pcm-indirect2.c

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/*
 * 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 <[email protected]>
 *
 *  Based on "pcm-indirect.h" (alsa-driver-1.0.13) by
 *
 *  Copyright (c) by Takashi Iwai <[email protected]>
 *                   Jaroslav Kysela <[email protected]>
 *
 *   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 transferred 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 transferred 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);
    }
}