64 lines
2.8 KiB
Zig
64 lines
2.8 KiB
Zig
//! /system/services/device-manager — the ring-3 process that turns the device
|
|
//! tree into a running system. The kernel enumerates the hardware and enforces the
|
|
//! claim capability (mechanism); this decides *which driver serves which device*
|
|
//! and, eventually, spawns it (policy). Keeping that split in user space is the
|
|
//! whole point of the microkernel: the manager is an ordinary, restartable process
|
|
//! with no special privilege — it uses the same `device_*` system calls any process
|
|
//! could ([drivers.md](../../../docs/drivers.md), [driver-model.md]).
|
|
//!
|
|
//! Increment 2 (this file): enumerate /system/devices, *match* each device to a
|
|
//! driver, and *spawn* it with `system_spawn` — the kernel loads the named binary
|
|
//! from the initial-ramdisk as a fresh ring-3 process. On QEMU this discovers the
|
|
//! HPET, decides `hpet` serves it, and brings that driver all the way up. (The
|
|
//! kernel still auto-spawns the whole initial-ramdisk at boot; increment 3 removes
|
|
//! that redundancy so the manager is the sole owner of driver spawning.)
|
|
|
|
const runtime = @import("runtime");
|
|
const device = runtime.device;
|
|
|
|
/// The driver that serves each device class — the policy table. In a fuller system
|
|
/// this comes from the drivers describing what they bind (or a manifest under
|
|
/// /system/drivers); for now it is a small static map, which is enough to prove the
|
|
/// manager reads the tree and decides. `null` = no driver for this class yet.
|
|
fn driverFor(class: u64) ?[]const u8 {
|
|
if (class == @intFromEnum(device.DeviceClass.timer)) return "hpet"; // the HPET
|
|
return null;
|
|
}
|
|
|
|
pub fn main() void {
|
|
// Enumerate into a heap buffer (too big for the one-page user stack).
|
|
const buffer = runtime.allocator().alloc(device.DeviceDescriptor, 64) catch {
|
|
_ = runtime.system.write("device-manager: out of memory\n");
|
|
return;
|
|
};
|
|
const total = device.enumerate(buffer);
|
|
const count = @min(total, buffer.len);
|
|
|
|
var matched: usize = 0;
|
|
for (buffer[0..count]) |descriptor| {
|
|
const driver_name = driverFor(descriptor.class) orelse continue;
|
|
matched += 1;
|
|
if (runtime.system.spawn(driver_name)) {
|
|
_ = runtime.system.write("device-manager: spawned ");
|
|
_ = runtime.system.write(driver_name);
|
|
_ = runtime.system.write("\n");
|
|
} else {
|
|
_ = runtime.system.write("device-manager: failed to spawn ");
|
|
_ = runtime.system.write(driver_name);
|
|
_ = runtime.system.write("\n");
|
|
}
|
|
}
|
|
|
|
if (matched == 0) {
|
|
_ = runtime.system.write("device-manager: no matchable devices\n");
|
|
return;
|
|
}
|
|
_ = runtime.system.write("device-manager: ok\n");
|
|
while (true) runtime.system.sleep(1000);
|
|
}
|
|
|
|
pub const panic = runtime.panic;
|
|
comptime {
|
|
_ = &runtime.start._start; // pull the runtime entry shim into the image
|
|
}
|