]> nv-tegra.nvidia Code Review - linux-2.6.git/blobdiff - sound/usb/usbaudio.c
[ALSA] usb-audio: actually schedule playback URBs at frame boundaries
[linux-2.6.git] / sound / usb / usbaudio.c
index 49075f06f84658c6a1415761bba29f2607f0c583..3f7930c0b6168e58f7bfa13e68d7f6c9ed43cfd4 100644 (file)
@@ -41,6 +41,7 @@
 #include <sound/driver.h>
 #include <linux/bitops.h>
 #include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/string.h>
@@ -129,8 +130,6 @@ struct snd_urb_ctx {
        snd_usb_substream_t *subs;
        int index;      /* index for urb array */
        int packets;    /* number of packets per urb */
-       int transfer;   /* transferred size */
-       char *buf;      /* buffer for capture */
 };
 
 struct snd_urb_ops {
@@ -165,12 +164,11 @@ struct snd_usb_substream {
        unsigned int curframesize;      /* current packet size in frames (for capture) */
        unsigned int fill_max: 1;       /* fill max packet size always */
        unsigned int fmt_type;          /* USB audio format type (1-3) */
+       unsigned int packs_per_ms;      /* packets per millisecond (for playback) */
 
        unsigned int running: 1;        /* running status */
 
-       unsigned int hwptr;                     /* free frame position in the buffer (only for playback) */
        unsigned int hwptr_done;                        /* processed frame position in the buffer */
-       unsigned int transfer_sched;            /* scheduled frames since last period (for playback) */
        unsigned int transfer_done;             /* processed frames since last period update */
        unsigned long active_mask;      /* bitmask of active urbs */
        unsigned long unlink_mask;      /* bitmask of unlinked urbs */
@@ -179,12 +177,12 @@ struct snd_usb_substream {
        snd_urb_ctx_t dataurb[MAX_URBS];        /* data urb table */
        snd_urb_ctx_t syncurb[SYNC_URBS];       /* sync urb table */
        char syncbuf[SYNC_URBS * 4];    /* sync buffer; it's so small - let's get static */
-       char *tmpbuf;                   /* temporary buffer for playback */
 
        u64 formats;                    /* format bitmasks (all or'ed) */
        unsigned int num_formats;               /* number of supported audio formats (list) */
        struct list_head fmt_list;      /* format list */
        spinlock_t lock;
+       struct tasklet_struct start_period_elapsed;     /* for start trigger */
 
        struct snd_urb_ops ops;         /* callbacks (must be filled at init) */
 };
@@ -311,27 +309,17 @@ static int prepare_capture_urb(snd_usb_substream_t *subs,
                               struct urb *urb)
 {
        int i, offs;
-       unsigned long flags;
        snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;
 
        offs = 0;
        urb->dev = ctx->subs->dev; /* we need to set this at each time */
-       urb->number_of_packets = 0;
-       spin_lock_irqsave(&subs->lock, flags);
        for (i = 0; i < ctx->packets; i++) {
                urb->iso_frame_desc[i].offset = offs;
                urb->iso_frame_desc[i].length = subs->curpacksize;
                offs += subs->curpacksize;
-               urb->number_of_packets++;
-               subs->transfer_sched += subs->curframesize;
-               if (subs->transfer_sched >= runtime->period_size) {
-                       subs->transfer_sched -= runtime->period_size;
-                       break;
-               }
        }
-       spin_unlock_irqrestore(&subs->lock, flags);
-       urb->transfer_buffer = ctx->buf;
        urb->transfer_buffer_length = offs;
+       urb->number_of_packets = ctx->packets;
 #if 0 // for check
        if (! urb->bandwidth) {
                int bustime;
@@ -359,6 +347,7 @@ static int retire_capture_urb(snd_usb_substream_t *subs,
        unsigned char *cp;
        int i;
        unsigned int stride, len, oldptr;
+       int period_elapsed = 0;
 
        stride = runtime->frame_bits >> 3;
 
