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pcm-indirect2.c

/*
 * Helper functions for indirect PCM data transfer to a simple FIFO in
 * hardware (small, no possibility to read "hardware io position",
 * updating position done by interrupt, ...)
 *
 *  Copyright (c) by 2007  Joachim Foerster <JOFT@gmx.de>
 *
 *  Based on "pcm-indirect.h" (alsa-driver-1.0.13) by
 *
 *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
 *                   Jaroslav Kysela <perex@suse.cz>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* snd_printk/d() */
#include <sound/core.h>
/* struct snd_pcm_substream, struct snd_pcm_runtime, snd_pcm_uframes_t
 * snd_pcm_period_elapsed() */
#include <sound/pcm.h>

#include "pcm-indirect2.h"

#ifdef SND_PCM_INDIRECT2_STAT
/* jiffies */
#include <linux/jiffies.h>

void snd_pcm_indirect2_stat(struct snd_pcm_substream *substream,
                      struct snd_pcm_indirect2 *rec)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      int i;
      int j;
      int k;
      int seconds = (rec->lastbytetime - rec->firstbytetime) / HZ;

      snd_printk(KERN_DEBUG "STAT: mul_elapsed: %u, mul_elapsed_real: %d, "
               "irq_occured: %d\n",
               rec->mul_elapsed, rec->mul_elapsed_real, rec->irq_occured);
      snd_printk(KERN_DEBUG "STAT: min_multiple: %d (irqs/period)\n",
               rec->min_multiple);
      snd_printk(KERN_DEBUG "STAT: firstbytetime: %lu, lastbytetime: %lu, "
               "firstzerotime: %lu\n",
             rec->firstbytetime, rec->lastbytetime, rec->firstzerotime);
      snd_printk(KERN_DEBUG "STAT: bytes2hw: %u Bytes => (by runtime->rate) "
               "length: %d s\n",
             rec->bytes2hw, rec->bytes2hw / 2 / 2 / runtime->rate);
      snd_printk(KERN_DEBUG "STAT: (by measurement) length: %d => "
               "rate: %d Bytes/s = %d Frames/s|Hz\n",
               seconds, rec->bytes2hw / seconds,
               rec->bytes2hw / 2 / 2 / seconds);
      snd_printk(KERN_DEBUG
               "STAT: zeros2hw: %u = %d ms ~ %d * %d zero copies\n",
               rec->zeros2hw, ((rec->zeros2hw / 2 / 2) * 1000) /
               runtime->rate,
               rec->zeros2hw / (rec->hw_buffer_size / 2),
               (rec->hw_buffer_size / 2));
      snd_printk(KERN_DEBUG "STAT: pointer_calls: %u, lastdifftime: %u\n",
               rec->pointer_calls, rec->lastdifftime);
      snd_printk(KERN_DEBUG "STAT: sw_io: %d, sw_data: %d\n", rec->sw_io,
               rec->sw_data);
      snd_printk(KERN_DEBUG "STAT: byte_sizes[]:\n");
      k = 0;
      for (j = 0; j < 8; j++) {
            for (i = j * 8; i < (j + 1) * 8; i++)
                  if (rec->byte_sizes[i] != 0) {
                        snd_printk(KERN_DEBUG "%u: %u",
                                 i, rec->byte_sizes[i]);
                        k++;
                  }
            if (((k % 8) == 0) && (k != 0)) {
                  snd_printk(KERN_DEBUG "\n");
                  k = 0;
            }
      }
      snd_printk(KERN_DEBUG "\n");
      snd_printk(KERN_DEBUG "STAT: zero_sizes[]:\n");
      for (j = 0; j < 8; j++) {
            k = 0;
            for (i = j * 8; i < (j + 1) * 8; i++)
                  if (rec->zero_sizes[i] != 0)
                        snd_printk(KERN_DEBUG "%u: %u",
                                 i, rec->zero_sizes[i]);
                  else
                        k++;
            if (!k)
                  snd_printk(KERN_DEBUG "\n");
      }
      snd_printk(KERN_DEBUG "\n");
      snd_printk(KERN_DEBUG "STAT: min_adds[]:\n");
      for (j = 0; j < 8; j++) {
            if (rec->min_adds[j] != 0)
                  snd_printk(KERN_DEBUG "%u: %u", j, rec->min_adds[j]);
      }
      snd_printk(KERN_DEBUG "\n");
      snd_printk(KERN_DEBUG "STAT: mul_adds[]:\n");
      for (j = 0; j < 8; j++) {
            if (rec->mul_adds[j] != 0)
                  snd_printk(KERN_DEBUG "%u: %u", j, rec->mul_adds[j]);
      }
      snd_printk(KERN_DEBUG "\n");
      snd_printk(KERN_DEBUG
               "STAT: zero_times_saved: %d, zero_times_notsaved: %d\n",
               rec->zero_times_saved, rec->zero_times_notsaved);
      /* snd_printk(KERN_DEBUG "STAT: zero_times[]\n");
      i = 0;
      for (j = 0; j < 3750; j++) {
            if (rec->zero_times[j] != 0) {
                  snd_printk(KERN_DEBUG "%u: %u", j, rec->zero_times[j]);
                  i++;
            }
            if (((i % 8) == 0) && (i != 0))
                  snd_printk(KERN_DEBUG "\n");
      }
      snd_printk(KERN_DEBUG "\n"); */
      return;
}
#endif

