feat: devices via caps (BootInfo, init assigns devices, drivers map MMIO/DMA themselves, IRQ-driven input); drop boot device wiring and info pages; headless display fallback

crates/types/src/bootinfo.rs

@@ -0,0 +1,54 @@
+//! What boot tells init: a read-only page at `BOOT_INFO_VA` saying which
+//! of init's capability slots hold which board device (seL4's BootInfo,
+//! reduced to what this system needs). Everything else init learns by
+//! asking the devices themselves.
+
+/// Where the page is mapped in init.
+pub const BOOT_INFO_VA: usize = 0x2F000;
+/// "kosboot1", so init can tell the page is really there.
+pub const MAGIC: u64 = 0x6b6f_7362_6f6f_7431;
+pub const MAX_BOOT_DEVICES: usize = 16;
+/// A slot field with no capability in it.
+pub const NO_SLOT: u64 = u64::MAX;
+
+/// What kind of device a board entry is. Board code knows; init asks the
+/// device itself only where a kind has several possibilities (which
+/// virtio device sits in a slot).
+pub const KIND_VIRTIO: u64 = 1;
+pub const KIND_UART_16550: u64 = 2;
+
+#[repr(C)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct BootDevice {
+    /// One of the `KIND_` constants.
+    pub kind: u64,
+    /// Physical base of the device's MMIO window.
+    pub phys_base: u64,
+    pub pages: u64,
+    /// The device's IRQ line, 0 if it has none.
+    pub irq: u64,
+    /// init's slot holding the MMIO region capability.
+    pub region_slot: u64,
+    /// init's slot holding the IRQ capability, or `NO_SLOT`.
+    pub irq_slot: u64,
+}
+
+#[repr(C)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct BootInfo {
+    pub magic: u64,
+    pub device_count: u64,
+    pub system_control_slot: u64,
+    pub devices: [BootDevice; MAX_BOOT_DEVICES],
+}
+
+impl BootInfo {
+    /// The devices actually listed; empty if the page is not a BootInfo.
+    pub fn devices(&self) -> &[BootDevice] {
+        if self.magic != MAGIC {
+            return &[];
+        }
+        let n = (self.device_count as usize).min(MAX_BOOT_DEVICES);
+        self.devices.get(..n).unwrap_or(&[])
+    }
+}

crates/types/src/lib.rs

@@ -2,6 +2,7 @@
 
 pub mod address;
 pub mod badge;
+pub mod bootinfo;
 pub mod bounded;
 pub mod display;
 pub mod generation;