usb_stream.c

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/*
 * Copyright (C) 2007, 2008 Karsten Wiese <[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.
 */

#include <linux/usb.h>
#include <linux/gfp.h>

#include "usb_stream.h"


/*                             setup                                  */

static unsigned usb_stream_next_packet_size(struct usb_stream_kernel *sk)
{
    struct usb_stream *s = sk->s;
    sk->out_phase_peeked = (sk->out_phase & 0xffff) + sk->freqn;
    return (sk->out_phase_peeked >> 16) * s->cfg.frame_size;
}

static void playback_prep_freqn(struct usb_stream_kernel *sk, struct urb *urb)
{
    struct usb_stream *s = sk->s;
    int pack, lb = 0;

    for (pack = 0; pack < sk->n_o_ps; pack++) {
        int l = usb_stream_next_packet_size(sk);
        if (s->idle_outsize + lb + l > s->period_size)
            goto check;

        sk->out_phase = sk->out_phase_peeked;
        urb->iso_frame_desc[pack].offset = lb;
        urb->iso_frame_desc[pack].length = l;
        lb += l;
    }
    snd_printdd(KERN_DEBUG "%i\n", lb);

check:
    urb->number_of_packets = pack;
    urb->transfer_buffer_length = lb;
    s->idle_outsize += lb - s->period_size;
    snd_printdd(KERN_DEBUG "idle=%i ul=%i ps=%i\n", s->idle_outsize,
            lb, s->period_size);
}

static void init_pipe_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
               struct urb **urbs, char *transfer,
               struct usb_device *dev, int pipe)
{
    int u, p;
    int maxpacket = use_packsize ?
        use_packsize : usb_maxpacket(dev, pipe, usb_pipeout(pipe));
    int transfer_length = maxpacket * sk->n_o_ps;

    for (u = 0; u < USB_STREAM_NURBS;
         ++u, transfer += transfer_length) {
        struct urb *urb = urbs[u];
        struct usb_iso_packet_descriptor *desc;
        urb->transfer_flags = URB_ISO_ASAP;
        urb->transfer_buffer = transfer;
        urb->dev = dev;
        urb->pipe = pipe;
        urb->number_of_packets = sk->n_o_ps;
        urb->context = sk;
        urb->interval = 1;
        if (usb_pipeout(pipe))
            continue;

        urb->transfer_buffer_length = transfer_length;
        desc = urb->iso_frame_desc;
        desc->offset = 0;
        desc->length = maxpacket;
        for (p = 1; p < sk->n_o_ps; ++p) {
            desc[p].offset = desc[p - 1].offset + maxpacket;
            desc[p].length = maxpacket;
        }
    }
}

static void init_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
              struct usb_device *dev, int in_pipe, int out_pipe)
{
    struct usb_stream   *s = sk->s;
    char            *indata = (char *)s + sizeof(*s) +
                    sizeof(struct usb_stream_packet) *
                    s->inpackets;
    int         u;

    for (u = 0; u < USB_STREAM_NURBS; ++u) {
        sk->inurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
        sk->outurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
    }

    init_pipe_urbs(sk, use_packsize, sk->inurb, indata, dev, in_pipe);
    init_pipe_urbs(sk, use_packsize, sk->outurb, sk->write_page, dev,
               out_pipe);
}


/*
 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
 * this will overflow at approx 524 kHz
 */
static inline unsigned get_usb_full_speed_rate(unsigned rate)
{
    return ((rate << 13) + 62) / 125;
}

