pcm_period
unsigned int pcm_period;
while (chip->pcm_tdone >= chip->pcm_period) {
chip->pcm_hwptr += chip->pcm_period;
chip->pcm_tdone -= chip->pcm_period;
chip->pcm_period = runtime->period_size;
struct pcm_period *next;
struct pcm_period *buffer;
struct pcm_period *pointer;
struct pcm_period *pointer_next;
struct pcm_period *pointer;
stream->buffer = kmalloc_obj(struct pcm_period);
pointer->next = kmalloc_obj(struct pcm_period);