implement first draft of RAMDiskDevice

4 files changed, 66 insertions, 6 deletions

diff --git a/kernel/devices/include/devices/BlockDevice.hpp b/kernel/devices/include/devices/BlockDevice.hpp
index db66683..69d7f81 100644
--- a/kernel/devices/include/devices/BlockDevice.hpp
+++ b/kernel/devices/include/devices/BlockDevice.hpp
@@ -1,10 +1,15 @@
 #ifndef TEACH_OS_KERNEL_DEVICES_BLOCK_DEVICE_HPP
 #define TEACH_OS_KERNEL_DEVICES_BLOCK_DEVICE_HPP
 
+#include <cstddef>
+
 namespace devices
 {
   struct block_device
   {
+    virtual ~block_device() = default;
+
+    virtual auto read_block(size_t block_index, void * buffer) const -> void = 0;
   };
 }  // namespace devices
 
diff --git a/kernel/devices/include/devices/storage/RAMDisk/RAMDiskDevice.hpp b/kernel/devices/include/devices/storage/RAMDisk/RAMDiskDevice.hpp
index 98471cf..aa736a4 100644
--- a/kernel/devices/include/devices/storage/RAMDisk/RAMDiskDevice.hpp
+++ b/kernel/devices/include/devices/storage/RAMDisk/RAMDiskDevice.hpp
@@ -1,10 +1,26 @@
 #ifndef TEACH_OS_KERNEL_DEVICES_STORAGE_RAM_DISK_DEVICE_HPP
 #define TEACH_OS_KERNEL_DEVICES_STORAGE_RAM_DISK_DEVICE_HPP
 
+#include "kapi/memory.hpp"
+
+#include "devices/BlockDevice.hpp"
+
+#include <cstddef>
+
 namespace devices::storage::ram_disk
 {
-  struct ram_disk_device
+  struct ram_disk_device : block_device
   {
+    constexpr size_t static block_size = 512uz;  // TODO BA-FS26 really correct / good??
+
+    ram_disk_device() = default;
+    ram_disk_device(kapi::memory::linear_address data_start, size_t data_size);
+
+    auto read_block(size_t block_index, void * buffer) const -> void override;
+
+  private:
+    kapi::memory::linear_address m_data_start{};
+    size_t m_data_size{};
   };
 }  // namespace devices::storage::ram_disk
 
diff --git a/kernel/devices/src/storage/RAMDisk/RAMDiskController.cpp b/kernel/devices/src/storage/RAMDisk/RAMDiskController.cpp
index 3e12e0d..48b9116 100644
--- a/kernel/devices/src/storage/RAMDisk/RAMDiskController.cpp
+++ b/kernel/devices/src/storage/RAMDisk/RAMDiskController.cpp
@@ -3,6 +3,8 @@
 #include "kapi/boot_module/boot_module.hpp"
 #include "kapi/boot_module/boot_module_registry.hpp"
 
+#include "devices/storage/RAMDisk/RAMDiskDevice.hpp"
+
 #include <kstd/print>
 
 #include <algorithm>
@@ -18,16 +20,21 @@ namespace devices::storage::ram_disk
   {
     std::ranges::for_each(*m_boot_module_registry,
                           [this](auto const & module) { create_device_from_boot_module(module); });
-  }
 
-  auto ram_disk_controller::devices_count() -> size_t
-  {
-    return m_devices.size();
+    // TODO BA-FS26 just for testing, remove again
+    std::ranges::for_each(m_devices, [](auto const & device) { device.read_block(0, nullptr); });
   }
 
   auto ram_disk_controller::create_device_from_boot_module(kapi::boot_modules::boot_module const & module) -> void
   {
+    m_devices.at(0) = ram_disk_device{module.start_address, module.size};
+
     kstd::println("[RAM DISK CONTROLLER] Found boot module: {} at address {} with size {} bytes", module.name,
                   module.start_address, module.size);
   }
+
+  auto ram_disk_controller::devices_count() -> size_t
+  {
+    return m_devices.size();
+  }
 }  // namespace devices::storage::ram_disk
\ No newline at end of file
diff --git a/kernel/devices/src/storage/RAMDisk/RAMDiskDevice.cpp b/kernel/devices/src/storage/RAMDisk/RAMDiskDevice.cpp
index 8d8f51e..1e650d8 100644
--- a/kernel/devices/src/storage/RAMDisk/RAMDiskDevice.cpp
+++ b/kernel/devices/src/storage/RAMDisk/RAMDiskDevice.cpp
@@ -1,6 +1,38 @@
 #include "devices/storage/RAMDisk/RAMDiskDevice.hpp"
 
+#include "kapi/memory.hpp"
+#include "kapi/system.hpp"
+
+#include <kstd/print>
+
+#include <cstddef>
+
 namespace devices::storage::ram_disk
 {
-  // TODO BA-FS26 implement ram disk device functionality
+  ram_disk_device::ram_disk_device(kapi::memory::linear_address data_start, size_t data_size)
+      : m_data_start(data_start)
+      , m_data_size(data_size)
+  {}
+
+  auto ram_disk_device::read_block(size_t block_index, void * /*buffer*/) const -> void
+  {
+    // if (buffer == nullptr)
+    // {
+    //   kapi::system::panic("[RAM DISK DEVICE] read_block called with null buffer.");
+    // }
+
+    auto const offset = block_index * block_size;
+    if (offset + block_size >
+        m_data_size)  // TODO BA-FS26 really correct, what if block_size doesn't divide m_data_size?
+    {
+      kapi::system::panic("[RAM DISK DEVICE] read_block out of bounds.");
+    }
+
+    auto const source = static_cast<std::byte *>(m_data_start) + offset;
+    for (size_t i = 0; i < block_size; ++i)
+    {
+      kstd::println("address: {}, value: {}", source + i, std::to_integer<unsigned int>(*(source + i)));
+    }
+    // std::memcpy(buffer, source, block_size);
+  }
 }  // namespace devices::storage::ram_disk
\ No newline at end of file