SPI: Generalize to multi-lane MISO/MISO

It is fairly common for single SPI bus to consist of a set of parallel
MISO/MOSI lanes (c.f. QSPI FLASH). For instance:

 * many multi-channel ADCs allow each converter to clock out over its
   own MISO lane to reduce the clockrate needed to achieve the designed
   conversion rate.

 * similarly, QSPI FLASH relies upon four bidirectional outputs to
   increase data rate.

Here we extend Clash.Cores.SPI to facilitate this use-case by
introducing `spiMaster'` and `spiSlave'`, which allow arbitrary
MISO/MOSI lane widths.

clash-cores/src/Clash/Cores/SPI.hs

@@ -12,11 +12,13 @@ module Clash.Cores.SPI
   , SpiMasterIn(..)
   , SpiMasterOut(..)
   , spiMaster
+  , spiMaster1
     -- * SPI slave
   , SpiSlaveIn(..)
   , SpiSlaveOut(..)
   , SPISlaveConfig(..)
   , spiSlave
+  , spiSlave1
     -- ** Vendor configured SPI slaves
   , spiSlaveLatticeSBIO
   , spiSlaveLatticeBB
@@ -125,7 +127,7 @@ sampleOnLeading _        = False
 sampleOnTrailing :: SPIMode -> Bool
 sampleOnTrailing = not . sampleOnLeading
 
-data SPISlaveConfig ds dom
+data SPISlaveConfig ds dom (misoW :: Nat) (mosiW :: Nat)
   = SPISlaveConfig
   { spiSlaveConfigMode :: SPIMode
   -- ^ SPI mode
@@ -139,30 +141,34 @@ data SPISlaveConfig ds dom
   --
   -- * Set to /False/ when core clock is twice as fast, or as fast, as the SCK
   , spiSlaveConfigBuffer
-      :: BiSignalIn ds dom 1
+      :: BiSignalIn ds dom misoW
       -> Signal dom Bool
-      -> Signal dom Bit
-      -> BiSignalOut ds dom 1
+      -> Signal dom (BitVector misoW)
+      -> BiSignalOut ds dom misoW
   -- ^ Tri-state buffer: first argument is the inout pin, second
   -- argument is the output enable, third argument is the value to
   -- output when the enable is high
   }
 
 -- | SPI capture and shift logic that is shared between slave and master
 spiCommon
-  :: forall n dom
-   . (HiddenClockResetEnable dom, KnownNat n, 1 <= n)
+  :: forall n dom inW outW
+   . ( HiddenClockResetEnable dom
+     , KnownNat inW
+     , KnownNat outW
+     , KnownNat n
+     , 1 <= n )
   => SPIMode
   -> Signal dom Bool
   -- ^ Slave select
-  -> Signal dom Bit
+  -> Signal dom (BitVector inW)
   -- ^ Slave: MOSI; Master: MISO
   -> Signal dom Bool
   -- ^ SCK
-  -> Signal dom (BitVector n)
-  -> ( Signal dom Bit   -- Slave: MISO; Master: MOSI
-     , Signal dom Bool  -- Acknowledge start of transfer
-     , Signal dom (Maybe (BitVector n))
+  -> Signal dom (Vec outW (BitVector n))
+  -> ( Signal dom (BitVector outW) -- Slave: MISO; Master: MOSI
+     , Signal dom Bool             -- Acknowledge start of transfer
+     , Signal dom (Maybe (Vec inW (BitVector n)))
      )
 spiCommon mode ssI msI sckI dinI =
   mooreB go cvt ( 0 :: Index n      -- cntR
@@ -176,13 +182,16 @@ spiCommon mode ssI msI sckI dinI =
                 (ssI,msI,sckI,dinI)
  where
   cvt (_,_,_,dataInQ,dataOutQ,ackQ,doneQ) =
-    ( head dataOutQ
+    ( v2bv $ map head dataOutQ
     , ackQ
     , if doneQ
-         then Just (pack dataInQ)
+         then Just (map v2bv dataInQ)
          else Nothing
     )
 
+  go :: (Index n, Bool, Bool, Vec inW (Vec n Bit), Vec outW (Vec n Bit), Bool, Bool)
+     -> (Bool, BitVector inW, Bool, Vec outW (BitVector n))
+     -> (Index n, Bool, Bool, Vec inW (Vec n Bit), Vec outW (Vec n Bit), Bool, Bool)
   go (cntQ,cntOldQ,sckOldQ,dataInQ,dataOutQ,_,_) (ss,ms,sck,din) =
     (cntD,cntOldD,sck,dataInD,dataOutD,ackD,doneD)
    where
@@ -191,16 +200,18 @@ spiCommon mode ssI msI sckI dinI =
       | sampleSck = if cntQ == maxBound then 0 else cntQ + 1
       | otherwise = cntQ
 
