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Linux/sound/firewire/amdtp-stream.c

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  1 /*
  2  * Audio and Music Data Transmission Protocol (IEC 61883-6) streams
  3  * with Common Isochronous Packet (IEC 61883-1) headers
  4  *
  5  * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
  6  * Licensed under the terms of the GNU General Public License, version 2.
  7  */
  8 
  9 #include <linux/device.h>
 10 #include <linux/err.h>
 11 #include <linux/firewire.h>
 12 #include <linux/module.h>
 13 #include <linux/slab.h>
 14 #include <sound/pcm.h>
 15 #include <sound/pcm_params.h>
 16 #include "amdtp-stream.h"
 17 
 18 #define TICKS_PER_CYCLE         3072
 19 #define CYCLES_PER_SECOND       8000
 20 #define TICKS_PER_SECOND        (TICKS_PER_CYCLE * CYCLES_PER_SECOND)
 21 
 22 /* Always support Linux tracing subsystem. */
 23 #define CREATE_TRACE_POINTS
 24 #include "amdtp-stream-trace.h"
 25 
 26 #define TRANSFER_DELAY_TICKS    0x2e00 /* 479.17 microseconds */
 27 
 28 /* isochronous header parameters */
 29 #define ISO_DATA_LENGTH_SHIFT   16
 30 #define TAG_NO_CIP_HEADER       0
 31 #define TAG_CIP                 1
 32 
 33 /* common isochronous packet header parameters */
 34 #define CIP_EOH_SHIFT           31
 35 #define CIP_EOH                 (1u << CIP_EOH_SHIFT)
 36 #define CIP_EOH_MASK            0x80000000
 37 #define CIP_SID_SHIFT           24
 38 #define CIP_SID_MASK            0x3f000000
 39 #define CIP_DBS_MASK            0x00ff0000
 40 #define CIP_DBS_SHIFT           16
 41 #define CIP_SPH_MASK            0x00000400
 42 #define CIP_SPH_SHIFT           10
 43 #define CIP_DBC_MASK            0x000000ff
 44 #define CIP_FMT_SHIFT           24
 45 #define CIP_FMT_MASK            0x3f000000
 46 #define CIP_FDF_MASK            0x00ff0000
 47 #define CIP_FDF_SHIFT           16
 48 #define CIP_SYT_MASK            0x0000ffff
 49 #define CIP_SYT_NO_INFO         0xffff
 50 
 51 /* Audio and Music transfer protocol specific parameters */
 52 #define CIP_FMT_AM              0x10
 53 #define AMDTP_FDF_NO_DATA       0xff
 54 
 55 /* TODO: make these configurable */
 56 #define INTERRUPT_INTERVAL      16
 57 #define QUEUE_LENGTH            48
 58 
 59 #define IN_PACKET_HEADER_SIZE   4
 60 #define OUT_PACKET_HEADER_SIZE  0
 61 
 62 static void pcm_period_tasklet(unsigned long data);
 63 
 64 /**
 65  * amdtp_stream_init - initialize an AMDTP stream structure
 66  * @s: the AMDTP stream to initialize
 67  * @unit: the target of the stream
 68  * @dir: the direction of stream
 69  * @flags: the packet transmission method to use
 70  * @fmt: the value of fmt field in CIP header
 71  * @process_data_blocks: callback handler to process data blocks
 72  * @protocol_size: the size to allocate newly for protocol
 73  */
 74 int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
 75                       enum amdtp_stream_direction dir, enum cip_flags flags,
 76                       unsigned int fmt,
 77                       amdtp_stream_process_data_blocks_t process_data_blocks,
 78                       unsigned int protocol_size)
 79 {
 80         if (process_data_blocks == NULL)
 81                 return -EINVAL;
 82 
 83         s->protocol = kzalloc(protocol_size, GFP_KERNEL);
 84         if (!s->protocol)
 85                 return -ENOMEM;
 86 
 87         s->unit = unit;
 88         s->direction = dir;
 89         s->flags = flags;
 90         s->context = ERR_PTR(-1);
 91         mutex_init(&s->mutex);
 92         tasklet_init(&s->period_tasklet, pcm_period_tasklet, (unsigned long)s);
 93         s->packet_index = 0;
 94 
 95         init_waitqueue_head(&s->callback_wait);
 96         s->callbacked = false;
 97 
 98         s->fmt = fmt;
 99         s->process_data_blocks = process_data_blocks;
100 
101         return 0;
102 }
103 EXPORT_SYMBOL(amdtp_stream_init);
104 
105 /**
106  * amdtp_stream_destroy - free stream resources
107  * @s: the AMDTP stream to destroy
108  */
109 void amdtp_stream_destroy(struct amdtp_stream *s)
110 {
111         /* Not initialized. */
112         if (s->protocol == NULL)
113                 return;
114 
115         WARN_ON(amdtp_stream_running(s));
116         kfree(s->protocol);
117         mutex_destroy(&s->mutex);
118 }
119 EXPORT_SYMBOL(amdtp_stream_destroy);
120 
121 const unsigned int amdtp_syt_intervals[CIP_SFC_COUNT] = {
122         [CIP_SFC_32000]  =  8,
123         [CIP_SFC_44100]  =  8,
124         [CIP_SFC_48000]  =  8,
125         [CIP_SFC_88200]  = 16,
126         [CIP_SFC_96000]  = 16,
127         [CIP_SFC_176400] = 32,
128         [CIP_SFC_192000] = 32,
129 };
130 EXPORT_SYMBOL(amdtp_syt_intervals);
131 
132 const unsigned int amdtp_rate_table[CIP_SFC_COUNT] = {
133         [CIP_SFC_32000]  =  32000,
134         [CIP_SFC_44100]  =  44100,
135         [CIP_SFC_48000]  =  48000,
136         [CIP_SFC_88200]  =  88200,
137         [CIP_SFC_96000]  =  96000,
138         [CIP_SFC_176400] = 176400,
139         [CIP_SFC_192000] = 192000,
140 };
141 EXPORT_SYMBOL(amdtp_rate_table);
142 
143 /**
144  * amdtp_stream_add_pcm_hw_constraints - add hw constraints for PCM substream
145  * @s:          the AMDTP stream, which must be initialized.