@@ -378,6 +367,10 @@ static int retire_capture_urb(snd_usb_substream_t *subs,
                if (subs->hwptr_done >= runtime->buffer_size)
                        subs->hwptr_done -= runtime->buffer_size;
                subs->transfer_done += len;
+               if (subs->transfer_done >= runtime->period_size) {
+                       subs->transfer_done -= runtime->period_size;
+                       period_elapsed = 1;
+               }
                spin_unlock_irqrestore(&subs->lock, flags);
                /* copy a data chunk */
                if (oldptr + len > runtime->buffer_size) {
@@ -388,15 +381,9 @@ static int retire_capture_urb(snd_usb_substream_t *subs,
                } else {
                        memcpy(runtime->dma_area + oldptr * stride, cp, len * stride);
                }
-               /* update the pointer, call callback if necessary */
-               spin_lock_irqsave(&subs->lock, flags);
-               if (subs->transfer_done >= runtime->period_size) {
-                       subs->transfer_done -= runtime->period_size;
-                       spin_unlock_irqrestore(&subs->lock, flags);
-                       snd_pcm_period_elapsed(subs->pcm_substream);
-               } else
-                       spin_unlock_irqrestore(&subs->lock, flags);
        }
+       if (period_elapsed)
+               snd_pcm_period_elapsed(subs->pcm_substream);
        return 0;
 }
 
@@ -492,12 +479,10 @@ static int retire_playback_sync_urb_hs(snd_usb_substream_t *subs,
 /*
  * prepare urb for playback data pipe
  *
- * we copy the data directly from the pcm buffer.
- * the current position to be copied is held in hwptr field.
- * since a urb can handle only a single linear buffer, if the total
- * transferred area overflows the buffer boundary, we cannot send
- * it directly from the buffer.  thus the data is once copied to
- * a temporary buffer and urb points to that.
+ * Since a URB can handle only a single linear buffer, we must use double
+ * buffering when the data to be transferred overflows the buffer boundary.
+ * To avoid inconsistencies when updating hwptr_done, we use double buffering
+ * for all URBs.
  */
 static int prepare_playback_urb(snd_usb_substream_t *subs,
                                snd_pcm_runtime_t *runtime,
@@ -506,6 +491,7 @@ static int prepare_playback_urb(snd_usb_substream_t *subs,
        int i, stride, offs;
        unsigned int counts;
        unsigned long flags;
+       int period_elapsed = 0;
        snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;
 
        stride = runtime->frame_bits >> 3;
@@ -530,80 +516,85 @@ static int prepare_playback_urb(snd_usb_substream_t *subs,
                urb->iso_frame_desc[i].length = counts * stride;
                offs += counts;
                urb->number_of_packets++;
-               subs->transfer_sched += counts;
-               if (subs->transfer_sched >= runtime->period_size) {
-                       subs->transfer_sched -= runtime->period_size;
+               subs->transfer_done += counts;
+               if (subs->transfer_done >= runtime->period_size) {
+                       subs->transfer_done -= runtime->period_size;
+                       period_elapsed = 1;
                        if (subs->fmt_type == USB_FORMAT_TYPE_II) {
-                               if (subs->transfer_sched > 0) {
-                                       /* FIXME: fill-max mode is not supported yet */
-                                       offs -= subs->transfer_sched;
-                                       counts -= subs->transfer_sched;
-                                       urb->iso_frame_desc[i].length = counts * stride;
-                                       subs->transfer_sched = 0;
+                               if (subs->transfer_done > 0) {
+                                       /* FIXME: fill-max mode is not
+                                        * supported yet */
+                                       offs -= subs->transfer_done;
+                                       counts -= subs->transfer_done;
+                                       urb->iso_frame_desc[i].length =
+                                               counts * stride;
+                                       subs->transfer_done = 0;
                                }
                                i++;
                                if (i < ctx->packets) {
                                        /* add a transfer delimiter */
-                                       urb->iso_frame_desc[i].offset = offs * stride;
+                                       urb->iso_frame_desc[i].offset =
+                                               offs * stride;
                                        urb->iso_frame_desc[i].length = 0;
                                        urb->number_of_packets++;
                                }
+                               break;
                        }
-                       break;
                }
+               /* finish at the frame boundary at/after the period boundary */
+               if (period_elapsed &&
+                   (i & (subs->packs_per_ms - 1)) == subs->packs_per_ms - 1)
+                       break;
        }
-       if (subs->hwptr + offs > runtime->buffer_size) {
-               /* err, the transferred area goes over buffer boundary.
-                * copy the data to the temp buffer.
-                */
-               int len;
-               len = runtime->buffer_size - subs->hwptr;
-               urb->transfer_buffer = subs->tmpbuf;
-               memcpy(subs->tmpbuf, runtime->dma_area + subs->hwptr * stride, len * stride);
-               memcpy(subs->tmpbuf + len * stride, runtime->dma_area, (offs - len) * stride);
-               subs->hwptr += offs;
-               subs->hwptr -= runtime->buffer_size;
+       if (subs->hwptr_done + offs > runtime->buffer_size) {
+               /* err, the transferred area goes over buffer boundary. */
+               unsigned int len = runtime->buffer_size - subs->hwptr_done;
+               memcpy(urb->transfer_buffer,
+                      runtime->dma_area + subs->hwptr_done * stride,
+                      len * stride);
+               memcpy(urb->transfer_buffer + len * stride,
+                      runtime->dma_area,
+                      (offs - len) * stride);
        } else {
-               /* set the buffer pointer */
-               urb->transfer_buffer = runtime->dma_area + subs->hwptr * stride;
-               subs->hwptr += offs;
-               if (subs->hwptr == runtime->buffer_size)
-                       subs->hwptr = 0;
+               memcpy(urb->transfer_buffer,
+                      runtime->dma_area + subs->hwptr_done * stride,
+                      offs * stride);
        }
+       subs->hwptr_done += offs;
+       if (subs->hwptr_done >= runtime->buffer_size)
+               subs->hwptr_done -= runtime->buffer_size;
        spin_unlock_irqrestore(&subs->lock, flags);
        urb->transfer_buffer_length = offs * stride;
-       ctx->transfer = offs;
-
+       if (period_elapsed) {
+               if (likely(subs->running))
+                       snd_pcm_period_elapsed(subs->pcm_substream);
+               else
+                       tasklet_hi_schedule(&subs->start_period_elapsed);
+       }
        return 0;
 }
 