+    dataInD :: Vec inW (Vec n Bit)
     dataInD
       | ss        = unpack undefined#
-      | sampleSck = tail @(n-1) dataInQ :< ms
+      | sampleSck = zipWith (\d m -> tail @(n-1) d :< m) dataInQ (bv2v ms)
       | otherwise = dataInQ
 
+    dataOutD :: Vec outW (Vec n Bit)
     dataOutD
-      | ss || (sampleOnTrailing mode && sampleSck && cntQ == maxBound) = unpack din
+      | ss || (sampleOnTrailing mode && sampleSck && cntQ == maxBound) = fmap bv2v din
       | shiftSck  = if sampleOnTrailing mode && cntQ == 0
                     then dataOutQ
-                    else tail @(n-1) dataOutQ :< unpack undefined#
+                    else map (\d -> tail @(n-1) d :< unpack undefined#) dataOutQ
       | otherwise = dataOutQ
 
     -- The counter is updated during the capture moment
@@ -222,19 +233,23 @@ spiCommon mode ssI msI sckI dinI =
 
 -- | SPI slave configurable SPI mode and tri-state buffer
 spiSlave
-  :: forall n ds dom
-   . (HiddenClockResetEnable dom, KnownNat n, 1 <= n)
-  => SPISlaveConfig ds dom
+  :: forall n ds dom misoW mosiW
+   . ( HiddenClockResetEnable dom
+     , KnownNat n
+     , 1 <= n
+     , KnownNat misoW
+     , KnownNat mosiW )
+  => SPISlaveConfig ds dom misoW mosiW
   -- ^ Configure SPI mode and tri-state buffer
-  -> SpiSlaveIn ds dom 1 1
+  -> SpiSlaveIn ds dom misoW mosiW
   -- ^ SPI interface
-  -> Signal dom (BitVector n)
+  -> Signal dom (Vec misoW (BitVector n))
   -- ^ Data to send from slave to master.
   --
   -- Input is latched the moment slave select goes low
-  -> ( SpiSlaveOut ds dom 1 1
+  -> ( SpiSlaveOut ds dom misoW mosiW
      , Signal dom Bool
-     , Signal dom (Maybe (BitVector n)))
+     , Signal dom (Maybe (Vec mosiW (BitVector n))) )
   -- ^ Parts of the tuple:
   --
   -- 1. The "out" part of the inout port of the MISO; used only for simulation.
@@ -246,17 +261,46 @@ spiSlave (SPISlaveConfig mode latch buf) (SpiSlaveIn mosi bin sclk ss) din =
   let ssL   = if latch then delay undefined ss   else ss
       mosiL = if latch then delay undefined mosi else mosi
       sclkL = if latch then delay undefined sclk else sclk
-      (miso, ack, dout) = spiCommon mode (bitToBool <$> ssL) (head . bv2v <$> mosiL) (bitToBool <$> sclkL) din
+      (miso, ack, dout) = spiCommon mode (bitToBool <$> ssL) mosiL (bitToBool <$> sclkL) din
       bout = buf bin (not . bitToBool <$> ssL) miso
   in  (SpiSlaveOut bout, ack, dout)
 
