src/bsv/actual_pinmux.py

   1 import math
   2 from string import digits
   3 try:
   4     from string import maketrans
   5 except ImportError:
   6     maketrans = str.maketrans
   7
   8
   9 # ============== common bsv templates ============ #
  10 # first argument is the io-cell number being assigned.
  11 # second argument is the mux value.
  12 # Third argument is the signal from the pinmap file
  13 mux_wire = '''\
  14       rule assign_{2}_on_cell{0}(wrcell{0}_mux=={1});
  15         {2}<=cell{0}_mux_in;
  16       endrule
  17 '''
  18 dedicated_wire = '''
  19       rule assign_{1}_on_cell{0};
  20         {1}<=cell{0}_mux_in;
  21       endrule
  22 '''
  23 # ============================================================
  24 digits = maketrans('0123456789', ' ' * 10)  # delete space later
  25
  26
  27 def get_cell_bit_width(p):
  28     max_num_cells = 0
  29     for cell in p.muxed_cells:
  30         max_num_cells = max(len(cell) - 1, max_num_cells)
  31     return int(math.log(max_num_cells + 1, 2))
  32
  33
  34 def cn(idx):  # idx is an integer
  35     return "cell%s_mux" % str(idx)
  36
  37
  38 def transfn(temp):
  39     """ removes the number from the string of signal name.
  40     """
  41     temp = temp.split('_')
  42     if len(temp) == 2:
  43         temp[0] = temp[0].translate(digits)
  44         temp[0] = temp[0] .replace(' ', '')
  45     return '_'.join(temp)
  46
  47
  48 # XXX this needs to move into interface_decl.py
  49 # and made to use ifaceoutfmtfn and ifaceinfmtfn
  50 def fmt(ifaces, cell, idx, suffix=None):
  51     """ blank entries need to output a 0 to the pin (it could just as
  52         well be a 1 but we choose 0).  reason: blank entries in
  53         the pinmap.txt file indicate that there's nothing to choose
  54         from.  however the user may still set the muxer to that value,
  55         and rather than throw an exception we choose to output... zero.
  56     """
  57     idx += 1
  58     if idx < len(cell):
  59         cell = cell[idx]
  60     else:
  61         cell = ''
  62     if not cell:
  63         return '0'
  64     temp = transfn(cell)
  65     x = ifaces.getifacetype(temp)
  66     if x == 'input':
  67         return '0'  # inputs don't get passed through to the out mux
  68     if suffix == '_outen' and x == 'out':
  69         return '1'
  70     return "wr%s%s" % (cell, suffix or '')
  71
  72 # XXX this needs to move into interface_decl.py
  73
  74
  75 def mkcomment(ifaces, cell, idx, outenmode=False):
  76     """ returns a comment string for the cell when muxed
  77     """
  78     idx += 1
  79     if idx >= len(cell):
  80         return ' // unused'
  81     cname = cell[idx]
  82     if not cname:
  83         return ' // unused'
  84     temp = transfn(cname)
  85     x = ifaces.getifacetype(temp)
  86     #print (cname, x)
  87     if x == 'input':
  88         return ' // %s is an input' % cname
  89     if outenmode and x == 'inout':
  90         return ' // bi-directional'
  91     if outenmode and x == 'out':
  92         return ' // %s is an output' % cname
  93
  94     return ""
  95
  96
  97 def mkmux(p, ifaces, cell, suffix, outenmode):
  98     """ creates a straight many-to-one muxer that accepts
  99         multiple inputs and, based on an "address" routes
 100         a given indexed input through to the (one) output
 101     """
 102     comment = 'outen' if outenmode else 'output'
 103     fmtstr = "\t\t\twr%s==%d?%s:%s\n"  # mux-selector format
 104     ret = ''
 105     ret += "      // %s muxer for cell idx %s\n" % (comment, cell[0])
 106     ret += "      %s%s=\n" % (cn(cell[0]), suffix)
 107     for i in range(
 108             0, (1 << p.cell_bitwidth) - 1):  # full mux range (minus 1)
 109         comment = mkcomment(ifaces, cell, i, outenmode)
 110         cf = fmt(ifaces, cell, i, suffix)
 111         ret += fmtstr % (cn(cell[0]), i, cf, comment)
 112     comment = mkcomment(ifaces, cell, i + 1, outenmode)
 113     ret += "\t\t\t" + fmt(ifaces, cell, i + 1, suffix)  # last line
 114     ret += ";%s\n" % comment
 115
 116     return ret
 117
 118
 119 def init(p, ifaces):
 120     """ generates the actual output pinmux for each io-cell.  blank lines
 121         need to output "0" to the iopad, if there is no entry in
 122         that column.
