ti_tx_desc
struct ti_tx_desc txdesc;
struct ti_tx_desc *cur_tx = NULL;
struct ti_tx_desc *f;
struct ti_tx_desc txdesc;
#define TI_TX_RING_SZ (sizeof(struct ti_tx_desc) * TI_TX_RING_CNT)
struct ti_tx_desc *ti_tx_ring;