146  * @runtime:    the PCM substream runtime
147  */
148 int amdtp_stream_add_pcm_hw_constraints(struct amdtp_stream *s,
149                                         struct snd_pcm_runtime *runtime)
150 {
151         int err;
152 
153         /*
154          * Currently firewire-lib processes 16 packets in one software
155          * interrupt callback. This equals to 2msec but actually the
156          * interval of the interrupts has a jitter.
157          * Additionally, even if adding a constraint to fit period size to
158          * 2msec, actual calculated frames per period doesn't equal to 2msec,
159          * depending on sampling rate.
160          * Anyway, the interval to call snd_pcm_period_elapsed() cannot 2msec.
161          * Here let us use 5msec for safe period interrupt.
162          */
163         err = snd_pcm_hw_constraint_minmax(runtime,
164                                            SNDRV_PCM_HW_PARAM_PERIOD_TIME,
165                                            5000, UINT_MAX);
166         if (err < 0)
167                 goto end;
168 
169         /* Non-Blocking stream has no more constraints */
170         if (!(s->flags & CIP_BLOCKING))
171                 goto end;
172 
173         /*
174          * One AMDTP packet can include some frames. In blocking mode, the
175          * number equals to SYT_INTERVAL. So the number is 8, 16 or 32,
176          * depending on its sampling rate. For accurate period interrupt, it's
177          * preferrable to align period/buffer sizes to current SYT_INTERVAL.
178          *
179          * TODO: These constraints can be improved with proper rules.
180          * Currently apply LCM of SYT_INTERVALs.
181          */
182         err = snd_pcm_hw_constraint_step(runtime, 0,
183                                          SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 32);
184         if (err < 0)
185                 goto end;
186         err = snd_pcm_hw_constraint_step(runtime, 0,
187                                          SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 32);
188 end:
189         return err;
190 }
191 EXPORT_SYMBOL(amdtp_stream_add_pcm_hw_constraints);
192 
193 /**
194  * amdtp_stream_set_parameters - set stream parameters
195  * @s: the AMDTP stream to configure
196  * @rate: the sample rate
197  * @data_block_quadlets: the size of a data block in quadlet unit
198  *
199  * The parameters must be set before the stream is started, and must not be
200  * changed while the stream is running.
201  */
202 int amdtp_stream_set_parameters(struct amdtp_stream *s, unsigned int rate,
203                                 unsigned int data_block_quadlets)
204 {
205         unsigned int sfc;
206 
207         for (sfc = 0; sfc < ARRAY_SIZE(amdtp_rate_table); ++sfc) {
208                 if (amdtp_rate_table[sfc] == rate)
209                         break;
210         }
211         if (sfc == ARRAY_SIZE(amdtp_rate_table))
212                 return -EINVAL;
213 
214         s->sfc = sfc;
215         s->data_block_quadlets = data_block_quadlets;
216         s->syt_interval = amdtp_syt_intervals[sfc];
217 
218         /* default buffering in the device */
219         s->transfer_delay = TRANSFER_DELAY_TICKS - TICKS_PER_CYCLE;
220         if (s->flags & CIP_BLOCKING)
221                 /* additional buffering needed to adjust for no-data packets */
222                 s->transfer_delay += TICKS_PER_SECOND * s->syt_interval / rate;
223 
224         return 0;
225 }
226 EXPORT_SYMBOL(amdtp_stream_set_parameters);
227 
228 /**
229  * amdtp_stream_get_max_payload - get the stream's packet size
230  * @s: the AMDTP stream
231  *
232  * This function must not be called before the stream has been configured
233  * with amdtp_stream_set_parameters().
