text: #ifndef __SOUND_PCM_H
  #define __SOUND_PCM_H
  
  /*
   *  Digital Audio (PCM) abstract layer
   *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   *                   Abramo Bagnara <abramo@alsa-project.org>
   *
   *
   *   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
   *
   */
  
  #include <sound/asound.h>
  #include <sound/memalloc.h>
  #include <sound/minors.h>
  #include <linux/poll.h>
  #include <linux/mm.h>
  #include <linux/bitops.h>
  #include <linux/pm_qos.h>
  
  #define snd_pcm_substream_chip(substream) ((substream)->private_data)
  #define snd_pcm_chip(pcm) ((pcm)->private_data)
  
  #if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
  #include "pcm_oss.h"
  #endif
  
  /*
   *  Hardware (lowlevel) section
   */
  
  struct snd_pcm_hardware {
  	unsigned int info;		/* SNDRV_PCM_INFO_* */
  	u64 formats;			/* SNDRV_PCM_FMTBIT_* */
  	unsigned int rates;		/* SNDRV_PCM_RATE_* */
  	unsigned int rate_min;		/* min rate */
  	unsigned int rate_max;		/* max rate */
  	unsigned int channels_min;	/* min channels */
  	unsigned int channels_max;	/* max channels */
  	size_t buffer_bytes_max;	/* max buffer size */
  	size_t period_bytes_min;	/* min period size */
  	size_t period_bytes_max;	/* max period size */
  	unsigned int periods_min;	/* min # of periods */
  	unsigned int periods_max;	/* max # of periods */
  	size_t fifo_size;		/* fifo size in bytes */
  };
  
  struct snd_pcm_substream;
  
  struct snd_pcm_ops {
  	int (*open)(struct snd_pcm_substream *substream);
  	int (*close)(struct snd_pcm_substream *substream);
  	int (*ioctl)(struct snd_pcm_substream * substream,
  		     unsigned int cmd, void *arg);
  	int (*hw_params)(struct snd_pcm_substream *substream,
  			 struct snd_pcm_hw_params *params);
  	int (*hw_free)(struct snd_pcm_substream *substream);
  	int (*prepare)(struct snd_pcm_substream *substream);
  	int (*trigger)(struct snd_pcm_substream *substream, int cmd);
  	snd_pcm_uframes_t (*pointer)(struct snd_pcm_substream *substream);
  	int (*copy)(struct snd_pcm_substream *substream, int channel,
  		    snd_pcm_uframes_t pos,
  		    void __user *buf, snd_pcm_uframes_t count);
  	int (*silence)(struct snd_pcm_substream *substream, int channel, 
  		       snd_pcm_uframes_t pos, snd_pcm_uframes_t count);
  	struct page *(*page)(struct snd_pcm_substream *substream,
  			     unsigned long offset);
  	int (*mmap)(struct snd_pcm_substream *substream, struct vm_area_struct *vma);
  	int (*ack)(struct snd_pcm_substream *substream);
  };
  
  /*
   *
   */
  
  #if defined(CONFIG_SND_DYNAMIC_MINORS)
  #define SNDRV_PCM_DEVICES	(SNDRV_OS_MINORS-2)
  #else
  #define SNDRV_PCM_DEVICES	8
  #endif
  
  #define SNDRV_PCM_IOCTL1_FALSE		((void *)0)
  #define SNDRV_PCM_IOCTL1_TRUE		((void *)1)
  
  #define SNDRV_PCM_IOCTL1_RESET		0
  #define SNDRV_PCM_IOCTL1_INFO		1
  #define SNDRV_PCM_IOCTL1_CHANNEL_INFO	2
  #define SNDRV_PCM_IOCTL1_GSTATE		3
  #define SNDRV_PCM_IOCTL1_FIFO_SIZE	4
  
  #define SNDRV_PCM_TRIGGER_STOP		0
  #define SNDRV_PCM_TRIGGER_START		1
  #define SNDRV_PCM_TRIGGER_PAUSE_PUSH	3
  #define SNDRV_PCM_TRIGGER_PAUSE_RELEASE	4
  #define SNDRV_PCM_TRIGGER_SUSPEND	5
  #define SNDRV_PCM_TRIGGER_RESUME	6
  
  #define SNDRV_PCM_POS_XRUN		((snd_pcm_uframes_t)-1)
  
  /* If you change this don't forget to change rates[] table in pcm_native.c */
  #define SNDRV_PCM_RATE_5512		(1<<0)		/* 5512Hz */
  #define SNDRV_PCM_RATE_8000		(1<<1)		/* 8000Hz */
  #define SNDRV_PCM_RATE_11025		(1<<2)		/* 11025Hz */
  #define SNDRV_PCM_RATE_16000		(1<<3)		/* 16000Hz */
  #define SNDRV_PCM_RATE_22050		(1<<4)		/* 22050Hz */
  #define SNDRV_PCM_RATE_32000		(1<<5)		/* 32000Hz */
  #define SNDRV_PCM_RATE_44100		(1<<6)		/* 44100Hz */
  #define SNDRV_PCM_RATE_48000		(1<<7)		/* 48000Hz */
  #define SNDRV_PCM_RATE_64000		(1<<8)		/* 64000Hz */
  #define SNDRV_PCM_RATE_88200		(1<<9)		/* 88200Hz */
  #define SNDRV_PCM_RATE_96000		(1<<10)		/* 96000Hz */
  #define SNDRV_PCM_RATE_176400		(1<<11)		/* 176400Hz */
  #define SNDRV_PCM_RATE_192000		(1<<12)		/* 192000Hz */
  