/*
 * _internal_ helper function for playback/capture transfer function
 */
static void
snd_pcm_indirect2_increase_min_periods(struct snd_pcm_substream *substream,
                               struct snd_pcm_indirect2 *rec,
                               int isplay, int iscopy,
                               unsigned int bytes)
{
      if (rec->min_periods >= 0) {
            if (iscopy) {
                  rec->sw_io += bytes;
                  if (rec->sw_io >= rec->sw_buffer_size)
                        rec->sw_io -= rec->sw_buffer_size;
            } else if (isplay) {
                  /* If application does not write data in multiples of
                   * a period, move sw_data to the next correctly aligned
                   * position, so that sw_io can converge to it (in the
                   * next step).
                   */
                  if (!rec->check_alignment) {
                        if (rec->bytes2hw %
                            snd_pcm_lib_period_bytes(substream)) {
                              unsigned bytes2hw_aligned =
                                  (1 +
                                   (rec->bytes2hw /
                                    snd_pcm_lib_period_bytes
                                    (substream))) *
                                  snd_pcm_lib_period_bytes
                                  (substream);
                              rec->sw_data =
                                  bytes2hw_aligned %
                                  rec->sw_buffer_size;
#ifdef SND_PCM_INDIRECT2_STAT
                              snd_printk(KERN_DEBUG
                                       "STAT: @re-align: aligned "
                                       "bytes2hw to next period "
                                       "size boundary: %d "
                                       "(instead of %d)\n",
                                       bytes2hw_aligned,
                                       rec->bytes2hw);
                              snd_printk(KERN_DEBUG
                                       "STAT: @re-align: sw_data "
                                       "moves to: %d\n",
                                       rec->sw_data);
#endif
                        }
                        rec->check_alignment = 1;
                  }
                  /* We are at the end and are copying zeros into the
                   * fifo.
                   * Now, we have to make sure that sw_io is increased
                   * until the position of sw_data: Filling the fifo with
                   * the first zeros means, the last bytes were played.
                   */
                  if (rec->sw_io != rec->sw_data) {
                        unsigned int diff;
                        if (rec->sw_data > rec->sw_io)
                              diff = rec->sw_data - rec->sw_io;
                        else
                              diff = (rec->sw_buffer_size -
                                    rec->sw_io) +
                                    rec->sw_data;
                        if (bytes >= diff)
                              rec->sw_io = rec->sw_data;
                        else {
                              rec->sw_io += bytes;
                              if (rec->sw_io >= rec->sw_buffer_size)
                                    rec->sw_io -=
                                        rec->sw_buffer_size;
                        }
                  }
            }
            rec->min_period_count += bytes;
            if (rec->min_period_count >= (rec->hw_buffer_size / 2)) {
                  rec->min_periods += (rec->min_period_count /
                                   (rec->hw_buffer_size / 2));
#ifdef SND_PCM_INDIRECT2_STAT
                  if ((rec->min_period_count /
                       (rec->hw_buffer_size / 2)) > 7)
                        snd_printk(KERN_DEBUG
                                 "STAT: more than 7 (%d) min_adds "
                                 "at once - too big to save!\n",
                                 (rec->min_period_count /
                                  (rec->hw_buffer_size / 2)));
                  else
                        rec->min_adds[(rec->min_period_count /
                                     (rec->hw_buffer_size / 2))]++;
#endif
                  rec->min_period_count = (rec->min_period_count %
                                     (rec->hw_buffer_size / 2));
            }
      } else if (isplay && iscopy)
            rec->min_periods = 0;
}

