ladybird/Kernel/Storage/StorageDevice.h
Liav A 4e0f85432a Kernel/Storage: Remove the ramdisk implementation
Nobody uses this because the x86 prekernel environment is corrupting the
ramdisk image prior to running the actual kernel. In the future we can
ensure that the prekernel doesn't corrupt the ramdisk if we want to
bring support back. In addition to that, we could just use a RAM based
filesystem to load whatever is needed like in Linux, without the need of
additional filesystem driver.

For the mentioned corruption problem, look at issue #9893.
2022-10-03 11:12:35 +02:00

111 lines
4.8 KiB
C++

/*
* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/IntrusiveList.h>
#include <Kernel/Devices/BlockDevice.h>
#include <Kernel/Interrupts/IRQHandler.h>
#include <Kernel/Locking/Mutex.h>
#include <Kernel/Storage/DiskPartition.h>
#include <Kernel/Storage/StorageController.h>
namespace Kernel {
class RamdiskDevice;
class StorageDevice : public BlockDevice {
friend class StorageManagement;
friend class DeviceManagement;
public:
// Note: this attribute describes the internal command set of a Storage device.
// For example, an ordinary harddrive utilizes the ATA command set, while
// an ATAPI device (e.g. Optical drive) that is connected to the ATA bus,
// is actually using SCSI commands (packets) encapsulated inside an ATA command.
// The IDE controller code being aware of the possibility of ATAPI devices attached
// to the ATA bus, will check whether the Command set is ATA or SCSI and will act
// accordingly.
// Note: For now, there's simply no distinction between the interface type and the commandset.
// As mentioned above, ATAPI devices use the ATA interface with actual SCSI packets so
// the commandset is SCSI while the interface type is ATA. We simply don't support SCSI over ATA (ATAPI)
// and ATAPI is the exception to no-distinction rule. If we ever put SCSI support in the kernel,
// we can create another enum class to put the distinction.
enum class CommandSet {
SCSI,
ATA,
NVMe,
};
// Note: The most reliable way to address this device from userspace interfaces,
// such as SysFS, is to have one way to enumerate everything in the eyes of userspace.
// Therefore, SCSI LUN (logical unit number) addressing seem to be the most generic way to do this.
// For example, on a legacy ATA instance, one might connect an harddrive to the second IDE controller,
// to the Primary channel as a slave device, which translates to LUN 1:0:1.
// On NVMe, for example, connecting a second PCIe NVMe storage device as a sole NVMe namespace translates
// to LUN 1:0:0.
struct LUNAddress {
u32 controller_id;
u32 target_id;
u32 disk_id;
};
public:
virtual u64 max_addressable_block() const { return m_max_addressable_block; }
// ^BlockDevice
virtual ErrorOr<size_t> read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t) override;
virtual bool can_read(OpenFileDescription const&, u64) const override;
virtual ErrorOr<size_t> write(OpenFileDescription&, u64, UserOrKernelBuffer const&, size_t) override;
virtual bool can_write(OpenFileDescription const&, u64) const override;
virtual void prepare_for_unplug() { m_partitions.clear(); }
NonnullLockRefPtrVector<DiskPartition> const& partitions() const { return m_partitions; }
void add_partition(NonnullLockRefPtr<DiskPartition> disk_partition) { MUST(m_partitions.try_append(disk_partition)); }
LUNAddress const& logical_unit_number_address() const { return m_logical_unit_number_address; }
u32 parent_controller_hardware_relative_id() const { return m_hardware_relative_controller_id; }
virtual CommandSet command_set() const = 0;
StringView command_set_to_string_view() const;
// ^File
virtual ErrorOr<void> ioctl(OpenFileDescription&, unsigned request, Userspace<void*> arg) final;
protected:
StorageDevice(LUNAddress, u32 hardware_relative_controller_id, size_t sector_size, u64);
// Note: We want to be able to put distinction between Storage devices and Ramdisk-based devices.
// We do this because it will make selecting ramdisk devices much more easier in boot time in the kernel commandline.
StorageDevice(Badge<RamdiskDevice>, LUNAddress, u32 hardware_relative_controller_id, MajorNumber, MinorNumber, size_t sector_size, u64);
// ^DiskDevice
virtual StringView class_name() const override;
private:
virtual void after_inserting() override;
virtual void will_be_destroyed() override;
mutable IntrusiveListNode<StorageDevice, LockRefPtr<StorageDevice>> m_list_node;
NonnullLockRefPtrVector<DiskPartition> m_partitions;
LUNAddress const m_logical_unit_number_address;
// Note: This data member should be used with LUNAddress target_id and disk_id.
// LUNs are agnostic system-wide addresses, so they are assigned without caring about the specific hardware interfaces.
// This class member on the other side, is meant to be assigned *per hardware type*,
// which means in contrast to the LUNAddress controller_id struct member, we take the index of the hardware
// controller among its fellow controllers of the same hardware type in the system.
u32 const m_hardware_relative_controller_id { 0 };
u64 m_max_addressable_block { 0 };
size_t m_blocks_per_page { 0 };
};
}