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	 d234e6b801
			
		
	
	
		d234e6b801
		
	
	
	
	
		
			
			Add polling support to NVMe so that it does not use interrupt to complete a IO but instead actively polls for completion. This probably is not very efficient in terms of CPU usage but it does not use interrupts to complete a IO which is beneficial at the moment as there is no MSI(X) support and it can reduce the latency of an IO in a very fast NVMe device. The NVMeQueue class has been made the base class for NVMeInterruptQueue and NVMePollQueue. The factory function `NVMeQueue::try_create` will return the appropriate queue to the controller based on the polling boot parameter. The polling mode can be enabled by adding an extra boot parameter: `nvme_poll`.
		
			
				
	
	
		
			81 lines
		
	
	
	
		
			2.8 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			81 lines
		
	
	
	
		
			2.8 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2021, Pankaj R <pankydev8@gmail.com>
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #pragma once
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| 
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| #include <AK/NonnullRefPtr.h>
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| #include <AK/NonnullRefPtrVector.h>
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| #include <AK/OwnPtr.h>
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| #include <AK/RefCounted.h>
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| #include <AK/RefPtr.h>
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| #include <AK/Types.h>
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| #include <Kernel/Bus/PCI/Device.h>
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| #include <Kernel/Interrupts/IRQHandler.h>
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| #include <Kernel/Locking/Spinlock.h>
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| #include <Kernel/Memory/MemoryManager.h>
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| #include <Kernel/Memory/TypedMapping.h>
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| #include <Kernel/Storage/NVMe/NVMeDefinitions.h>
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| 
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| namespace Kernel {
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| 
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| struct DoorbellRegister {
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|     u32 sq_tail;
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|     u32 cq_head;
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| };
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| 
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| class AsyncBlockDeviceRequest;
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| class NVMeQueue : public RefCounted<NVMeQueue> {
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| public:
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|     static ErrorOr<NonnullRefPtr<NVMeQueue>> try_create(u16 qid, Optional<u8> irq, u32 q_depth, OwnPtr<Memory::Region> cq_dma_region, NonnullRefPtrVector<Memory::PhysicalPage> cq_dma_page, OwnPtr<Memory::Region> sq_dma_region, NonnullRefPtrVector<Memory::PhysicalPage> sq_dma_page, Memory::TypedMapping<volatile DoorbellRegister> db_regs);
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|     bool is_admin_queue() { return m_admin_queue; };
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|     u16 submit_sync_sqe(NVMeSubmission&);
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|     void read(AsyncBlockDeviceRequest& request, u16 nsid, u64 index, u32 count);
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|     void write(AsyncBlockDeviceRequest& request, u16 nsid, u64 index, u32 count);
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|     virtual void submit_sqe(NVMeSubmission&);
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|     virtual ~NVMeQueue();
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| 
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| protected:
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|     u32 process_cq();
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|     void update_sq_doorbell()
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|     {
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|         m_db_regs->sq_tail = m_sq_tail;
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|     }
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|     NVMeQueue(NonnullOwnPtr<Memory::Region> rw_dma_region, Memory::PhysicalPage const& rw_dma_page, u16 qid, u32 q_depth, OwnPtr<Memory::Region> cq_dma_region, NonnullRefPtrVector<Memory::PhysicalPage> cq_dma_page, OwnPtr<Memory::Region> sq_dma_region, NonnullRefPtrVector<Memory::PhysicalPage> sq_dma_page, Memory::TypedMapping<volatile DoorbellRegister> db_regs);
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| 
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| private:
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|     bool cqe_available();
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|     void update_cqe_head();
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|     virtual void complete_current_request(u16 status) = 0;
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|     void update_cq_doorbell()
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|     {
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|         m_db_regs->cq_head = m_cq_head;
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|     }
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| 
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| protected:
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|     Spinlock m_cq_lock { LockRank::Interrupts };
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|     RefPtr<AsyncBlockDeviceRequest> m_current_request;
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|     NonnullOwnPtr<Memory::Region> m_rw_dma_region;
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|     Spinlock m_request_lock;
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| 
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| private:
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|     u16 m_qid {};
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|     u8 m_cq_valid_phase { 1 };
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|     u16 m_sq_tail {};
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|     u16 m_prev_sq_tail {};
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|     u16 m_cq_head {};
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|     bool m_admin_queue { false };
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|     u32 m_qdepth {};
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|     Spinlock m_sq_lock { LockRank::Interrupts };
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|     OwnPtr<Memory::Region> m_cq_dma_region;
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|     NonnullRefPtrVector<Memory::PhysicalPage> m_cq_dma_page;
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|     Span<NVMeSubmission> m_sqe_array;
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|     OwnPtr<Memory::Region> m_sq_dma_region;
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|     NonnullRefPtrVector<Memory::PhysicalPage> m_sq_dma_page;
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|     Span<NVMeCompletion> m_cqe_array;
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|     Memory::TypedMapping<volatile DoorbellRegister> m_db_regs;
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|     NonnullRefPtr<Memory::PhysicalPage> m_rw_dma_page;
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| };
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| }
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