/*
 * helper function for playback/capture pointer callback
 */
snd_pcm_uframes_t
snd_pcm_indirect2_pointer(struct snd_pcm_substream *substream,
                    struct snd_pcm_indirect2 *rec)
{
#ifdef SND_PCM_INDIRECT2_STAT
      rec->pointer_calls++;
#endif
      return bytes_to_frames(substream->runtime, rec->sw_io);
}

/*
 * _internal_ helper function for playback interrupt callback
 */
static void
snd_pcm_indirect2_playback_transfer(struct snd_pcm_substream *substream,
                            struct snd_pcm_indirect2 *rec,
                            snd_pcm_indirect2_copy_t copy,
                            snd_pcm_indirect2_zero_t zero)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr;

      /* runtime->control->appl_ptr: position where ALSA will write next time
       * rec->appl_ptr: position where ALSA was last time
       * diff: obviously ALSA wrote that much bytes into the intermediate
       * buffer since we checked last time
       */
      snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr;

      if (diff) {
#ifdef SND_PCM_INDIRECT2_STAT
            rec->lastdifftime = jiffies;
#endif
            if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2))
                  diff += runtime->boundary;
            /* number of bytes "added" by ALSA increases the number of
             * bytes which are ready to "be transfered to HW"/"played"
             * Then, set rec->appl_ptr to not count bytes twice next time.
             */
            rec->sw_ready += (int)frames_to_bytes(runtime, diff);
            rec->appl_ptr = appl_ptr;
      }
      if (rec->hw_ready && (rec->sw_ready <= 0)) {
            unsigned int bytes;

#ifdef SND_PCM_INDIRECT2_STAT
            if (rec->firstzerotime == 0) {
                  rec->firstzerotime = jiffies;
                  snd_printk(KERN_DEBUG
                           "STAT: @firstzerotime: mul_elapsed: %d, "
                           "min_period_count: %d\n",
                           rec->mul_elapsed, rec->min_period_count);
                  snd_printk(KERN_DEBUG
                           "STAT: @firstzerotime: sw_io: %d, "
                           "sw_data: %d, appl_ptr: %u\n",
                           rec->sw_io, rec->sw_data,
                           (unsigned int)appl_ptr);
            }
            if ((jiffies - rec->firstzerotime) < 3750) {
                  rec->zero_times[(jiffies - rec->firstzerotime)]++;
                  rec->zero_times_saved++;
            } else
                  rec->zero_times_notsaved++;
#endif
            bytes = zero(substream, rec);

#ifdef SND_PCM_INDIRECT2_STAT
            rec->zeros2hw += bytes;
            if (bytes < 64)
                  rec->zero_sizes[bytes]++;
            else
                  snd_printk(KERN_DEBUG
                           "STAT: %d zero Bytes copied to hardware at "
                           "once - too big to save!\n",
                           bytes);
#endif
            snd_pcm_indirect2_increase_min_periods(substream, rec, 1, 0,
                                           bytes);
            return;
      }
      while (rec->hw_ready && (rec->sw_ready > 0)) {
            /* sw_to_end: max. number of bytes that can be read/take from
             * the current position (sw_data) in _one_ step
             */
            unsigned int sw_to_end = rec->sw_buffer_size - rec->sw_data;

            /* bytes: number of bytes we have available (for reading) */
            unsigned int bytes = rec->sw_ready;

            if (sw_to_end < bytes)
                  bytes = sw_to_end;
            if (!bytes)
                  break;

#ifdef SND_PCM_INDIRECT2_STAT
            if (rec->firstbytetime == 0)
                  rec->firstbytetime = jiffies;
            rec->lastbytetime = jiffies;
#endif
            /* copy bytes from intermediate buffer position sw_data to the
             * HW and return number of bytes actually written
             * Furthermore, set hw_ready to 0, if the fifo isn't empty
             * now => more could be transfered to fifo
             */
            bytes = copy(substream, rec, bytes);
            rec->bytes2hw += bytes;

