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Takashi Iwai54704402005-06-03 11:27:00 +02001Software Interface ALSA-DSP MADI Driver
2
3(translated from German, so no good English ;-),
42004 - winfried ritsch
5
6
7
8 Full functionality has been added to the driver. Since some of
9 the Controls and startup-options are ALSA-Standard and only the
10 special Controls are described and discussed below.
11
12
13 hardware functionality:
14
15
16 Audio transmission:
17
18 number of channels -- depends on transmission mode
19
20 The number of channels chosen is from 1..Nmax. The reason to
21 use for a lower number of channels is only resource allocation,
22 since unused DMA channels are disabled and less memory is
23 allocated. So also the throughput of the PCI system can be
24 scaled. (Only important for low performance boards).
25
26 Single Speed -- 1..64 channels
27
28 (Note: Choosing the 56channel mode for transmission or as
29 receiver, only 56 are transmitted/received over the MADI, but
30 all 64 channels are available for the mixer, so channel count
31 for the driver)
32
33 Double Speed -- 1..32 channels
34
35 Note: Choosing the 56-channel mode for
36 transmission/receive-mode , only 28 are transmitted/received
37 over the MADI, but all 32 channels are available for the mixer,
38 so channel count for the driver
39
40
41 Quad Speed -- 1..16 channels
42
43 Note: Choosing the 56-channel mode for
44 transmission/receive-mode , only 14 are transmitted/received
45 over the MADI, but all 16 channels are available for the mixer,
46 so channel count for the driver
47
48 Format -- signed 32 Bit Little Endian (SNDRV_PCM_FMTBIT_S32_LE)
49
50 Sample Rates --
51
52 Single Speed -- 32000, 44100, 48000
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54 Double Speed -- 64000, 88200, 96000 (untested)
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56 Quad Speed -- 128000, 176400, 192000 (untested)
57
58 access-mode -- MMAP (memory mapped), Not interleaved
59 (PCM_NON-INTERLEAVED)
60
61 buffer-sizes -- 64,128,256,512,1024,2048,8192 Samples
62
63 fragments -- 2
64
65 Hardware-pointer -- 2 Modi
66
67
68 The Card supports the readout of the actual Buffer-pointer,
69 where DMA reads/writes. Since of the bulk mode of PCI it is only
70 64 Byte accurate. SO it is not really usable for the
71 ALSA-mid-level functions (here the buffer-ID gives a better
72 result), but if MMAP is used by the application. Therefore it
73 can be configured at load-time with the parameter
74 precise-pointer.
75
76
77 (Hint: Experimenting I found that the pointer is maximum 64 to
78 large never to small. So if you subtract 64 you always have a
79 safe pointer for writing, which is used on this mode inside
80 ALSA. In theory now you can get now a latency as low as 16
81 Samples, which is a quarter of the interrupt possibilities.)
82
83 Precise Pointer -- off
84 interrupt used for pointer-calculation
85
86 Precise Pointer -- on
87 hardware pointer used.
88
89 Controller:
90
91
92 Since DSP-MADI-Mixer has 8152 Fader, it does not make sense to
93 use the standard mixer-controls, since this would break most of
94 (especially graphic) ALSA-Mixer GUIs. So Mixer control has be
95 provided by a 2-dimensional controller using the
96 hwdep-interface.
97
98 Also all 128+256 Peak and RMS-Meter can be accessed via the
99 hwdep-interface. Since it could be a performance problem always
100 copying and converting Peak and RMS-Levels even if you just need
101 one, I decided to export the hardware structure, so that of
102 needed some driver-guru can implement a memory-mapping of mixer
103 or peak-meters over ioctl, or also to do only copying and no
104 conversion. A test-application shows the usage of the controller.
105
106 Latency Controls --- not implemented !!!
107
108
109 Note: Within the windows-driver the latency is accessible of a
110 control-panel, but buffer-sizes are controlled with ALSA from
111 hwparams-calls and should not be changed in run-state, I did not
112 implement it here.
113
114
115 System Clock -- suspended !!!!
116
117 Name -- "System Clock Mode"
118
119 Access -- Read Write
120
121 Values -- "Master" "Slave"
122
123
124 !!!! This is a hardware-function but is in conflict with the
125 Clock-source controller, which is a kind of ALSA-standard. I
126 makes sense to set the card to a special mode (master at some
127 frequency or slave), since even not using an Audio-application
128 a studio should have working synchronisations setup. So use
129 Clock-source-controller instead !!!!
130
131 Clock Source
132
133 Name -- "Sample Clock Source"
134
135 Access -- Read Write
136
137 Values -- "AutoSync", "Internal 32.0 kHz", "Internal 44.1 kHz",
138 "Internal 48.0 kHz", "Internal 64.0 kHz", "Internal 88.2 kHz",
139 "Internal 96.0 kHz"
140
141 Choose between Master at a specific Frequency and so also the
142 Speed-mode or Slave (Autosync). Also see "Preferred Sync Ref"
143
144
145 !!!! This is no pure hardware function but was implemented by
146 ALSA by some ALSA-drivers before, so I use it also. !!!
147
148
149 Preferred Sync Ref
150
151 Name -- "Preferred Sync Reference"
152
153 Access -- Read Write
154
155 Values -- "Word" "MADI"
156
157
158 Within the Auto-sync-Mode the preferred Sync Source can be
159 chosen. If it is not available another is used if possible.
