usbaudio.c

linux 内核源代码

/*
 *   (Tentative) USB Audio Driver for ALSA
 *
 *   Main and PCM part
 *
 *   Copyright (c) 2002 by Takashi Iwai <[e-mail]>
 *
 *   Many codes borrowed from audio.c by
 *	    Alan Cox ([e-mail])
 *	    Thomas Sailer ([e-mail])
 *
 *
 *   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 *
 *  NOTES:
 *
 *   - async unlink should be used for avoiding the sleep inside lock.
 *     2.4.22 usb-uhci seems buggy for async unlinking and results in
 *     oops.  in such a cse, pass async_unlink=0 option.
 *   - the linked URBs would be preferred but not used so far because of
 *     the instability of unlinking.
 *   - type II is not supported properly.  there is no device which supports
 *     this type *correctly*.  SB extigy looks as if it supports, but it's
 *     indeed an AC3 stream packed in SPDIF frames (i.e. no real AC3 stream).
 */


#include <sound/driver.h>
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/usb.h>
#include <linux/vmalloc.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <sound/core.h>
#include <sound/info.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/initval.h>

#include "usbaudio.h"


MODULE_AUTHOR("Takashi Iwai <[e-mail]>");
MODULE_DESCRIPTION("USB Audio");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{Generic,USB Audio}}");


static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;	/* Enable this card */
static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 }; /* Vendor ID for this card */
static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 }; /* Product ID for this card */
static int nrpacks = 8;		/* max. number of packets per urb */
static int async_unlink = 1;
static int device_setup[SNDRV_CARDS]; /* device parameter for this card*/

module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
module_param_array(vid, int, NULL, 0444);
MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
module_param_array(pid, int, NULL, 0444);
MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
module_param(nrpacks, int, 0644);
MODULE_PARM_DESC(nrpacks, "Max. number of packets per URB.");
module_param(async_unlink, bool, 0444);
MODULE_PARM_DESC(async_unlink, "Use async unlink mode.");
module_param_array(device_setup, int, NULL, 0444);
MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");


/*
 * debug the h/w constraints
 */
/* #define HW_CONST_DEBUG */


/*
 *
 */

#define MAX_PACKS	20
#define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
#define MAX_URBS	8
#define SYNC_URBS	4	/* always four urbs for sync */
#define MIN_PACKS_URB	1	/* minimum 1 packet per urb */

struct audioformat {
	struct list_head list;
	snd_pcm_format_t format;	/* format type */
	unsigned int channels;		/* # channels */
	unsigned int fmt_type;		/* USB audio format type (1-3) */
	unsigned int frame_size;	/* samples per frame for non-audio */
	int iface;			/* interface number */
	unsigned char altsetting;	/* corresponding alternate setting */
	unsigned char altset_idx;	/* array index of altenate setting */
	unsigned char attributes;	/* corresponding attributes of cs endpoint */
	unsigned char endpoint;		/* endpoint */
	unsigned char ep_attr;		/* endpoint attributes */
	unsigned int maxpacksize;	/* max. packet size */
	unsigned int rates;		/* rate bitmasks */
	unsigned int rate_min, rate_max;	/* min/max rates */
	unsigned int nr_rates;		/* number of rate table entries */
	unsigned int *rate_table;	/* rate table */
};

struct snd_usb_substream;

struct snd_urb_ctx {
	struct urb *urb;
	unsigned int buffer_size;	/* size of data buffer, if data URB */
	struct snd_usb_substream *subs;
	int index;	/* index for urb array */
	int packets;	/* number of packets per urb */
};

struct snd_urb_ops {
	int (*prepare)(struct snd_usb_substream *subs, struct snd_pcm_runtime *runtime, struct urb *u);
	int (*retire)(struct snd_usb_substream *subs, struct snd_pcm_runtime *runtime, struct urb *u);
	int (*prepare_sync)(struct snd_usb_substream *subs, struct snd_pcm_runtime *runtime, struct urb *u);
	int (*retire_sync)(struct snd_usb_substream *subs, struct snd_pcm_runtime *runtime, struct urb *u);
};

