ALSA #

1 ALSA

1.1 ALSA란?

1.2 드라이버 개발을 위한 문서

1.3 드라이버 API

1.3.1 자료 구조

1.3.2 snd_card_new

1.3.3 snd_card_register

1.3.4 snd_card_free

1.3.5 전원 관리

1.3.5.1 snd_card_set_pm_callback

1.3.5.2 snd_power_change_state

1.3.5.3 snd_pcm_suspend_all

1.3.6 PCM

1.3.6.1 자료 구조

1.3.6.2 PCM 연산

1.3.6.2.1 open

1.3.6.2.2 close

1.3.6.2.3 ioctl

1.3.6.2.4 hw_params

1.3.6.2.5 hw_free

1.3.6.2.6 prepare

1.3.6.2.7 trigger

1.3.6.2.8 pointer

1.3.6.3 snd_pcm_new

1.3.6.4 snd_pcm_lib_preallocate_pages_for_all

1.3.6.5 snd_pcm_set_ops

1.3.7 MIXER

1.3.7.1 snd_ctl_new

1.3.7.2 snd_ctl_new1

struct _snd_card {
  char driver[16];     /* �~S~\�~]��~]��~D �~]��~D */
  char shortname[32];  /* �~B��~Z��~S~\ 카�~S~\�~]~X 짧�~]~@ �~]��~D */
  char longname[80];   /* �~B��~Z��~S~\ 카�~S~\�~]~X �~]��~D */

  void *private_data;  /* �~B��~Z��~S~\ 카�~S~\�~W~P �~L~@�~U~\ �~T�~@ �| ~U보 */
  void (*private_free) (snd_card_t *card);  /* �~T�~@ �| ~U보�~]~D �~\~D�~U� �~U| �~K��~[�~]~@ �~^~P�~[~P */
                                            /* �~X�~Y~X�~]~D �~\~D�~U~\ �~\백 */

snd_card_t *snd_card_new(int idx, const char *xid,
                         struct module *module, int extra_size)

snd_card_t *card;

card = snd_card_new(-1, id, THIS_MODULE, sizeof(foo_bar));
if (card == NULL)
  return -ENOMEM;

int snd_card_register(snd_card_t *card)

int snd_card_free(snd_card_t *card)

#ifdef CONFIG_PM
static int snd_foo_suspend(...)
{
...
}
#endif

int snd_card_set_pm_callback(snd_card_t *card,
                             int (*suspend)(snd_card_t *, pm_message_t),
                             int (*resume)(snd_card_t *),
                             void *private_data)

snd_card_set_pm_callback(card, snd_foo_suspend, snd_foo_resume, foo);

typedef struct _snd_pcm_ops {
  int (*open)(snd_pcm_substream_t *substream);
  int (*close)(snd_pcm_substream_t *substream);
  int (*ioctl)(snd_pcm_substream_t *substream, unsigned int cmd, void *arg);
  int (*hw_params)(snd_pcm_substream_t *substream, snd_pcm_hw_params_t *params);
  int (*hw_free)(snd_pcm_substream_t *substream);
  int (*prepare)(snd_pcm_substream_t *substream);
  int (*trigger)(snd_pcm_substream_t *substream, int cmd);
  snd_pcm_uframes_t (*pointer)(snd_pcm_substream_t *substream);
  int (*copy)(snd_pcm_substream_t *substream, int channel, snd_pcm_uframes_t pos,
              void __user *buf, snd_pcm_ufreams_t count);
  struct page *(*page)(snd_pcm_substream_t *substream, unsigned long offset);
  int (*mmap)(snd_pcm_substream_t *substream, struct vm_area_struct *vma);
  int (*ack)(snd_pcm_substream_t *substream);
} snd_pcm_ops_t;

static int xxx_open(snd_pcm_substream_t *substream)

static int xxx_prepare(snd_pcm_substream_t *substream)

static int xxx_trigger(snd_pcm_substream_t *substream, int cmd)

static snd_pcm_uframes_t xxx_pointer(snd_pcm_substream_t *substream)

int snd_pcm_new(snd_card_t *card, char *id, int device,
                int playback_count, int capture_count,
                snd_pcm_t **rpcm)

int err;
snd_pcm_t *pcm;

if ((err = snd_pcm_new(foo->card, "FOO ACM", device, 1, 1, &pcm)) < 0)
  return err;
}

int snd_pcm_lib_preallocate_pages_for_all(snd_pcm_t *pcm, int type, void *data,
                                          size_t size, size_t max)

snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINOUS,
                                      snd_dma_continues_data(GFP_KERNEL),
                                      128 * 1024, 128 * 1024);

void snd_pcm_set_ops(snd_pcm_t *pcm, int direction, snd_pcm_ops_t *ops)

int snd_ctl_add(snd_card_t *card, snd_kcontrl_t *kcontrol)

if ((err = snd_ctl_add(card, snd_ctl_new1(&xxx_contols[idx], chip))) < 0)
  return err;

snd_kctonrol_t *snd_ctl_new1(const snd_kcontol_new_t *ncontrol, void *private_data)

if ((err = snd_ctl_add(card, snd_ctl_new1(&xxx_contols[idx], chip))) < 0)
  return err;