src/dev/arm/FlashDevice.py

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# Authors: Rene de Jong
#

from m5.params import *
from m5.proxy import *

from m5.objects.AbstractNVM import *

#Distribution of the data.
#sequential: sequential (address n+1 is likely to be on the same plane as n)
#Random: @TODO Not yet implemented
#stripe: striping over all the planes
class DataDistribution(Enum): vals = ['sequential', 'stripe']

class FlashDevice(AbstractNVM):
    type = 'FlashDevice'
    cxx_header = "dev/arm/flash_device.hh"
    # default blocksize is 128 kB.This seems to be the most common size in
    # mobile devices (not the image blocksize)
    blk_size = Param.MemorySize("128kB", "Size of one disk block")
    # disk page size is 2 kB. This is the most commonly used page size in
    # flash devices
    page_size = Param.MemorySize("2kB", "Size of one disk page")
    # There are many GC flavours. It is impossible to cover them all; this
    # parameter enables the approximation of different GC algorithms
    GC_active = Param.Percent(50, "Percentage of the time (in whole numbers) \
        that the GC is activated if a block is full")
    # Access latencies. Different devices will have different latencies, but
    # the latencies will be around the default values.
    read_lat = Param.Latency("25us", "Read Latency")
    write_lat = Param.Latency("200us", "Write Latency")
    erase_lat = Param.Latency("1500us", "Erase Delay")
    # Number of planes ought to be a power of two according to ONFI standard
    num_planes = Param.UInt32(1, "Number of planes per die")
    # Data distribution. Default is none. It is adviced to switch to stripe
    # when more than one plane is used.
    data_distribution = Param.DataDistribution('sequential', "Distribution \
        of the data in the adress table; Stripe needed for multiple\
        planes; otherwise use: sequential")