_init(iomem, GFP_KERNEL)?; - /// - /// let io = iomem.access(pdev.as_ref())?; + /// let iomem = request.iomap()?; /// - /// let data = io.try_read32(offset)?; + /// let data = iomem.try_read32(offset)?; /// - /// io.try_write32(data, offset)?; + /// iomem.try_write32(data, offset)?; /// /// # Ok(SampleDriver) /// } /// } /// ``` - pub fn iomap(self) -> impl PinInit<Devres<IoMem<0>>, Error> + 'a { - Self::iomap_sized::<0>(self) + pub fn iomap(self) -> Result<IoMem<'bound>> { + self.iomap_sized::<0>() } /// Same as [`Self::iomap`] but with exclusive access to the underlying /// region. - pub fn iomap_exclusive(self) -> impl PinInit<Devres<ExclusiveIoMem<0>>, Error> + 'a { - Self::iomap_exclusive_sized::<0>(self) + pub fn iomap_exclusive(self) -> Result<ExclusiveIoMem<'bound, 0>> { + self.iomap_exclusive_sized::<0>() } } @@ -167,9 +159,9 @@ pub fn iomap_exclusive(self) -> impl PinInit<Devres<ExclusiveIoMem<0>>, Error> + /// # Invariants /// /// - [`ExclusiveIoMem`] has exclusive access to the underlying [`IoMem`]. -pub struct ExclusiveIoMem<const SIZE: usize> { +pub struct ExclusiveIoMem<'bound, const SIZE: usize> { /// The underlying `IoMem` instance. - iomem: IoMem<SIZE>, + iomem: IoMem<'bound, SIZE>, /// The region abstraction. This represents exclusive access to the /// range represented by the underlying `iomem`. @@ -178,9 +170,9 @@ pub struct ExclusiveIoMem<const SIZE: usize> { _region: Region, } -impl<const SIZE: usize> ExclusiveIoMem<SIZE> { +impl<'bound, const SIZE: usize> ExclusiveIoMem<'bound, SIZE> { /// Creates a new `ExclusiveIoMem` instance. - fn ioremap(resource: &Resource) -> Result<Self> { + fn ioremap(dev: &'bound Device<Bound>, resource: &Resource) -> Result<Self> { let start = resource.start(); let size = resource.size(); let name = resource.name().unwrap_or_default(); @@ -194,26 +186,29 @@ fn ioremap(resource: &Resource) -> Result<Self> { ) .ok_or(EBUSY)?; - let iomem = IoMem::ioremap(resource)?; + let iomem = IoMem::ioremap(dev, resource)?; - let iomem = ExclusiveIoMem { + Ok(ExclusiveIoMem { iomem, _region: region, - }; - - Ok(iomem) + }) } - /// Creates a new `ExclusiveIoMem` instance from a previously acquired [`IoRequest`]. - pub fn new<'a>(io_request: IoRequest<'a>) -> impl PinInit<Devres<Self>, Error> + 'a { - let dev = io_request.device; - let res = io_request.resource; - - Devres::new(dev, Self::ioremap(res)) + /// Consume the `ExclusiveIoMem` and register it as a device-managed resource. + /// + /// The returned `Devres<ExclusiveIoMem<'static, SIZE>>` can outlive the original lifetime + /// `'bound`. Access to the I/O memory is revoked when the device is unbound. + pub fn into_devres(self) -> Result<Devres<ExclusiveIoMem<'static, SIZE>>> { + // SAFETY: Casting to `'static` is sound because `Devres` guarantees the + // `ExclusiveIoMem` does not actually outlive the device -- access is revoked and the + // resource is released when the device is unbound. + let iomem: ExclusiveIoMem<'static, SIZE> = unsafe { core::mem::transmute(self) }; + let dev = iomem.iomem.dev; + Devres::new(dev, iomem) } } -impl<const SIZE: usize> Deref for ExclusiveIoMem<SIZE> { +impl<const SIZE: usize> Deref for ExclusiveIoMem<'_, SIZE> { type Target = Mmio<SIZE>; fn deref(&self) -> &Self::Target { @@ -230,12 +225,13 @@ fn deref(&self) -> &Self::Target { /// /// [`IoMem`] always holds an [`MmioRaw`] instance that holds a valid pointer to the /// start of the I/O memory mapped region. -pub struct IoMem<const SIZE: usize = 0> { +pub struct IoMem<'bound, const SIZE: usize = 0> { + dev: &'bound Device<Bound>, io: MmioRaw<SIZE>, } -impl<const SIZE: usize> IoMem<SIZE> { - fn ioremap(resource: &Resource) -> Result<Self> { +impl<'bound, const SIZE: usize> IoMem<'bound, SIZE> { + fn ioremap(dev: &'bound Device<Bound>, resource: &Resource) -> Result<Self> { // Note: Some ioremap() implementations use types that depend on the CPU // word width rather than the bus address width. // @@ -267,28 +263,33 @@ fn ioremap(resource: &Resource) -> Result<Self> { } let io = MmioRaw::new(addr as usize, size)?; - let io = IoMem { io }; - Ok(io) + Ok(IoMem { dev, io }) } - /// Creates a new `IoMem` instance from a previously acquired [`IoRequest`]. - pub fn new<'a>(io_request: IoRequest<'a>) -> impl PinInit<Devres<Self>, Error> + 'a { - let dev = io_request.device; - let res = io_request.resource; - - Devres::new(dev, Self::ioremap(res)) + /// Consume the `IoMem` and register it as a device-managed resource. + /// + /// The returned `Devres<IoMem<'static, SIZE>>` can outlive the original + /// lifetime `'bound`. Access to the I/O memory is revoked when the device + /// is unbound. + pub fn into_devres(self) -> Result<Devres<IoMem<'static, SIZE>>> { + // SAFETY: Casting to `'static` is sound because `Devres` guarantees the `IoMem` does not + // actually outlive the device -- access is revoked and the resource is released when the + // device is unbound. + let iomem: IoMem<'static, SIZE> = unsafe { core::mem::transmute(self) }; + let dev = iomem.dev; + Devres::new(dev, iomem) } } -impl<const SIZE: usize> Drop for IoMem<SIZE> { +impl<const SIZE: usize> Drop for IoMem<'_, SIZE> { fn drop(&mut self) { // SAFETY: Safe as by the invariant of `Io`. unsafe { bindings::iounmap(self.io.addr() as *mut c_void) } } } -impl<const SIZE: usize> Deref for IoMem<SIZE> { +impl<const SIZE: usize> Deref for IoMem<'_, SIZE> { type Target = Mmio<SIZE>; fn deref(&self) -> &Self::Target { -- 2.54.0