/*
 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
 * this will overflow at approx 4 MHz
 */
static inline unsigned get_usb_high_speed_rate(unsigned rate)
{
    return ((rate << 10) + 62) / 125;
}

void usb_stream_free(struct usb_stream_kernel *sk)
{
    struct usb_stream *s;
    unsigned u;

    for (u = 0; u < USB_STREAM_NURBS; ++u) {
        usb_free_urb(sk->inurb[u]);
        sk->inurb[u] = NULL;
        usb_free_urb(sk->outurb[u]);
        sk->outurb[u] = NULL;
    }

    s = sk->s;
    if (!s)
        return;

    free_pages((unsigned long)sk->write_page, get_order(s->write_size));
    sk->write_page = NULL;
    free_pages((unsigned long)s, get_order(s->read_size));
    sk->s = NULL;
}

struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
                  struct usb_device *dev,
                  unsigned in_endpoint, unsigned out_endpoint,
                  unsigned sample_rate, unsigned use_packsize,
                  unsigned period_frames, unsigned frame_size)
{
    int packets, max_packsize;
    int in_pipe, out_pipe;
    int read_size = sizeof(struct usb_stream);
    int write_size;
    int usb_frames = dev->speed == USB_SPEED_HIGH ? 8000 : 1000;
    int pg;

    in_pipe = usb_rcvisocpipe(dev, in_endpoint);
    out_pipe = usb_sndisocpipe(dev, out_endpoint);

    max_packsize = use_packsize ?
        use_packsize : usb_maxpacket(dev, in_pipe, 0);

    /*
        t_period = period_frames / sample_rate
        iso_packs = t_period / t_iso_frame
            = (period_frames / sample_rate) * (1 / t_iso_frame)
    */

    packets = period_frames * usb_frames / sample_rate + 1;

    if (dev->speed == USB_SPEED_HIGH)
        packets = (packets + 7) & ~7;

    read_size += packets * USB_STREAM_URBDEPTH *
        (max_packsize + sizeof(struct usb_stream_packet));

    max_packsize = usb_maxpacket(dev, out_pipe, 1);
    write_size = max_packsize * packets * USB_STREAM_URBDEPTH;

    if (read_size >= 256*PAGE_SIZE || write_size >= 256*PAGE_SIZE) {
        snd_printk(KERN_WARNING "a size exceeds 128*PAGE_SIZE\n");
        goto out;
    }

    pg = get_order(read_size);
    sk->s = (void *) __get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO, pg);
    if (!sk->s) {
        snd_printk(KERN_WARNING "couldn't __get_free_pages()\n");
        goto out;
    }
    sk->s->cfg.version = USB_STREAM_INTERFACE_VERSION;

    sk->s->read_size = read_size;

    sk->s->cfg.sample_rate = sample_rate;
    sk->s->cfg.frame_size = frame_size;
    sk->n_o_ps = packets;
    sk->s->inpackets = packets * USB_STREAM_URBDEPTH;
    sk->s->cfg.period_frames = period_frames;
    sk->s->period_size = frame_size * period_frames;

    sk->s->write_size = write_size;
    pg = get_order(write_size);

    sk->write_page =
        (void *)__get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO, pg);
    if (!sk->write_page) {
        snd_printk(KERN_WARNING "couldn't __get_free_pages()\n");
        usb_stream_free(sk);
        return NULL;
    }

    /* calculate the frequency in 16.16 format */
    if (dev->speed == USB_SPEED_FULL)
        sk->freqn = get_usb_full_speed_rate(sample_rate);
    else
        sk->freqn = get_usb_high_speed_rate(sample_rate);

    init_urbs(sk, use_packsize, dev, in_pipe, out_pipe);
    sk->s->state = usb_stream_stopped;
out:
    return sk->s;
}


/*                             start                                  */

static bool balance_check(struct usb_stream_kernel *sk, struct urb *urb)
{
    bool r;
    if (unlikely(urb->status)) {
        if (urb->status != -ESHUTDOWN && urb->status != -ENOENT)
            snd_printk(KERN_WARNING "status=%i\n", urb->status);
        sk->iso_frame_balance = 0x7FFFFFFF;
        return false;
    }
    r = sk->iso_frame_balance == 0;
    if (!r)
        sk->i_urb = urb;
    return r;
}

static bool balance_playback(struct usb_stream_kernel *sk, struct urb *urb)
{
    sk->iso_frame_balance += urb->number_of_packets;
    return balance_check(sk, urb);
}

static bool balance_capture(struct usb_stream_kernel *sk, struct urb *urb)
{
    sk->iso_frame_balance -= urb->number_of_packets;
    return balance_check(sk, urb);
}

