2 ## This file is part of the libsigrokdecode project.
4 ## Copyright (C) 2012-2013 Uwe Hermann <uwe@hermann-uwe.de>
6 ## This program is free software; you can redistribute it and/or modify
7 ## it under the terms of the GNU General Public License as published by
8 ## the Free Software Foundation; either version 2 of the License, or
9 ## (at your option) any later version.
11 ## This program is distributed in the hope that it will be useful,
12 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 ## GNU General Public License for more details.
16 ## You should have received a copy of the GNU General Public License
17 ## along with this program; if not, see <http://www.gnu.org/licenses/>.
20 import sigrokdecode as srd
24 # START field (indicates start or stop of a transaction)
26 0b0000: 'Start of cycle for a target',
28 0b0010: 'Grant for bus master 0',
29 0b0011: 'Grant for bus master 1',
39 0b1101: 'Start of cycle for a Firmware Memory Read cycle',
40 0b1110: 'Start of cycle for a Firmware Memory Write cycle',
41 0b1111: 'Stop/abort (end of a cycle for a target)',
43 # Cycle type / direction field
44 # Bit 0 (LAD[0]) is unused, should always be 0.
45 # Neither host nor peripheral are allowed to drive 0b11x0.
49 0b0100: 'Memory read',
50 0b0110: 'Memory write',
53 0b1100: 'Reserved / not allowed',
54 0b1110: 'Reserved / not allowed',
56 # SIZE field (determines how many bytes are to be transferred)
57 # Bits[3:2] are reserved, must be driven to 0b00.
58 # Neither host nor peripheral are allowed to drive 0b0010.
60 0b0000: '8 bits (1 byte)',
61 0b0001: '16 bits (2 bytes)',
62 0b0010: 'Reserved / not allowed',
63 0b0011: '32 bits (4 bytes)',
65 # CHANNEL field (bits[2:0] contain the DMA channel number)
76 # SYNC field (used to add wait states)
87 0b1001: 'Ready more (DMA only)',
97 class Decoder(srd.Decoder):
101 longname = 'Low-Pin-Count'
102 desc = 'Protocol for low-bandwidth devices on PC mainboards.'
107 {'id': 'lframe', 'name': 'LFRAME#', 'desc': 'Frame'},
108 {'id': 'lclk', 'name': 'LCLK', 'desc': 'Clock'},
109 {'id': 'lad0', 'name': 'LAD[0]', 'desc': 'Addr/control/data 0'},
110 {'id': 'lad1', 'name': 'LAD[1]', 'desc': 'Addr/control/data 1'},
111 {'id': 'lad2', 'name': 'LAD[2]', 'desc': 'Addr/control/data 2'},
112 {'id': 'lad3', 'name': 'LAD[3]', 'desc': 'Addr/control/data 3'},
114 optional_channels = (
115 {'id': 'lreset', 'name': 'LRESET#', 'desc': 'Reset'},
116 {'id': 'ldrq', 'name': 'LDRQ#', 'desc': 'Encoded DMA / bus master request'},
117 {'id': 'serirq', 'name': 'SERIRQ', 'desc': 'Serialized IRQ'},
118 {'id': 'clkrun', 'name': 'CLKRUN#', 'desc': 'Clock run'},
119 {'id': 'lpme', 'name': 'LPME#', 'desc': 'LPC power management event'},
120 {'id': 'lpcpd', 'name': 'LPCPD#', 'desc': 'Power down'},
121 {'id': 'lsmi', 'name': 'LSMI#', 'desc': 'System Management Interrupt'},
124 ('warnings', 'Warnings'),
126 ('cycle-type', 'Cycle-type/direction'),
128 ('tar1', 'Turn-around cycle 1'),
131 ('tar2', 'Turn-around cycle 2'),
134 ('data', 'Data', (1, 2, 3, 4, 5, 6, 7)),
135 ('warnings', 'Warnings', (0,)),
150 self.ss_block = self.es_block = None
153 self.out_ann = self.register(srd.OUTPUT_ANN)
155 def putb(self, data):
156 self.put(self.ss_block, self.es_block, self.out_ann, data)
158 def handle_get_start(self, lad, lad_bits, lframe):
159 # LAD[3:0]: START field (1 clock cycle).
