1/*
2 * Helper functions for indirect PCM data transfer to a simple FIFO in
3 * hardware (small, no possibility to read "hardware io position",
4 * updating position done by interrupt, ...)
5 *
6 *  Copyright (c) by 2007  Joachim Foerster <JOFT@gmx.de>
7 *
8 *  Based on "pcm-indirect.h" (alsa-driver-1.0.13) by
9 *
10 *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
11 *                   Jaroslav Kysela <perex@suse.cz>
12 *
13 *   This program is free software; you can redistribute it and/or modify
14 *   it under the terms of the GNU General Public License as published by
15 *   the Free Software Foundation; either version 2 of the License, or
16 *   (at your option) any later version.
17 *
18 *   This program is distributed in the hope that it will be useful,
19 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
20 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21 *   GNU General Public License for more details.
22 *
23 *   You should have received a copy of the GNU General Public License
24 *   along with this program; if not, write to the Free Software
25 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 */
27
28#ifndef __SOUND_PCM_INDIRECT2_H
29#define __SOUND_PCM_INDIRECT2_H
30
31/* struct snd_pcm_substream, struct snd_pcm_runtime, snd_pcm_uframes_t */
32#include <sound/pcm.h>
33
34/* Debug options for code which may be removed completely in a final version */
35#ifdef CONFIG_SND_DEBUG
36#define SND_PCM_INDIRECT2_STAT    /* turn on some "statistics" about the
37				   * process of copying bytes from the
38				   * intermediate buffer to the hardware
39				   * fifo and the other way round
40				   */
41#endif
42
43struct snd_pcm_indirect2 {
44	unsigned int hw_buffer_size;  /* Byte size of hardware buffer */
45	int hw_ready;		      /* playback: 1 = hw fifo has room left,
46				       * 0 = hw fifo is full
47				       */
48	unsigned int min_multiple;
49	int min_periods;	      /* counts number of min. periods until
50				       * min_multiple is reached
51				       */
52	int min_period_count;	      /* counts bytes to count number of
53				       * min. periods
54				       */
55
56	unsigned int sw_buffer_size;  /* Byte size of software buffer */
57
58	/* sw_data: position in intermediate buffer, where we will read (or
59	 *          write) from/to next time (to transfer data to/from HW)
60	 */
61	unsigned int sw_data;         /* Offset to next dst (or src) in sw
62				       * ring buffer
63				       */
64	/* easiest case (playback):
65	 * sw_data is nearly the same as ~ runtime->control->appl_ptr, with the
66	 * exception that sw_data is "behind" by the number if bytes ALSA wrote
67	 * to the intermediate buffer last time.
68	 * A call to ack() callback synchronizes both indirectly.
69	 */
70
71	/* We have no real sw_io pointer here. Usually sw_io is pointing to the
72	 * current playback/capture position _inside_ the hardware. Devices
73	 * with plain FIFOs often have no possibility to publish this position.
74	 * So we say: if sw_data is updated, that means bytes were copied to
75	 * the hardware, we increase sw_io by that amount, because there have
76	 * to be as much bytes which were played. So sw_io will stay behind
77	 * sw_data all the time and has to converge to sw_data at the end of
78	 * playback.
79	 */
80	unsigned int sw_io;           /* Current software pointer in bytes */
81
82	/* sw_ready: number of bytes ALSA copied to the intermediate buffer, so
83	 * it represents the number of bytes which wait for transfer to the HW
84	 */
85	int sw_ready;		  /* Bytes ready to be transferred to/from hw */
86
87	/* appl_ptr: last known position of ALSA (where ALSA is going to write
88	 * next time into the intermediate buffer
89	 */
90	snd_pcm_uframes_t appl_ptr;   /* Last seen appl_ptr */
91
92	unsigned int bytes2hw;
93	int check_alignment;
94
95#ifdef SND_PCM_INDIRECT2_STAT
96	unsigned int zeros2hw;
97	unsigned int mul_elapsed;
98	unsigned int mul_elapsed_real;
99	unsigned long firstbytetime;
100	unsigned long lastbytetime;
101	unsigned long firstzerotime;
102	unsigned int byte_sizes[64];
103	unsigned int zero_sizes[64];
104	unsigned int min_adds[8];
105	unsigned int mul_adds[8];
106	unsigned int zero_times[3750];	/* = 15s */
107	unsigned int zero_times_saved;
108	unsigned int zero_times_notsaved;
109	unsigned int irq_occured;
110	unsigned int pointer_calls;
111	unsigned int lastdifftime;
112#endif
113};
114
115typedef size_t (*snd_pcm_indirect2_copy_t) (struct snd_pcm_substream *substream,
116					   struct snd_pcm_indirect2 *rec,
117					   size_t bytes);
118typedef size_t (*snd_pcm_indirect2_zero_t) (struct snd_pcm_substream *substream,
119					   struct snd_pcm_indirect2 *rec);
120
121#ifdef SND_PCM_INDIRECT2_STAT
122void snd_pcm_indirect2_stat(struct snd_pcm_substream *substream,
123				   struct snd_pcm_indirect2 *rec);
124#endif
125
126snd_pcm_uframes_t
127snd_pcm_indirect2_pointer(struct snd_pcm_substream *substream,
128			  struct snd_pcm_indirect2 *rec);
129void
130snd_pcm_indirect2_playback_interrupt(struct snd_pcm_substream *substream,
131				     struct snd_pcm_indirect2 *rec,
132				     snd_pcm_indirect2_copy_t copy,
133				     snd_pcm_indirect2_zero_t zero);
134void
135snd_pcm_indirect2_capture_interrupt(struct snd_pcm_substream *substream,
136				    struct snd_pcm_indirect2 *rec,
137				    snd_pcm_indirect2_copy_t copy,
138				    snd_pcm_indirect2_zero_t null);
139
140#endif /* __SOUND_PCM_INDIRECT2_H */
141