target/linux/layerscape/patches-5.4/802-can-0008-can-flexcan-flexcan_irq_state-only-read-timestamp-if.patch

   1 From 1a92e5a9109963e2491eec111b84b35b4e2adc8f Mon Sep 17 00:00:00 2001
   2 From: Marc Kleine-Budde <mkl@pengutronix.de>
   3 Date: Wed, 9 Oct 2019 15:15:37 +0200
   4 Subject: [PATCH] can: flexcan: flexcan_irq_state(): only read timestamp if
   5  needed
   6
   7 The function flexcan_irq_state() checks the controller for CAN state
   8 changes and pushes a skb with the new state and a timestamp into the
   9 rx-offload framework.
  10
  11 This patch optimizes the function by only reading the timestamp, if a
  12 state change is detected.
  13
  14 Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
  15 ---
  16  drivers/net/can/flexcan.c | 4 ++--
  17  1 file changed, 2 insertions(+), 2 deletions(-)
  18
  19 --- a/drivers/net/can/flexcan.c
  20 +++ b/drivers/net/can/flexcan.c
  21 @@ -743,8 +743,6 @@ static void flexcan_irq_state(struct net
  22         u32 timestamp;
  23         int err;
  24
  25 -       timestamp = priv->read(&regs->timer) << 16;
  26 -
  27         flt = reg_esr & FLEXCAN_ESR_FLT_CONF_MASK;
  28         if (likely(flt == FLEXCAN_ESR_FLT_CONF_ACTIVE)) {
  29                 tx_state = unlikely(reg_esr & FLEXCAN_ESR_TX_WRN) ?
  30 @@ -764,6 +762,8 @@ static void flexcan_irq_state(struct net
  31         if (likely(new_state == priv->can.state))
  32                 return;
  33
  34 +       timestamp = priv->read(&regs->timer) << 16;
  35 +
  36         skb = alloc_can_err_skb(dev, &cf);
  37         if (unlikely(!skb))
  38                 return;