From 5a7513adab521909e836fa5b9aaabbf22b48859f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 18 Mar 2014 17:19:14 +0000 Subject: [PATCH] can: c_can: Simplify TX interrupt cleanup The function loads the message object from the hardware to get the payload length. The previous patch stores that information in an array, so we can avoid the hardware access. Remove the hardware access and move the led toggle outside of the spinlocked region. Toggle the led only once when at least one packet has been received. Binary size shrinks along with the code Signed-off-by: Thomas Gleixner Signed-off-by: Marc Kleine-Budde --- drivers/net/can/c_can/c_can.c | 37 ++++++++++++++++------------------- 1 file changed, 17 insertions(+), 20 deletions(-) diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 1e75223d614f..42c038d523c9 100644 --- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -232,10 +232,9 @@ static inline int get_tx_next_msg_obj(const struct c_can_priv *priv) C_CAN_MSG_OBJ_TX_FIRST; } -static inline int get_tx_echo_msg_obj(const struct c_can_priv *priv) +static inline int get_tx_echo_msg_obj(int txecho) { - return (priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) + - C_CAN_MSG_OBJ_TX_FIRST; + return (txecho & C_CAN_NEXT_MSG_OBJ_MASK) + C_CAN_MSG_OBJ_TX_FIRST; } static u32 c_can_read_reg32(struct c_can_priv *priv, enum reg index) @@ -729,8 +728,6 @@ static int c_can_get_berr_counter(const struct net_device *dev, } /* - * theory of operation: - * * priv->tx_echo holds the number of the oldest can_frame put for * transmission into the hardware, but not yet ACKed by the CAN tx * complete IRQ. @@ -741,29 +738,23 @@ static int c_can_get_berr_counter(const struct net_device *dev, */ static void c_can_do_tx(struct net_device *dev) { - u32 val; - u32 msg_obj_no; struct c_can_priv *priv = netdev_priv(dev); struct net_device_stats *stats = &dev->stats; + u32 val, obj, pkts = 0, bytes = 0; spin_lock_bh(&priv->xmit_lock); for (; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) { - msg_obj_no = get_tx_echo_msg_obj(priv); + obj = get_tx_echo_msg_obj(priv->tx_echo); val = c_can_read_reg32(priv, C_CAN_TXRQST1_REG); - if (!(val & (1 << (msg_obj_no - 1)))) { - can_get_echo_skb(dev, - msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST); - c_can_object_get(dev, IF_TX, msg_obj_no, IF_COMM_ALL); - stats->tx_bytes += priv->read_reg(priv, - C_CAN_IFACE(MSGCTRL_REG, IF_TX)) - & IF_MCONT_DLC_MASK; - stats->tx_packets++; - can_led_event(dev, CAN_LED_EVENT_TX); - c_can_inval_msg_object(dev, IF_TX, msg_obj_no); - } else { + + if (val & (1 << (obj - 1))) break; - } + + can_get_echo_skb(dev, obj - C_CAN_MSG_OBJ_TX_FIRST); + bytes += priv->dlc[obj - C_CAN_MSG_OBJ_TX_FIRST]; + pkts++; + c_can_inval_msg_object(dev, IF_TX, obj); } /* restart queue if wrap-up or if queue stalled on last pkt */ @@ -772,6 +763,12 @@ static void c_can_do_tx(struct net_device *dev) netif_wake_queue(dev); spin_unlock_bh(&priv->xmit_lock); + + if (pkts) { + stats->tx_bytes += bytes; + stats->tx_packets += pkts; + can_led_event(dev, CAN_LED_EVENT_TX); + } } /*