  #define SNDRV_PCM_RATE_CONTINUOUS	(1<<30)		/* continuous range */
  #define SNDRV_PCM_RATE_KNOT		(1<<31)		/* supports more non-continuos rates */
  
  #define SNDRV_PCM_RATE_8000_44100	(SNDRV_PCM_RATE_8000|SNDRV_PCM_RATE_11025|\
  					 SNDRV_PCM_RATE_16000|SNDRV_PCM_RATE_22050|\
  					 SNDRV_PCM_RATE_32000|SNDRV_PCM_RATE_44100)
  #define SNDRV_PCM_RATE_8000_48000	(SNDRV_PCM_RATE_8000_44100|SNDRV_PCM_RATE_48000)
  #define SNDRV_PCM_RATE_8000_96000	(SNDRV_PCM_RATE_8000_48000|SNDRV_PCM_RATE_64000|\
  					 SNDRV_PCM_RATE_88200|SNDRV_PCM_RATE_96000)
  #define SNDRV_PCM_RATE_8000_192000	(SNDRV_PCM_RATE_8000_96000|SNDRV_PCM_RATE_176400|\
  					 SNDRV_PCM_RATE_192000)
  #define _SNDRV_PCM_FMTBIT(fmt)		(1ULL << (__force int)SNDRV_PCM_FORMAT_##fmt)
  #define SNDRV_PCM_FMTBIT_S8		_SNDRV_PCM_FMTBIT(S8)
  #define SNDRV_PCM_FMTBIT_U8		_SNDRV_PCM_FMTBIT(U8)
  #define SNDRV_PCM_FMTBIT_S16_LE		_SNDRV_PCM_FMTBIT(S16_LE)
  #define SNDRV_PCM_FMTBIT_S16_BE		_SNDRV_PCM_FMTBIT(S16_BE)
  #define SNDRV_PCM_FMTBIT_U16_LE		_SNDRV_PCM_FMTBIT(U16_LE)
  #define SNDRV_PCM_FMTBIT_U16_BE		_SNDRV_PCM_FMTBIT(U16_BE)
  #define SNDRV_PCM_FMTBIT_S24_LE		_SNDRV_PCM_FMTBIT(S24_LE)
  #define SNDRV_PCM_FMTBIT_S24_BE		_SNDRV_PCM_FMTBIT(S24_BE)
  #define SNDRV_PCM_FMTBIT_U24_LE		_SNDRV_PCM_FMTBIT(U24_LE)
  #define SNDRV_PCM_FMTBIT_U24_BE		_SNDRV_PCM_FMTBIT(U24_BE)
  #define SNDRV_PCM_FMTBIT_S32_LE		_SNDRV_PCM_FMTBIT(S32_LE)
  #define SNDRV_PCM_FMTBIT_S32_BE		_SNDRV_PCM_FMTBIT(S32_BE)
  #define SNDRV_PCM_FMTBIT_U32_LE		_SNDRV_PCM_FMTBIT(U32_LE)
  #define SNDRV_PCM_FMTBIT_U32_BE		_SNDRV_PCM_FMTBIT(U32_BE)
  #define SNDRV_PCM_FMTBIT_FLOAT_LE	_SNDRV_PCM_FMTBIT(FLOAT_LE)
  #define SNDRV_PCM_FMTBIT_FLOAT_BE	_SNDRV_PCM_FMTBIT(FLOAT_BE)
  #define SNDRV_PCM_FMTBIT_FLOAT64_LE	_SNDRV_PCM_FMTBIT(FLOAT64_LE)
  #define SNDRV_PCM_FMTBIT_FLOAT64_BE	_SNDRV_PCM_FMTBIT(FLOAT64_BE)
  #define SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE _SNDRV_PCM_FMTBIT(IEC958_SUBFRAME_LE)
  #define SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_BE _SNDRV_PCM_FMTBIT(IEC958_SUBFRAME_BE)
  #define SNDRV_PCM_FMTBIT_MU_LAW		_SNDRV_PCM_FMTBIT(MU_LAW)
  #define SNDRV_PCM_FMTBIT_A_LAW		_SNDRV_PCM_FMTBIT(A_LAW)
  #define SNDRV_PCM_FMTBIT_IMA_ADPCM	_SNDRV_PCM_FMTBIT(IMA_ADPCM)
  #define SNDRV_PCM_FMTBIT_MPEG		_SNDRV_PCM_FMTBIT(MPEG)
  #define SNDRV_PCM_FMTBIT_GSM		_SNDRV_PCM_FMTBIT(GSM)
  #define SNDRV_PCM_FMTBIT_SPECIAL	_SNDRV_PCM_FMTBIT(SPECIAL)
  #define SNDRV_PCM_FMTBIT_S24_3LE	_SNDRV_PCM_FMTBIT(S24_3LE)
  #define SNDRV_PCM_FMTBIT_U24_3LE	_SNDRV_PCM_FMTBIT(U24_3LE)
  #define SNDRV_PCM_FMTBIT_S24_3BE	_SNDRV_PCM_FMTBIT(S24_3BE)
  #define SNDRV_PCM_FMTBIT_U24_3BE	_SNDRV_PCM_FMTBIT(U24_3BE)
  #define SNDRV_PCM_FMTBIT_S20_3LE	_SNDRV_PCM_FMTBIT(S20_3LE)
  #define SNDRV_PCM_FMTBIT_U20_3LE	_SNDRV_PCM_FMTBIT(U20_3LE)
  #define SNDRV_PCM_FMTBIT_S20_3BE	_SNDRV_PCM_FMTBIT(S20_3BE)
  #define SNDRV_PCM_FMTBIT_U20_3BE	_SNDRV_PCM_FMTBIT(U20_3BE)
  #define SNDRV_PCM_FMTBIT_S18_3LE	_SNDRV_PCM_FMTBIT(S18_3LE)
  #define SNDRV_PCM_FMTBIT_U18_3LE	_SNDRV_PCM_FMTBIT(U18_3LE)
  #define SNDRV_PCM_FMTBIT_S18_3BE	_SNDRV_PCM_FMTBIT(S18_3BE)
  #define SNDRV_PCM_FMTBIT_U18_3BE	_SNDRV_PCM_FMTBIT(U18_3BE)
  #define SNDRV_PCM_FMTBIT_G723_24	_SNDRV_PCM_FMTBIT(G723_24)
  #define SNDRV_PCM_FMTBIT_G723_24_1B	_SNDRV_PCM_FMTBIT(G723_24_1B)
  #define SNDRV_PCM_FMTBIT_G723_40	_SNDRV_PCM_FMTBIT(G723_40)
  #define SNDRV_PCM_FMTBIT_G723_40_1B	_SNDRV_PCM_FMTBIT(G723_40_1B)
  
