From 878852c94c4d56f303366cec177b3edef9b3b9c5 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Wed, 8 Apr 2026 13:54:52 +0200
Subject: kapi: add basic support for MMIO mapping

---
 kernel/kapi/memory.cpp | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

(limited to 'kernel/kapi')

diff --git a/kernel/kapi/memory.cpp b/kernel/kapi/memory.cpp
index 06a3165..b224c50 100644
--- a/kernel/kapi/memory.cpp
+++ b/kernel/kapi/memory.cpp
@@ -3,6 +3,7 @@
 #include "kapi/system.hpp"
 
 #include "kernel/memory/bitmap_allocator.hpp"
+#include "kernel/memory/mmio_allocator.hpp"
 
 #include <kstd/print>
 #include <kstd/units>
@@ -63,6 +64,7 @@ namespace kapi::memory
     constinit bad_frame_allocator bad_frame_allocator::instance{};
     constinit bad_page_mapper bad_page_mapper::instance{};
     auto constinit allocator = std::optional<kernel::memory::bitmap_frame_allocator>{};
+    auto constinit mmio_allocator = std::optional<kernel::memory::mmio_allocator>{};
   }  // namespace
 
   constinit auto static active_frame_allocator = static_cast<frame_allocator *>(&bad_frame_allocator::instance);
@@ -147,4 +149,27 @@ namespace kapi::memory
     kstd::println("[OS:MEM] Physical memory manager initialized.");
   }
 
+  auto init_mmio(linear_address base, std::size_t page_count) -> void
+  {
+    mmio_allocator.emplace(base, page_count);
+  }
+
+  auto allocate_mmio_region(std::size_t page_count) -> linear_address
+  {
+    auto region = mmio_allocator->allocate(page_count);
+    return region;
+  }
+
+  auto map_mmio_region(linear_address base, physical_address hw_base, page_mapper::flags flags) -> std::byte *
+  {
+    auto start_page = page::containing(base);
+    auto start_frame = frame::containing(hw_base);
+    return map(start_page, start_frame, flags | page_mapper::flags::uncached);
+  }
+
+  auto release_mmio_region(linear_address base) -> void
+  {
+    mmio_allocator->release(base);
+  }
+
 }  // namespace kapi::memory
-- 
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