234  */
235 unsigned int amdtp_stream_get_max_payload(struct amdtp_stream *s)
236 {
237         unsigned int multiplier = 1;
238         unsigned int header_size = 0;
239 
240         if (s->flags & CIP_JUMBO_PAYLOAD)
241                 multiplier = 5;
242         if (!(s->flags & CIP_NO_HEADER))
243                 header_size = 8;
244 
245         return header_size +
246                 s->syt_interval * s->data_block_quadlets * 4 * multiplier;
247 }
248 EXPORT_SYMBOL(amdtp_stream_get_max_payload);
249 
250 /**
251  * amdtp_stream_pcm_prepare - prepare PCM device for running
252  * @s: the AMDTP stream
253  *
254  * This function should be called from the PCM device's .prepare callback.
255  */
256 void amdtp_stream_pcm_prepare(struct amdtp_stream *s)
257 {
258         tasklet_kill(&s->period_tasklet);
259         s->pcm_buffer_pointer = 0;
260         s->pcm_period_pointer = 0;
261 }
262 EXPORT_SYMBOL(amdtp_stream_pcm_prepare);
263 
264 static unsigned int calculate_data_blocks(struct amdtp_stream *s,
265                                           unsigned int syt)
266 {
267         unsigned int phase, data_blocks;
268 
269         /* Blocking mode. */
270         if (s->flags & CIP_BLOCKING) {
271                 /* This module generate empty packet for 'no data'. */
272                 if (syt == CIP_SYT_NO_INFO)
273                         data_blocks = 0;
274                 else
275                         data_blocks = s->syt_interval;
276         /* Non-blocking mode. */
277         } else {
278                 if (!cip_sfc_is_base_44100(s->sfc)) {
279                         /* Sample_rate / 8000 is an integer, and precomputed. */
280                         data_blocks = s->data_block_state;
281                 } else {
282                         phase = s->data_block_state;
283 
284                 /*
285                  * This calculates the number of data blocks per packet so that
286                  * 1) the overall rate is correct and exactly synchronized to
287                  *    the bus clock, and
288                  * 2) packets with a rounded-up number of blocks occur as early
289                  *    as possible in the sequence (to prevent underruns of the
290                  *    device's buffer).
291                  */
292                         if (s->sfc == CIP_SFC_44100)
293                                 /* 6 6 5 6 5 6 5 ... */
294                                 data_blocks = 5 + ((phase & 1) ^
295                                                    (phase == 0 || phase >= 40));
296                         else
297                                 /* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
298                                 data_blocks = 11 * (s->sfc >> 1) + (phase == 0);
299                         if (++phase >= (80 >> (s->sfc >> 1)))
300                                 phase = 0;
301                         s->data_block_state = phase;
302                 }
303         }
304 
305         return data_blocks;
306 }
307 
308 static unsigned int calculate_syt(struct amdtp_stream *s,
309                                   unsigned int cycle)
310 {
311         unsigned int syt_offset, phase, index, syt;
312 
313         if (s->last_syt_offset < TICKS_PER_CYCLE) {
314                 if (!cip_sfc_is_base_44100(s->sfc))
315                         syt_offset = s->last_syt_offset + s->syt_offset_state;
316                 else {
317                 /*
318                  * The time, in ticks, of the n'th SYT_INTERVAL sample is:
319                  *   n * SYT_INTERVAL * 24576000 / sample_rate
320                  * Modulo TICKS_PER_CYCLE, the difference between successive
321                  * elements is about 1386.23.  Rounding the results of this
322                  * formula to the SYT precision results in a sequence of
323                  * differences that begins with:
324                  *   1386 1386 1387 1386 1386 1386 1387 1386 1386 1386 1387 ...
325                  * This code generates _exactly_ the same sequence.
