linux-stable/sound/firewire/cmp.h
Takashi Sakamoto 7bc93821a7 ALSA: firewire-lib: split allocation of isochronous resources from establishment of connection
In current implementation, establishment connection corresponds to
allocation of isochronous resources. Although this is an ideal
implementation of CMP described in IEC 61883-1, it's not enough
efficient to recover PCM substream multiplexed in packet streaming.
The packet streaming can always restart on the same allocated
isochronous resources even if the previous packet streaming
corrupted.

This commit splits allocation of isochronous resources from
establishment of connection so that CMP runs with allocated
isochronous resources.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2019-06-17 08:18:36 +02:00

53 lines
1.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef SOUND_FIREWIRE_CMP_H_INCLUDED
#define SOUND_FIREWIRE_CMP_H_INCLUDED
#include <linux/mutex.h>
#include <linux/types.h>
#include "iso-resources.h"
struct fw_unit;
enum cmp_direction {
CMP_INPUT = 0,
CMP_OUTPUT,
};
/**
* struct cmp_connection - manages an isochronous connection to a device
* @speed: the connection's actual speed
*
* This structure manages (using CMP) an isochronous stream between the local
* computer and a device's input plug (iPCR) and output plug (oPCR).
*
* There is no corresponding oPCR created on the local computer, so it is not
* possible to overlay connections on top of this one.
*/
struct cmp_connection {
int speed;
/* private: */
bool connected;
struct mutex mutex;
struct fw_iso_resources resources;
__be32 last_pcr_value;
unsigned int pcr_index;
unsigned int max_speed;
enum cmp_direction direction;
};
int cmp_connection_init(struct cmp_connection *connection,
struct fw_unit *unit,
enum cmp_direction direction,
unsigned int pcr_index);
int cmp_connection_check_used(struct cmp_connection *connection, bool *used);
void cmp_connection_destroy(struct cmp_connection *connection);
int cmp_connection_reserve(struct cmp_connection *connection,
unsigned int max_payload);
void cmp_connection_release(struct cmp_connection *connection);
int cmp_connection_establish(struct cmp_connection *connection);
int cmp_connection_update(struct cmp_connection *connection);
void cmp_connection_break(struct cmp_connection *connection);
#endif