  #ifdef SNDRV_LITTLE_ENDIAN
  #define SNDRV_PCM_FMTBIT_S16		SNDRV_PCM_FMTBIT_S16_LE
  #define SNDRV_PCM_FMTBIT_U16		SNDRV_PCM_FMTBIT_U16_LE
  #define SNDRV_PCM_FMTBIT_S24		SNDRV_PCM_FMTBIT_S24_LE
  #define SNDRV_PCM_FMTBIT_U24		SNDRV_PCM_FMTBIT_U24_LE
  #define SNDRV_PCM_FMTBIT_S32		SNDRV_PCM_FMTBIT_S32_LE
  #define SNDRV_PCM_FMTBIT_U32		SNDRV_PCM_FMTBIT_U32_LE
  #define SNDRV_PCM_FMTBIT_FLOAT		SNDRV_PCM_FMTBIT_FLOAT_LE
  #define SNDRV_PCM_FMTBIT_FLOAT64	SNDRV_PCM_FMTBIT_FLOAT64_LE
  #define SNDRV_PCM_FMTBIT_IEC958_SUBFRAME SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE
  #endif
  #ifdef SNDRV_BIG_ENDIAN
  #define SNDRV_PCM_FMTBIT_S16		SNDRV_PCM_FMTBIT_S16_BE
  #define SNDRV_PCM_FMTBIT_U16		SNDRV_PCM_FMTBIT_U16_BE
  #define SNDRV_PCM_FMTBIT_S24		SNDRV_PCM_FMTBIT_S24_BE
  #define SNDRV_PCM_FMTBIT_U24		SNDRV_PCM_FMTBIT_U24_BE
  #define SNDRV_PCM_FMTBIT_S32		SNDRV_PCM_FMTBIT_S32_BE
  #define SNDRV_PCM_FMTBIT_U32		SNDRV_PCM_FMTBIT_U32_BE
  #define SNDRV_PCM_FMTBIT_FLOAT		SNDRV_PCM_FMTBIT_FLOAT_BE
  #define SNDRV_PCM_FMTBIT_FLOAT64	SNDRV_PCM_FMTBIT_FLOAT64_BE
  #define SNDRV_PCM_FMTBIT_IEC958_SUBFRAME SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_BE
  #endif
  
  struct snd_pcm_file {
  	struct snd_pcm_substream *substream;
  	int no_compat_mmap;
  };
  
  struct snd_pcm_hw_rule;
  typedef int (*snd_pcm_hw_rule_func_t)(struct snd_pcm_hw_params *params,
  				      struct snd_pcm_hw_rule *rule);
  
  struct snd_pcm_hw_rule {
  	unsigned int cond;
  	snd_pcm_hw_rule_func_t func;
  	int var;
  	int deps[4];
  	void *private;
  };
  
  struct snd_pcm_hw_constraints {
  	struct snd_mask masks[SNDRV_PCM_HW_PARAM_LAST_MASK - 
  			 SNDRV_PCM_HW_PARAM_FIRST_MASK + 1];
  	struct snd_interval intervals[SNDRV_PCM_HW_PARAM_LAST_INTERVAL -
  			     SNDRV_PCM_HW_PARAM_FIRST_INTERVAL + 1];
  	unsigned int rules_num;
  	unsigned int rules_all;
  	struct snd_pcm_hw_rule *rules;
  };
  
