diff options
author | Anssi Hannula <anssi.hannula@bitwise.fi> | 2019-10-04 12:02:56 +0300 |
---|---|---|
committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2019-11-11 23:58:09 +0300 |
commit | 91e9f2c0e7a49ec6a6673b4d97d535b838396fc9 (patch) | |
tree | 8e4946a42f62965160ed9fde7b9ba8ed05bee328 /drivers/net/can/xilinx_can.c | |
parent | b687a7792b9c28778f1d4359fafcec3c17147c58 (diff) | |
download | linux-91e9f2c0e7a49ec6a6673b4d97d535b838396fc9.tar.xz |
can: xilinx_can: avoid non-requested bus error frames
Userspace can signal with CAN_CTRLMODE_BERR_REPORTING whether they need
reporting of bus errors (CAN_ERR_BUSERROR) or not.
However, xilinx_can driver currently always sends CAN_ERR_BUSERROR
frames to userspace on bus errors.
To improve performance on error conditions when bus error reporting is
not needed, avoid sending CAN_ERR_BUSERROR frames unless requested via
CAN_CTRLMODE_BERR_REPORTING.
The error interrupt is still kept enabled as there is no dedicated state
transition interrupt, but just disabling error frame submission still
yields a significant performance improvement. In a simple test with
continuous bus errors and no userspace programs reading/writing CAN I
saw system CPU load reduced by 1/3.
Tested on a ZynqMP board with CAN-FD v1.0.
Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'drivers/net/can/xilinx_can.c')
-rw-r--r-- | drivers/net/can/xilinx_can.c | 89 |
1 files changed, 48 insertions, 41 deletions
diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index b6fa735e47f1..f33863379036 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -470,7 +470,13 @@ static int xcan_chip_start(struct net_device *ndev) if (err < 0) return err; - /* Enable interrupts */ + /* Enable interrupts + * + * We enable the ERROR interrupt even with + * CAN_CTRLMODE_BERR_REPORTING disabled as there is no + * dedicated interrupt for a state change to + * ERROR_WARNING/ERROR_PASSIVE. + */ ier = XCAN_IXR_TXOK_MASK | XCAN_IXR_BSOFF_MASK | XCAN_IXR_WKUP_MASK | XCAN_IXR_SLP_MASK | XCAN_IXR_ERROR_MASK | XCAN_IXR_RXOFLW_MASK | @@ -980,12 +986,9 @@ static void xcan_err_interrupt(struct net_device *ndev, u32 isr) { struct xcan_priv *priv = netdev_priv(ndev); struct net_device_stats *stats = &ndev->stats; - struct can_frame *cf; - struct sk_buff *skb; + struct can_frame cf = { }; u32 err_status; - skb = alloc_can_err_skb(ndev, &cf); - err_status = priv->read_reg(priv, XCAN_ESR_OFFSET); priv->write_reg(priv, XCAN_ESR_OFFSET, err_status); @@ -995,32 +998,27 @@ static void xcan_err_interrupt(struct net_device *ndev, u32 isr) /* Leave device in Config Mode in bus-off state */ priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK); can_bus_off(ndev); - if (skb) - cf->can_id |= CAN_ERR_BUSOFF; + cf.can_id |= CAN_ERR_BUSOFF; } else { enum can_state new_state = xcan_current_error_state(ndev); if (new_state != priv->can.state) - xcan_set_error_state(ndev, new_state, skb ? cf : NULL); + xcan_set_error_state(ndev, new_state, &cf); } /* Check for Arbitration lost interrupt */ if (isr & XCAN_IXR_ARBLST_MASK) { priv->can.can_stats.arbitration_lost++; - if (skb) { - cf->can_id |= CAN_ERR_LOSTARB; - cf->data[0] = CAN_ERR_LOSTARB_UNSPEC; - } + cf.can_id |= CAN_ERR_LOSTARB; + cf.data[0] = CAN_ERR_LOSTARB_UNSPEC; } /* Check for RX FIFO Overflow interrupt */ if (isr & XCAN_IXR_RXOFLW_MASK) { stats->rx_over_errors++; stats->rx_errors++; - if (skb) { - cf->can_id |= CAN_ERR_CRTL; - cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW; - } + cf.can_id |= CAN_ERR_CRTL; + cf.data[1] |= CAN_ERR_CRTL_RX_OVERFLOW; } /* Check for RX Match Not Finished interrupt */ @@ -1028,68 +1026,77 @@ static void xcan_err_interrupt(struct net_device *ndev, u32 isr) stats->rx_dropped++; stats->rx_errors++; netdev_err(ndev, "RX match not finished, frame discarded\n"); - if (skb) { - cf->can_id |= CAN_ERR_CRTL; - cf->data[1] |= CAN_ERR_CRTL_UNSPEC; - } + cf.can_id |= CAN_ERR_CRTL; + cf.data[1] |= CAN_ERR_CRTL_UNSPEC; } /* Check for error interrupt */ if (isr & XCAN_IXR_ERROR_MASK) { - if (skb) - cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR; + bool berr_reporting = false; + + if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) { + berr_reporting = true; + cf.can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR; + } /* Check for Ack error interrupt */ if (err_status & XCAN_ESR_ACKER_MASK) { stats->tx_errors++; - if (skb) { - cf->can_id |= CAN_ERR_ACK; - cf->data[3] = CAN_ERR_PROT_LOC_ACK; + if (berr_reporting) { + cf.can_id |= CAN_ERR_ACK; + cf.data[3] = CAN_ERR_PROT_LOC_ACK; } } /* Check for Bit error interrupt */ if (err_status & XCAN_ESR_BERR_MASK) { stats->tx_errors++; - if (skb) { - cf->can_id |= CAN_ERR_PROT; - cf->data[2] = CAN_ERR_PROT_BIT; + if (berr_reporting) { + cf.can_id |= CAN_ERR_PROT; + cf.data[2] = CAN_ERR_PROT_BIT; } } /* Check for Stuff error interrupt */ if (err_status & XCAN_ESR_STER_MASK) { stats->rx_errors++; - if (skb) { - cf->can_id |= CAN_ERR_PROT; - cf->data[2] = CAN_ERR_PROT_STUFF; + if (berr_reporting) { + cf.can_id |= CAN_ERR_PROT; + cf.data[2] = CAN_ERR_PROT_STUFF; } } /* Check for Form error interrupt */ if (err_status & XCAN_ESR_FMER_MASK) { stats->rx_errors++; - if (skb) { - cf->can_id |= CAN_ERR_PROT; - cf->data[2] = CAN_ERR_PROT_FORM; + if (berr_reporting) { + cf.can_id |= CAN_ERR_PROT; + cf.data[2] = CAN_ERR_PROT_FORM; } } /* Check for CRC error interrupt */ if (err_status & XCAN_ESR_CRCER_MASK) { stats->rx_errors++; - if (skb) { - cf->can_id |= CAN_ERR_PROT; - cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ; + if (berr_reporting) { + cf.can_id |= CAN_ERR_PROT; + cf.data[3] = CAN_ERR_PROT_LOC_CRC_SEQ; } } priv->can.can_stats.bus_error++; } - if (skb) { - stats->rx_packets++; - stats->rx_bytes += cf->can_dlc; - netif_rx(skb); + if (cf.can_id) { + struct can_frame *skb_cf; + struct sk_buff *skb = alloc_can_err_skb(ndev, &skb_cf); + + if (skb) { + skb_cf->can_id |= cf.can_id; + memcpy(skb_cf->data, cf.data, CAN_ERR_DLC); + stats->rx_packets++; + stats->rx_bytes += CAN_ERR_DLC; + netif_rx(skb); + } } netdev_dbg(ndev, "%s: error status register:0x%x\n", |