sndsrv.h

Go to the documentation of this file.

 
#ifndef __SNDSRV_H__
#define __SNDSRV_H__
 
#include <stdint.h>
 
#define SNDSRV_RING_MAGIC   0x31565253u      /* 'SRV1' */
#define SNDSRV_DATA_OFFSET  4096
 
#define SNDSRV_IOC_ATTACH   0x5301           /* arg: SndsrvAttach */
#define SNDSRV_IOC_DETACH   0x5302
#define SNDSRV_IOC_STATS    0x5303           /* arg: SndsrvStats  */
 
#define SNDSRV_OK        0
#define SNDSRV_E_PERM   -1
#define SNDSRV_E_INVAL  -2
#define SNDSRV_E_BUSY   -3
 
typedef struct {
    uint32_t magic;
    uint32_t size;                /* data area bytes, a power of two */
    uint32_t period;              /* PCM period in bytes */
    uint32_t reserved;
    volatile uint32_t head;       /* bytes produced by the kernel */
    volatile uint32_t tail;       /* bytes consumed by the server */
    volatile uint32_t running;    /* 1 between start_output and stop_output */
    volatile uint32_t dropped;    /* bytes the kernel discarded: server too slow */
} SndRingHdr;
 
typedef struct { uint64_t ring_phys; uint64_t ring_len; } SndsrvAttach;
typedef struct { uint64_t written; uint64_t dropped; uint64_t calls; } SndsrvStats;
 
#endif