static void subs_set_complete(struct urb **urbs, void (*complete)(struct urb *))
{
    int u;

    for (u = 0; u < USB_STREAM_NURBS; u++) {
        struct urb *urb = urbs[u];
        urb->complete = complete;
    }
}

static int usb_stream_prepare_playback(struct usb_stream_kernel *sk,
        struct urb *inurb)
{
    struct usb_stream *s = sk->s;
    struct urb *io;
    struct usb_iso_packet_descriptor *id, *od;
    int p = 0, lb = 0, l = 0;

    io = sk->idle_outurb;
    od = io->iso_frame_desc;

    for (; s->sync_packet < 0; ++p, ++s->sync_packet) {
        struct urb *ii = sk->completed_inurb;
        id = ii->iso_frame_desc +
            ii->number_of_packets + s->sync_packet;
        l = id->actual_length;

        od[p].length = l;
        od[p].offset = lb;
        lb += l;
    }

    for (;
         s->sync_packet < inurb->number_of_packets && p < sk->n_o_ps;
         ++p, ++s->sync_packet) {
        l = inurb->iso_frame_desc[s->sync_packet].actual_length;

        if (s->idle_outsize + lb + l > s->period_size)
            goto check_ok;

        od[p].length = l;
        od[p].offset = lb;
        lb += l;
    }

check_ok:
    s->sync_packet -= inurb->number_of_packets;
    if (unlikely(s->sync_packet < -2 || s->sync_packet > 0)) {
        snd_printk(KERN_WARNING "invalid sync_packet = %i;"
               " p=%i nop=%i %i %x %x %x > %x\n",
               s->sync_packet, p, inurb->number_of_packets,
               s->idle_outsize + lb + l,
               s->idle_outsize, lb,  l,
               s->period_size);
        return -1;
    }
    if (unlikely(lb % s->cfg.frame_size)) {
        snd_printk(KERN_WARNING"invalid outsize = %i\n",
               lb);
        return -1;
    }
    s->idle_outsize += lb - s->period_size;
    io->number_of_packets = p;
    io->transfer_buffer_length = lb;
    if (s->idle_outsize <= 0)
        return 0;

    snd_printk(KERN_WARNING "idle=%i\n", s->idle_outsize);
    return -1;
}

static void prepare_inurb(int number_of_packets, struct urb *iu)
{
    struct usb_iso_packet_descriptor *id;
    int p;

    iu->number_of_packets = number_of_packets;
    id = iu->iso_frame_desc;
    id->offset = 0;
    for (p = 0; p < iu->number_of_packets - 1; ++p)
        id[p + 1].offset = id[p].offset + id[p].length;

    iu->transfer_buffer_length =
        id[0].length * iu->number_of_packets;
}

static int submit_urbs(struct usb_stream_kernel *sk,
               struct urb *inurb, struct urb *outurb)
{
    int err;
    prepare_inurb(sk->idle_outurb->number_of_packets, sk->idle_inurb);
    err = usb_submit_urb(sk->idle_inurb, GFP_ATOMIC);
    if (err < 0) {
        snd_printk(KERN_ERR "%i\n", err);
        return err;
    }
    sk->idle_inurb = sk->completed_inurb;
    sk->completed_inurb = inurb;
    err = usb_submit_urb(sk->idle_outurb, GFP_ATOMIC);
    if (err < 0) {
        snd_printk(KERN_ERR "%i\n", err);
        return err;
    }
    sk->idle_outurb = sk->completed_outurb;
    sk->completed_outurb = outurb;
    return 0;
}

