SGentry
#define SEGMENTX_LEN (sizeof(struct SGentry)*DC395x_MAX_SG_LISTENTRY)
struct SGentry *psge = srb->segment_x + srb->sg_index;
struct SGentry *segment_x; /* Linear array of hw sg entries (up to 64 entries) */
sizeof(struct SGentry) *
struct SGentry *ptr;
struct SGentry *sgp = srb->segment_x;