69 lines
1.8 KiB
Haskell
69 lines
1.8 KiB
Haskell
package BusTypes(
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BusVal(..),
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BusError(..),
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TransactionSize(..),
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ReadRequest(..),
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WriteRequest(..)
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) where
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import Types
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data BusError
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= UnMapped
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| UnAligned
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deriving (Bits, Eq, FShow)
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data TransactionSize
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= SizeByte
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| SizeHalfWord
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| SizeFullWord
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| SizeDoubleWord
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| SizeQuadWord
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deriving (Bits, Eq, FShow)
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data BusVal
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= BusByte Byte
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| BusHalfWord HalfWord
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| BusFullWord FullWord
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| BusDoubleWord DoubleWord
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| BusQuadWord QuadWord
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deriving (Bits, Eq, FShow)
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data ReadRequest = ReadRequest Addr TransactionSize
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deriving (Bits, Eq, FShow)
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data WriteRequest = WriteRequest Addr BusVal
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deriving (Bits, Eq, FShow)
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type ReadResponse = Either BusError BusVal
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type WriteResponse = Either BusError ()
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data BusRequest
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= BusReadRequest ReadRequest
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| WriteReadRequest WriteRequest
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deriving (Bits, Eq, FShow)
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data BusResponse
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= BusReadResponse ReadResponse
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| BusWriteResponse WriteResponse
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deriving (Bits, Eq, FShow)
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interface BusMaster =
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-- The Bus arbiter will call the Bus Master's request method
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-- if and only if it's the Bus Master's turn to make a request, and the Bus Master
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-- has a request to make.
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-- It is up to the BusMaster to guard it's request method such that calling
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-- it's request method is only valid when the BusMaster has a request to make.
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-- This has implications about for the implementor of BusMaster, namely, that it
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-- should hold its request until it's request method gets called.
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request :: BusRequest
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-- From the masters's perspective, the response should not be called until
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-- the client is ready to accept the response. In other words, response
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-- should be guarded by the client.
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response :: BusResponse -> Action
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type Token = UInt 5
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a :: UInt 5
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a = 3
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