161 # The last value of LAD[3:0] before LFRAME# gets de-asserted is what
162 # the peripherals must use. However, the host can keep LFRAME# asserted
163 # multiple clocks, and we output all START fields that occur, even
164 # though the peripherals are supposed to ignore all but the last one.
165 self.es_block = self.samplenum
166 self.putb([1, [fields['START'][lad], 'START', 'St', 'S']])
167 self.ss_block = self.samplenum
169 # Output a warning if LAD[3:0] changes while LFRAME# is low.
171 if (self.lad != -1 and self.lad != lad):
172 self.putb([0, ['LAD[3:0] changed while LFRAME# was asserted']])
174 # LFRAME# is asserted (low). Wait until it gets de-asserted again
175 # (the host is allowed to keep it asserted multiple clocks).
179 self.start_field = self.lad
180 self.state = 'GET CT/DR'
182 def handle_get_ct_dr(self, lad, lad_bits):
183 # LAD[3:0]: Cycle type / direction field (1 clock cycle).
185 self.cycle_type = fields['CT_DR'].get(lad, 'Reserved / unknown')
187 # TODO: Warning/error on invalid cycle types.
188 if 'Reserved' in self.cycle_type:
189 self.putb([0, ['Invalid cycle type (%s)' % lad_bits]])
191 self.es_block = self.samplenum
192 self.putb([2, ['Cycle type: %s' % self.cycle_type]])
193 self.ss_block = self.samplenum
195 self.state = 'GET ADDR'
199 def handle_get_addr(self, lad, lad_bits):
200 # LAD[3:0]: ADDR field (4/8/0 clock cycles).
202 # I/O cycles: 4 ADDR clocks. Memory cycles: 8 ADDR clocks.
203 # DMA cycles: no ADDR clocks at all.
204 if self.cycle_type in ('I/O read', 'I/O write'):
205 addr_nibbles = 4 # Address is 16bits.
206 elif self.cycle_type in ('Memory read', 'Memory write'):
207 addr_nibbles = 8 # Address is 32bits.
209 addr_nibbles = 0 # TODO: How to handle later on?
211 # Addresses are driven MSN-first.
212 offset = ((addr_nibbles - 1) - self.cur_nibble) * 4
213 self.addr |= (lad << offset)
215 # Continue if we haven't seen all ADDR cycles, yet.
216 if (self.cur_nibble < addr_nibbles - 1):
220 self.es_block = self.samplenum
221 s = 'Address: 0x%%0%dx' % addr_nibbles
222 self.putb([3, [s % self.addr]])
223 self.ss_block = self.samplenum
225 self.state = 'GET TAR'
228 def handle_get_tar(self, lad, lad_bits):
229 # LAD[3:0]: First TAR (turn-around) field (2 clock cycles).
231 self.es_block = self.samplenum
232 self.putb([4, ['TAR, cycle %d: %s' % (self.tarcount, lad_bits)]])
233 self.ss_block = self.samplenum
235 # On the first TAR clock cycle LAD[3:0] is driven to 1111 by
236 # either the host or peripheral. On the second clock cycle,
237 # the host or peripheral tri-states LAD[3:0], but its value
238 # should still be 1111, due to pull-ups on the LAD lines.
239 if lad_bits != '1111':
240 self.putb([0, ['TAR, cycle %d: %s (expected 1111)' % \
241 (self.tarcount, lad_bits)]])
243 if (self.tarcount != 1):
248 self.state = 'GET SYNC'
250 def handle_get_sync(self, lad, lad_bits):
251 # LAD[3:0]: SYNC field (1-n clock cycles).