326                  */
327                         phase = s->syt_offset_state;
328                         index = phase % 13;
329                         syt_offset = s->last_syt_offset;
330                         syt_offset += 1386 + ((index && !(index & 3)) ||
331                                               phase == 146);
332                         if (++phase >= 147)
333                                 phase = 0;
334                         s->syt_offset_state = phase;
335                 }
336         } else
337                 syt_offset = s->last_syt_offset - TICKS_PER_CYCLE;
338         s->last_syt_offset = syt_offset;
339 
340         if (syt_offset < TICKS_PER_CYCLE) {
341                 syt_offset += s->transfer_delay;
342                 syt = (cycle + syt_offset / TICKS_PER_CYCLE) << 12;
343                 syt += syt_offset % TICKS_PER_CYCLE;
344 
345                 return syt & CIP_SYT_MASK;
346         } else {
347                 return CIP_SYT_NO_INFO;
348         }
349 }
350 
351 static void update_pcm_pointers(struct amdtp_stream *s,
352                                 struct snd_pcm_substream *pcm,
353                                 unsigned int frames)
354 {
355         unsigned int ptr;
356 
357         ptr = s->pcm_buffer_pointer + frames;
358         if (ptr >= pcm->runtime->buffer_size)
359                 ptr -= pcm->runtime->buffer_size;
360         ACCESS_ONCE(s->pcm_buffer_pointer) = ptr;
361 
362         s->pcm_period_pointer += frames;
363         if (s->pcm_period_pointer >= pcm->runtime->period_size) {
364                 s->pcm_period_pointer -= pcm->runtime->period_size;
365                 tasklet_hi_schedule(&s->period_tasklet);
366         }
367 }
368 
369 static void pcm_period_tasklet(unsigned long data)
370 {
371         struct amdtp_stream *s = (void *)data;
372         struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm);
373 
374         if (pcm)
375                 snd_pcm_period_elapsed(pcm);
376 }
377 
378 static int queue_packet(struct amdtp_stream *s, unsigned int header_length,
379                         unsigned int payload_length)
380 {
381         struct fw_iso_packet p = {0};
382         int err = 0;
383 
384         if (IS_ERR(s->context))
385                 goto end;
386 
387         p.interrupt = IS_ALIGNED(s->packet_index + 1, INTERRUPT_INTERVAL);
388         p.tag = s->tag;
389         p.header_length = header_length;
390         if (payload_length > 0)
391                 p.payload_length = payload_length;
392         else
393                 p.skip = true;
394         err = fw_iso_context_queue(s->context, &p, &s->buffer.iso_buffer,
395                                    s->buffer.packets[s->packet_index].offset);
396         if (err < 0) {
397                 dev_err(&s->unit->device, "queueing error: %d\n", err);
398                 goto end;
399         }
400 
401         if (++s->packet_index >= QUEUE_LENGTH)
402                 s->packet_index = 0;
403 end:
404         return err;
405 }
406 
407 static inline int queue_out_packet(struct amdtp_stream *s,
408                                    unsigned int payload_length)
409 {
410         return queue_packet(s, OUT_PACKET_HEADER_SIZE, payload_length);
411 }
412 
413 static inline int queue_in_packet(struct amdtp_stream *s)
414 {
415         return queue_packet(s, IN_PACKET_HEADER_SIZE, s->max_payload_length);
416 }
417 
418 static int handle_out_packet(struct amdtp_stream *s,
419                              unsigned int payload_length, unsigned int cycle,
420                              unsigned int index)
421 {
422         __be32 *buffer;
423         unsigned int syt;
424         unsigned int data_blocks;
425         unsigned int pcm_frames;
426         struct snd_pcm_substream *pcm;
427 
428         buffer = s->buffer.packets[s->packet_index].buffer;
429         syt = calculate_syt(s, cycle);
430         data_blocks = calculate_data_blocks(s, syt);
431         pcm_frames = s->process_data_blocks(s, buffer + 2, data_blocks, &syt);
432 
433         if (s->flags & CIP_DBC_IS_END_EVENT)
434                 s->data_block_counter =
435                                 (s->data_block_counter + data_blocks) & 0xff;
436 
437         buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |
438                                 (s->data_block_quadlets << CIP_DBS_SHIFT) |
439                                 ((s->sph << CIP_SPH_SHIFT) & CIP_SPH_MASK) |
440                                 s->data_block_counter);
441         buffer[1] = cpu_to_be32(CIP_EOH |
442                                 ((s->fmt << CIP_FMT_SHIFT) & CIP_FMT_MASK) |
443                                 ((s->fdf << CIP_FDF_SHIFT) & CIP_FDF_MASK) |
444                                 (syt & CIP_SYT_MASK));
445 
446         if (!(s->flags & CIP_DBC_IS_END_EVENT))
447                 s->data_block_counter =
448                                 (s->data_block_counter + data_blocks) & 0xff;
449         payload_length = 8 + data_blocks * 4 * s->data_block_quadlets;
450 
451         trace_out_packet(s, cycle, buffer, payload_length, index);
452 
453         if (queue_out_packet(s, payload_length) < 0)
454                 return -EIO;
455 
456         pcm = ACCESS_ONCE(s->pcm);
457         if (pcm && pcm_frames > 0)
458                 update_pcm_pointers(s, pcm, pcm_frames);
459 
460         /* No need to return the number of handled data blocks. */
461         return 0;
462 }
463 
464 static int handle_out_packet_without_header(struct amdtp_stream *s,
465                         unsigned int payload_length, unsigned int cycle,
466                         unsigned int index)
467 {
468         __be32 *buffer;
469         unsigned int syt;
470         unsigned int data_blocks;
471         unsigned int pcm_frames;
472         struct snd_pcm_substream *pcm;
473 
474         buffer = s->buffer.packets[s->packet_index].buffer;
475         syt = calculate_syt(s, cycle);
476         data_blocks = calculate_data_blocks(s, syt);
477         pcm_frames = s->process_data_blocks(s, buffer, data_blocks, &syt);
478         s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;
479 
480         payload_length = data_blocks * 4 * s->data_block_quadlets;
481 
482         trace_out_packet_without_header(s, cycle, payload_length, data_blocks,
483                                         index);
484 
485         if (queue_out_packet(s, payload_length) < 0)
486                 return -EIO;
487 
488         pcm = ACCESS_ONCE(s->pcm);
489         if (pcm && pcm_frames > 0)
490                 update_pcm_pointers(s, pcm, pcm_frames);
491 
492         /* No need to return the number of handled data blocks. */
493         return 0;
494 }
495 
496 static int handle_in_packet(struct amdtp_stream *s,
497                             unsigned int payload_length, unsigned int cycle,
498                             unsigned int index)
499 {
500         __be32 *buffer;
501         u32 cip_header[2];
502         unsigned int sph, fmt, fdf, syt;
503         unsigned int data_block_quadlets, data_block_counter, dbc_interval;
504         unsigned int data_blocks;
505         struct snd_pcm_substream *pcm;
506         unsigned int pcm_frames;
507         bool lost;
508 
509         buffer = s->buffer.packets[s->packet_index].buffer;
510         cip_header[0] = be32_to_cpu(buffer[0]);
511         cip_header[1] = be32_to_cpu(buffer[1]);
512 
513         trace_in_packet(s, cycle, cip_header, payload_length, index);
514 
515         /*
516          * This module supports 'Two-quadlet CIP header with SYT field'.
