--- /dev/null
+/*
+ * Helper functions for indirect PCM data transfer to a simple FIFO in
+ * hardware (small, no possibility to read "hardware io position",
+ * updating position done by interrupt, ...)
+ *
+ * Copyright (c) by 2007 Joachim Foerster <JOFT@gmx.de>
+ *
+ * Based on "pcm-indirect.h" (alsa-driver-1.0.13) by
+ *
+ * Copyright (c) by Takashi Iwai <tiwai@suse.de>
+ * Jaroslav Kysela <perex@suse.cz>
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef __SOUND_PCM_INDIRECT2_H
+#define __SOUND_PCM_INDIRECT2_H
+
+/* struct snd_pcm_substream, struct snd_pcm_runtime, snd_pcm_uframes_t */
+#include <sound/pcm.h>
+
+/* Debug options for code which may be removed completely in a final version */
+#ifdef CONFIG_SND_DEBUG
+#define SND_PCM_INDIRECT2_STAT /* turn on some "statistics" about the
+ * process of copying bytes from the
+ * intermediate buffer to the hardware
+ * fifo and the other way round
+ */
+#endif
+
+struct snd_pcm_indirect2 {
+ unsigned int hw_buffer_size; /* Byte size of hardware buffer */
+ int hw_ready; /* playback: 1 = hw fifo has room left,
+ * 0 = hw fifo is full
+ */
+ unsigned int min_multiple;
+ int min_periods; /* counts number of min. periods until
+ * min_multiple is reached
+ */
+ int min_period_count; /* counts bytes to count number of
+ * min. periods
+ */
+
+ unsigned int sw_buffer_size; /* Byte size of software buffer */
+
+ /* sw_data: position in intermediate buffer, where we will read (or
+ * write) from/to next time (to transfer data to/from HW)
+ */
+ unsigned int sw_data; /* Offset to next dst (or src) in sw
+ * ring buffer
+ */
+ /* easiest case (playback):
+ * sw_data is nearly the same as ~ runtime->control->appl_ptr, with the
+ * exception that sw_data is "behind" by the number if bytes ALSA wrote
+ * to the intermediate buffer last time.
+ * A call to ack() callback synchronizes both indirectly.
+ */
+
+ /* We have no real sw_io pointer here. Usually sw_io is pointing to the
+ * current playback/capture position _inside_ the hardware. Devices
+ * with plain FIFOs often have no possibility to publish this position.
+ * So we say: if sw_data is updated, that means bytes were copied to
+ * the hardware, we increase sw_io by that amount, because there have
+ * to be as much bytes which were played. So sw_io will stay behind
+ * sw_data all the time and has to converge to sw_data at the end of
+ * playback.
+ */
+ unsigned int sw_io; /* Current software pointer in bytes */
+
+ /* sw_ready: number of bytes ALSA copied to the intermediate buffer, so
+ * it represents the number of bytes which wait for transfer to the HW
+ */
+ int sw_ready; /* Bytes ready to be transferred to/from hw */
+
+ /* appl_ptr: last known position of ALSA (where ALSA is going to write
+ * next time into the intermediate buffer
+ */
+ snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */
+
+ unsigned int bytes2hw;
+ int check_alignment;
+
+#ifdef SND_PCM_INDIRECT2_STAT
+ unsigned int zeros2hw;
+ unsigned int mul_elapsed;
+ unsigned int mul_elapsed_real;
+ unsigned long firstbytetime;
+ unsigned long lastbytetime;
+ unsigned long firstzerotime;
+ unsigned int byte_sizes[64];
+ unsigned int zero_sizes[64];
+ unsigned int min_adds[8];
+ unsigned int mul_adds[8];
+ unsigned int zero_times[3750]; /* = 15s */
+ unsigned int zero_times_saved;
+ unsigned int zero_times_notsaved;
+ unsigned int irq_occured;
+ unsigned int pointer_calls;
+ unsigned int lastdifftime;
+#endif
+};
+
+typedef size_t (*snd_pcm_indirect2_copy_t) (struct snd_pcm_substream *substream,
+ struct snd_pcm_indirect2 *rec,
+ size_t bytes);
+typedef size_t (*snd_pcm_indirect2_zero_t) (struct snd_pcm_substream *substream,
+ struct snd_pcm_indirect2 *rec);
+
+#ifdef SND_PCM_INDIRECT2_STAT
+void snd_pcm_indirect2_stat(struct snd_pcm_substream *substream,
+ struct snd_pcm_indirect2 *rec);
+#endif
+
+snd_pcm_uframes_t
+snd_pcm_indirect2_pointer(struct snd_pcm_substream *substream,
+ struct snd_pcm_indirect2 *rec);
+void
+snd_pcm_indirect2_playback_interrupt(struct snd_pcm_substream *substream,
+ struct snd_pcm_indirect2 *rec,
+ snd_pcm_indirect2_copy_t copy,
+ snd_pcm_indirect2_zero_t zero);
+void
+snd_pcm_indirect2_capture_interrupt(struct snd_pcm_substream *substream,
+ struct snd_pcm_indirect2 *rec,
+ snd_pcm_indirect2_copy_t copy,
+ snd_pcm_indirect2_zero_t null);
+
+#endif /* __SOUND_PCM_INDIRECT2_H */
Code Review / kvmfornfv.git / blobdiff