Kernel/USB: Add a crude USB MassStorage driver :^)

Kernel/Devices/Storage/USB/BulkSCSIInterface.h

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2023, Leon Albrecht <leon.a@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/IntrusiveList.h>
+#include <Kernel/Bus/USB/USBDevice.h>
+#include <Kernel/Bus/USB/USBPipe.h>
+#include <Kernel/Devices/Storage/StorageDevice.h>
+
+namespace Kernel::USB {
+
+enum class CBWDirection : u8 {
+    DataOut = 0,
+    DataIn = 1
+};
+
+struct CommandBlockWrapper {
+    LittleEndian<u32> signature { 0x43425355 };
+    LittleEndian<u32> tag { 0 };
+    LittleEndian<u32> transfer_length { 0 };
+    union {
+        u8 flags { 0 };
+        struct {
+            u8 flag_reserved : 6;
+            u8 flag_obsolete : 1;
+            CBWDirection direction : 1;
+        };
+    };
+    u8 lun { 0 };            // only 4 bits
+    u8 command_length { 0 }; // 5 bits, range 1-16
+    u8 command_block[16] { 0 };
+
+    template<typename T>
+    requires(sizeof(T) <= 16)
+    void set_command(T const& command)
+    {
+        command_length = sizeof(command);
+        memcpy(&command_block, &command, sizeof(command));
+    }
+};
+static_assert(AssertSize<CommandBlockWrapper, 31>());
+
+enum class CSWStatus : u8 {
+    Passed = 0x00,
+    Failed = 0x01,
+    PhaseError = 0x02
+};
+
+struct CommandStatusWrapper {
+    LittleEndian<u32> signature;
+    LittleEndian<u32> tag;
+    LittleEndian<u32> data_residue;
+    CSWStatus status;
+};
+static_assert(AssertSize<CommandStatusWrapper, 13>());
+
+class BulkSCSIInterface : public StorageDevice {
+    // https://www.usb.org/sites/default/files/usbmassbulk_10.pdf
+public:
+    BulkSCSIInterface(LUNAddress logical_unit_number_address, u32 hardware_relative_controller_id, size_t sector_size, u64 max_addressable_block, USB::Device& device, NonnullOwnPtr<BulkInPipe> in_pipe, NonnullOwnPtr<BulkOutPipe> out_pipe);
+
+    USB::Device const& device() const { return m_device; }
+
+    virtual void start_request(AsyncBlockDeviceRequest&) override;
+    virtual CommandSet command_set() const override { return CommandSet::SCSI; }
+
+private:
+    USB::Device& m_device;
+    NonnullOwnPtr<BulkInPipe> m_in_pipe;
+    NonnullOwnPtr<BulkOutPipe> m_out_pipe;
+
+    ErrorOr<void> do_read(u32 block_index, u32 block_count, UserOrKernelBuffer& buffer, size_t buffer_size);
+    ErrorOr<void> do_write(u32 block_index, u32 block_count, UserOrKernelBuffer& buffer, size_t buffer_size);
+
+    IntrusiveListNode<BulkSCSIInterface, NonnullLockRefPtr<BulkSCSIInterface>> m_list_node;
+
+public:
+    using List = IntrusiveList<&BulkSCSIInterface::m_list_node>;
+};
+
+}