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     comment = 'outen' if outenmode else 'output'
  99     fmtstr = "\t\t\twr%s==%d?%s:%s\n"  # mux-selector format
 100     ret = ''
 101     ret += "      // %s muxer for cell idx %s\n" % (comment, cell[0])
 102     ret += "      %s%s=\n" % (cn(cell[0]), suffix)
 103     for i in range(
 104             0, (1 << p.cell_bitwidth) - 1):  # full mux range (minus 1)
 105         comment = mkcomment(ifaces, cell, i, outenmode)
 106         cf = fmt(ifaces, cell, i, suffix)
 107         ret += fmtstr % (cn(cell[0]), i, cf, comment)
 108     comment = mkcomment(ifaces, cell, i + 1, outenmode)
 109     ret += "\t\t\t" + fmt(ifaces, cell, i + 1, suffix)  # last line
 110     ret += ";%s\n" % comment
 111
 112     return ret
 113
 114
 115 def init(p, ifaces):
 116     """ generates the actual output pinmux for each io-cell.  blank lines
 117         need to output "0" to the iopad, if there is no entry in
 118         that column.
 119
 120         text is outputted in the format:
 121             x_out =
 122                 muxer_sel==0 ? a :
 123                 muxer_sel==1 ? b :
 124                 muxer_sel==2 ? 0 :
 125                 d
 126
 127         last line doesn't need selector-logic, obviously.
 128
 129         note that it's *important* that all muxer options be covered
 130         (hence going up to 1<<cell_bitwidth) even if the muxer cells
 131         are blank (no entries), because muxer selection could be to
 132         the last one, and we do not want the "default" (last line)
 133         to be the output.
 134     """
 135     p.cell_bitwidth = get_cell_bit_width(p)
 136     p.pinmux = ' '
 137     global dedicated_wire
 138     for cell in p.muxed_cells:
 139
 140         # first do the outputs
 141         p.pinmux += mkmux(p, ifaces, cell, '_out', False)
 142         p.pinmux += "\n"
 143
 144         # now do the output enablers (outens)
 145         p.pinmux += mkmux(p, ifaces, cell, '_outen', True)
 146
 147         # ======================================================== #
 148
 149         # check each cell if "peripheral input/inout" then assign its wire
 150         # Here we check the direction of each signal in the dictionary.
 151         # We choose to keep the dictionary within the code and not user-input
 152         # since the interfaces are always standard and cannot change from
 153         # user-to-user. Plus this also reduces human-error as well :)
 154         p.pinmux += "\n"
 155         p.pinmux += "      // priority-in-muxer for cell idx %s\n" % (cell[0])
 156         for i in range(0, len(cell) - 1):
 157             cname = cell[i + 1]
 158             if not cname:  # skip blank entries, no need to test
 159                 continue
 160             temp = transfn(cname)
 161             x = ifaces.getifacetype(temp)
 162             #print (cname, temp, x)
 163             assert x is not None, "ERROR: The signal : " + \
 164                 str(cname) + \
 165                 " of pinmap.txt isn't present \nin the current" + \
 166                 " dictionary. Update dictionary or fix-typo."
 167             if x == "input":
 168                 p.pinmux += \
 169                     mux_wire.format(cell[0], i, "wr" + cname) + "\n"
 170             elif x == "inout":
 171                 p.pinmux += \
 172                     mux_wire.format(cell[0], i, "wr" + cname +
 173                                                 "_in") + "\n"
 174     # ============================================================ #
 175
 176     # ==================  Logic for dedicated pins ========= #
 177     for cell in p.dedicated_cells:
 178         p.pinmux += "      %s_out=%s_io;\n" % (cn(cell[0]), cell[1])
 179         temp = cell[1].translate(digits)
 180         x = ifaces.getifacetype(temp)
 181         if x == "input":
 182             pinmux = pinmux + \
 183                 dedicated_wire.format(cell[0], "wr" + cell[1]) + "\n"
 184         elif x == "inout":
 185             pinmux = pinmux + \
 186                 dedicated_wire.format(cell[0], "wr" + cell[1] + "_in") + "\n"
 187     # =======================================================#