 123
 124         text is outputted in the format:
 125             x_out =
 126                 muxer_sel==0 ? a :
 127                 muxer_sel==1 ? b :
 128                 muxer_sel==2 ? 0 :
 129                 d
 130
 131         last line doesn't need selector-logic, obviously.
 132
 133         note that it's *important* that all muxer options be covered
 134         (hence going up to 1<<cell_bitwidth) even if the muxer cells
 135         are blank (no entries), because muxer selection could be to
 136         the last one, and we do not want the "default" (last line)
 137         to be the output.
 138     """
 139     p.cell_bitwidth = get_cell_bit_width(p)
 140     p.pinmux = ' '
 141     global dedicated_wire
 142     for cell in p.muxed_cells:
 143
 144         # first do the outputs
 145         p.pinmux += mkmux(p, ifaces, cell, '_out', False)
 146         p.pinmux += "\n"
 147
 148         # now do the output enablers (outens)
 149         p.pinmux += mkmux(p, ifaces, cell, '_outen', True)
 150
 151         # ======================================================== #
 152
 153         # check each cell if "peripheral input/inout" then assign its wire
 154         # Here we check the direction of each signal in the dictionary.
 155         # We choose to keep the dictionary within the code and not user-input
 156         # since the interfaces are always standard and cannot change from
 157         # user-to-user. Plus this also reduces human-error as well :)
 158         p.pinmux += "\n"
 159         p.pinmux += "      // priority-in-muxer for cell idx %s\n" % (cell[0])
 160         for i in range(0, len(cell) - 1):
 161             cname = cell[i + 1]
 162             if not cname:  # skip blank entries, no need to test
 163                 continue
 164             temp = transfn(cname)
 165             x = ifaces.getifacetype(temp)
 166             #print (cname, temp, x)
 167             assert x is not None, "ERROR: The signal : " + \
 168                 str(cname) + \
 169                 " of pinmap.txt isn't present \nin the current" + \
 170                 " dictionary. Update dictionary or fix-typo."
 171             if x == "input":
 172                 p.pinmux += \
 173                     mux_wire.format(cell[0], i, "wr" + cname) + "\n"
 174             elif x == "inout":
 175                 p.pinmux += \
 176                     mux_wire.format(cell[0], i, "wr" + cname +
 177                                                 "_in") + "\n"
 178     # ============================================================ #
 179
 180     # ==================  Logic for dedicated pins ========= #
 181     p.pinmux += "\n      /*=========================================*/\n"
 182     p.pinmux += "      // dedicated cells\n\n"
 183     for cell in p.dedicated_cells:
 184         p.pinmux += "      // dedicated cell idx %s\n" % (cell[0])
 185         p.pinmux += "      %s_out=%s_io;\n" % (cn(cell[0]), cell[1])
 186         temp = transfn(cell[1])
 187         x = ifaces.getifacetype(temp)
 188         #print cell, temp, x
 189         if x == "input":
 190             p.pinmux += \
 191                 dedicated_wire.format(cell[0], "wr" + cell[1]) + "\n"
 192         elif x == "inout":
 193             p.pinmux += \
 194                 dedicated_wire.format(cell[0], "wr" + cell[1] + "_in") + "\n"
 195         else:
 196             p.pinmux += "\n"
 197     # =======================================================#