src/vendor/redox_syscall/src/io/dma.rs

   1 use core::{mem, ptr};
   2 use core::ops::{Deref, DerefMut};
   3
   4 use Result;
   5
   6 struct PhysBox {
   7     address: usize,
   8     size: usize
   9 }
  10
  11 impl PhysBox {
  12     fn new(size: usize) -> Result<PhysBox> {
  13         let address = unsafe { ::physalloc(size)? };
  14         Ok(PhysBox {
  15             address: address,
  16             size: size
  17         })
  18     }
  19 }
  20
  21 impl Drop for PhysBox {
  22     fn drop(&mut self) {
  23         let _ = unsafe { ::physfree(self.address, self.size) };
  24     }
  25 }
  26
  27 pub struct Dma<T> {
  28     phys: PhysBox,
  29     virt: *mut T
  30 }
  31
  32 impl<T> Dma<T> {
  33     pub fn new(value: T) -> Result<Dma<T>> {
  34         let phys = PhysBox::new(mem::size_of::<T>())?;
  35         let virt = unsafe { ::physmap(phys.address, phys.size, ::MAP_WRITE)? } as *mut T;
  36         unsafe { ptr::write(virt, value); }
  37         Ok(Dma {
  38             phys: phys,
  39             virt: virt
  40         })
  41     }
  42
  43     pub fn zeroed() -> Result<Dma<T>> {
  44         let phys = PhysBox::new(mem::size_of::<T>())?;
  45         let virt = unsafe { ::physmap(phys.address, phys.size, ::MAP_WRITE)? } as *mut T;
  46         unsafe { ptr::write_bytes(virt as *mut u8, 0, phys.size); }
  47         Ok(Dma {
  48             phys: phys,
  49             virt: virt
  50         })
  51     }
  52
  53     pub fn physical(&self) -> usize {
  54         self.phys.address
  55     }
  56 }
  57
  58 impl<T> Deref for Dma<T> {
  59     type Target = T;
  60     fn deref(&self) -> &T {
  61         unsafe { &*self.virt }
  62     }
  63 }
  64
  65 impl<T> DerefMut for Dma<T> {
  66     fn deref_mut(&mut self) -> &mut T {
  67         unsafe { &mut *self.virt }
  68     }
  69 }
  70
  71 impl<T> Drop for Dma<T> {
  72     fn drop(&mut self) {
  73         unsafe { drop(ptr::read(self.virt)); }
  74         let _ = unsafe { ::physunmap(self.virt as usize) };
  75     }
  76 }