517          * For convenience, also check FMT field is AM824 or not.
518          */
519         if ((((cip_header[0] & CIP_EOH_MASK) == CIP_EOH) ||
520              ((cip_header[1] & CIP_EOH_MASK) != CIP_EOH)) &&
521             (!(s->flags & CIP_HEADER_WITHOUT_EOH))) {
522                 dev_info_ratelimited(&s->unit->device,
523                                 "Invalid CIP header for AMDTP: %08X:%08X\n",
524                                 cip_header[0], cip_header[1]);
525                 data_blocks = 0;
526                 pcm_frames = 0;
527                 goto end;
528         }
529 
530         /* Check valid protocol or not. */
531         sph = (cip_header[0] & CIP_SPH_MASK) >> CIP_SPH_SHIFT;
532         fmt = (cip_header[1] & CIP_FMT_MASK) >> CIP_FMT_SHIFT;
533         if (sph != s->sph || fmt != s->fmt) {
534                 dev_info_ratelimited(&s->unit->device,
535                                      "Detect unexpected protocol: %08x %08x\n",
536                                      cip_header[0], cip_header[1]);
537                 data_blocks = 0;
538                 pcm_frames = 0;
539                 goto end;
540         }
541 
542         /* Calculate data blocks */
543         fdf = (cip_header[1] & CIP_FDF_MASK) >> CIP_FDF_SHIFT;
544         if (payload_length < 12 ||
545             (fmt == CIP_FMT_AM && fdf == AMDTP_FDF_NO_DATA)) {
546                 data_blocks = 0;
547         } else {
548                 data_block_quadlets =
549                         (cip_header[0] & CIP_DBS_MASK) >> CIP_DBS_SHIFT;
550                 /* avoid division by zero */
551                 if (data_block_quadlets == 0) {
552                         dev_err(&s->unit->device,
553                                 "Detect invalid value in dbs field: %08X\n",
554                                 cip_header[0]);
555                         return -EPROTO;
556                 }
557                 if (s->flags & CIP_WRONG_DBS)
558                         data_block_quadlets = s->data_block_quadlets;
559 
560                 data_blocks = (payload_length / 4 - 2) /
561                                                         data_block_quadlets;
562         }
563 
564         /* Check data block counter continuity */
565         data_block_counter = cip_header[0] & CIP_DBC_MASK;
566         if (data_blocks == 0 && (s->flags & CIP_EMPTY_HAS_WRONG_DBC) &&
567             s->data_block_counter != UINT_MAX)
568                 data_block_counter = s->data_block_counter;
569 
570         if (((s->flags & CIP_SKIP_DBC_ZERO_CHECK) &&
571              data_block_counter == s->tx_first_dbc) ||
572             s->data_block_counter == UINT_MAX) {
573                 lost = false;
574         } else if (!(s->flags & CIP_DBC_IS_END_EVENT)) {
575                 lost = data_block_counter != s->data_block_counter;
576         } else {
577                 if (data_blocks > 0 && s->tx_dbc_interval > 0)
578                         dbc_interval = s->tx_dbc_interval;
579                 else
580                         dbc_interval = data_blocks;
581 
582                 lost = data_block_counter !=
583                        ((s->data_block_counter + dbc_interval) & 0xff);
584         }
585 
586         if (lost) {
587                 dev_err(&s->unit->device,
588                         "Detect discontinuity of CIP: %02X %02X\n",
589                         s->data_block_counter, data_block_counter);
590                 return -EIO;
591         }
592 
593         syt = be32_to_cpu(buffer[1]) & CIP_SYT_MASK;
594         pcm_frames = s->process_data_blocks(s, buffer + 2, data_blocks, &syt);
595 
596         if (s->flags & CIP_DBC_IS_END_EVENT)
597                 s->data_block_counter = data_block_counter;
598         else
599                 s->data_block_counter =
600                                 (data_block_counter + data_blocks) & 0xff;
601 end:
602         if (queue_in_packet(s) < 0)
603                 return -EIO;
604 
605         pcm = ACCESS_ONCE(s->pcm);
606         if (pcm && pcm_frames > 0)
607                 update_pcm_pointers(s, pcm, pcm_frames);
608 
609         return 0;
610 }
611 
612 static int handle_in_packet_without_header(struct amdtp_stream *s,
613                         unsigned int payload_quadlets, unsigned int cycle,
614                         unsigned int index)
615 {
616         __be32 *buffer;
617         unsigned int data_blocks;
618         struct snd_pcm_substream *pcm;
619         unsigned int pcm_frames;
620 
621         buffer = s->buffer.packets[s->packet_index].buffer;
622         data_blocks = payload_quadlets / s->data_block_quadlets;
623 
624         trace_in_packet_without_header(s, cycle, payload_quadlets, data_blocks,
625                                        index);
626 
627         pcm_frames = s->process_data_blocks(s, buffer, data_blocks, NULL);
628         s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;
