src/dev/arm/flash_device.hh

   1 /*
   2  * Copyright (c) 2013-2015 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37 #ifndef __DEV_ARM_FLASH_DEVICE_HH__
  38 #define __DEV_ARM_FLASH_DEVICE_HH__
  39
  40 #include <deque>
  41
  42 #include "base/statistics.hh"
  43 #include "debug/FlashDevice.hh"
  44 #include "dev/arm/abstract_nvm.hh"
  45 #include "enums/DataDistribution.hh"
  46 #include "params/FlashDevice.hh"
  47 #include "sim/serialize.hh"
  48
  49 /**
  50  * Flash Device model
  51  * The Flash Device model is a timing model for a NAND flash device.
  52  * It doesn't tranfer any data
  53  */
  54 class FlashDevice : public AbstractNVM
  55 {
  56   public:
  57
  58     /** Initialize functions*/
  59     FlashDevice(const FlashDeviceParams*);
  60     ~FlashDevice();
  61
  62     /** Checkpoint functions*/
  63     DrainState drain() override;
  64     void checkDrain();
  65
  66     void serialize(CheckpointOut &cp) const override;
  67     void unserialize(CheckpointIn &cp) override;
  68
  69   private:
  70     /** Defines the possible actions to the flash*/
  71     enum Actions {
  72         ActionRead,
  73         ActionWrite,
  74         ActionErase,
  75         /**
  76          * A copy involves taking all the used pages from a block and store
  77          *  it in another
  78          */
  79         ActionCopy
  80     };
  81
  82     /** Every logical address maps to a physical block and a physical page*/
  83     struct PageMapEntry {
  84         uint32_t page;
  85         uint32_t block;
  86     };
  87
  88     struct CallBackEntry {
  89         Tick time;
  90         Callback *function;
  91     };
  92
  93     struct FlashDeviceStats {
  94         /** Amount of GC activations*/
  95         Stats::Scalar totalGCActivations;
  96
  97         /** Histogram of address accesses*/
  98         Stats::Histogram writeAccess;
  99         Stats::Histogram readAccess;
 100         Stats::Histogram fileSystemAccess;
 101
 102         /** Histogram of access latencies*/
 103         Stats::Histogram writeLatency;
 104         Stats::Histogram readLatency;
 105     };
 106
 107     /** Device access functions Inherrited from AbstractNVM*/
 108     void initializeMemory(uint64_t disk_size, uint32_t sector_size) override
 109     {
 110         initializeFlash(disk_size, sector_size);
 111     }
 112
 113     void readMemory(uint64_t address, uint32_t amount,
 114                     Callback *event) override
 115     {
 116         accessDevice(address, amount, event, ActionRead);
 117     }
 118
 119     void writeMemory(uint64_t address, uint32_t amount,
 120                      Callback *event) override
 121     {
 122         accessDevice(address, amount, event, ActionWrite);
 123     }
 124
 125     /**Initialization function; called when all disk specifics are known*/
 126     void initializeFlash(uint64_t disk_size, uint32_t sector_size);
 127
 128     /**Flash action function*/
 129     void accessDevice(uint64_t address, uint32_t amount, Callback *event,
 130                       Actions action);
 131
 132     /** Event rescheduler*/
 133     void actionComplete();
 134
 135     /** FTL functionality */
 136     Tick remap(uint64_t logic_page_addr);
 137
 138     /** Access time calculator*/
 139     Tick accessTimes(uint64_t address, Actions accesstype);
 140
 141     /** Function to indicate that a page is known*/
 142     void clearUnknownPages(uint32_t index);
 143
 144     /** Function to test if a page is known*/
 145     bool getUnknownPages(uint32_t index);
 146
 147     /**Stats register function*/
 148     void regStats() override;
 149
 150     /** Disk sizes in bytes */
 151     uint64_t diskSize;
 152     const uint32_t blockSize;
 153     const uint32_t pageSize;
 154
 155     /** Garbage collection algorithm emulator */
 156     const uint32_t GCActivePercentage;
 157
 158     /** Access latencies */
 159     const Tick readLatency;
 160     const Tick writeLatency;
 161     const Tick eraseLatency;
 162
 163     /** Flash organization */
 164     const Enums::DataDistribution dataDistribution;
 165     const uint32_t numPlanes;
 166
 167     /** RequestHandler stats */
 168     struct FlashDeviceStats stats;
 169
 170     /** Disk dimensions in pages and blocks */
 171     uint32_t pagesPerBlock;
 172     uint32_t pagesPerDisk;
 173     uint32_t blocksPerDisk;
 174
 175     uint32_t planeMask;
 176
 177     /**
 178      * when the disk is first started we are unsure of the number of
 179      * used pages, this variable will help determining what we do know.
 180      */
 181     std::vector<uint32_t> unknownPages;
 182     /** address to logic place has a block and a page field*/
 183     std::vector<struct PageMapEntry> locationTable;
 184     /** number of valid entries per block*/
 185     std::vector<uint32_t> blockValidEntries;
 186     /** number of empty entries*/
 187     std::vector<uint32_t> blockEmptyEntries;
 188
 189     /**This vector of queues keeps track of all the callbacks per plane*/
 190     std::vector<std::deque<struct CallBackEntry> > planeEventQueue;
 191
 192     /** Completion event */
 193     EventFunctionWrapper planeEvent;
 194 };
 195 #endif //__DEV_ARM_FLASH_DEVICE_HH__