 /*
  * process after playback data complete
- *
- * update the current position and call callback if a period is processed.
+ * - nothing to do
  */
 static int retire_playback_urb(snd_usb_substream_t *subs,
                               snd_pcm_runtime_t *runtime,
                               struct urb *urb)
 {
-       unsigned long flags;
-       snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;
-
-       spin_lock_irqsave(&subs->lock, flags);
-       subs->transfer_done += ctx->transfer;
-       subs->hwptr_done += ctx->transfer;
-       ctx->transfer = 0;
-       if (subs->hwptr_done >= runtime->buffer_size)
-               subs->hwptr_done -= runtime->buffer_size;
-       if (subs->transfer_done >= runtime->period_size) {
-               subs->transfer_done -= runtime->period_size;
-               spin_unlock_irqrestore(&subs->lock, flags);
-               snd_pcm_period_elapsed(subs->pcm_substream);
-       } else
-               spin_unlock_irqrestore(&subs->lock, flags);
        return 0;
 }
 
+/*
+ * Delay the snd_pcm_period_elapsed() call until after the start trigger
+ * callback so that we're not longer in the substream's lock.
+ */
+static void start_period_elapsed(unsigned long data)
+{
+       snd_usb_substream_t *subs = (snd_usb_substream_t *)data;
+       snd_pcm_period_elapsed(subs->pcm_substream);
+}
+
 
 /*
  */
@@ -858,11 +849,10 @@ static int snd_usb_pcm_trigger(snd_pcm_substream_t *substream, int cmd)
 static void release_urb_ctx(snd_urb_ctx_t *u)
 {
        if (u->urb) {
+               kfree(u->urb->transfer_buffer);
                usb_free_urb(u->urb);
                u->urb = NULL;
        }
-       kfree(u->buf);
-       u->buf = NULL;
 }
 
 /*
@@ -880,8 +870,6 @@ static void release_substream_urbs(snd_usb_substream_t *subs, int force)
                release_urb_ctx(&subs->dataurb[i]);
        for (i = 0; i < SYNC_URBS; i++)
                release_urb_ctx(&subs->syncurb[i]);
-       kfree(subs->tmpbuf);
-       subs->tmpbuf = NULL;
        subs->nurbs = 0;
 }
 
@@ -893,7 +881,7 @@ static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_by
 {
        unsigned int maxsize, n, i;
        int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
-       unsigned int npacks[MAX_URBS], urb_packs, total_packs;
+       unsigned int npacks[MAX_URBS], urb_packs, total_packs, packs_per_ms;
 
        /* calculate the frequency in 16.16 format */
        if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
@@ -920,23 +908,19 @@ static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_by
        else
                subs->curpacksize = maxsize;
 
+       if (snd_usb_get_speed(subs->dev) == USB_SPEED_HIGH)
+               packs_per_ms = 8 >> subs->datainterval;
+       else
+               packs_per_ms = 1;
+       subs->packs_per_ms = packs_per_ms;
+
        if (is_playback) {
                urb_packs = nrpacks;
                urb_packs = max(urb_packs, (unsigned int)MIN_PACKS_URB);
                urb_packs = min(urb_packs, (unsigned int)MAX_PACKS);
        } else
                urb_packs = 1;
-       if (snd_usb_get_speed(subs->dev) == USB_SPEED_HIGH)
-               urb_packs = (urb_packs * 8) >> subs->datainterval;
-
-       /* allocate a temporary buffer for playback */
-       if (is_playback) {
-               subs->tmpbuf = kmalloc(maxsize * urb_packs, GFP_KERNEL);
-               if (! subs->tmpbuf) {
-                       snd_printk(KERN_ERR "cannot malloc tmpbuf\n");
-                       return -ENOMEM;
-               }
-       }
+       urb_packs *= packs_per_ms;
 