253 self.sync_val = lad_bits
254 self.cycle_type = fields['SYNC'].get(lad, 'Reserved / unknown')
256 # TODO: Warnings if reserved value are seen?
257 if 'Reserved' in self.cycle_type:
258 self.putb([0, ['SYNC, cycle %d: %s (reserved value)' % \
259 (self.synccount, self.sync_val)]])
261 self.es_block = self.samplenum
262 self.putb([5, ['SYNC, cycle %d: %s' % (self.synccount, self.sync_val)]])
263 self.ss_block = self.samplenum
268 self.state = 'GET DATA'
270 def handle_get_data(self, lad, lad_bits):
271 # LAD[3:0]: DATA field (2 clock cycles).
273 # Data is driven LSN-first.
274 if (self.cycle_count == 0):
276 elif (self.cycle_count == 1):
277 self.databyte |= (lad << 4)
279 raise Exception('Invalid cycle_count: %d' % self.cycle_count)
281 if (self.cycle_count != 1):
282 self.cycle_count += 1
285 self.es_block = self.samplenum
286 self.putb([6, ['DATA: 0x%02x' % self.databyte]])
287 self.ss_block = self.samplenum
290 self.state = 'GET TAR2'
292 def handle_get_tar2(self, lad, lad_bits):
293 # LAD[3:0]: Second TAR field (2 clock cycles).
295 self.es_block = self.samplenum
296 self.putb([7, ['TAR, cycle %d: %s' % (self.tarcount, lad_bits)]])
297 self.ss_block = self.samplenum
299 # On the first TAR clock cycle LAD[3:0] is driven to 1111 by
300 # either the host or peripheral. On the second clock cycle,
301 # the host or peripheral tri-states LAD[3:0], but its value
302 # should still be 1111, due to pull-ups on the LAD lines.
303 if lad_bits != '1111':
304 self.putb([0, ['Warning: TAR, cycle %d: %s (expected 1111)'
305 % (self.tarcount, lad_bits)]])
307 if (self.tarcount != 1):
316 # TODO: Come up with more appropriate self.wait() conditions.
319 # If none of the pins changed, there's nothing to do.
320 if self.oldpins == pins:
323 # Store current pin values for the next round.
326 # Get individual pin values into local variables.
327 (lframe, lclk, lad0, lad1, lad2, lad3) = pins[:6]
328 (lreset, ldrq, serirq, clkrun, lpme, lpcpd, lsmi) = pins[6:]
330 # Only look at the signals upon rising LCLK edges. The LPC clock
331 # is the same as the PCI clock (which is sampled at rising edges).
332 if not (self.oldlclk == 0 and lclk == 1):
336 # Store LAD[3:0] bit values (one nibble) in local variables.
337 # Most (but not all) states need this.
338 if self.state != 'IDLE':
339 lad = (lad3 << 3) | (lad2 << 2) | (lad1 << 1) | lad0
340 lad_bits = bin(lad)[2:].zfill(4)
341 # self.putb([0, ['LAD: %s' % lad_bits]])
343 # TODO: Only memory read/write is currently supported/tested.
346 if self.state == 'IDLE':
347 # A valid LPC cycle starts with LFRAME# being asserted (low).
350 self.ss_block = self.samplenum
351 self.state = 'GET START'
353 elif self.state == 'GET START':
354 self.handle_get_start(lad, lad_bits, lframe)
355 elif self.state == 'GET CT/DR':
356 self.handle_get_ct_dr(lad, lad_bits)
357 elif self.state == 'GET ADDR':
358 self.handle_get_addr(lad, lad_bits)
359 elif self.state == 'GET TAR':
360 self.handle_get_tar(lad, lad_bits)
361 elif self.state == 'GET SYNC':
362 self.handle_get_sync(lad, lad_bits)
363 elif self.state == 'GET DATA':
364 self.handle_get_data(lad, lad_bits)
365 elif self.state == 'GET TAR2':
366 self.handle_get_tar2(lad, lad_bits)