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, cells, 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         NOTE: IMPORTANT.  when a function is an output-only there
  58         is a special-case assumption that:
  59         * (a) GPIO is always the first mux entry
  60         * (b) GPIO's outen is also used to set the pad
  61         the reason for this is that it is assumed better that
  62         multiple pads be switched simutaneously to outputs
  63         by setting the GPIO direction rather than having them
  64         set arbitrarily by changing the muxer registers.
  65     """
  66     idx += 1
  67     if idx < len(cells):
  68         cell = cells[idx]
  69     else:
  70         cell = ''
  71     if not cell:
  72         return '0'
  73     temp = transfn(cell)
  74     x = ifaces.getifacetype(temp)
  75     if x == 'input':
  76         return '0'  # inputs don't get passed through to the out mux
  77     if suffix == '_outen' and x == 'out':
  78         return "wr%s%s" % (cells[1], suffix or '') # USE GPIO FOR SELECTION
  79     return "wr%s%s" % (cell, suffix or '')
  80
  81 # XXX this needs to move into interface_decl.py
  82
  83
  84 def mkcomment(ifaces, cell, idx, outenmode=False):
  85     """ returns a comment string for the cell when muxed
  86     """
  87     idx += 1
  88     if idx >= len(cell):
  89         return ' // unused'
  90     cname = cell[idx]
  91     if not cname:
  92         return ' // unused'
  93     temp = transfn(cname)
  94     x = ifaces.getifacetype(temp)
  95     #print (cname, x)
  96     if x == 'input':
  97         return ' // %s is an input' % cname
  98     if outenmode and x == 'inout':
  99         return ' // bi-directional'
 100     if outenmode and x == 'out':
 101         return ' // %s is an output' % cname
 102
 103     return ""
 104
 105
 106 def mkmux(p, ifaces, cell, suffix, outenmode):
 107     """ creates a straight many-to-one muxer that accepts
 108         multiple inputs and, based on an "address" routes
 109         a given indexed input through to the (one) output
 110     """
 111     comment = 'outen' if outenmode else 'output'
 112     fmtstr = "\t\t\twr%s==%d?%s:%s\n"  # mux-selector format
 113     ret = ''
 114     ret += "      // %s muxer for cell idx %s\n" % (comment, cell[0])
 115     ret += "      %s%s=\n" % (cn(cell[0]), suffix)
 116     for i in range(
 117             0, (1 << p.cell_bitwidth) - 1):  # full mux range (minus 1)
 118         comment = mkcomment(ifaces, cell, i, outenmode)
 119         cf = fmt(ifaces, cell, i, suffix)
 120         ret += fmtstr % (cn(cell[0]), i, cf, comment)
 121     comment = mkcomment(ifaces, cell, i + 1, outenmode)
 122     ret += "\t\t\t" + fmt(ifaces, cell, i + 1, suffix)  # last line
 123     ret += ";%s\n" % comment
 124
 125     return ret
 126
 127
 128 def init(p, ifaces):
 129     """ generates the actual output pinmux for each io-cell.  blank lines
 130         need to output "0" to the iopad, if there is no entry in
 131         that column.
 132
 133         text is outputted in the format:
 134             x_out =
 135                 muxer_sel==0 ? a :
 136                 muxer_sel==1 ? b :
 137                 muxer_sel==2 ? 0 :
 138                 d
 139
 140         last line doesn't need selector-logic, obviously.
 141
 142         note that it's *important* that all muxer options be covered
 143         (hence going up to 1<<cell_bitwidth) even if the muxer cells
 144         are blank (no entries), because muxer selection could be to
 145         the last one, and we do not want the "default" (last line)
 146         to be the output.
 147     """
 148     p.cell_bitwidth = get_cell_bit_width(p)
 149     p.pinmux = ' '
 150     global dedicated_wire
 151     for cell in p.muxed_cells:
 152
 153         # first do the outputs
 154         p.pinmux += mkmux(p, ifaces, cell, '_out', False)
 155         p.pinmux += "\n"
 156
 157         # now do the output enablers (outens)
 158         p.pinmux += mkmux(p, ifaces, cell, '_outen', True)
 159
 160         # ======================================================== #
 161
 162         # check each cell if "peripheral input/inout" then assign its wire
 163         # Here we check the direction of each signal in the dictionary.
 164         # We choose to keep the dictionary within the code and not user-input
 165         # since the interfaces are always standard and cannot change from
 166         # user-to-user. Plus this also reduces human-error as well :)
 167         p.pinmux += "\n"
 168         p.pinmux += "      // priority-in-muxer for cell idx %s\n" % (cell[0])
 169         for i in range(0, len(cell) - 1):
 170             cname = cell[i + 1]
 171             if not cname:  # skip blank entries, no need to test
 172                 continue
 173             temp = transfn(cname)
 174             x = ifaces.getifacetype(temp)
 175             #print (cname, temp, x)
 176             assert x is not None, "ERROR: The signal : " + \
 177                 str(cname) + \
 178                 " of pinmap.txt isn't present \nin the current" + \
 179                 " dictionary. Update dictionary or fix-typo."
 180             if x == "input":
 181                 p.pinmux += \
 182                     mux_wire.format(cell[0], i, "wr" + cname) + "\n"
 183             elif x == "inout":
 184                 p.pinmux += \
 185                     mux_wire.format(cell[0], i, "wr" + cname +
 186                                                 "_in") + "\n"
 187     # ============================================================ #
 188
 189     # ==================  Logic for dedicated pins ========= #
 190     p.pinmux += "\n      /*=========================================*/\n"
 191     p.pinmux += "      // dedicated cells\n\n"
 192     for cell in p.dedicated_cells:
 193         p.pinmux += "      // dedicated cell idx %s\n" % (cell[0])
 194         p.pinmux += "      %s_out=%s_io;\n" % (cn(cell[0]), cell[1])
 195         temp = transfn(cell[1])
 196         x = ifaces.getifacetype(temp)
 197         #print cell, temp, x
 198         if x == "input":
 199             p.pinmux += \
 200                 dedicated_wire.format(cell[0], "wr" + cell[1]) + "\n"
 201         elif x == "inout":
 202             p.pinmux += \
 203                 dedicated_wire.format(cell[0], "wr" + cell[1] + "_in") + "\n"
 204         else:
 205             p.pinmux += "\n"
 206     # =======================================================#