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runtime: consolidate the device-manager hello into runtime.device_manager

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Every supervised driver owes the device manager a hello at startup, and
the retry-lookup-call-check for it had been copied into five drivers:
usb.helloManager (misfiled in the USB client) plus hand-rolled twins in
display, virtio-gpu, pci-bus, and usb-xhci-bus.

Extract it once as a runtime client, runtime.device_manager.hello(role,
device_id) ?Handle — returns the manager endpoint (bus drivers keep it to
report children through), null when there is no manager or it refused the
handshake, and logs the outcome itself so each call site is one line.

Also correct two roles while collapsing their calls: virtio-gpu and the
display driver each claim one PCI function and report no children, so they
are Role.device, not Role.bus. The manager ignores role today, so this is
cosmetic, but it matches the protocol's own definition (bus = reports
children via child_added).

Behavior-preserving otherwise: pci-bus and usb-xhci-bus move their hello
logging from raw serial writes to std.log, which the kernel renders with
the same "<path>: " prefix, so driver-restart still matches
"usb-xhci-bus: hello acknowledged". zig build clean; 8 QEMU cases pass
(driver-restart, pci-scan, usb-hid, usb-storage, virtio-gpu,
display-reattach, device-list, device-manager).
This commit is contained in:
Daniel Samson
2026-07-22 19:27:20 +01:00
parent d27377ab1e
commit ea470afe84
10 changed files with 85 additions and 108 deletions
Download Patch File Download Diff File Expand all files Collapse all files
library/runtime/usb.zig
+1 -18
View File
@@ -5,7 +5,7 @@
//! service and `device.zig` over the raw device calls.
//!
//! A class driver, spawned with its interface's assigned device id as argv[1]:
//! if (!usb.helloManager(id)) return; // meet the spawn deadline
//! if (device_manager.hello(.device, id) == null) return; // meet the spawn deadline
//! var device = usb.open(id) orelse return; // open + get its endpoints
//! _ = device.controlOut(usb_abi.setProtocol(...));// class requests, descriptors
//! _ = device.subscribeInterrupt(address, length); // reports arrive asynchronously
@@ -19,7 +19,6 @@ const std = @import("std");
const ipc = @import("ipc.zig");
const system = @import("system.zig");
const protocol = @import("usb-transfer-protocol");
const device_manager = @import("device-manager-protocol");
pub const Endpoint = protocol.Endpoint;
pub const InterruptReport = protocol.InterruptReport;
@@ -144,19 +143,3 @@ pub fn open(device_id: u64) ?Device {
for (0..device.endpoint_count) |index| device.endpoints[index] = open_reply.endpoints[index];
return device;
}
/// Hello the device manager as a class driver (Role.device) so a supervised
/// spawn meets its hello deadline. Retries while the manager comes up.
pub fn helloManager(device_id: u64) bool {
var attempts: usize = 0;
const manager = while (attempts < 100) : (attempts += 1) {
if (ipc.lookup(.device_manager)) |handle| break handle;
system.sleep(20);
} else return false;
const hello = device_manager.Hello{ .role = @intFromEnum(device_manager.Role.device), .device_id = device_id };
var reply: [device_manager.message_maximum]u8 = undefined;
const length = ipc.call(manager, std.mem.asBytes(&hello), &reply) catch return false;
if (length < device_manager.reply_size) return false;
return std.mem.bytesToValue(device_manager.HelloReply, reply[0..device_manager.reply_size]).status == 0;
}