forked from M-Labs/zynq-rs
63 lines
1.6 KiB
Rust
63 lines
1.6 KiB
Rust
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use core::{
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ops::{Deref, DerefMut},
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mem::{align_of, size_of},
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};
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use alloc::alloc::{alloc_zeroed, dealloc, Layout, LayoutErr};
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use crate::mmu::{L1_PAGE_SIZE, L1Table};
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pub struct Uncached<'t, T: 't> {
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layout: Layout,
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data: &'t mut T,
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}
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impl<'t, T: 't> Uncached<'t, T> {
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/// allocates in chunks of 1 MB
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pub fn alloc(src: T) -> Result<Self, LayoutErr> {
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// round to full pages
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let size = (size_of::<T>() | (L1_PAGE_SIZE - 1)) + 1;
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let align = align_of::<T>()
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.max(L1_PAGE_SIZE);
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let layout = Layout::from_size_align(size, align)?;
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let ptr = unsafe { alloc::alloc::alloc(layout).cast::<T>() };
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assert_eq!((ptr as usize) & (L1_PAGE_SIZE - 1), 0);
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let start = ptr as usize;
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for page_start in (start..(start + size)).step_by(L1_PAGE_SIZE) {
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L1Table::get()
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.update(page_start as *const (), |l1_section| {
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l1_section.cacheable = false;
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l1_section.bufferable = false;
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});
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}
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// initialize
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unsafe {
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core::ptr::write(ptr, src);
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}
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let data = unsafe { &mut *ptr };
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Ok(Uncached { layout, data })
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}
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}
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impl<'t, T: 't> Drop for Uncached<'t, T> {
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fn drop(&mut self) {
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unsafe {
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dealloc(self.data as *mut _ as *mut u8, self.layout);
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}
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}
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}
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impl<'t, T: 't> Deref for Uncached<'t, T> {
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type Target = T;
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fn deref(&self) -> &Self::Target {
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self.data
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}
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}
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impl<'t, T: 't> DerefMut for Uncached<'t, T> {
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fn deref_mut(&mut self) -> &mut Self::Target {
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self.data
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}
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}
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