struct snd_usb_substream {
	struct snd_usb_stream *stream;
	struct usb_device *dev;
	struct snd_pcm_substream *pcm_substream;
	int direction;	/* playback or capture */
	int interface;	/* current interface */
	int endpoint;	/* assigned endpoint */
	struct audioformat *cur_audiofmt;	/* current audioformat pointer (for hw_params callback) */
	unsigned int cur_rate;		/* current rate (for hw_params callback) */
	unsigned int period_bytes;	/* current period bytes (for hw_params callback) */
	unsigned int format;     /* USB data format */
	unsigned int datapipe;   /* the data i/o pipe */
	unsigned int syncpipe;   /* 1 - async out or adaptive in */
	unsigned int datainterval;	/* log_2 of data packet interval */
	unsigned int syncinterval;  /* P for adaptive mode, 0 otherwise */
	unsigned int freqn;      /* nominal sampling rate in fs/fps in Q16.16 format */
	unsigned int freqm;      /* momentary sampling rate in fs/fps in Q16.16 format */
	unsigned int freqmax;    /* maximum sampling rate, used for buffer management */
	unsigned int phase;      /* phase accumulator */
	unsigned int maxpacksize;	/* max packet size in bytes */
	unsigned int maxframesize;	/* max packet size in frames */
	unsigned int curpacksize;	/* current packet size in bytes (for capture) */
	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_done;			/* processed frame position in the buffer */
	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 */

	unsigned int nurbs;			/* # urbs */
	struct snd_urb_ctx dataurb[MAX_URBS];	/* data urb table */
	struct snd_urb_ctx syncurb[SYNC_URBS];	/* sync urb table */
	char *syncbuf;				/* sync buffer for all sync URBs */
	dma_addr_t sync_dma;			/* DMA address of syncbuf */

	u64 formats;			/* format bitmasks (all or'ed) */
	unsigned int num_formats;		/* number of supported audio formats (list) */
	struct list_head fmt_list;	/* format list */
	struct snd_pcm_hw_constraint_list rate_list;	/* limited rates */
	spinlock_t lock;

	struct snd_urb_ops ops;		/* callbacks (must be filled at init) */
};


struct snd_usb_stream {
	struct snd_usb_audio *chip;
	struct snd_pcm *pcm;
	int pcm_index;
	unsigned int fmt_type;		/* USB audio format type (1-3) */
	struct snd_usb_substream substream[2];
	struct list_head list;
};


/*
 * we keep the snd_usb_audio_t instances by ourselves for merging
 * the all interfaces on the same card as one sound device.
 */

static DEFINE_MUTEX(register_mutex);
static struct snd_usb_audio *usb_chip[SNDRV_CARDS];


/*
 * 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 int 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 int rate)
{
	return ((rate << 10) + 62) / 125;
}

/* convert our full speed USB rate into sampling rate in Hz */
static inline unsigned get_full_speed_hz(unsigned int usb_rate)
{
	return (usb_rate * 125 + (1 << 12)) >> 13;
}

/* convert our high speed USB rate into sampling rate in Hz */
static inline unsigned get_high_speed_hz(unsigned int usb_rate)
{
	return (usb_rate * 125 + (1 << 9)) >> 10;
}


/*
 * prepare urb for full speed capture sync pipe
 *
 * fill the length and offset of each urb descriptor.
 * the fixed 10.14 frequency is passed through the pipe.
 */
static int prepare_capture_sync_urb(struct snd_usb_substream *subs,
				    struct snd_pcm_runtime *runtime,
				    struct urb *urb)
{
	unsigned char *cp = urb->transfer_buffer;
	struct snd_urb_ctx *ctx = urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = 3;
	urb->iso_frame_desc[0].offset = 0;
	cp[0] = subs->freqn >> 2;
	cp[1] = subs->freqn >> 10;
	cp[2] = subs->freqn >> 18;
	return 0;
}

/*
 * prepare urb for high speed capture sync pipe
 *
 * fill the length and offset of each urb descriptor.
 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
 */
static int prepare_capture_sync_urb_hs(struct snd_usb_substream *subs,
				       struct snd_pcm_runtime *runtime,
				       struct urb *urb)
{
	unsigned char *cp = urb->transfer_buffer;
	struct snd_urb_ctx *ctx = urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = 4;
	urb->iso_frame_desc[0].offset = 0;
	cp[0] = subs->freqn;
	cp[1] = subs->freqn >> 8;
	cp[2] = subs->freqn >> 16;
	cp[3] = subs->freqn >> 24;
	return 0;
}