#ifdef SND_PCM_INDIRECT2_STAT
            if (bytes < 64)
                  rec->byte_sizes[bytes]++;
            else
                  snd_printk(KERN_DEBUG
                           "STAT: %d Bytes copied to hardware at once "
                           "- too big to save!\n",
                           bytes);
#endif
            /* increase sw_data by the number of actually written bytes
             * (= number of taken bytes from intermediate buffer)
             */
            rec->sw_data += bytes;
            if (rec->sw_data == rec->sw_buffer_size)
                  rec->sw_data = 0;
            /* now sw_data is the position where ALSA is going to write
             * in the intermediate buffer next time = position we are going
             * to read from next time
             */

            snd_pcm_indirect2_increase_min_periods(substream, rec, 1, 1,
                                           bytes);

            /* we read bytes from intermediate buffer, so we need to say
             * that the number of bytes ready for transfer are decreased
             * now
             */
            rec->sw_ready -= bytes;
      }
      return;
}

/*
 * helper function for playback interrupt routine
 */
void
snd_pcm_indirect2_playback_interrupt(struct snd_pcm_substream *substream,
                             struct snd_pcm_indirect2 *rec,
                             snd_pcm_indirect2_copy_t copy,
                             snd_pcm_indirect2_zero_t zero)
{
#ifdef SND_PCM_INDIRECT2_STAT
      rec->irq_occured++;
#endif
      /* hardware played some bytes, so there is room again (in fifo) */
      rec->hw_ready = 1;

      /* don't call ack() now, instead call transfer() function directly
       * (normally called by ack() )
       */
      snd_pcm_indirect2_playback_transfer(substream, rec, copy, zero);

      if (rec->min_periods >= rec->min_multiple) {
#ifdef SND_PCM_INDIRECT2_STAT
            if ((rec->min_periods / rec->min_multiple) > 7)
                  snd_printk(KERN_DEBUG
                           "STAT: more than 7 (%d) mul_adds - too big "
                           "to save!\n",
                           (rec->min_periods / rec->min_multiple));
            else
                  rec->mul_adds[(rec->min_periods /
                               rec->min_multiple)]++;
            rec->mul_elapsed_real += (rec->min_periods /
                                rec->min_multiple);
            rec->mul_elapsed++;
#endif
            rec->min_periods = (rec->min_periods % rec->min_multiple);
            snd_pcm_period_elapsed(substream);
      }
}

/*
 * _internal_ helper function for capture interrupt callback
 */
static void
snd_pcm_indirect2_capture_transfer(struct snd_pcm_substream *substream,
                           struct snd_pcm_indirect2 *rec,
                           snd_pcm_indirect2_copy_t copy,
                           snd_pcm_indirect2_zero_t null)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr;
      snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr;

      if (diff) {
#ifdef SND_PCM_INDIRECT2_STAT
            rec->lastdifftime = jiffies;
#endif
            if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2))
                  diff += runtime->boundary;
            rec->sw_ready -= frames_to_bytes(runtime, diff);
            rec->appl_ptr = appl_ptr;
      }
      /* if hardware has something, but the intermediate buffer is full
       * => skip contents of buffer
       */
      if (rec->hw_ready && (rec->sw_ready >= (int)rec->sw_buffer_size)) {
            unsigned int bytes;

#ifdef SND_PCM_INDIRECT2_STAT
            if (rec->firstzerotime == 0) {
                  rec->firstzerotime = jiffies;
                  snd_printk(KERN_DEBUG "STAT: (capture) "
                           "@firstzerotime: mul_elapsed: %d, "
                           "min_period_count: %d\n",
                           rec->mul_elapsed, rec->min_period_count);
                  snd_printk(KERN_DEBUG "STAT: (capture) "
                           "@firstzerotime: sw_io: %d, sw_data: %d, "
                           "appl_ptr: %u\n",
                           rec->sw_io, rec->sw_data,
                           (unsigned int)appl_ptr);
            }
            if ((jiffies - rec->firstzerotime) < 3750) {
                  rec->zero_times[(jiffies - rec->firstzerotime)]++;
                  rec->zero_times_saved++;
            } else
                  rec->zero_times_notsaved++;
#endif
            bytes = null(substream, rec);

