start adding smoltcp/ethernet support

zynq-mmu/src/lib.rs

@@ -0,0 +1,51 @@
+//! The MMU structures live inside a dedicated shared crate so it can be used by both the Zynq
+//! runtime crate and teh HAL crate.
+#![no_std]
+
+use cortex_ar::{
+    asm::{dsb, isb},
+    cache::clean_and_invalidate_l1_cache,
+    mmu::SectionAttributes,
+    register::{BpIAll, TlbIAll},
+};
+
+pub const NUM_L1_PAGE_TABLE_ENTRIES: usize = 4096;
+
+#[derive(Debug, PartialEq, Eq, thiserror::Error)]
+#[error("address is not aligned to 1MB boundary")]
+pub struct AddrNotAlignedToOneMb;
+
+#[repr(C, align(16384))]
+pub struct L1Table(pub [u32; NUM_L1_PAGE_TABLE_ENTRIES]);
+
+impl L1Table {
+    #[inline(always)]
+    pub const fn as_ptr(&self) -> *const u32 {
+        self.0.as_ptr()
+    }
+
+    #[inline(always)]
+    pub const fn as_mut_ptr(&mut self) -> *mut u32 {
+        self.0.as_mut_ptr()
+    }
+
+    pub fn update(
+        &mut self,
+        addr: u32,
+        section_attrs: SectionAttributes,
+    ) -> Result<(), AddrNotAlignedToOneMb> {
+        if addr & 0x000F_FFFF != 0 {
+            return Err(AddrNotAlignedToOneMb);
+        }
+        let index = addr as usize / 0x10_0000;
+        self.0[index] = (self.0[index] & 0xFFF0_0000) | section_attrs.as_raw_bits();
+
+        clean_and_invalidate_l1_cache();
+        TlbIAll::write();
+        BpIAll::write();
+        dsb();
+        isb();
+
+        Ok(())
+    }
+}