From 40ff805f7dfe3cc02d155c91c491bcbab3283196 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sat, 10 Jun 2023 09:35:52 -0400
Subject: [PATCH] Add Pci.Address struct

---
 src/hulk/pci.d | 54 ++++++++++++++++++++++++++++++++++----------------
 1 file changed, 37 insertions(+), 17 deletions(-)

diff --git a/src/hulk/pci.d b/src/hulk/pci.d
index e3f6048..034aaf5 100644
--- a/src/hulk/pci.d
+++ b/src/hulk/pci.d
@@ -11,6 +11,18 @@ struct Pci
     /* IO address for PCI configuration data. */
     enum IO_ADDR_CONFIG_DATA = 0xCFCu;
 
+    struct Address
+    {
+        /** Bus number (0-255). */
+        ubyte bus_nr;
+
+        /** Device number (0-31). */
+        ubyte device_nr;
+
+        /** Function number (0-7). */
+        ubyte function_nr;
+    }
+
     struct SerialBusController
     {
         enum ID = 0x0Cu;
@@ -26,17 +38,25 @@ struct Pci
         }
     }
 
-    private static uint read_config_register(uint bus_id, uint device_idx, uint function_idx, uint register_id)
+    private static uint read_config_register(Address address, uint register_id)
     {
-        uint addr = 0x8000_0000u | (bus_id << 16u) | (device_idx << 11u) | (function_idx << 8u) | (register_id << 2u);
-        out32(IO_ADDR_CONFIG_ADDRESS, addr);
+        uint cfg_addr = 0x8000_0000u |
+            (address.bus_nr << 16u) |
+            (address.device_nr << 11u) |
+            (address.function_nr << 8u) |
+            (register_id << 2u);
+        out32(IO_ADDR_CONFIG_ADDRESS, cfg_addr);
         return in32(IO_ADDR_CONFIG_DATA);
     }
 
-    private static void write_config_register(uint bus_id, uint device_idx, uint function_idx, uint register_id, uint value)
+    private static void write_config_register(Address address, uint register_id, uint value)
     {
-        uint addr = 0x8000_0000u | (bus_id << 16u) | (device_idx << 11u) | (function_idx << 8u) | (register_id << 2u);
-        out32(IO_ADDR_CONFIG_ADDRESS, addr);
+        uint cfg_addr = 0x8000_0000u |
+            (address.bus_nr << 16u) |
+            (address.device_nr << 11u) |
+            (address.function_nr << 8u) |
+            (register_id << 2u);
+        out32(IO_ADDR_CONFIG_ADDRESS, cfg_addr);
         out32(IO_ADDR_CONFIG_DATA, value);
     }
 
@@ -66,12 +86,12 @@ struct Pci
         }
     }
 
-    private static void scan(uint bus_id, uint device_idx, uint function_idx)
+    private static void scan(Address address)
     {
-        ulong reg0 = read_config_register(bus_id, device_idx, function_idx, 0u);
+        ulong reg0 = read_config_register(address, 0u);
         if (reg0 != 0xFFFFFFFFu)
         {
-            uint reg2 = read_config_register(bus_id, device_idx, function_idx, 2u);
+            uint reg2 = read_config_register(address, 2u);
             ushort vendor_id = reg0 & 0xFFFFu;
             ushort device_id = (reg0 >> 16u) & 0xFFFFu;
             ubyte class_id = (reg2 >> 24u) & 0xFFu;
@@ -80,17 +100,17 @@ struct Pci
             Klog.writefln("Found PCI device %04x:%04x (%02x:%02x:%02x) at %02u:%02u.%u",
                     vendor_id, device_id,
                     class_id, subclass_id, if_id,
-                    bus_id, device_idx, function_idx);
+                    address.bus_nr, address.device_nr, address.function_nr);
             init_device(class_id, subclass_id, if_id);
-            if (function_idx == 0u)
+            if (address.function_nr == 0u)
             {
-                uint reg3 = read_config_register(bus_id, device_idx, function_idx, 3u);
+                uint reg3 = read_config_register(address, 3u);
                 if ((reg3 & (1u << 23u)) != 0u)
                 {
                     /* Multi-function device found. */
-                    for (function_idx = 1u; function_idx < 8u; function_idx++)
+                    for (address.function_nr = 1u; address.function_nr < 8u; address.function_nr++)
                     {
-                        scan(bus_id, device_idx, function_idx);
+                        scan(address);
                     }
                 }
             }
@@ -100,11 +120,11 @@ struct Pci
     public static void initialize()
     {
         Klog.writefln("Scanning PCI devices...");
-        for (uint bus_id = 0u; bus_id < 256u; bus_id++)
+        for (uint bus_nr = 0u; bus_nr < 256u; bus_nr++)
         {
-            for (uint device_idx = 0u; device_idx < 32u; device_idx++)
+            for (ubyte device_nr = 0u; device_nr < 32u; device_nr++)
             {
-                scan(bus_id, device_idx, 0u);
+                scan(Address(cast(ubyte)bus_nr, device_nr, 0u));
             }
         }
         Klog.writefln("PCI scan complete.");