diff options
Diffstat (limited to 'drivers/net/can/c_can/c_can_main.c')
-rw-r--r-- | drivers/net/can/c_can/c_can_main.c | 123 |
1 files changed, 86 insertions, 37 deletions
diff --git a/drivers/net/can/c_can/c_can_main.c b/drivers/net/can/c_can/c_can_main.c index 7588f70ca0fe..52671d1ea17d 100644 --- a/drivers/net/can/c_can/c_can_main.c +++ b/drivers/net/can/c_can/c_can_main.c @@ -160,8 +160,8 @@ #define IF_MCONT_TX (IF_MCONT_TXIE | IF_MCONT_EOB) -/* Use IF1 for RX and IF2 for TX */ -#define IF_RX 0 +/* Use IF1 in NAPI path and IF2 in TX path */ +#define IF_NAPI 0 #define IF_TX 1 /* minimum timeout for checking BUSY status */ @@ -427,24 +427,51 @@ static void c_can_setup_receive_object(struct net_device *dev, int iface, c_can_object_put(dev, iface, obj, IF_COMM_RCV_SETUP); } +static bool c_can_tx_busy(const struct c_can_priv *priv, + const struct c_can_tx_ring *tx_ring) +{ + if (c_can_get_tx_free(tx_ring) > 0) + return false; + + netif_stop_queue(priv->dev); + + /* Memory barrier before checking tx_free (head and tail) */ + smp_mb(); + + if (c_can_get_tx_free(tx_ring) == 0) { + netdev_dbg(priv->dev, + "Stopping tx-queue (tx_head=0x%08x, tx_tail=0x%08x, len=%d).\n", + tx_ring->head, tx_ring->tail, + tx_ring->head - tx_ring->tail); + return true; + } + + netif_start_queue(priv->dev); + return false; +} + static netdev_tx_t c_can_start_xmit(struct sk_buff *skb, struct net_device *dev) { struct can_frame *frame = (struct can_frame *)skb->data; struct c_can_priv *priv = netdev_priv(dev); - u32 idx, obj; + struct c_can_tx_ring *tx_ring = &priv->tx; + u32 idx, obj, cmd = IF_COMM_TX; if (can_dropped_invalid_skb(dev, skb)) return NETDEV_TX_OK; - /* This is not a FIFO. C/D_CAN sends out the buffers - * prioritized. The lowest buffer number wins. - */ - idx = fls(atomic_read(&priv->tx_active)); - obj = idx + priv->msg_obj_tx_first; - /* If this is the last buffer, stop the xmit queue */ - if (idx == priv->msg_obj_tx_num - 1) + if (c_can_tx_busy(priv, tx_ring)) + return NETDEV_TX_BUSY; + + idx = c_can_get_tx_head(tx_ring); + tx_ring->head++; + if (c_can_get_tx_free(tx_ring) == 0) netif_stop_queue(dev); + + if (idx < c_can_get_tx_tail(tx_ring)) + cmd &= ~IF_COMM_TXRQST; /* Cache the message */ + /* Store the message in the interface so we can call * can_put_echo_skb(). We must do this before we enable * transmit as we might race against do_tx(). @@ -452,11 +479,8 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb, c_can_setup_tx_object(dev, IF_TX, frame, idx); priv->dlc[idx] = frame->len; can_put_echo_skb(skb, dev, idx, 0); - - /* Update the active bits */ - atomic_add(BIT(idx), &priv->tx_active); - /* Start transmission */ - c_can_object_put(dev, IF_TX, obj, IF_COMM_TX); + obj = idx + priv->msg_obj_tx_first; + c_can_object_put(dev, IF_TX, obj, cmd); return NETDEV_TX_OK; } @@ -529,13 +553,13 @@ static void c_can_configure_msg_objects(struct net_device *dev) /* first invalidate all message objects */ for (i = priv->msg_obj_rx_first; i <= priv->msg_obj_num; i++) - c_can_inval_msg_object(dev, IF_RX, i); + c_can_inval_msg_object(dev, IF_NAPI, i); /* setup receive message objects */ for (i = priv->msg_obj_rx_first; i < priv->msg_obj_rx_last; i++) - c_can_setup_receive_object(dev, IF_RX, i, 0, 0, IF_MCONT_RCV); + c_can_setup_receive_object(dev, IF_NAPI, i, 0, 0, IF_MCONT_RCV); - c_can_setup_receive_object(dev, IF_RX, priv->msg_obj_rx_last, 0, 0, + c_can_setup_receive_object(dev, IF_NAPI, priv->msg_obj_rx_last, 0, 0, IF_MCONT_RCV_EOB); } @@ -567,6 +591,7 @@ static int c_can_software_reset(struct net_device *dev) static int c_can_chip_config(struct net_device *dev) { struct c_can_priv *priv = netdev_priv(dev); + struct c_can_tx_ring *tx_ring = &priv->tx; int err; err = c_can_software_reset(dev); @@ -598,7 +623,8 @@ static int c_can_chip_config(struct