+spiSlave1
+  :: forall n ds dom
+   . ( HiddenClockResetEnable dom
+     , KnownNat n
+     , 1 <= n )
+  => SPISlaveConfig ds dom 1 1
+  -- ^ Configure SPI mode and tri-state buffer
+  -> SpiSlaveIn ds dom 1 1
+  -- ^ SPI interface
+  -> Signal dom (BitVector n)
+  -- ^ Data to send from slave to master.
+  --
+  -- Input is latched the moment slave select goes low
+  -> ( SpiSlaveOut ds dom 1 1
+     , Signal dom Bool
+     , Signal dom (Maybe (BitVector n)) )
+  -- ^ Parts of the tuple:
+  --
+  -- 1. The "out" part of the inout port of the MISO; used only for simulation.
+  --
+  -- 2. the acknowledgement for the data sent from the master to the slave.
+  --
+  -- 2. (Maybe) the word sent by the master
+spiSlave1 config spiIn dout =
+    let (spiOut, ack, din) = spiSlave config spiIn (singleton <$> dout)
+    in (spiOut, ack, fmap head <$> din)
+
 -- | SPI master configurable in the SPI mode and clock divider
 --
 -- Adds latch to MISO line if the (half period) clock divider is
 -- set to 2 or higher.
 spiMaster
-  :: forall n halfPeriod waitTime dom
+  :: forall n halfPeriod waitTime dom misoW mosiW
    . ( HiddenClockResetEnable dom
+     , KnownNat misoW
+     , KnownNat mosiW
      , KnownNat n
      , 1 <= n
      , 1 <= halfPeriod
@@ -270,14 +314,14 @@ spiMaster
   -> SNat waitTime
   -- ^ (core clock) cycles between de-asserting slave-select and start of
   -- the SPI clock
-  -> Signal dom (Maybe (BitVector n))
+  -> Signal dom (Maybe (Vec mosiW (BitVector n)))
   -- ^ Data to send from master to slave, transmission starts when receiving
   -- /Just/ a value
-  -> SpiMasterIn dom 1 1
-  -> ( SpiMasterOut dom 1 1
+  -> SpiMasterIn dom misoW mosiW
+  -> ( SpiMasterOut dom misoW mosiW
      , Signal dom Bool -- Busy
      , Signal dom Bool -- Acknowledge
-     , Signal dom (Maybe (BitVector n)) -- Data: Slave -> Master
+     , Signal dom (Maybe (Vec misoW (BitVector n))) -- Data: Slave -> Master
      )
   -- ^ Parts of the tuple:
   --
@@ -288,27 +332,59 @@ spiMaster
   --    the data line will be ignored when /True/
   -- 5. (Maybe) the word send from the slave to the master
 spiMaster mode fN fW din (SpiMasterIn miso) =
-  let (mosi, ack, dout)   = spiCommon mode ssL (head . bv2v <$> misoL) sclkL
-                        (fromMaybe undefined# <$> din)
+  let (mosi, ack, dout)   = spiCommon mode ssL misoL sclkL
+                        (fromMaybe (repeat undefined#) <$> din)
       latch = snatToInteger fN /= 1
       ssL   = if latch then delay undefined ss   else ss
       misoL = if latch then delay undefined miso else miso
       sclkL = if latch then delay undefined sclk else sclk
       (ss, sclk, busy) = spiGen mode fN fW din
-  in  (SpiMasterOut (v2bv . singleton <$> mosi) (boolToBit <$> sclk) (boolToBit <$> ss), busy, ack, dout)
+  in  (SpiMasterOut mosi (boolToBit <$> sclk) (boolToBit <$> ss), busy, ack, dout)
+
+-- | SPI master with single-bit MISO and MOSI width.
+spiMaster1
+  :: forall n halfPeriod waitTime dom 
+   . ( HiddenClockResetEnable dom
+     , KnownNat n
+     , 1 <= n
+     , 1 <= halfPeriod
+     , 1 <= waitTime )
+  => SPIMode
+  -- ^ SPI Mode
+  -> SNat halfPeriod
+  -- ^ Clock divider (half period)
+  --
+  -- If set to two or higher, the MISO line will be latched
+  -> SNat waitTime
+  -- ^ (core clock) cycles between de-asserting slave-select and start of
+  -- the SPI clock
+  -> Signal dom (Maybe (BitVector n))
+  -- ^ Data to send from master to slave, transmission starts when receiving
+  -- /Just/ a value
+  -> SpiMasterIn dom 1 1
+  -> ( SpiMasterOut dom 1 1
+     , Signal dom Bool -- Busy
+     , Signal dom Bool -- Acknowledge
+     , Signal dom (Maybe (BitVector n)) -- Data: Slave -> Master
+     )
+spiMaster1 mode halfPeriod waitTime dout spiIn =
+    let (spiOut, busy, ack, din) =
+            spiMaster mode halfPeriod waitTime (fmap singleton <$> dout) spiIn
+    in (spiOut, busy, ack, fmap head <$> din)
 
 -- | Generate slave select and SCK
 spiGen
-  :: forall n halfPeriod waitTime dom
+  :: forall n halfPeriod waitTime dom outW
    . ( HiddenClockResetEnable dom
      , KnownNat n
+     , KnownNat outW
      , 1 <= n
      , 1 <= halfPeriod
      , 1 <= waitTime )
   => SPIMode
   -> SNat halfPeriod
   -> SNat waitTime
-  -> Signal dom (Maybe (BitVector n))
+  -> Signal dom (Maybe (Vec outW (BitVector n)))
   -> ( Signal dom Bool
      , Signal dom Bool
      , Signal dom Bool
@@ -386,11 +462,11 @@ spiSlaveLatticeSBIO
   --
   -- 2. (Maybe) the word send by the master
 spiSlaveLatticeSBIO mode latchSPI =
-  spiSlave (SPISlaveConfig mode latchSPI sbioX)
+  spiSlave1 (SPISlaveConfig mode latchSPI sbioX)
  where
   sbioX bin en dout = bout
    where
-    (bout,_,_) = sbio 0b101001 bin (pure 0) dout (pure undefined) en
+    (bout,_,_) = sbio 0b101001 bin (pure 0) (head . bv2v <$> dout) (pure undefined) en
 
 
 -- | SPI slave configurable SPI mode, using the BB tri-state buffer
@@ -423,8 +499,8 @@ spiSlaveLatticeBB
   --
   -- 2. (Maybe) the word send by the master
 spiSlaveLatticeBB mode latchSPI =
-  spiSlave (SPISlaveConfig mode latchSPI bbX)
+  spiSlave1 (SPISlaveConfig mode latchSPI bbX)
  where
     bbX bin en dout = bout
       where
-        (bout,_) = bidirectionalBuffer (toEnable en) bin dout
+        (bout,_) = bidirectionalBuffer (toEnable en) bin (head . bv2v <$> dout)