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Diffstat (limited to 'vendor/redox_syscall/src/io/dma.rs')
-rw-r--r-- | vendor/redox_syscall/src/io/dma.rs | 219 |
1 files changed, 0 insertions, 219 deletions
diff --git a/vendor/redox_syscall/src/io/dma.rs b/vendor/redox_syscall/src/io/dma.rs deleted file mode 100644 index 0613fc9..0000000 --- a/vendor/redox_syscall/src/io/dma.rs +++ /dev/null @@ -1,219 +0,0 @@ -use core::mem::{self, MaybeUninit}; -use core::ops::{Deref, DerefMut}; -use core::{ptr, slice}; - -use crate::Result; -use crate::{PartialAllocStrategy, PhysallocFlags, PhysmapFlags}; -use crate::arch::PAGE_SIZE; - -/// An RAII guard of a physical memory allocation. Currently all physically allocated memory are -/// page-aligned and take up at least 4k of space (on x86_64). -#[derive(Debug)] -pub struct PhysBox { - address: usize, - size: usize -} - -const fn round_up(x: usize) -> usize { - (x + PAGE_SIZE - 1) / PAGE_SIZE * PAGE_SIZE -} -fn assert_aligned(x: usize) { - assert_eq!(x % PAGE_SIZE, 0); -} - -#[cfg(target_arch = "aarch64")] -fn physmap_flags() -> PhysmapFlags { - // aarch64 currently must map DMA memory without caching to ensure coherence - crate::PHYSMAP_NO_CACHE | crate::PHYSMAP_WRITE -} - -#[cfg(any(target_arch = "x86", target_arch = "x86_64"))] -fn physmap_flags() -> PhysmapFlags { - // x86 ensures cache coherence with DMA memory - crate::PHYSMAP_WRITE -} - -impl PhysBox { - /// Construct a PhysBox from an address and a size. The address must be page-aligned, and the - /// size must similarly be a multiple of the page size. - /// - /// # Safety - /// This function is unsafe because when dropping, Self has to a valid allocation. - pub unsafe fn from_raw_parts(address: usize, size: usize) -> Self { - assert_aligned(address); - assert_aligned(size); - - Self { - address, - size, - } - } - - /// Retrieve the byte address in physical memory, of this allocation. - pub fn address(&self) -> usize { - self.address - } - - /// Retrieve the size in bytes of the alloc. - pub fn size(&self) -> usize { - self.size - } - - /// Allocate physical memory that must reside in 32-bit space. - pub fn new_in_32bit_space(size: usize) -> Result<Self> { - Self::new_with_flags(size, PhysallocFlags::SPACE_32) - } - - pub fn new_with_flags(size: usize, flags: PhysallocFlags) -> Result<Self> { - assert!(!flags.contains(PhysallocFlags::PARTIAL_ALLOC)); - assert_aligned(size); - - let address = unsafe { crate::physalloc2(size, flags.bits())? }; - Ok(unsafe { Self::from_raw_parts(address, size) }) - } - - /// "Partially" allocate physical memory, in the sense that the allocation may be smaller than - /// expected, but still with a minimum limit. This is particularly useful when the physical - /// memory space is fragmented, and a device supports scatter-gather I/O. In that case, the - /// driver can optimistically request e.g. 1 alloc of 1 MiB, with the minimum of 512 KiB. If - /// that first allocation only returns half the size, the driver can do another allocation - /// and then let the device use both buffers. - pub fn new_partial_allocation(size: usize, flags: PhysallocFlags, strategy: Option<PartialAllocStrategy>, mut min: usize) -> Result<Self> { - assert_aligned(size); - debug_assert!(!