net_device *dev) priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED); /* Clear all internal status */ - atomic_set(&priv->tx_active, 0); + tx_ring->head = 0; + tx_ring->tail = 0; priv->tx_dir = 0; /* set bittiming params */ @@ -696,40 +722,57 @@ static int c_can_get_berr_counter(const struct net_device *dev, static void c_can_do_tx(struct net_device *dev) { struct c_can_priv *priv = netdev_priv(dev); + struct c_can_tx_ring *tx_ring = &priv->tx; struct net_device_stats *stats = &dev->stats; - u32 idx, obj, pkts = 0, bytes = 0, pend, clr; + u32 idx, obj, pkts = 0, bytes = 0, pend; + u8 tail; if (priv->msg_obj_tx_last > 32) pend = priv->read_reg32(priv, C_CAN_INTPND3_REG); else pend = priv->read_reg(priv, C_CAN_INTPND2_REG); - clr = pend; while ((idx = ffs(pend))) { idx--; pend &= ~BIT(idx); obj = idx + priv->msg_obj_tx_first; - /* We use IF_RX interface instead of IF_TX because we + /* We use IF_NAPI interface instead of IF_TX because we * are called from c_can_poll(), which runs inside - * NAPI. We are not trasmitting. + * NAPI. We are not transmitting. */ - c_can_inval_tx_object(dev, IF_RX, obj); + c_can_inval_tx_object(dev, IF_NAPI, obj); can_get_echo_skb(dev, idx, NULL); bytes += priv->dlc[idx]; pkts++; } - /* Clear the bits in the tx_active mask */ - atomic_sub(clr, &priv->tx_active); + if (!pkts) + return; - if (clr & BIT(priv->msg_obj_tx_num - 1)) - netif_wake_queue(dev); + tx_ring->tail += pkts; + if (c_can_get_tx_free(tx_ring)) { + /* Make sure that anybody stopping the queue after + * this sees the new tx_ring->tail. + */ + smp_mb(); + netif_wake_queue(priv->dev); + } - if (pkts) { - stats->tx_bytes += bytes; - stats->tx_packets += pkts; - can_led_event(dev, CAN_LED_EVENT_TX); + stats->tx_bytes += bytes; + stats->tx_packets += pkts; + can_led_event(dev, CAN_LED_EVENT_TX); + + tail = c_can_get_tx_tail(tx_ring); + + if (tail == 0) { + u8 head = c_can_get_tx_head(tx_ring); + + /* Start transmission for all cached messages */ + for (idx = tail; idx < head; idx++) { + obj = idx + priv->msg_obj_tx_first; + c_can_object_put(dev, IF_NAPI, obj, IF_COMM_TXRQST); + } } } @@ -766,14 +809,14 @@ static u32 c_can_adjust_pending(u32 pend, u32 rx_mask) static inline void c_can_rx_object_get(struct net_device *dev, struct c_can_priv *priv, u32 obj) { - c_can_object_get(dev, IF_RX, obj, priv->comm_rcv_high); + c_can_object_get(dev, IF_NAPI, obj, priv->comm_rcv_high); } static inline void c_can_rx_finalize(struct net_device *dev, struct c_can_priv *priv, u32 obj) { if (priv->type != BOSCH_D_CAN) - c_can_object_get(dev, IF_RX, obj, IF_COMM_CLR_NEWDAT); + c_can_object_get(dev, IF_NAPI, obj, IF_COMM_CLR_NEWDAT); } static int c_can_read_objects(struct net_device *dev, struct c_can_priv *priv, @@ -785,10 +828,12 @@ static int c_can_read_objects(struct net_device *dev, struct c_can_priv *priv, pend &= ~BIT(obj - 1); c_can_rx_object_get(dev, priv, obj); - ctrl = priv->read_reg(priv, C_CAN_IFACE(MSGCTRL_REG, IF_RX)); + ctrl = priv->read_reg(priv, C_CAN_IFACE(MSGCTRL_REG, IF_NAPI)); if (ctrl & IF_MCONT_MSGLST) { - int n = c_can_handle_lost_msg_obj(dev, IF_RX, obj, ctrl); + int n; + + n = c_can_handle_lost_msg_obj(dev, IF_NAPI, obj, ctrl); pkts += n; quota -= n; @@ -803,7 +848,7 @@ static int c_can_read_objects(struct net_device *dev, struct c_can_priv *priv, continue; /* read the data from the message object */ - c_can_read_msg_object(dev, IF_RX, ctrl); + c_can_read_msg_object(dev, IF_NAPI, ctrl); c_can_rx_finalize(dev, priv, obj); @@ -1205,6 +1250,10 @@ struct net_device *alloc_c_can_dev(int msg_obj_num) priv->msg_obj_tx_last = priv->msg_obj_tx_first + priv->msg_obj_tx_num - 1; + priv->tx.head = 0; + priv->tx.tail = 0; + priv->tx.obj_num = msg_obj_tx_num; + netif_napi_add(dev, &priv->napi, c_can_poll, priv->msg_obj_rx_num); priv->dev = dev; |