  static inline struct snd_mask *constrs_mask(struct snd_pcm_hw_constraints *constrs,
  					    snd_pcm_hw_param_t var)
  {
  	return &constrs->masks[var - SNDRV_PCM_HW_PARAM_FIRST_MASK];
  }
  
  static inline struct snd_interval *constrs_interval(struct snd_pcm_hw_constraints *constrs,
  						    snd_pcm_hw_param_t var)
  {
  	return &constrs->intervals[var - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL];
  }
  
  struct snd_ratnum {
  	unsigned int num;
  	unsigned int den_min, den_max, den_step;
  };
  
  struct snd_ratden {
  	unsigned int num_min, num_max, num_step;
  	unsigned int den;
  };
  
  struct snd_pcm_hw_constraint_ratnums {
  	int nrats;
  	struct snd_ratnum *rats;
  };
  
  struct snd_pcm_hw_constraint_ratdens {
  	int nrats;
  	struct snd_ratden *rats;
  };
  
  struct snd_pcm_hw_constraint_list {
  	unsigned int count;
  	const unsigned int *list;
  	unsigned int mask;
  };
  
  struct snd_pcm_hwptr_log;
  
  struct snd_pcm_runtime {
  	/* -- Status -- */
  	struct snd_pcm_substream *trigger_master;
  	struct timespec trigger_tstamp;	/* trigger timestamp */
  	int overrange;
  	snd_pcm_uframes_t avail_max;
  	snd_pcm_uframes_t hw_ptr_base;	/* Position at buffer restart */
  	snd_pcm_uframes_t hw_ptr_interrupt; /* Position at interrupt time */
  	unsigned long hw_ptr_jiffies;	/* Time when hw_ptr is updated */
  	unsigned long hw_ptr_buffer_jiffies; /* buffer time in jiffies */
  	snd_pcm_sframes_t delay;	/* extra delay; typically FIFO size */
  
  	/* -- HW params -- */
  	snd_pcm_access_t access;	/* access mode */
  	snd_pcm_format_t format;	/* SNDRV_PCM_FORMAT_* */
  	snd_pcm_subformat_t subformat;	/* subformat */
  	unsigned int rate;		/* rate in Hz */
  	unsigned int channels;		/* channels */
  	snd_pcm_uframes_t period_size;	/* period size */
  	unsigned int periods;		/* periods */
  	snd_pcm_uframes_t buffer_size;	/* buffer size */
  	snd_pcm_uframes_t min_align;	/* Min alignment for the format */
  	size_t byte_align;
  	unsigned int frame_bits;
  	unsigned int sample_bits;
  	unsigned int info;
  	unsigned int rate_num;
  	unsigned int rate_den;
  	unsigned int no_period_wakeup: 1;
  
  	/* -- SW params -- */
  	int tstamp_mode;		/* mmap timestamp is updated */
    	unsigned int period_step;
  	snd_pcm_uframes_t start_threshold;
  	snd_pcm_uframes_t stop_threshold;
  	snd_pcm_uframes_t silence_threshold; /* Silence filling happens when
  						noise is nearest than this */
  	snd_pcm_uframes_t silence_size;	/* Silence filling size */
  	snd_pcm_uframes_t boundary;	/* pointers wrap point */
  
  	snd_pcm_uframes_t silence_start; /* starting pointer to silence area */
  	snd_pcm_uframes_t silence_filled; /* size filled with silence */
  
  	union snd_pcm_sync_id sync;	/* hardware synchronization ID */
  
  	/* -- mmap -- */
  	struct snd_pcm_mmap_status *status;
  	struct snd_pcm_mmap_control *control;
  
  	/* -- locking / scheduling -- */
  	snd_pcm_uframes_t twake; 	/* do transfer (!poll) wakeup if non-zero */
  	wait_queue_head_t sleep;	/* poll sleep */
  	wait_queue_head_t tsleep;	/* transfer sleep */
  	struct fasync_struct *fasync;
  
  	/* -- private section -- */
  	void *private_data;
  	void (*private_free)(struct snd_pcm_runtime *runtime);
  
  	/* -- hardware description -- */
  	struct snd_pcm_hardware hw;
  	struct snd_pcm_hw_constraints hw_constraints;
  
  	/* -- interrupt callbacks -- */
  	void (*transfer_ack_begin)(struct snd_pcm_substream *substream);
  	void (*transfer_ack_end)(struct snd_pcm_substream *substream);
  
  	/* -- timer -- */
  	unsigned int timer_resolution;	/* timer resolution */
  	int tstamp_type;		/* timestamp type */
  
  	/* -- DMA -- */           
  	unsigned char *dma_area;	/* DMA area */
  	dma_addr_t dma_addr;		/* physical bus address (not accessible from main CPU) */
  	size_t dma_bytes;		/* size of DMA area */
  
  	struct snd_dma_buffer *dma_buffer_p;	/* allocated buffer */
  
  #if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
  	/* -- OSS things -- */
  	struct snd_pcm_oss_runtime oss;
  #endif
  