#ifdef SND_PCM_INDIRECT2_STAT
            rec->zeros2hw += bytes;
            if (bytes < 64)
                  rec->zero_sizes[bytes]++;
            else
                  snd_printk(KERN_DEBUG
                           "STAT: (capture) %d zero Bytes copied to "
                           "hardware at once - too big to save!\n",
                           bytes);
#endif
            snd_pcm_indirect2_increase_min_periods(substream, rec, 0, 0,
                                           bytes);
            /* report an overrun */
            rec->sw_io = SNDRV_PCM_POS_XRUN;
            return;
      }
      while (rec->hw_ready && (rec->sw_ready < (int)rec->sw_buffer_size)) {
            /* sw_to_end: max. number of bytes that we can write to the
             *  intermediate buffer (until it's end)
             */
            size_t sw_to_end = rec->sw_buffer_size - rec->sw_data;

            /* bytes: max. number of bytes, which may be copied to the
             *  intermediate buffer without overflow (in _one_ step)
             */
            size_t bytes = rec->sw_buffer_size - rec->sw_ready;

            /* limit number of bytes (for transfer) by available room in
             * the intermediate buffer
             */
            if (sw_to_end < bytes)
                  bytes = sw_to_end;
            if (!bytes)
                  break;

#ifdef SND_PCM_INDIRECT2_STAT
            if (rec->firstbytetime == 0)
                  rec->firstbytetime = jiffies;
            rec->lastbytetime = jiffies;
#endif
            /* copy bytes from the intermediate buffer (position sw_data)
             * to the HW at most and return number of bytes actually copied
             * from HW
             * Furthermore, set hw_ready to 0, if the fifo is empty now.
             */
            bytes = copy(substream, rec, bytes);
            rec->bytes2hw += bytes;

#ifdef SND_PCM_INDIRECT2_STAT
            if (bytes < 64)
                  rec->byte_sizes[bytes]++;
            else
                  snd_printk(KERN_DEBUG
                           "STAT: (capture) %d Bytes copied to "
                           "hardware at once - too big to save!\n",
                           bytes);
#endif
            /* increase sw_data by the number of actually copied bytes from
             * HW
             */
            rec->sw_data += bytes;
            if (rec->sw_data == rec->sw_buffer_size)
                  rec->sw_data = 0;

            snd_pcm_indirect2_increase_min_periods(substream, rec, 0, 1,
                                           bytes);

            /* number of bytes in the intermediate buffer, which haven't
             * been fetched by ALSA yet.
             */
            rec->sw_ready += bytes;
      }
      return;
}

/*
 * helper function for capture interrupt routine
 */
void
snd_pcm_indirect2_capture_interrupt(struct snd_pcm_substream *substream,
                            struct snd_pcm_indirect2 *rec,
                            snd_pcm_indirect2_copy_t copy,
                            snd_pcm_indirect2_zero_t null)
{
#ifdef SND_PCM_INDIRECT2_STAT
      rec->irq_occured++;
#endif
      /* hardware recorded some bytes, so there is something to read from the
       * record fifo:
       */
      rec->hw_ready = 1;

      /* don't call ack() now, instead call transfer() function directly
       * (normally called by ack() )
       */
      snd_pcm_indirect2_capture_transfer(substream, rec, copy, null);

      if (rec->min_periods >= rec->min_multiple) {

#ifdef SND_PCM_INDIRECT2_STAT
            if ((rec->min_periods / rec->min_multiple) > 7)
                  snd_printk(KERN_DEBUG
                           "STAT: more than 7 (%d) mul_adds - "
                           "too big to save!\n",
                           (rec->min_periods / rec->min_multiple));
            else
                  rec->mul_adds[(rec->min_periods /
                               rec->min_multiple)]++;
            rec->mul_elapsed_real += (rec->min_periods /
                                rec->min_multiple);
            rec->mul_elapsed++;
#endif
            rec->min_periods = (rec->min_periods % rec->min_multiple);
            snd_pcm_period_elapsed(substream);
      }
}

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