(flags.contains(PhysallocFlags::PARTIAL_ALLOC) && strategy.is_none())); - - let address = unsafe { crate::physalloc3(size, flags.bits() | strategy.map_or(0, |s| s as usize), &mut min)? }; - Ok(unsafe { Self::from_raw_parts(address, size) }) - } - - pub fn new(size: usize) -> Result<Self> { - assert_aligned(size); - - let address = unsafe { crate::physalloc(size)? }; - Ok(unsafe { Self::from_raw_parts(address, size) }) - } -} - -impl Drop for PhysBox { - fn drop(&mut self) { - let _ = unsafe { crate::physfree(self.address, self.size) }; - } -} - -pub struct Dma<T: ?Sized> { - phys: PhysBox, - virt: *mut T, -} - -impl<T> Dma<T> { - pub fn from_physbox_uninit(phys: PhysBox) -> Result<Dma<MaybeUninit<T>>> { - let virt = unsafe { crate::physmap(phys.address, phys.size, physmap_flags())? } as *mut MaybeUninit<T>; - - Ok(Dma { - phys, - virt, - }) - } - pub fn from_physbox_zeroed(phys: PhysBox) -> Result<Dma<MaybeUninit<T>>> { - let this = Self::from_physbox_uninit(phys)?; - unsafe { ptr::write_bytes(this.virt as *mut MaybeUninit<u8>, 0, this.phys.size) } - Ok(this) - } - - pub fn from_physbox(phys: PhysBox, value: T) -> Result<Self> { - let this = Self::from_physbox_uninit(phys)?; - - Ok(unsafe { - ptr::write(this.virt, MaybeUninit::new(value)); - this.assume_init() - }) - } - - pub fn new(value: T) -> Result<Self> { - let phys = PhysBox::new(round_up(mem::size_of::<T>()))?; - Self::from_physbox(phys, value) - } - pub fn zeroed() -> Result<Dma<MaybeUninit<T>>> { - let phys = PhysBox::new(round_up(mem::size_of::<T>()))?; - Self::from_physbox_zeroed(phys) - } -} - -impl<T> Dma<MaybeUninit<T>> { - pub unsafe fn assume_init(self) -> Dma<T> { - let &Dma { phys: PhysBox { address, size }, virt } = &self; - mem::forget(self); - - Dma { - phys: PhysBox { address, size }, - virt: virt as *mut T, - } - } -} -impl<T: ?Sized> Dma<T> { - pub fn physical(&self) -> usize { - self.phys.address() - } - pub fn size(&self) -> usize { - self.phys.size() - } - pub fn phys(&self) -> &PhysBox { - &self.phys - } -} - -impl<T> Dma<[T]> { - pub fn from_physbox_uninit_unsized(phys: PhysBox, len: usize) -> Result<Dma<[MaybeUninit<T>]>> { - let max_len = phys.size() / mem::size_of::<T>(); - assert!(len <= max_len); - - Ok(Dma { - virt: unsafe { slice::from_raw_parts_mut(crate::physmap(phys.address, phys.size, physmap_flags())? as *mut MaybeUninit<T>, len) } as *mut [MaybeUninit<T>], - phys, - }) - } - pub fn from_physbox_zeroed_unsized(phys: PhysBox, len: usize) -> Result<Dma<[MaybeUninit<T>]>> { - let this = Self::from_physbox_uninit_unsized(phys, len)?; - unsafe { ptr::write_bytes(this.virt as *mut MaybeUninit<u8>, 0, this.phys.size()) } - Ok(this) - } - /// Creates a new DMA buffer with a size only known at runtime. - /// ## Safety - /// * `T` must be properly aligned. - /// * `T` must be valid as zeroed (i.e. no NonNull pointers). - pub unsafe fn zeroed_unsized(count: usize) -> Result<Self> { - let phys = PhysBox::new(round_up(mem::size_of::<T>() * count))?; - Ok(Self::from_physbox_zeroed_unsized(phys, count)?.assume_init()) - } -} -impl<T> Dma<[MaybeUninit<T>]> { - pub unsafe fn assume_init(self) -> Dma<[T]> { - let &Dma { phys: PhysBox { address, size }, virt } = &self; - mem::forget(self); - - Dma { - phys: PhysBox { address, size }, - virt: virt as *mut [T], - } - } -} - -impl<T: ?Sized> Deref for Dma<T> { - type Target = T; - fn deref(&self) -> &T { - unsafe { &*self.virt } - } -} - -impl<T: ?Sized> DerefMut for Dma<T> { - fn deref_mut(&mut self) -> &mut T { - unsafe { &mut *self.virt } - } -} - -impl<T: ?Sized> Drop for Dma<T> { - fn drop(&mut self) { - unsafe { ptr::drop_in_place(self.virt) } - let _ = unsafe { crate::funmap(self.virt as *mut u8 as usize, self.phys.size) }; - } -} |