  #ifdef CONFIG_SND_PCM_XRUN_DEBUG
  	struct snd_pcm_hwptr_log *hwptr_log;
  #endif
  };
  
  struct snd_pcm_group {		/* keep linked substreams */
  	spinlock_t lock;
  	struct list_head substreams;
  	int count;
  };
  
  struct pid;
  
  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) */
  	struct pm_qos_request latency_pm_qos_req; /* pm_qos request */
  	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 */
  	/* -- 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 *);
  	struct pid *pid;
  #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;
  	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 */
  	bool internal; /* pcm is for internal use only */
  #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, const char *id, int device,
  		int playback_count, int capture_count,
  		struct snd_pcm **rpcm);
  int snd_pcm_new_internal(struct snd_card *card, const 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, snd_pcm_state_t 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);
  
  
  #ifdef CONFIG_SND_DEBUG
  void snd_pcm_debug_name(struct snd_pcm_substream *substream,
  			   char *name, size_t len);
  #else
  static inline void
  snd_pcm_debug_name(struct snd_pcm_substream *substream, char *buf, size_t size)
  {
  	*buf = 0;
  }
  #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;
  }
  
  static inline snd_pcm_sframes_t snd_pcm_playback_hw_avail(struct snd_pcm_runtime *runtime)
  {
  	return runtime->buffer_size - snd_pcm_playback_avail(runtime);
  }
  
  static inline snd_pcm_sframes_t snd_pcm_capture_hw_avail(struct snd_pcm_runtime *runtime)
  {
  	return runtime->buffer_size - snd_pcm_capture_avail(runtime);
  }
  
  /**
   * snd_pcm_playback_ready - check whether the playback buffer is available
   * @substream: the pcm substream instance
   *
   * Checks whether enough free space is available on the playback buffer.
   *
   * Returns non-zero if available, or zero if not.
   */
  static inline int snd_pcm_playback_ready(struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	return snd_pcm_playback_avail(runtime) >= runtime->control->avail_min;
  }
  
  /**
   * snd_pcm_capture_ready - check whether the capture buffer is available
   * @substream: the pcm substream instance
   *
   * Checks whether enough capture data is available on the capture buffer.
   *
   * Returns non-zero if available, or zero if not.
   */
  static inline int snd_pcm_capture_ready(struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	return snd_pcm_capture_avail(runtime) >= runtime->control->avail_min;
  }
  
  /**
   * snd_pcm_playback_data - check whether any data exists on the playback buffer
   * @substream: the pcm substream instance
   *
   * Checks whether any data exists on the playback buffer. If stop_threshold
   * is bigger or equal to boundary, then this function returns always non-zero.
   *
   * Returns non-zero if exists, or zero if not.
   */
  static inline int snd_pcm_playback_data(struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	
  	if (runtime->stop_threshold >= runtime->boundary)
  		return 1;
  	return snd_pcm_playback_avail(runtime) < runtime->buffer_size;
  }
  
  /**
   * snd_pcm_playback_empty - check whether the playback buffer is empty
   * @substream: the pcm substream instance
   *
   * Checks whether the playback buffer is empty.
   *
   * Returns non-zero if empty, or zero if not.
   */
  static inline int snd_pcm_playback_empty(struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	return snd_pcm_playback_avail(runtime) >= runtime->buffer_size;
  }
  
  /**
   * snd_pcm_capture_empty - check whether the capture buffer is empty
   * @substream: the pcm substream instance
   *
   * Checks whether the capture buffer is empty.
   *
   * Returns non-zero if empty, or zero if not.
   */
  static inline int snd_pcm_capture_empty(struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	return snd_pcm_capture_avail(runtime) == 0;
  }
  
  static inline void snd_pcm_trigger_done(struct snd_pcm_substream *substream, 
  					struct snd_pcm_substream *master)
  {
  	substream->runtime->trigger_master = master;
  }
  
  static inline int hw_is_mask(int var)
  {
  	return var >= SNDRV_PCM_HW_PARAM_FIRST_MASK &&
  		var <= SNDRV_PCM_HW_PARAM_LAST_MASK;
  }
  
  static inline int hw_is_interval(int var)
  {
  	return var >= SNDRV_PCM_HW_PARAM_FIRST_INTERVAL &&
  		var <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL;
  }
  
  static inline struct snd_mask *hw_param_mask(struct snd_pcm_hw_params *params,
  				     snd_pcm_hw_param_t var)
  {
  	return &params->masks[var - SNDRV_PCM_HW_PARAM_FIRST_MASK];
  }
  
  static inline struct snd_interval *hw_param_interval(struct snd_pcm_hw_params *params,
  					     snd_pcm_hw_param_t var)
  {
  	return &params->intervals[var - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL];
  }
  
  static inline const struct snd_mask *hw_param_mask_c(const struct snd_pcm_hw_params *params,
  					     snd_pcm_hw_param_t var)
  {
  	return &params->masks[var - SNDRV_PCM_HW_PARAM_FIRST_MASK];
  }
  
  static inline const struct snd_interval *hw_param_interval_c(const struct snd_pcm_hw_params *params,
  						     snd_pcm_hw_param_t var)
  {
  	return &params->intervals[var - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL];
  }
  
