Add basic xHCI driver and USB devices enumeration

src/kernel/usb.c

@@ -0,0 +1,44 @@
+#include "src/kernel/usb.h"
+#include "src/kernel/log.h"
+#include "src/kernel/stream.h"
+#include "src/kernel/xhci.h"
+
+typedef struct __attribute__((packed)) {
+  uint8_t length;
+  uint8_t descriptor_type; // 0x01 for device descriptor
+  uint16_t usb_version;    // BCD, e.g. 0x0200 for USB 2.0
+  uint8_t device_class;
+  uint8_t device_subclass;
+  uint8_t device_protocol;
+  uint8_t max_packet_size; // for ep0
+  uint16_t vendor_id;
+  uint16_t product_id;
+  uint16_t device_version;
+  uint8_t manufacturer_str;
+  uint8_t product_str;
+  uint8_t serial_str;
+  uint8_t num_configurations;
+} usb_device_descriptor_t;
+
+static usb_device_descriptor_t device_descriptor __attribute__((aligned(64)));
+
+void usb_init() {
+  LOG_LN("Enumerating devices...");
+  usb_enumerate(kernel_log);
+  LOG_LN("Done.");
+}
+
+void usb_enumerate(stream_t *out) {
+  for (uint8_t i = 0; i < xhci_port_count(); i++) {
+    if (!xhci_port_connected(i)) {
+      continue;
+    }
+
+    xhci_slot_t slot = xhci_attach(i);
+
+    xhci_control_transfer(slot, 0x0012000001000680ULL, &device_descriptor, sizeof(usb_device_descriptor_t));
+
+    PRINT_LN(out, "%hx:%hx class=%hx subclass=%hx protocol=%hx", device_descriptor.vendor_id, device_descriptor.product_id,
+             device_descriptor.device_class, device_descriptor.device_subclass, device_descriptor.device_protocol);
+  }
+}