pcm.h

linux 内核源代码

struct snd_pcm_group {		/* keep linked substreams */
	spinlock_t lock;
	struct list_head substreams;
	int count;
};

struct snd_pcm_substream {
	struct snd_pcm *pcm;
	struct snd_pcm_str *pstr;
	void *private_data;		/* copied from pcm->private_data */
	int number;
	char name[32];			/* substream name */
	int stream;			/* stream (direction) */
	char latency_id[20];		/* latency identifier */
	size_t buffer_bytes_max;	/* limit ring buffer size */
	struct snd_dma_buffer dma_buffer;
	unsigned int dma_buf_id;
	size_t dma_max;
	/* -- hardware operations -- */
	struct snd_pcm_ops *ops;
	/* -- runtime information -- */
	struct snd_pcm_runtime *runtime;
        /* -- timer section -- */
	struct snd_timer *timer;		/* timer */
	unsigned timer_running: 1;	/* time is running */
	spinlock_t timer_lock;
	/* -- next substream -- */
	struct snd_pcm_substream *next;
	/* -- linked substreams -- */
	struct list_head link_list;	/* linked list member */
	struct snd_pcm_group self_group;	/* fake group for non linked substream (with substream lock inside) */
	struct snd_pcm_group *group;		/* pointer to current group */
	/* -- assigned files -- */
	void *file;
	int ref_count;
	atomic_t mmap_count;
	unsigned int f_flags;
	void (*pcm_release)(struct snd_pcm_substream *);
#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
	/* -- OSS things -- */
	struct snd_pcm_oss_substream oss;
#endif
#ifdef CONFIG_SND_VERBOSE_PROCFS
	struct snd_info_entry *proc_root;
	struct snd_info_entry *proc_info_entry;
	struct snd_info_entry *proc_hw_params_entry;
	struct snd_info_entry *proc_sw_params_entry;
	struct snd_info_entry *proc_status_entry;
	struct snd_info_entry *proc_prealloc_entry;
	struct snd_info_entry *proc_prealloc_max_entry;
#endif
	/* misc flags */
	unsigned int hw_opened: 1;
};

#define SUBSTREAM_BUSY(substream) ((substream)->ref_count > 0)


struct snd_pcm_str {
	int stream;				/* stream (direction) */
	struct snd_pcm *pcm;
	/* -- substreams -- */
	unsigned int substream_count;
	unsigned int substream_opened;
	struct snd_pcm_substream *substream;
#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
	/* -- OSS things -- */
	struct snd_pcm_oss_stream oss;
#endif
#ifdef CONFIG_SND_VERBOSE_PROCFS
	struct snd_info_entry *proc_root;
	struct snd_info_entry *proc_info_entry;
#ifdef CONFIG_SND_PCM_XRUN_DEBUG
	unsigned int xrun_debug;	/* 0 = disabled, 1 = verbose, 2 = stacktrace */
	struct snd_info_entry *proc_xrun_debug_entry;
#endif
#endif
};

struct snd_pcm {
	struct snd_card *card;
	struct list_head list;
	unsigned int device;	/* device number */
	unsigned int info_flags;
	unsigned short dev_class;
	unsigned short dev_subclass;
	char id[64];
	char name[80];
	struct snd_pcm_str streams[2];
	struct mutex open_mutex;
	wait_queue_head_t open_wait;
	void *private_data;
	void (*private_free) (struct snd_pcm *pcm);
	struct device *dev; /* actual hw device this belongs to */
#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
	struct snd_pcm_oss oss;
#endif
};

struct snd_pcm_notify {
	int (*n_register) (struct snd_pcm * pcm);
	int (*n_disconnect) (struct snd_pcm * pcm);
	int (*n_unregister) (struct snd_pcm * pcm);
	struct list_head list;
};

/*
 *  Registering
 */

extern const struct file_operations snd_pcm_f_ops[2];

int snd_pcm_new(struct snd_card *card, char *id, int device,
		int playback_count, int capture_count,
		struct snd_pcm **rpcm);
int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count);

int snd_pcm_notify(struct snd_pcm_notify *notify, int nfree);

/*
 *  Native I/O
 */

extern rwlock_t snd_pcm_link_rwlock;

int snd_pcm_info(struct snd_pcm_substream *substream, struct snd_pcm_info *info);
int snd_pcm_info_user(struct snd_pcm_substream *substream,
		      struct snd_pcm_info __user *info);
int snd_pcm_status(struct snd_pcm_substream *substream,
		   struct snd_pcm_status *status);
int snd_pcm_start(struct snd_pcm_substream *substream);
int snd_pcm_stop(struct snd_pcm_substream *substream, int status);
int snd_pcm_drain_done(struct snd_pcm_substream *substream);
#ifdef CONFIG_PM
int snd_pcm_suspend(struct snd_pcm_substream *substream);
int snd_pcm_suspend_all(struct snd_pcm *pcm);
#endif
int snd_pcm_kernel_ioctl(struct snd_pcm_substream *substream, unsigned int cmd, void *arg);
int snd_pcm_open_substream(struct snd_pcm *pcm, int stream, struct file *file,
			   struct snd_pcm_substream **rsubstream);
void snd_pcm_release_substream(struct snd_pcm_substream *substream);
int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream, struct file *file,
			     struct snd_pcm_substream **rsubstream);
void snd_pcm_detach_substream(struct snd_pcm_substream *substream);
void snd_pcm_vma_notify_data(void *client, void *data);
int snd_pcm_mmap_data(struct snd_pcm_substream *substream, struct file *file, struct vm_area_struct *area);