  #define params_channels(p) \
  	(hw_param_interval_c((p), SNDRV_PCM_HW_PARAM_CHANNELS)->min)
  #define params_rate(p) \
  	(hw_param_interval_c((p), SNDRV_PCM_HW_PARAM_RATE)->min)
  #define params_period_size(p) \
  	(hw_param_interval_c((p), SNDRV_PCM_HW_PARAM_PERIOD_SIZE)->min)
  #define params_periods(p) \
  	(hw_param_interval_c((p), SNDRV_PCM_HW_PARAM_PERIODS)->min)
  #define params_buffer_size(p) \
  	(hw_param_interval_c((p), SNDRV_PCM_HW_PARAM_BUFFER_SIZE)->min)
  #define params_buffer_bytes(p) \
  	(hw_param_interval_c((p), SNDRV_PCM_HW_PARAM_BUFFER_BYTES)->min)
  
  int snd_interval_refine(struct snd_interval *i, const struct snd_interval *v);
  void snd_interval_mul(const struct snd_interval *a, const struct snd_interval *b, struct snd_interval *c);
  void snd_interval_div(const struct snd_interval *a, const struct snd_interval *b, struct snd_interval *c);
  void snd_interval_muldivk(const struct snd_interval *a, const struct snd_interval *b, 
  			  unsigned int k, struct snd_interval *c);
  void snd_interval_mulkdiv(const struct snd_interval *a, unsigned int k,
  			  const struct snd_interval *b, struct snd_interval *c);
  int snd_interval_list(struct snd_interval *i, unsigned int count,
  		      const unsigned int *list, unsigned int mask);
  int snd_interval_ratnum(struct snd_interval *i,
  			unsigned int rats_count, struct snd_ratnum *rats,
  			unsigned int *nump, unsigned int *denp);
  
  void _snd_pcm_hw_params_any(struct snd_pcm_hw_params *params);
  void _snd_pcm_hw_param_setempty(struct snd_pcm_hw_params *params, snd_pcm_hw_param_t var);
  int snd_pcm_hw_params_choose(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params);
  
  int snd_pcm_hw_refine(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params);
  
  int snd_pcm_hw_constraints_init(struct snd_pcm_substream *substream);
  int snd_pcm_hw_constraints_complete(struct snd_pcm_substream *substream);
  
  int snd_pcm_hw_constraint_mask(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var,
  			       u_int32_t mask);
  int snd_pcm_hw_constraint_mask64(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var,
  				 u_int64_t mask);
  int snd_pcm_hw_constraint_minmax(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var,
  				 unsigned int min, unsigned int max);
  int snd_pcm_hw_constraint_integer(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var);
  int snd_pcm_hw_constraint_list(struct snd_pcm_runtime *runtime, 
  			       unsigned int cond,
  			       snd_pcm_hw_param_t var,
  			       const struct snd_pcm_hw_constraint_list *l);
  int snd_pcm_hw_constraint_ratnums(struct snd_pcm_runtime *runtime, 
  				  unsigned int cond,
  				  snd_pcm_hw_param_t var,
  				  struct snd_pcm_hw_constraint_ratnums *r);
  int snd_pcm_hw_constraint_ratdens(struct snd_pcm_runtime *runtime, 
  				  unsigned int cond,
  				  snd_pcm_hw_param_t var,
  				  struct snd_pcm_hw_constraint_ratdens *r);
  int snd_pcm_hw_constraint_msbits(struct snd_pcm_runtime *runtime, 
  				 unsigned int cond,
  				 unsigned int width,
  				 unsigned int msbits);
  int snd_pcm_hw_constraint_step(struct snd_pcm_runtime *runtime,
  			       unsigned int cond,
  			       snd_pcm_hw_param_t var,
  			       unsigned long step);
  int snd_pcm_hw_constraint_pow2(struct snd_pcm_runtime *runtime,
  			       unsigned int cond,
  			       snd_pcm_hw_param_t var);
  int snd_pcm_hw_rule_noresample(struct snd_pcm_runtime *runtime,
  			       unsigned int base_rate);
  int snd_pcm_hw_rule_add(struct snd_pcm_runtime *runtime,
  			unsigned int cond,
  			int var,
  			snd_pcm_hw_rule_func_t func, void *private,
  			int dep, ...);
  