629 
630         if (queue_in_packet(s) < 0)
631                 return -EIO;
632 
633         pcm = ACCESS_ONCE(s->pcm);
634         if (pcm && pcm_frames > 0)
635                 update_pcm_pointers(s, pcm, pcm_frames);
636 
637         return 0;
638 }
639 
640 /*
641  * In CYCLE_TIMER register of IEEE 1394, 7 bits are used to represent second. On
642  * the other hand, in DMA descriptors of 1394 OHCI, 3 bits are used to represent
643  * it. Thus, via Linux firewire subsystem, we can get the 3 bits for second.
644  */
645 static inline u32 compute_cycle_count(u32 tstamp)
646 {
647         return (((tstamp >> 13) & 0x07) * 8000) + (tstamp & 0x1fff);
648 }
649 
650 static inline u32 increment_cycle_count(u32 cycle, unsigned int addend)
651 {
652         cycle += addend;
653         if (cycle >= 8 * CYCLES_PER_SECOND)
654                 cycle -= 8 * CYCLES_PER_SECOND;
655         return cycle;
656 }
657 
658 static inline u32 decrement_cycle_count(u32 cycle, unsigned int subtrahend)
659 {
660         if (cycle < subtrahend)
661                 cycle += 8 * CYCLES_PER_SECOND;
662         return cycle - subtrahend;
663 }
664 
665 static void out_stream_callback(struct fw_iso_context *context, u32 tstamp,
666                                 size_t header_length, void *header,
667                                 void *private_data)
668 {
669         struct amdtp_stream *s = private_data;
670         unsigned int i, packets = header_length / 4;
671         u32 cycle;
672 
673         if (s->packet_index < 0)
674                 return;
675 
676         cycle = compute_cycle_count(tstamp);
677 
678         /* Align to actual cycle count for the last packet. */
679         cycle = increment_cycle_count(cycle, QUEUE_LENGTH - packets);
680 
681         for (i = 0; i < packets; ++i) {
682                 cycle = increment_cycle_count(cycle, 1);
683                 if (s->handle_packet(s, 0, cycle, i) < 0) {
684                         s->packet_index = -1;
685                         if (in_interrupt())
686                                 amdtp_stream_pcm_abort(s);
687                         WRITE_ONCE(s->pcm_buffer_pointer, SNDRV_PCM_POS_XRUN);
688                         return;
689                 }
690         }
691 
692         fw_iso_context_queue_flush(s->context);
693 }
694 
695 static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
696                                size_t header_length, void *header,
697                                void *private_data)
698 {
699         struct amdtp_stream *s = private_data;
700         unsigned int i, packets;
701         unsigned int payload_length, max_payload_length;
702         __be32 *headers = header;
703         u32 cycle;
704 
705         if (s->packet_index < 0)
706                 return;
707 
708         /* The number of packets in buffer */
709         packets = header_length / IN_PACKET_HEADER_SIZE;
710 
711         cycle = compute_cycle_count(tstamp);
712 
713         /* Align to actual cycle count for the last packet. */
714         cycle = decrement_cycle_count(cycle, packets);
715 
716         /* For buffer-over-run prevention. */
717         max_payload_length = s->max_payload_length;
718 
719         for (i = 0; i < packets; i++) {
720                 cycle = increment_cycle_count(cycle, 1);
721 
722                 /* The number of bytes in this packet */
723                 payload_length =
724                         (be32_to_cpu(headers[i]) >> ISO_DATA_LENGTH_SHIFT);
725                 if (payload_length > max_payload_length) {
726                         dev_err(&s->unit->device,
727                                 "Detect jumbo payload: %04x %04x\n",
728                                 payload_length, max_payload_length);
729                         break;
730                 }
731 
732                 if (s->handle_packet(s, payload_length, cycle, i) < 0)
733                         break;
734         }
735 
736         /* Queueing error or detecting invalid payload. */
737         if (i < packets) {
738                 s->packet_index = -1;
739                 if (in_interrupt())
740                         amdtp_stream_pcm_abort(s);
741                 WRITE_ONCE(s->pcm_buffer_pointer, SNDRV_PCM_POS_XRUN);
742                 return;
743         }
744 
745         fw_iso_context_queue_flush(s->context);
746 }
747 
748 /* this is executed one time */
749 static void amdtp_stream_first_callback(struct fw_iso_context *context,
750                                         u32 tstamp, size_t header_length,
751                                         void *header, void *private_data)
752 {
753         struct amdtp_stream *s = private_data;
754         u32 cycle;
755         unsigned int packets;
756 
757         s->max_payload_length = amdtp_stream_get_max_payload(s);
758 
759         /*
760          * For in-stream, first packet has come.
