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 def mkcomment(ifaces, cell, idx, outenmode=False):
  74     """ returns a comment string for the cell when muxed
  75     """
  76     idx += 1
  77     if idx >= len(cell):
  78         return ' // unused'
  79     cname = cell[idx]
  80     if not cname:
  81         return ' // unused'
  82     temp = transfn(cname)
  83     x = ifaces.getifacetype(temp)
  84     print (cname, x)
  85     if x == 'input':
  86         return ' // %s is an input' % cname
  87     if outenmode and x == 'inout':
  88         return ' // bi-directional'
  89     if outenmode and x == 'out':
  90         return ' // %s is an output' % cname
  91
  92     return ""
  93
  94
  95 def mkmux(p, ifaces, cell, suffix, outenmode):
  96     comment = 'outen' if outenmode else 'output'
  97     fmtstr = "\t\t\twr%s==%d?%s:%s\n"  # mux-selector format
  98     ret = ''
  99     ret += "      // %s muxer for cell idx %s\n" % (comment, cell[0])
 100     ret += "      %s%s=\n" % (cn(cell[0]), suffix)
 101     for i in range(
 102             0, (1 << p.cell_bitwidth) - 1):  # full mux range (minus 1)
 103         comment = mkcomment(ifaces, cell, i, outenmode)
 104         cf = fmt(ifaces, cell, i, suffix)
 105         ret += fmtstr % (cn(cell[0]), i, cf, comment)
 106     comment = mkcomment(ifaces, cell, i + 1, outenmode)
 107     ret += "\t\t\t" + fmt(ifaces, cell, i + 1, suffix) # last line
 108     ret += ";%s\n" % comment
 109
 110     return ret
 111
 112 def init(p, ifaces):
 113     """ generates the actual output pinmux for each io-cell.  blank lines
 114         need to output "0" to the iopad, if there is no entry in
 115         that column.
 116
 117         text is outputted in the format:
 118             x_out =
 119                 muxer_sel==0 ? a :
 120                 muxer_sel==1 ? b :
 121                 muxer_sel==2 ? 0 :
 122                 d
 123
 124         last line doesn't need selector-logic, obviously.
 125
 126         note that it's *important* that all muxer options be covered
 127         (hence going up to 1<<cell_bitwidth) even if the muxer cells
 128         are blank (no entries), because muxer selection could be to
 129         the last one, and we do not want the "default" (last line)
 130         to be the output.
 131     """
 132     p.cell_bitwidth = get_cell_bit_width(p)
 133     p.pinmux = ' '
 134     global dedicated_wire
 135     for cell in p.muxed_cells:
 136
 137         # first do the outputs
 138         p.pinmux += mkmux(p, ifaces, cell, '_out', False)
 139         p.pinmux += "\n"
 140
 141         # now do the output enablers (outens)
 142         p.pinmux += mkmux(p, ifaces, cell, '_outen', True)
 143
 144         # ======================================================== #
 145
 146         # check each cell if "peripheral input/inout" then assign its wire
 147         # Here we check the direction of each signal in the dictionary.
 148         # We choose to keep the dictionary within the code and not user-input
 149         # since the interfaces are always standard and cannot change from
 150         # user-to-user. Plus this also reduces human-error as well :)
 151         for i in range(0, len(cell) - 1):
 152             cname = cell[i + 1]
 153             if not cname:  # skip blank entries, no need to test
 154                 continue
 155             temp = transfn(cname)
 156             x = ifaces.getifacetype(temp)
 157             #print (cname, temp, x)
 158             assert x is not None, "ERROR: The signal : " + \
 159                 str(cname) + \
 160                 " of pinmap.txt isn't present \nin the current" + \
 161                 " dictionary. Update dictionary or fix-typo."
 162             if x == "input":
 163                 p.pinmux += \
 164                     mux_wire.format(cell[0], i, "wr" + cname) + "\n"
 165             elif x == "inout":
 166                 p.pinmux += \
 167                     mux_wire.format(cell[0], i, "wr" + cname +
 168                                                 "_in") + "\n"
 169     # ============================================================ #
 170
 171     # ==================  Logic for dedicated pins ========= #
 172     for cell in p.dedicated_cells:
 173         p.pinmux += "      %s_out=%s_io;\n" % (cn(cell[0]), cell[1])
 174         temp = cell[1].translate(digits)
 175         x = ifaces.getifacetype(temp)
 176         if x == "input":
 177             pinmux = pinmux + \
 178                 dedicated_wire.format(cell[0], "wr" + cell[1]) + "\n"
 179         elif x == "inout":
 180             pinmux = pinmux + \
 181                 dedicated_wire.format(cell[0], "wr" + cell[1] + "_in") + "\n"
 182     # =======================================================#