  int snd_pcm_format_signed(snd_pcm_format_t format);
  int snd_pcm_format_unsigned(snd_pcm_format_t format);
  int snd_pcm_format_linear(snd_pcm_format_t format);
  int snd_pcm_format_little_endian(snd_pcm_format_t format);
  int snd_pcm_format_big_endian(snd_pcm_format_t format);
  #if 0 /* just for DocBook */
  /**
   * snd_pcm_format_cpu_endian - Check the PCM format is CPU-endian
   * @format: the format to check
   *
   * Returns 1 if the given PCM format is CPU-endian, 0 if
   * opposite, or a negative error code if endian not specified.
   */
  int snd_pcm_format_cpu_endian(snd_pcm_format_t format);
  #endif /* DocBook */
  #ifdef SNDRV_LITTLE_ENDIAN
  #define snd_pcm_format_cpu_endian(format) snd_pcm_format_little_endian(format)
  #else
  #define snd_pcm_format_cpu_endian(format) snd_pcm_format_big_endian(format)
  #endif
  int snd_pcm_format_width(snd_pcm_format_t format);			/* in bits */
  int snd_pcm_format_physical_width(snd_pcm_format_t format);		/* in bits */
  ssize_t snd_pcm_format_size(snd_pcm_format_t format, size_t samples);
  const unsigned char *snd_pcm_format_silence_64(snd_pcm_format_t format);
  int snd_pcm_format_set_silence(snd_pcm_format_t format, void *buf, unsigned int frames);
  snd_pcm_format_t snd_pcm_build_linear_format(int width, int unsignd, int big_endian);
  
  void snd_pcm_set_ops(struct snd_pcm * pcm, int direction, struct snd_pcm_ops *ops);
  void snd_pcm_set_sync(struct snd_pcm_substream *substream);
  int snd_pcm_lib_interleave_len(struct snd_pcm_substream *substream);
  int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream,
  		      unsigned int cmd, void *arg);                      
  int snd_pcm_update_state(struct snd_pcm_substream *substream,
  			 struct snd_pcm_runtime *runtime);
  int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream);
  int snd_pcm_playback_xrun_check(struct snd_pcm_substream *substream);
  int snd_pcm_capture_xrun_check(struct snd_pcm_substream *substream);
  int snd_pcm_playback_xrun_asap(struct snd_pcm_substream *substream);
  int snd_pcm_capture_xrun_asap(struct snd_pcm_substream *substream);
  void snd_pcm_playback_silence(struct snd_pcm_substream *substream, snd_pcm_uframes_t new_hw_ptr);
  void snd_pcm_period_elapsed(struct snd_pcm_substream *substream);
  snd_pcm_sframes_t snd_pcm_lib_write(struct snd_pcm_substream *substream,
  				    const void __user *buf,
  				    snd_pcm_uframes_t frames);
  snd_pcm_sframes_t snd_pcm_lib_read(struct snd_pcm_substream *substream,
  				   void __user *buf, snd_pcm_uframes_t frames);
  snd_pcm_sframes_t snd_pcm_lib_writev(struct snd_pcm_substream *substream,
  				     void __user **bufs, snd_pcm_uframes_t frames);
  snd_pcm_sframes_t snd_pcm_lib_readv(struct snd_pcm_substream *substream,
  				    void __user **bufs, snd_pcm_uframes_t frames);
  
  extern const struct snd_pcm_hw_constraint_list snd_pcm_known_rates;
  
  int snd_pcm_limit_hw_rates(struct snd_pcm_runtime *runtime);
  unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate);
  unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit);
  
  static inline void snd_pcm_set_runtime_buffer(struct snd_pcm_substream *substream,
  					      struct snd_dma_buffer *bufp)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	if (bufp) {
  		runtime->dma_buffer_p = bufp;
  		runtime->dma_area = bufp->area;
  		runtime->dma_addr = bufp->addr;
  		runtime->dma_bytes = bufp->bytes;
  	} else {
  		runtime->dma_buffer_p = NULL;
  		runtime->dma_area = NULL;
  		runtime->dma_addr = 0;
  		runtime->dma_bytes = 0;
  	}
  }
  
  /*
   *  Timer interface
   */
  
  void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream);
  void snd_pcm_timer_init(struct snd_pcm_substream *substream);
  void snd_pcm_timer_done(struct snd_pcm_substream *substream);
  
  static inline void snd_pcm_gettime(struct snd_pcm_runtime *runtime,
  				   struct timespec *tv)
  {
  	if (runtime->tstamp_type == SNDRV_PCM_TSTAMP_TYPE_MONOTONIC)
  		do_posix_clock_monotonic_gettime(tv);
  	else
  		getnstimeofday(tv);
  }
  
  /*
   *  Memory
   */
  
  int snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream);
  int snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm);
  int snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
  				  int type, struct device *data,
  				  size_t size, size_t max);
  int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
  					  int type, void *data,
  					  size_t size, size_t max);
  int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size);
  int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream);
  
  int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
  				      size_t size, gfp_t gfp_flags);
  int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream);
  struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
  					  unsigned long offset);
  #if 0 /* for kernel-doc */
  /**
   * snd_pcm_lib_alloc_vmalloc_buffer - allocate virtual DMA buffer
   * @substream: the substream to allocate the buffer to
   * @size: the requested buffer size, in bytes
   *
   * Allocates the PCM substream buffer using vmalloc(), i.e., the memory is
   * contiguous in kernel virtual space, but not in physical memory.  Use this
   * if the buffer is accessed by kernel code but not by device DMA.
   *
   * Returns 1 if the buffer was changed, 0 if not changed, or a negative error
   * code.
   */
  static int snd_pcm_lib_alloc_vmalloc_buffer
  			(struct snd_pcm_substream *substream, size_t size);
  /**
   * snd_pcm_lib_alloc_vmalloc_32_buffer - allocate 32-bit-addressable buffer
   * @substream: the substream to allocate the buffer to
   * @size: the requested buffer size, in bytes
   *
   * This function works like snd_pcm_lib_alloc_vmalloc_buffer(), but uses
   * vmalloc_32(), i.e., the pages are allocated from 32-bit-addressable memory.
   */
  static int snd_pcm_lib_alloc_vmalloc_32_buffer
  			(struct snd_pcm_substream *substream, size_t size);
  #endif
  #define snd_pcm_lib_alloc_vmalloc_buffer(subs, size) \
  	_snd_pcm_lib_alloc_vmalloc_buffer \
  			(subs, size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO)
  #define snd_pcm_lib_alloc_vmalloc_32_buffer(subs, size) \
  	_snd_pcm_lib_alloc_vmalloc_buffer \
  			(subs, size, GFP_KERNEL | GFP_DMA32 | __GFP_ZERO)
  