#if BITS_PER_LONG >= 64

static inline void div64_32(u_int64_t *n, u_int32_t div, u_int32_t *rem)
{
	*rem = *n % div;
	*n /= div;
}

#elif defined(i386)

static inline void div64_32(u_int64_t *n, u_int32_t div, u_int32_t *rem)
{
	u_int32_t low, high;
	low = *n & 0xffffffff;
	high = *n >> 32;
	if (high) {
		u_int32_t high1 = high % div;
		high /= div;
		asm("divl %2":"=a" (low), "=d" (*rem):"rm" (div), "a" (low), "d" (high1));
		*n = (u_int64_t)high << 32 | low;
	} else {
		*n = low / div;
		*rem = low % div;
	}
}
#else

static inline void divl(u_int32_t high, u_int32_t low,
			u_int32_t div,
			u_int32_t *q, u_int32_t *r)
{
	u_int64_t n = (u_int64_t)high << 32 | low;
	u_int64_t d = (u_int64_t)div << 31;
	u_int32_t q1 = 0;
	int c = 32;
	while (n > 0xffffffffU) {
		q1 <<= 1;
		if (n >= d) {
			n -= d;
			q1 |= 1;
		}
		d >>= 1;
		c--;
	}
	q1 <<= c;
	if (n) {
		low = n;
		*q = q1 | (low / div);
		*r = low % div;
	} else {
		*r = 0;
		*q = q1;
	}
	return;
}

static inline void div64_32(u_int64_t *n, u_int32_t div, u_int32_t *rem)
{
	u_int32_t low, high;
	low = *n & 0xffffffff;
	high = *n >> 32;
	if (high) {
		u_int32_t high1 = high % div;
		u_int32_t low1 = low;
		high /= div;
		divl(high1, low1, div, &low, rem);
		*n = (u_int64_t)high << 32 | low;
	} else {
		*n = low / div;
		*rem = low % div;
	}
}
#endif

/*
 *  PCM library
 */

static inline int snd_pcm_stream_linked(struct snd_pcm_substream *substream)
{
	return substream->group != &substream->self_group;
}

static inline void snd_pcm_stream_lock(struct snd_pcm_substream *substream)
{
	read_lock(&snd_pcm_link_rwlock);
	spin_lock(&substream->self_group.lock);
}

static inline void snd_pcm_stream_unlock(struct snd_pcm_substream *substream)
{
	spin_unlock(&substream->self_group.lock);
	read_unlock(&snd_pcm_link_rwlock);
}

static inline void snd_pcm_stream_lock_irq(struct snd_pcm_substream *substream)
{
	read_lock_irq(&snd_pcm_link_rwlock);
	spin_lock(&substream->self_group.lock);
}

static inline void snd_pcm_stream_unlock_irq(struct snd_pcm_substream *substream)
{
	spin_unlock(&substream->self_group.lock);
	read_unlock_irq(&snd_pcm_link_rwlock);
}

#define snd_pcm_stream_lock_irqsave(substream, flags) \
do { \
	read_lock_irqsave(&snd_pcm_link_rwlock, (flags)); \
	spin_lock(&substream->self_group.lock); \
} while (0)

#define snd_pcm_stream_unlock_irqrestore(substream, flags) \
do { \
	spin_unlock(&substream->self_group.lock); \
	read_unlock_irqrestore(&snd_pcm_link_rwlock, (flags)); \
} while (0)

#define snd_pcm_group_for_each_entry(s, substream) \
	list_for_each_entry(s, &substream->group->substreams, link_list)

static inline int snd_pcm_running(struct snd_pcm_substream *substream)
{
	return (substream->runtime->status->state == SNDRV_PCM_STATE_RUNNING ||
		(substream->runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
		 substream->stream == SNDRV_PCM_STREAM_PLAYBACK));
}

static inline ssize_t bytes_to_samples(struct snd_pcm_runtime *runtime, ssize_t size)
{
	return size * 8 / runtime->sample_bits;
}

static inline snd_pcm_sframes_t bytes_to_frames(struct snd_pcm_runtime *runtime, ssize_t size)
{
	return size * 8 / runtime->frame_bits;
}

static inline ssize_t samples_to_bytes(struct snd_pcm_runtime *runtime, ssize_t size)
{
	return size * runtime->sample_bits / 8;
}

static inline ssize_t frames_to_bytes(struct snd_pcm_runtime *runtime, snd_pcm_sframes_t size)
{
	return size * runtime->frame_bits / 8;
}

static inline int frame_aligned(struct snd_pcm_runtime *runtime, ssize_t bytes)
{
	return bytes % runtime->byte_align == 0;
}

static inline size_t snd_pcm_lib_buffer_bytes(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	return frames_to_bytes(runtime, runtime->buffer_size);
}

static inline size_t snd_pcm_lib_period_bytes(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	return frames_to_bytes(runtime, runtime->period_size);
}

/*
 *  result is: 0 ... (boundary - 1)
 */
static inline snd_pcm_uframes_t snd_pcm_playback_avail(struct snd_pcm_runtime *runtime)
{
	snd_pcm_sframes_t avail = runtime->status->hw_ptr + runtime->buffer_size - runtime->control->appl_ptr;
	if (avail < 0)
		avail += runtime->boundary;
	else if ((snd_pcm_uframes_t) avail >= runtime->boundary)
		avail -= runtime->boundary;
	return avail;
}

/*
 *  result is: 0 ... (boundary - 1)
 */
static inline snd_pcm_uframes_t snd_pcm_capture_avail(struct snd_pcm_runtime *runtime)
{
	snd_pcm_sframes_t avail = runtime->status->hw_ptr - runtime->control->appl_ptr;
	if (avail < 0)
		avail += runtime->boundary;
	return avail;
}