/*
 * process after capture sync complete
 * - nothing to do
 */
static int retire_capture_sync_urb(struct snd_usb_substream *subs,
				   struct snd_pcm_runtime *runtime,
				   struct urb *urb)
{
	return 0;
}

/*
 * prepare urb for capture data pipe
 *
 * fill the offset and length of each descriptor.
 *
 * we use a temporary buffer to write the captured data.
 * since the length of written data is determined by host, we cannot
 * write onto the pcm buffer directly...  the data is thus copied
 * later at complete callback to the global buffer.
 */
static int prepare_capture_urb(struct snd_usb_substream *subs,
			       struct snd_pcm_runtime *runtime,
			       struct urb *urb)
{
	int i, offs;
	struct snd_urb_ctx *ctx = urb->context;

	offs = 0;
	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	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->transfer_buffer_length = offs;
	urb->number_of_packets = ctx->packets;
	return 0;
}

/*
 * process after capture complete
 *
 * copy the data from each desctiptor to the pcm buffer, and
 * update the current position.
 */
static int retire_capture_urb(struct snd_usb_substream *subs,
			      struct snd_pcm_runtime *runtime,
			      struct urb *urb)
{
	unsigned long flags;
	unsigned char *cp;
	int i;
	unsigned int stride, len, oldptr;
	int period_elapsed = 0;

	stride = runtime->frame_bits >> 3;

	for (i = 0; i < urb->number_of_packets; i++) {
		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
		if (urb->iso_frame_desc[i].status) {
			snd_printd(KERN_ERR "frame %d active: %d\n", i, urb->iso_frame_desc[i].status);
			// continue;
		}
		len = urb->iso_frame_desc[i].actual_length / stride;
		if (! len)
			continue;
		/* update the current pointer */
		spin_lock_irqsave(&subs->lock, flags);
		oldptr = subs->hwptr_done;
		subs->hwptr_done += len;
		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) {
			unsigned int cnt = runtime->buffer_size - oldptr;
			unsigned int blen = cnt * stride;
			memcpy(runtime->dma_area + oldptr * stride, cp, blen);
			memcpy(runtime->dma_area, cp + blen, len * stride - blen);
		} else {
			memcpy(runtime->dma_area + oldptr * stride, cp, len * stride);
		}
	}
	if (period_elapsed)
		snd_pcm_period_elapsed(subs->pcm_substream);
	return 0;
}

/*
 * Process after capture complete when paused.  Nothing to do.
 */
static int retire_paused_capture_urb(struct snd_usb_substream *subs,
				     struct snd_pcm_runtime *runtime,
				     struct urb *urb)
{
	return 0;
}


/*
 * prepare urb for full speed playback sync pipe
 *
 * set up the offset and length to receive the current frequency.
 */

static int prepare_playback_sync_urb(struct snd_usb_substream *subs,
				     struct snd_pcm_runtime *runtime,
				     struct urb *urb)
{
	struct snd_urb_ctx *ctx = urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = 3;
	urb->iso_frame_desc[0].offset = 0;
	return 0;
}

/*
 * prepare urb for high speed playback sync pipe
 *
 * set up the offset and length to receive the current frequency.
 */

static int prepare_playback_sync_urb_hs(struct snd_usb_substream *subs,
					struct snd_pcm_runtime *runtime,
					struct urb *urb)
{
	struct snd_urb_ctx *ctx = urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = 4;
	urb->iso_frame_desc[0].offset = 0;
	return 0;
}

/*
 * process after full speed playback sync complete
 *
 * retrieve the current 10.14 frequency from pipe, and set it.
 * the value is referred in prepare_playback_urb().
 */
static int retire_playback_sync_urb(struct snd_usb_substream *subs,
				    struct snd_pcm_runtime *runtime,
				    struct urb *urb)
{
	unsigned int f;
	unsigned long flags;

	if (urb->iso_frame_desc[0].status == 0 &&
	    urb->iso_frame_desc[0].actual_length == 3) {
		f = combine_triple((u8*)urb->transfer_buffer) << 2;
		if (f >= subs->freqn - subs->freqn / 8 && f <= subs->freqmax) {
			spin_lock_irqsave(&subs->lock, flags);
			subs->freqm = f;
			spin_unlock_irqrestore(&subs->lock, flags);
		}
	}

	return 0;
}

/*
 * process after high speed playback sync complete