rge_tx_desc
struct rge_tx_desc *d;
idx * sizeof(struct rge_tx_desc), len * sizeof(struct rge_tx_desc),
struct rge_tx_desc *d = NULL;
#define RGE_TX_LIST_SZ (sizeof(struct rge_tx_desc) * RGE_TX_LIST_CNT)
struct rge_tx_desc *rge_tx_list;