        /* decide how many packets to be used */
        if (is_playback) {
@@ -944,13 +928,17 @@ static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_by
                /* determine how small a packet can be */
                minsize = (subs->freqn >> (16 - subs->datainterval))
                          * (frame_bits >> 3);
-               /* with sync from device, assume it can be 25% lower */
+               /* with sync from device, assume it can be 12% lower */
                if (subs->syncpipe)
-                       minsize -= minsize >> 2;
+                       minsize -= minsize >> 3;
                minsize = max(minsize, 1u);
                total_packs = (period_bytes + minsize - 1) / minsize;
-               if (total_packs < 2 * MIN_PACKS_URB)
-                       total_packs = 2 * MIN_PACKS_URB;
+               /* round up to multiple of packs_per_ms */
+               total_packs = (total_packs + packs_per_ms - 1)
+                               & ~(packs_per_ms - 1);
+               /* we need at least two URBs for queueing */
+               if (total_packs < 2 * MIN_PACKS_URB * packs_per_ms)
+                       total_packs = 2 * MIN_PACKS_URB * packs_per_ms;
        } else {
                total_packs = MAX_URBS * urb_packs;
        }
@@ -972,7 +960,7 @@ static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_by
                subs->nurbs = 2;
                npacks[0] = (total_packs + 1) / 2;
                npacks[1] = total_packs - npacks[0];
-       } else if (npacks[subs->nurbs-1] < MIN_PACKS_URB) {
+       } else if (npacks[subs->nurbs-1] < MIN_PACKS_URB * packs_per_ms) {
                /* the last packet is too small.. */
                if (subs->nurbs > 2) {
                        /* merge to the first one */
@@ -991,27 +979,22 @@ static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_by
                snd_urb_ctx_t *u = &subs->dataurb[i];
                u->index = i;
                u->subs = subs;
-               u->transfer = 0;
                u->packets = npacks[i];
                if (subs->fmt_type == USB_FORMAT_TYPE_II)
                        u->packets++; /* for transfer delimiter */
-               if (! is_playback) {
-                       /* allocate a capture buffer per urb */
-                       u->buf = kmalloc(maxsize * u->packets, GFP_KERNEL);
-                       if (! u->buf) {
-                               release_substream_urbs(subs, 0);
-                               return -ENOMEM;
-                       }
-               }
                u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
                if (! u->urb) {
                        release_substream_urbs(subs, 0);
                        return -ENOMEM;
                }
-               u->urb->dev = subs->dev;
+               u->urb->transfer_buffer = kmalloc(maxsize * u->packets,
+                                                 GFP_KERNEL);
+               if (! u->urb->transfer_buffer) {
+                       release_substream_urbs(subs, 0);
+                       return -ENOMEM;
+               }
                u->urb->pipe = subs->datapipe;
                u->urb->transfer_flags = URB_ISO_ASAP;
-               u->urb->number_of_packets = u->packets;
                u->urb->interval = 1 << subs->datainterval;
                u->urb->context = u;
                u->urb->complete = snd_usb_complete_callback(snd_complete_urb);
@@ -1031,7 +1014,6 @@ static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_by
                        }
                        u->urb->transfer_buffer = subs->syncbuf + i * 4;
                        u->urb->transfer_buffer_length = 4;
-                       u->urb->dev = subs->dev;
                        u->urb->pipe = subs->syncpipe;
                        u->urb->transfer_flags = URB_ISO_ASAP;
                        u->urb->number_of_packets = 1;
@@ -1388,9 +1370,7 @@ static int snd_usb_pcm_prepare(snd_pcm_substream_t *substream)
        subs->curframesize = bytes_to_frames(runtime, subs->curpacksize);
 
        /* reset the pointer */
-       subs->hwptr = 0;
        subs->hwptr_done = 0;
-       subs->transfer_sched = 0;
        subs->transfer_done = 0;
        subs->phase = 0;
 
@@ -2037,6 +2017,9 @@ static void init_substream(snd_usb_stream_t *as, int stream, struct audioformat
 
        INIT_LIST_HEAD(&subs->fmt_list);
        spin_lock_init(&subs->lock);
+       if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+               tasklet_init(&subs->start_period_elapsed, start_period_elapsed,
+                            (unsigned long)subs);
 
        subs->stream = as;
        subs->direction = stream;