160
161 Note: Since MADI has a much higher bit-rate than word-clock, the
162 card should synchronise better in MADI Mode. But since the
163 RME-PLL is very good, there are almost no problems with
164 word-clock too. I never found a difference.
165
166
167 TX 64 channel ---
168
169 Name -- "TX 64 channels mode"
170
171 Access -- Read Write
172
173 Values -- 0 1
174
175 Using 64-channel-modus (1) or 56-channel-modus for
176 MADI-transmission (0).
177
178
179 Note: This control is for output only. Input-mode is detected
180 automatically from hardware sending MADI.
181
182
183 Clear TMS ---
184
185 Name -- "Clear Track Marker"
186
187 Access -- Read Write
188
189 Values -- 0 1
190
191
192 Don't use to lower 5 Audio-bits on AES as additional Bits.
193
194
195 Safe Mode oder Auto Input ---
196
197 Name -- "Safe Mode"
198
199 Access -- Read Write
200
201 Values -- 0 1
202
203 (default on)
204
205 If on (1), then if either the optical or coaxial connection
206 has a failure, there is a takeover to the working one, with no
207 sample failure. Its only useful if you use the second as a
208 backup connection.
209
210 Input ---
211
212 Name -- "Input Select"
213
214 Access -- Read Write
215
216 Values -- optical coaxial
217
218
219 Choosing the Input, optical or coaxial. If Safe-mode is active,
220 this is the preferred Input.
221
222-------------- Mixer ----------------------
223
224 Mixer
225
226 Name -- "Mixer"
227
228 Access -- Read Write
229
230 Values - <channel-number 0-127> <Value 0-65535>
231
232
233 Here as a first value the channel-index is taken to get/set the
234 corresponding mixer channel, where 0-63 are the input to output
235 fader and 64-127 the playback to outputs fader. Value 0
236 is channel muted 0 and 32768 an amplification of 1.
237
238 Chn 1-64
239
240 fast mixer for the ALSA-mixer utils. The diagonal of the
241 mixer-matrix is implemented from playback to output.
242
243
244 Line Out
245
246 Name -- "Line Out"
247
248 Access -- Read Write
249
250 Values -- 0 1
251
252 Switching on and off the analog out, which has nothing to do
253 with mixing or routing. the analog outs reflects channel 63,64.
254
255
256--- information (only read access):
257
258 Sample Rate
259
260 Name -- "System Sample Rate"
261
262 Access -- Read-only
263
264 getting the sample rate.
265
266
267 External Rate measured
268
269 Name -- "External Rate"
270
271 Access -- Read only
272
273
274 Should be "Autosync Rate", but Name used is
275 ALSA-Scheme. External Sample frequency liked used on Autosync is
276 reported.
277
278
279 MADI Sync Status
280
281 Name -- "MADI Sync Lock Status"
282
283 Access -- Read
284
285 Values -- 0,1,2
286
287 MADI-Input is 0=Unlocked, 1=Locked, or 2=Synced.
288
289
290 Word Clock Sync Status
291
292 Name -- "Word Clock Lock Status"
293
294 Access -- Read
295
296 Values -- 0,1,2
297
298 Word Clock Input is 0=Unlocked, 1=Locked, or 2=Synced.
299
300 AutoSync
301
302 Name -- "AutoSync Reference"
303
304 Access -- Read
305
306 Values -- "WordClock", "MADI", "None"
307
308 Sync-Reference is either "WordClock", "MADI" or none.
309
310 RX 64ch --- noch nicht implementiert
311
312 MADI-Receiver is in 64 channel mode oder 56 channel mode.
313
314
315 AB_inp --- not tested
316
317 Used input for Auto-Input.
318
319
320 actual Buffer Position --- not implemented
321
322 !!! this is a ALSA internal function, so no control is used !!!
323
324
325
326Calling Parameter:
327
328 index int array (min = 1, max = 8),
329 "Index value for RME HDSPM interface." card-index within ALSA
330
331 note: ALSA-standard
332
333 id string array (min = 1, max = 8),
334 "ID string for RME HDSPM interface."
335
336 note: ALSA-standard
337
338 enable int array (min = 1, max = 8),
339 "Enable/disable specific HDSPM sound-cards."
340
341 note: ALSA-standard
342
343 precise_ptr int array (min = 1, max = 8),
344 "Enable precise pointer, or disable."
345
346 note: Use only when the application supports this (which is a special case).
347
348 line_outs_monitor int array (min = 1, max = 8),
349 "Send playback streams to analog outs by default."
350
351
352 note: each playback channel is mixed to the same numbered output
353 channel (routed). This is against the ALSA-convention, where all
354 channels have to be muted on after loading the driver, but was
355 used before on other cards, so i historically use it again)
356
357
358
359 enable_monitor int array (min = 1, max = 8),
360 "Enable Analog Out on Channel 63/64 by default."
361
362 note: here the analog output is enabled (but not routed).