#ifdef DEBUG_LOOP_BACK
/*
  This loop_back() shows how to read/write the period data.
 */
static void loop_back(struct usb_stream *s)
{
    char *i, *o;
    int il, ol, l, p;
    struct urb *iu;
    struct usb_iso_packet_descriptor *id;

    o = s->playback1st_to;
    ol = s->playback1st_size;
    l = 0;

    if (s->insplit_pack >= 0) {
        iu = sk->idle_inurb;
        id = iu->iso_frame_desc;
        p = s->insplit_pack;
    } else
        goto second;
loop:
    for (; p < iu->number_of_packets && l < s->period_size; ++p) {
        i = iu->transfer_buffer + id[p].offset;
        il = id[p].actual_length;
        if (l + il > s->period_size)
            il = s->period_size - l;
        if (il <= ol) {
            memcpy(o, i, il);
            o += il;
            ol -= il;
        } else {
            memcpy(o, i, ol);
            singen_6pack(o, ol);
            o = s->playback_to;
            memcpy(o, i + ol, il - ol);
            o += il - ol;
            ol = s->period_size - s->playback1st_size;
        }
        l += il;
    }
    if (iu == sk->completed_inurb) {
        if (l != s->period_size)
            printk(KERN_DEBUG"%s:%i %i\n", __func__, __LINE__,
                   l/(int)s->cfg.frame_size);

        return;
    }
second:
    iu = sk->completed_inurb;
    id = iu->iso_frame_desc;
    p = 0;
    goto loop;

}
#else
static void loop_back(struct usb_stream *s)
{
}
#endif

static void stream_idle(struct usb_stream_kernel *sk,
            struct urb *inurb, struct urb *outurb)
{
    struct usb_stream *s = sk->s;
    int l, p;
    int insize = s->idle_insize;
    int urb_size = 0;

    s->inpacket_split = s->next_inpacket_split;
    s->inpacket_split_at = s->next_inpacket_split_at;
    s->next_inpacket_split = -1;
    s->next_inpacket_split_at = 0;

    for (p = 0; p < inurb->number_of_packets; ++p) {
        struct usb_iso_packet_descriptor *id = inurb->iso_frame_desc;
        l = id[p].actual_length;
        if (unlikely(l == 0 || id[p].status)) {
            snd_printk(KERN_WARNING "underrun, status=%u\n",
                   id[p].status);
            goto err_out;
        }
        s->inpacket_head++;
        s->inpacket_head %= s->inpackets;
        if (s->inpacket_split == -1)
            s->inpacket_split = s->inpacket_head;

        s->inpacket[s->inpacket_head].offset =
            id[p].offset + (inurb->transfer_buffer - (void *)s);
        s->inpacket[s->inpacket_head].length = l;
        if (insize + l > s->period_size &&
            s->next_inpacket_split == -1) {
            s->next_inpacket_split = s->inpacket_head;
            s->next_inpacket_split_at = s->period_size - insize;
        }
        insize += l;
        urb_size += l;
    }
    s->idle_insize += urb_size - s->period_size;
    if (s->idle_insize < 0) {
        snd_printk(KERN_WARNING "%i\n",
               (s->idle_insize)/(int)s->cfg.frame_size);
        goto err_out;
    }
    s->insize_done += urb_size;

    l = s->idle_outsize;
    s->outpacket[0].offset = (sk->idle_outurb->transfer_buffer -
                  sk->write_page) - l;

    if (usb_stream_prepare_playback(sk, inurb) < 0)
        goto err_out;

    s->outpacket[0].length = sk->idle_outurb->transfer_buffer_length + l;
    s->outpacket[1].offset = sk->completed_outurb->transfer_buffer -
        sk->write_page;

    if (submit_urbs(sk, inurb, outurb) < 0)
        goto err_out;

    loop_back(s);
    s->periods_done++;
    wake_up_all(&sk->sleep);
    return;
err_out:
    s->state = usb_stream_xrun;
    wake_up_all(&sk->sleep);
}

static void i_capture_idle(struct urb *urb)
{
    struct usb_stream_kernel *sk = urb->context;
    if (balance_capture(sk, urb))
        stream_idle(sk, urb, sk->i_urb);
}

static void i_playback_idle(struct urb *urb)
{
    struct usb_stream_kernel *sk = urb->context;
    if (balance_playback(sk, urb))
        stream_idle(sk, sk->i_urb, urb);
}