761          * For out-stream, prepared to transmit first packet
762          */
763         s->callbacked = true;
764         wake_up(&s->callback_wait);
765 
766         cycle = compute_cycle_count(tstamp);
767 
768         if (s->direction == AMDTP_IN_STREAM) {
769                 packets = header_length / IN_PACKET_HEADER_SIZE;
770                 cycle = decrement_cycle_count(cycle, packets);
771                 context->callback.sc = in_stream_callback;
772                 if (s->flags & CIP_NO_HEADER)
773                         s->handle_packet = handle_in_packet_without_header;
774                 else
775                         s->handle_packet = handle_in_packet;
776         } else {
777                 packets = header_length / 4;
778                 cycle = increment_cycle_count(cycle, QUEUE_LENGTH - packets);
779                 context->callback.sc = out_stream_callback;
780                 if (s->flags & CIP_NO_HEADER)
781                         s->handle_packet = handle_out_packet_without_header;
782                 else
783                         s->handle_packet = handle_out_packet;
784         }
785 
786         s->start_cycle = cycle;
787 
788         context->callback.sc(context, tstamp, header_length, header, s);
789 }
790 
791 /**
792  * amdtp_stream_start - start transferring packets
793  * @s: the AMDTP stream to start
794  * @channel: the isochronous channel on the bus
795  * @speed: firewire speed code
796  *
797  * The stream cannot be started until it has been configured with
798  * amdtp_stream_set_parameters() and it must be started before any PCM or MIDI
799  * device can be started.
800  */
801 int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
802 {
803         static const struct {
804                 unsigned int data_block;
805                 unsigned int syt_offset;
806         } initial_state[] = {
807                 [CIP_SFC_32000]  = {  4, 3072 },
808                 [CIP_SFC_48000]  = {  6, 1024 },
809                 [CIP_SFC_96000]  = { 12, 1024 },
810                 [CIP_SFC_192000] = { 24, 1024 },
811                 [CIP_SFC_44100]  = {  0,   67 },
812                 [CIP_SFC_88200]  = {  0,   67 },
813                 [CIP_SFC_176400] = {  0,   67 },
814         };
815         unsigned int header_size;
816         enum dma_data_direction dir;
817         int type, tag, err;
818 
819         mutex_lock(&s->mutex);
820 
821         if (WARN_ON(amdtp_stream_running(s) ||
822                     (s->data_block_quadlets < 1))) {
823                 err = -EBADFD;
824                 goto err_unlock;
825         }
826 
827         if (s->direction == AMDTP_IN_STREAM)
828                 s->data_block_counter = UINT_MAX;
829         else
830                 s->data_block_counter = 0;
831         s->data_block_state = initial_state[s->sfc].data_block;
832         s->syt_offset_state = initial_state[s->sfc].syt_offset;
833         s->last_syt_offset = TICKS_PER_CYCLE;
834 
835         /* initialize packet buffer */
836         if (s->direction == AMDTP_IN_STREAM) {
837                 dir = DMA_FROM_DEVICE;
838                 type = FW_ISO_CONTEXT_RECEIVE;
839                 header_size = IN_PACKET_HEADER_SIZE;
840         } else {
841                 dir = DMA_TO_DEVICE;
842                 type = FW_ISO_CONTEXT_TRANSMIT;
843                 header_size = OUT_PACKET_HEADER_SIZE;
844         }
845         err = iso_packets_buffer_init(&s->buffer, s->unit, QUEUE_LENGTH,
846                                       amdtp_stream_get_max_payload(s), dir);
847         if (err < 0)
848                 goto err_unlock;
849 
850         s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
851                                            type, channel, speed, header_size,
852                                            amdtp_stream_first_callback, s);
853         if (IS_ERR(s->context)) {
854                 err = PTR_ERR(s->context);
855                 if (err == -EBUSY)
856                         dev_err(&s->unit->device,
857                                 "no free stream on this controller\n");
858                 goto err_buffer;
859         }
860 
861         amdtp_stream_update(s);
862 
863         if (s->flags & CIP_NO_HEADER)
864                 s->tag = TAG_NO_CIP_HEADER;
865         else
866                 s->tag = TAG_CIP;
867 
868         s->packet_index = 0;
