From a02df12924219b423a68f85acaedeee404c67109 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Tue, 20 Feb 2024 11:23:12 -0500
Subject: [PATCH] Add XHCI.reset()

---
 src/hulk/usb/xhci.d | 60 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/src/hulk/usb/xhci.d b/src/hulk/usb/xhci.d
index d23f8e1..f012b89 100644
--- a/src/hulk/usb/xhci.d
+++ b/src/hulk/usb/xhci.d
@@ -11,6 +11,8 @@ module hulk.usb.xhci;
 import hulk.pci;
 import hulk.hurl.a1;
 import hulk.klog;
+import hulk.time;
+import core.volatile;
 
 struct XHCI
 {
@@ -351,6 +353,14 @@ struct XHCI
         m_runtime_registers = cast(RuntimeRegisters *)(base_address + m_capability_registers.rts_offset);
         m_doorbell_registers = cast(DoorbellRegister *)(base_address + m_capability_registers.doorbell_offset);
         dump_extended_capabilities();
+        if (reset())
+        {
+            Klog.writefln("XHCI controller initialization successful");
+        }
+        else
+        {
+            Klog.writefln("XHCI controller failed to initialize");
+        }
     }
 
     private void dump_extended_capabilities()
@@ -393,6 +403,56 @@ struct XHCI
         }
     }
 
+    private bool reset()
+    {
+        /* Clear run/stop bit. */
+        m_operational_registers.usb_command &= ~0x1u;
+
+        /* Wait for HCHalted bit to be set. */
+        enum halt_timeout = 40u;
+        for (size_t halt_timeout_counter = 0u;;)
+        {
+            Time.msleep(1u);
+
+            if ((volatileLoad(&m_operational_registers.usb_status) & 1u) != 0u)
+            {
+                break;
+            }
+
+            halt_timeout_counter++;
+            if (halt_timeout_counter >= halt_timeout)
+            {
+                Klog.writefln("XHCI controller failed to halt");
+                return false;
+            }
+        }
+
+        /* Set HC reset bit. */
+        m_operational_registers.usb_command |= (1u << 1u);
+
+        /* Wait for controller to be ready. */
+        enum reset_timeout = 100u;
+        for (size_t reset_timeout_counter = 0u;;)
+        {
+            Time.msleep(1u);
+
+            if (((volatileLoad(&m_operational_registers.usb_command) & (1u << 1u)) == 0u) &&
+                ((volatileLoad(&m_operational_registers.usb_status) & (1u << 11u)) == 0u))
+            {
+                break;
+            }
+
+            reset_timeout_counter++;
+            if (reset_timeout_counter >= reset_timeout)
+            {
+                Klog.writefln("XHCI controller failed to reset");
+                return false;
+            }
+        }
+
+        return true;
+    }
+
     static void build(Pci.Device * pci_device)
     {
         if (pci_device.memory_ranges[0].address != null)