static void stream_start(struct usb_stream_kernel *sk,
             struct urb *inurb, struct urb *outurb)
{
    struct usb_stream *s = sk->s;
    if (s->state >= usb_stream_sync1) {
        int l, p, max_diff, max_diff_0;
        int urb_size = 0;
        unsigned frames_per_packet, min_frames = 0;
        frames_per_packet = (s->period_size - s->idle_insize);
        frames_per_packet <<= 8;
        frames_per_packet /=
            s->cfg.frame_size * inurb->number_of_packets;
        frames_per_packet++;

        max_diff_0 = s->cfg.frame_size;
        if (s->cfg.period_frames >= 256)
            max_diff_0 <<= 1;
        if (s->cfg.period_frames >= 1024)
            max_diff_0 <<= 1;
        max_diff = max_diff_0;
        for (p = 0; p < inurb->number_of_packets; ++p) {
            int diff;
            l = inurb->iso_frame_desc[p].actual_length;
            urb_size += l;

            min_frames += frames_per_packet;
            diff = urb_size -
                (min_frames >> 8) * s->cfg.frame_size;
            if (diff < max_diff) {
                snd_printdd(KERN_DEBUG "%i %i %i %i\n",
                        s->insize_done,
                        urb_size / (int)s->cfg.frame_size,
                        inurb->number_of_packets, diff);
                max_diff = diff;
            }
        }
        s->idle_insize -= max_diff - max_diff_0;
        s->idle_insize += urb_size - s->period_size;
        if (s->idle_insize < 0) {
            snd_printk(KERN_WARNING "%i %i %i\n",
                   s->idle_insize, urb_size, s->period_size);
            return;
        } else if (s->idle_insize == 0) {
            s->next_inpacket_split =
                (s->inpacket_head + 1) % s->inpackets;
            s->next_inpacket_split_at = 0;
        } else {
            unsigned split = s->inpacket_head;
            l = s->idle_insize;
            while (l > s->inpacket[split].length) {
                l -= s->inpacket[split].length;
                if (split == 0)
                    split = s->inpackets - 1;
                else
                    split--;
            }
            s->next_inpacket_split = split;
            s->next_inpacket_split_at =
                s->inpacket[split].length - l;
        }

        s->insize_done += urb_size;

        if (usb_stream_prepare_playback(sk, inurb) < 0)
            return;

    } else
        playback_prep_freqn(sk, sk->idle_outurb);

    if (submit_urbs(sk, inurb, outurb) < 0)
        return;

    if (s->state == usb_stream_sync1 && s->insize_done > 360000) {
        /* just guesswork                            ^^^^^^ */
        s->state = usb_stream_ready;
        subs_set_complete(sk->inurb, i_capture_idle);
        subs_set_complete(sk->outurb, i_playback_idle);
    }
}

static void i_capture_start(struct urb *urb)
{
    struct usb_iso_packet_descriptor *id = urb->iso_frame_desc;
    struct usb_stream_kernel *sk = urb->context;
    struct usb_stream *s = sk->s;
    int p;
    int empty = 0;

    if (urb->status) {
        snd_printk(KERN_WARNING "status=%i\n", urb->status);
        return;
    }

    for (p = 0; p < urb->number_of_packets; ++p) {
        int l = id[p].actual_length;
        if (l < s->cfg.frame_size) {
            ++empty;
            if (s->state >= usb_stream_sync0) {
                snd_printk(KERN_WARNING "%i\n", l);
                return;
            }
        }
        s->inpacket_head++;
        s->inpacket_head %= s->inpackets;
        s->inpacket[s->inpacket_head].offset =
            id[p].offset + (urb->transfer_buffer - (void *)s);
        s->inpacket[s->inpacket_head].length = l;
    }
#ifdef SHOW_EMPTY
    if (empty) {
        printk(KERN_DEBUG"%s:%i: %i", __func__, __LINE__,
               urb->iso_frame_desc[0].actual_length);
        for (pack = 1; pack < urb->number_of_packets; ++pack) {
            int l = urb->iso_frame_desc[pack].actual_length;
            printk(" %i", l);
        }
        printk("\n");
    }
#endif
    if (!empty && s->state < usb_stream_sync1)
        ++s->state;

