From 082d70b6142f623c10f7a032d9b63a2399fb4ded Mon Sep 17 00:00:00 2001 From: "Ahmed S. Darwish" Date: Sun, 15 Mar 2015 11:03:38 -0400 Subject: [PATCH] can: kvaser_usb: Comply with firmware max tx URBs value Current driver code arbitrarily assumes a max outstanding tx value of 16 parallel transmissions. Meanwhile, the device firmware provides its actual maximum inside its reply to the CMD_GET_SOFTWARE_INFO message. Under heavy tx traffic, if the interleaved transmissions count increases above the limit reported by firmware, the firmware breaks up badly, reports a massive list of internal errors, and the candump traces hardly matches the actual frames sent and received. On the other hand, in certain models, the firmware can support up to 48 tx URBs instead of just 16, increasing the driver throughput by two-fold and reducing the possibility of -ENOBUFs. Thus dynamically set the driver's max tx URBs value according to firmware replies. Signed-off-by: Ahmed S. Darwish Signed-off-by: Marc Kleine-Budde --- drivers/net/can/usb/kvaser_usb.c | 62 +++++++++++++++++++------------- 1 file changed, 38 insertions(+), 24 deletions(-) diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c index e97a08ce0b90..2f9733a8e125 100644 --- a/drivers/net/can/usb/kvaser_usb.c +++ b/drivers/net/can/usb/kvaser_usb.c @@ -25,7 +25,6 @@ #include #include -#define MAX_TX_URBS 16 #define MAX_RX_URBS 4 #define START_TIMEOUT 1000 /* msecs */ #define STOP_TIMEOUT 1000 /* msecs */ @@ -443,6 +442,7 @@ struct kvaser_usb_error_summary { }; }; +/* Context for an outstanding, not yet ACKed, transmission */ struct kvaser_usb_tx_urb_context { struct kvaser_usb_net_priv *priv; u32 echo_index; @@ -456,8 +456,13 @@ struct kvaser_usb { struct usb_endpoint_descriptor *bulk_in, *bulk_out; struct usb_anchor rx_submitted; + /* @max_tx_urbs: Firmware-reported maximum number of oustanding, + * not yet ACKed, transmissions on this device. This value is + * also used as a sentinel for marking free tx contexts. + */ u32 fw_version; unsigned int nchannels; + unsigned int max_tx_urbs; enum kvaser_usb_family family; bool rxinitdone; @@ -467,19 +472,18 @@ struct kvaser_usb { struct kvaser_usb_net_priv { struct can_priv can; - - spinlock_t tx_contexts_lock; - int active_tx_contexts; - struct kvaser_usb_tx_urb_context tx_contexts[MAX_TX_URBS]; - - struct usb_anchor tx_submitted; - struct completion start_comp, stop_comp; + struct can_berr_counter bec; struct kvaser_usb *dev; struct net_device *netdev; int channel; - struct can_berr_counter bec; + struct completion start_comp, stop_comp; + struct usb_anchor tx_submitted; + + spinlock_t tx_contexts_lock; + int active_tx_contexts; + struct kvaser_usb_tx_urb_context tx_contexts[]; }; static const struct usb_device_id kvaser_usb_table[] = { @@ -657,9 +661,13 @@ static int kvaser_usb_get_software_info(struct kvaser_usb *dev) switch (dev->family) { case KVASER_LEAF: dev->fw_version = le32_to_cpu(msg.u.leaf.softinfo.fw_version); + dev->max_tx_urbs = + le16_to_cpu(msg.u.leaf.softinfo.max_outstanding_tx); break; case KVASER_USBCAN: dev->fw_version = le32_to_cpu(msg.u.usbcan.softinfo.fw_version); + dev->max_tx_urbs = + le16_to_cpu(msg.u.usbcan.softinfo.max_outstanding_tx); break; } @@ -715,7 +723,7 @@ static void kvaser_usb_tx_acknowledge(const struct kvaser_usb *dev, stats = &priv->netdev->stats; - context = &priv->tx_contexts[tid % MAX_TX_URBS]; + context = &priv->tx_contexts[tid % dev->max_tx_urbs]; /* Sometimes the state change doesn't come after a bus-off event */ if (priv->can.restart_ms && @@ -744,7 +752,7 @@ static void kvaser_usb_tx_acknowledge(const struct kvaser_usb *dev, spin_lock_irqsave(&priv->tx_contexts_lock, flags); can_get_echo_skb(priv->netdev, context->echo_index); - context->echo_index = MAX_TX_URBS; + context->echo_index = dev->max_tx_urbs; --priv->active_tx_contexts; netif_wake_queue(priv->netdev); @@ -1512,11 +1520,13 @@ error: static void kvaser_usb_reset_tx_urb_contexts(struct kvaser_usb_net_priv *priv) { - int i; + int i, max_tx_urbs; + + max_tx_urbs = priv->dev->max_tx_urbs; priv->active_tx_contexts = 0; - for (i = 0; i < MAX_TX_URBS; i++) - priv->tx_contexts[i].echo_index = MAX_TX_URBS; + for (i = 0; i < max_tx_urbs; i++) + priv->tx_contexts[i].echo_index = max_tx_urbs; } /* This method might sleep. Do not call it in the atomic context @@ -1702,14 +1712,14 @@ static netdev_tx_t kvaser_usb_start_xmit(struct sk_buff *skb, *msg_tx_can_flags |= MSG_FLAG_REMOTE_FRAME; spin_lock_irqsave(&priv->tx_contexts_lock, flags); - for (i = 0; i < ARRAY_SIZE(priv->tx_contexts); i++) { - if (priv->tx_contexts[i].echo_index == MAX_TX_URBS) { + for (i = 0; i < dev->max_tx_urbs; i++) { + if (priv->tx_contexts[i].echo_index == dev->max_tx_urbs) { context = &priv->tx_contexts[i]; context->echo_index = i; can_put_echo_skb(skb, netdev, context->echo_index); ++priv->active_tx_contexts; - if (priv->active_tx_contexts >= MAX_TX_URBS) + if (priv->active_tx_contexts >= dev->max_tx_urbs) netif_stop_queue(netdev); break; @@ -1743,7 +1753,7 @@ static netdev_tx_t kvaser_usb_start_xmit(struct sk_buff *skb, spin_lock_irqsave(&priv->tx_contexts_lock, flags); can_free_echo_skb(netdev, context->echo_index); - context->echo_index = MAX_TX_URBS; + context->echo_index = dev->max_tx_urbs; --priv->active_tx_contexts; netif_wake_queue(netdev); @@ -1881,7 +1891,9 @@ static int kvaser_usb_init_one(struct usb_interface *intf, if (err) return err; - netdev = alloc_candev(sizeof(*priv), MAX_TX_URBS); + netdev = alloc_candev(sizeof(*priv) + + dev->max_tx_urbs * sizeof(*priv->tx_contexts), + dev->max_tx_urbs); if (!netdev) { dev_err(&intf->dev, "Cannot alloc candev\n"); return -ENOMEM; @@ -2009,6 +2021,13 @@ static int kvaser_usb_probe(struct usb_interface *intf, return err; } + dev_dbg(&intf->dev, "Firmware version: %d.%d.%d\n", + ((dev->fw_version >> 24) & 0xff), + ((dev->fw_version >> 16) & 0xff), + (dev->fw_version & 0xffff)); + + dev_dbg(&intf->dev, "Max oustanding tx = %d URBs\n", dev->max_tx_urbs); + err = kvaser_usb_get_card_info(dev); if (err) { dev_err(&intf->dev, @@ -2016,11 +2035,6 @@ static int kvaser_usb_probe(struct usb_interface *intf, return err; } - dev_dbg(&intf->dev, "Firmware version: %d.%d.%d\n", - ((dev->fw_version >> 24) & 0xff), - ((dev->fw_version >> 16) & 0xff), - (dev->fw_version & 0xffff)); - for (i = 0; i < dev->nchannels; i++) { err = kvaser_usb_init_one(intf, id, i); if (err) { -- 2.30.2