869         do {
870                 if (s->direction == AMDTP_IN_STREAM)
871                         err = queue_in_packet(s);
872                 else
873                         err = queue_out_packet(s, 0);
874                 if (err < 0)
875                         goto err_context;
876         } while (s->packet_index > 0);
877 
878         /* NOTE: TAG1 matches CIP. This just affects in stream. */
879         tag = FW_ISO_CONTEXT_MATCH_TAG1;
880         if ((s->flags & CIP_EMPTY_WITH_TAG0) || (s->flags & CIP_NO_HEADER))
881                 tag |= FW_ISO_CONTEXT_MATCH_TAG0;
882 
883         s->callbacked = false;
884         err = fw_iso_context_start(s->context, -1, 0, tag);
885         if (err < 0)
886                 goto err_context;
887 
888         mutex_unlock(&s->mutex);
889 
890         return 0;
891 
892 err_context:
893         fw_iso_context_destroy(s->context);
894         s->context = ERR_PTR(-1);
895 err_buffer:
896         iso_packets_buffer_destroy(&s->buffer, s->unit);
897 err_unlock:
898         mutex_unlock(&s->mutex);
899 
900         return err;
901 }
902 EXPORT_SYMBOL(amdtp_stream_start);
903 
904 /**
905  * amdtp_stream_pcm_pointer - get the PCM buffer position
906  * @s: the AMDTP stream that transports the PCM data
907  *
908  * Returns the current buffer position, in frames.
909  */
910 unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s)
911 {
912         /*
913          * This function is called in software IRQ context of period_tasklet or
914          * process context.
915          *
916          * When the software IRQ context was scheduled by software IRQ context
917          * of IR/IT contexts, queued packets were already handled. Therefore,
918          * no need to flush the queue in buffer anymore.
919          *
920          * When the process context reach here, some packets will be already
921          * queued in the buffer. These packets should be handled immediately
922          * to keep better granularity of PCM pointer.
923          *
924          * Later, the process context will sometimes schedules software IRQ
925          * context of the period_tasklet. Then, no need to flush the queue by
926          * the same reason as described for IR/IT contexts.
927          */
928         if (!in_interrupt() && amdtp_stream_running(s))
929                 fw_iso_context_flush_completions(s->context);
930 
931         return ACCESS_ONCE(s->pcm_buffer_pointer);
932 }
933 EXPORT_SYMBOL(amdtp_stream_pcm_pointer);
934 
935 /**
936  * amdtp_stream_update - update the stream after a bus reset
937  * @s: the AMDTP stream
938  */
939 void amdtp_stream_update(struct amdtp_stream *s)
940 {
941         /* Precomputing. */
942         ACCESS_ONCE(s->source_node_id_field) =
943                 (fw_parent_device(s->unit)->card->node_id << CIP_SID_SHIFT) &
944                                                                 CIP_SID_MASK;
945 }
946 EXPORT_SYMBOL(amdtp_stream_update);
947 
948 /**
949  * amdtp_stream_stop - stop sending packets
950  * @s: the AMDTP stream to stop
951  *
952  * All PCM and MIDI devices of the stream must be stopped before the stream
953  * itself can be stopped.
954  */
955 void amdtp_stream_stop(struct amdtp_stream *s)
956 {
957         mutex_lock(&s->mutex);
958 
959         if (!amdtp_stream_running(s)) {
960                 mutex_unlock(&s->mutex);
961                 return;
962         }
963 
964         tasklet_kill(&s->period_tasklet);
965         fw_iso_context_stop(s->context);
966         fw_iso_context_destroy(s->context);
967         s->context = ERR_PTR(-1);
968         iso_packets_buffer_destroy(&s->buffer, s->unit);
969 
970         s->callbacked = false;
971 
972         mutex_unlock(&s->mutex);
973 }
974 EXPORT_SYMBOL(amdtp_stream_stop);
975 
976 /**
977  * amdtp_stream_pcm_abort - abort the running PCM device
978  * @s: the AMDTP stream about to be stopped
979  *
980  * If the isochronous stream needs to be stopped asynchronously, call this
981  * function first to stop the PCM device.
982  */
983 void amdtp_stream_pcm_abort(struct amdtp_stream *s)
984 {
985         struct snd_pcm_substream *pcm;
986 
987         pcm = ACCESS_ONCE(s->pcm);
988         if (pcm)
989                 snd_pcm_stop_xrun(pcm);
990 }
991 EXPORT_SYMBOL(amdtp_stream_pcm_abort);
992 

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