  #ifdef CONFIG_SND_DMA_SGBUF
  /*
   * SG-buffer handling
   */
  #define snd_pcm_substream_sgbuf(substream) \
  	((substream)->runtime->dma_buffer_p->private_data)
  
  static inline dma_addr_t
  snd_pcm_sgbuf_get_addr(struct snd_pcm_substream *substream, unsigned int ofs)
  {
  	struct snd_sg_buf *sg = snd_pcm_substream_sgbuf(substream);
  	return snd_sgbuf_get_addr(sg, ofs);
  }
  
  static inline void *
  snd_pcm_sgbuf_get_ptr(struct snd_pcm_substream *substream, unsigned int ofs)
  {
  	struct snd_sg_buf *sg = snd_pcm_substream_sgbuf(substream);
  	return snd_sgbuf_get_ptr(sg, ofs);
  }
  
  struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream,
  				    unsigned long offset);
  unsigned int snd_pcm_sgbuf_get_chunk_size(struct snd_pcm_substream *substream,
  					  unsigned int ofs, unsigned int size);
  
  #else /* !SND_DMA_SGBUF */
  /*
   * fake using a continuous buffer
   */
  static inline dma_addr_t
  snd_pcm_sgbuf_get_addr(struct snd_pcm_substream *substream, unsigned int ofs)
  {
  	return substream->runtime->dma_addr + ofs;
  }
  
  static inline void *
  snd_pcm_sgbuf_get_ptr(struct snd_pcm_substream *substream, unsigned int ofs)
  {
  	return substream->runtime->dma_area + ofs;
  }
  
  #define snd_pcm_sgbuf_ops_page	NULL
  
  #define snd_pcm_sgbuf_get_chunk_size(subs, ofs, size)	(size)
  
  #endif /* SND_DMA_SGBUF */
  
  /* handle mmap counter - PCM mmap callback should handle this counter properly */
  static inline void snd_pcm_mmap_data_open(struct vm_area_struct *area)
  {
  	struct snd_pcm_substream *substream = (struct snd_pcm_substream *)area->vm_private_data;
  	atomic_inc(&substream->mmap_count);
  }
  
  static inline void snd_pcm_mmap_data_close(struct vm_area_struct *area)
  {
  	struct snd_pcm_substream *substream = (struct snd_pcm_substream *)area->vm_private_data;
  	atomic_dec(&substream->mmap_count);
  }
  
  int snd_pcm_lib_default_mmap(struct snd_pcm_substream *substream,
  			     struct vm_area_struct *area);
  /* mmap for io-memory area */
  #if defined(CONFIG_X86) || defined(CONFIG_PPC) || defined(CONFIG_ALPHA)
  #define SNDRV_PCM_INFO_MMAP_IOMEM	SNDRV_PCM_INFO_MMAP
  int snd_pcm_lib_mmap_iomem(struct snd_pcm_substream *substream, struct vm_area_struct *area);
  #else
  #define SNDRV_PCM_INFO_MMAP_IOMEM	0
  #define snd_pcm_lib_mmap_iomem	NULL
  #endif
  
  #define snd_pcm_lib_mmap_vmalloc NULL
  
  static inline void snd_pcm_limit_isa_dma_size(int dma, size_t *max)
  {
  	*max = dma < 4 ? 64 * 1024 : 128 * 1024;
  }
  
  /*
   *  Misc
   */
  
  #define SNDRV_PCM_DEFAULT_CON_SPDIF	(IEC958_AES0_CON_EMPHASIS_NONE|\
  					 (IEC958_AES1_CON_ORIGINAL<<8)|\
  					 (IEC958_AES1_CON_PCM_CODER<<8)|\
  					 (IEC958_AES3_CON_FS_48000<<24))
  
  #define PCM_RUNTIME_CHECK(sub) snd_BUG_ON(!(sub) || !(sub)->runtime)
  
  const char *snd_pcm_format_name(snd_pcm_format_t format);
  
  /**
   * snd_pcm_stream_str - Get a string naming the direction of a stream
   * @substream: the pcm substream instance
   */
  static inline const char *snd_pcm_stream_str(struct snd_pcm_substream *substream)
  {
  	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
  		return "Playback";
  	else
  		return "Capture";
  }
  
  #endif /* __SOUND_PCM_H */
  