    if (balance_capture(sk, urb))
        stream_start(sk, urb, sk->i_urb);
}

static void i_playback_start(struct urb *urb)
{
    struct usb_stream_kernel *sk = urb->context;
    if (balance_playback(sk, urb))
        stream_start(sk, sk->i_urb, urb);
}

int usb_stream_start(struct usb_stream_kernel *sk)
{
    struct usb_stream *s = sk->s;
    int frame = 0, iters = 0;
    int u, err;
    int try = 0;

    if (s->state != usb_stream_stopped)
        return -EAGAIN;

    subs_set_complete(sk->inurb, i_capture_start);
    subs_set_complete(sk->outurb, i_playback_start);
    memset(sk->write_page, 0, s->write_size);
dotry:
    s->insize_done = 0;
    s->idle_insize = 0;
    s->idle_outsize = 0;
    s->sync_packet = -1;
    s->inpacket_head = -1;
    sk->iso_frame_balance = 0;
    ++try;
    for (u = 0; u < 2; u++) {
        struct urb *inurb = sk->inurb[u];
        struct urb *outurb = sk->outurb[u];
        playback_prep_freqn(sk, outurb);
        inurb->number_of_packets = outurb->number_of_packets;
        inurb->transfer_buffer_length =
            inurb->number_of_packets *
            inurb->iso_frame_desc[0].length;

        if (u == 0) {
            int now;
            struct usb_device *dev = inurb->dev;
            frame = usb_get_current_frame_number(dev);
            do {
                now = usb_get_current_frame_number(dev);
                ++iters;
            } while (now > -1 && now == frame);
        }
        err = usb_submit_urb(inurb, GFP_ATOMIC);
        if (err < 0) {
            snd_printk(KERN_ERR"usb_submit_urb(sk->inurb[%i])"
                   " returned %i\n", u, err);
            return err;
        }
        err = usb_submit_urb(outurb, GFP_ATOMIC);
        if (err < 0) {
            snd_printk(KERN_ERR"usb_submit_urb(sk->outurb[%i])"
                   " returned %i\n", u, err);
            return err;
        }

        if (inurb->start_frame != outurb->start_frame) {
            snd_printd(KERN_DEBUG
                   "u[%i] start_frames differ in:%u out:%u\n",
                   u, inurb->start_frame, outurb->start_frame);
            goto check_retry;
        }
    }
    snd_printdd(KERN_DEBUG "%i %i\n", frame, iters);
    try = 0;
check_retry:
    if (try) {
        usb_stream_stop(sk);
        if (try < 5) {
            msleep(1500);
            snd_printd(KERN_DEBUG "goto dotry;\n");
            goto dotry;
        }
        snd_printk(KERN_WARNING"couldn't start"
               " all urbs on the same start_frame.\n");
        return -EFAULT;
    }

    sk->idle_inurb = sk->inurb[USB_STREAM_NURBS - 2];
    sk->idle_outurb = sk->outurb[USB_STREAM_NURBS - 2];
    sk->completed_inurb = sk->inurb[USB_STREAM_NURBS - 1];
    sk->completed_outurb = sk->outurb[USB_STREAM_NURBS - 1];

/* wait, check */
    {
        int wait_ms = 3000;
        while (s->state != usb_stream_ready && wait_ms > 0) {
            snd_printdd(KERN_DEBUG "%i\n", s->state);
            msleep(200);
            wait_ms -= 200;
        }
    }

    return s->state == usb_stream_ready ? 0 : -EFAULT;
}


/*                             stop                                   */

void usb_stream_stop(struct usb_stream_kernel *sk)
{
    int u;
    if (!sk->s)
        return;
    for (u = 0; u < USB_STREAM_NURBS; ++u) {
        usb_kill_urb(sk->inurb[u]);
        usb_kill_urb(sk->outurb[u]);
    }
    sk->s->state = usb_stream_stopped;
    msleep(400);
}