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# Copyright (c) 2013 Amin Farmahini-Farahani
# Copyright (c) 2015 University of Kaiserslautern
# Copyright (c) 2015 The University of Bologna
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"""Interfaces for WideIO memory devices

These memory "interfaces" contain the timing,energy,etc parameters for each
memory type and are usually based on datasheets for the memory devices.

You can use these interfaces in the MemCtrl object as the `dram` timing
interface.
"""

from m5.objects import DRAMInterface


class WideIO_200_1x128(DRAMInterface):
    """
    A single WideIO x128 interface (one command and address bus), with
    default timings based on an estimated WIO-200 8 Gbit part.
    """

    # No DLL for WideIO
    dll = False

    # size of device
    device_size = "1024MiB"

    # 1x128 configuration, 1 device with a 128-bit interface
    device_bus_width = 128

    # This is a BL4 device
    burst_length = 4

    # Each device has a page (row buffer) size of 4KB
    # (this depends on the memory density)
    device_rowbuffer_size = "4KiB"

    # 1x128 configuration, so 1 device
    devices_per_rank = 1

    # Use one rank for a one-high die stack
    ranks_per_channel = 1

    # WideIO has 4 banks in all configurations
    banks_per_rank = 4

    # 200 MHz
    tCK = "5ns"

    # WIO-200
    tRCD = "18ns"
    tCL = "18ns"
    tRP = "18ns"
    tRAS = "42ns"
    tWR = "15ns"
    # Read to precharge is same as the burst
    tRTP = "20ns"

    # 4 beats across an x128 SDR interface translates to 4 clocks @ 200 MHz.
    # Note this is a BL4 SDR device.
    tBURST = "20ns"

    # WIO 8 Gb
    tRFC = "210ns"

    # WIO 8 Gb, <=85C, half for >85C
    tREFI = "3.9us"

    # Greater of 2 CK or 15 ns, 2 CK @ 200 MHz = 10 ns
    tWTR = "15ns"

    # Default same rank rd-to-wr bus turnaround to 2 CK, @200 MHz = 10 ns
    tRTW = "10ns"

    # Default different rank bus delay to 2 CK, @200 MHz = 10 ns
    tCS = "10ns"

    # Activate to activate irrespective of density and speed grade
    tRRD = "10.0ns"

    # Two instead of four activation window
    tXAW = "50ns"
    activation_limit = 2

    # The WideIO specification does not provide current information