can: kvaser_usb: Consolidate and unify state change handling

Replace most of the can interface's state and error counters
handling with the new can-dev can_change_state() mechanism.

Suggested-by: Andri Yngvason <andri.yngvason@marel.com>
Signed-off-by: Ahmed S. Darwish <ahmed.darwish@valeo.com>
Acked-by: Andri Yngvason <andri.yngvason@marel.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c
index f57ce55..ddc2954 100644 (file)
--- a/drivers/net/can/usb/kvaser_usb.c
+++ b/drivers/net/can/usb/kvaser_usb.c
@@ -620,39 +620,44 @@ static void kvaser_usb_unlink_tx_urbs(struct kvaser_usb_net_priv *priv)
 }
 
 static void kvaser_usb_rx_error_update_can_state(struct kvaser_usb_net_priv *priv,
-                                                const struct kvaser_usb_error_summary *es)
+                                                const struct kvaser_usb_error_summary *es,
+                                                struct can_frame *cf)
 {
        struct net_device_stats *stats;
-       enum can_state new_state;
-
-       stats = &priv->netdev->stats;
-       new_state = priv->can.state;
+       enum can_state cur_state, new_state, tx_state, rx_state;
 
        netdev_dbg(priv->netdev, "Error status: 0x%02x\n", es->status);
 
-       if (es->status & (M16C_STATE_BUS_OFF | M16C_STATE_BUS_RESET)) {
-               priv->can.can_stats.bus_off++;
+       stats = &priv->netdev->stats;
+       new_state = cur_state = priv->can.state;
+
+       if (es->status & (M16C_STATE_BUS_OFF | M16C_STATE_BUS_RESET))
                new_state = CAN_STATE_BUS_OFF;
-       } else if (es->status & M16C_STATE_BUS_PASSIVE) {
-               if (priv->can.state != CAN_STATE_ERROR_PASSIVE)
-                       priv->can.can_stats.error_passive++;
+       else if (es->status & M16C_STATE_BUS_PASSIVE)
                new_state = CAN_STATE_ERROR_PASSIVE;
-       } else if (es->status & M16C_STATE_BUS_ERROR) {
-               if ((priv->can.state < CAN_STATE_ERROR_WARNING) &&
-                   ((es->txerr >= 96) || (es->rxerr >= 96))) {
-                       priv->can.can_stats.error_warning++;
+       else if (es->status & M16C_STATE_BUS_ERROR) {
+               if ((es->txerr >= 256) || (es->rxerr >= 256))
+                       new_state = CAN_STATE_BUS_OFF;
+               else if ((es->txerr >= 128) || (es->rxerr >= 128))
+                       new_state = CAN_STATE_ERROR_PASSIVE;
+               else if ((es->txerr >= 96) || (es->rxerr >= 96))
                        new_state = CAN_STATE_ERROR_WARNING;
-               } else if ((priv->can.state > CAN_STATE_ERROR_ACTIVE) &&
-                          ((es->txerr < 96) && (es->rxerr < 96))) {
+               else if (cur_state > CAN_STATE_ERROR_ACTIVE)
                        new_state = CAN_STATE_ERROR_ACTIVE;
-               }
        }
 
        if (!es->status)
                new_state = CAN_STATE_ERROR_ACTIVE;
 
+       if (new_state != cur_state) {
+               tx_state = (es->txerr >= es->rxerr) ? new_state : 0;
+               rx_state = (es->txerr <= es->rxerr) ? new_state : 0;
+
+               can_change_state(priv->netdev, cf, tx_state, rx_state);
+       }
+
        if (priv->can.restart_ms &&
-           (priv->can.state >= CAN_STATE_BUS_OFF) &&
+           (cur_state >= CAN_STATE_BUS_OFF) &&
            (new_state < CAN_STATE_BUS_OFF)) {
                priv->can.can_stats.restarts++;
        }
@@ -664,18 +669,17 @@ static void kvaser_usb_rx_error_update_can_state(struct kvaser_usb_net_priv *pri
 
        priv->bec.txerr = es->txerr;
        priv->bec.rxerr = es->rxerr;
-       priv->can.state = new_state;
 }
 
 static void kvaser_usb_rx_error(const struct kvaser_usb *dev,
                                const struct kvaser_msg *msg)
 {
-       struct can_frame *cf;
+       struct can_frame *cf, tmp_cf = { .can_id = CAN_ERR_FLAG, .can_dlc = CAN_ERR_DLC };
        struct sk_buff *skb;
        struct net_device_stats *stats;
        struct kvaser_usb_net_priv *priv;
        struct kvaser_usb_error_summary es = { };
-       enum can_state old_state;
+       enum can_state old_state, new_state;
 
        switch (msg->id) {
        case CMD_CAN_ERROR_EVENT:
@@ -715,59 +719,40 @@ static void kvaser_usb_rx_error(const struct kvaser_usb *dev,
        stats = &priv->netdev->stats;
 
        /* Update all of the can interface's state and error counters before
-        * trying any skb allocation that can actually fail with -ENOMEM.
+        * trying any memory allocation that can actually fail with -ENOMEM.
+        *
+        * We send a temporary stack-allocated error can frame to
+        * can_change_state() for the very same reason.
+        *
+        * TODO: Split can_change_state() responsibility between updating the
+        * can interface's state and counters, and the setting up of can error
+        * frame ID and data to userspace. Remove stack allocation afterwards.
         */
        old_state = priv->can.state;
-       kvaser_usb_rx_error_update_can_state(priv, &es);
+       kvaser_usb_rx_error_update_can_state(priv, &es, &tmp_cf);
+       new_state = priv->can.state;
 
        skb = alloc_can_err_skb(priv->netdev, &cf);
        if (!skb) {
                stats->rx_dropped++;
                return;
        }
-
-       if (es.status & (M16C_STATE_BUS_OFF | M16C_STATE_BUS_RESET)) {
-               cf->can_id |= CAN_ERR_BUSOFF;
-
-               if (!priv->can.restart_ms)
-                       kvaser_usb_simple_msg_async(priv, CMD_STOP_CHIP);
-               netif_carrier_off(priv->netdev);
-       } else if (es.status & M16C_STATE_BUS_PASSIVE) {
-               if (old_state != CAN_STATE_ERROR_PASSIVE) {
-                       cf->can_id |= CAN_ERR_CRTL;
-
-                       if (es.txerr || es.rxerr)
-                               cf->data[1] = (es.txerr > es.rxerr)
-                                               ? CAN_ERR_CRTL_TX_PASSIVE
-                                               : CAN_ERR_CRTL_RX_PASSIVE;
-                       else
-                               cf->data[1] = CAN_ERR_CRTL_TX_PASSIVE |
-                                             CAN_ERR_CRTL_RX_PASSIVE;
-               }
-       } else if (es.status & M16C_STATE_BUS_ERROR) {
-               if ((old_state < CAN_STATE_ERROR_WARNING) &&
-                   ((es.txerr >= 96) || (es.rxerr >= 96))) {
-                       cf->can_id |= CAN_ERR_CRTL;
-                       cf->data[1] = (es.txerr > es.rxerr)
-                                       ? CAN_ERR_CRTL_TX_WARNING
-                                       : CAN_ERR_CRTL_RX_WARNING;
-               } else if ((old_state > CAN_STATE_ERROR_ACTIVE) &&
-                          ((es.txerr < 96) && (es.rxerr < 96))) {
-                       cf->can_id |= CAN_ERR_PROT;
-                       cf->data[2] = CAN_ERR_PROT_ACTIVE;
+       memcpy(cf, &tmp_cf, sizeof(*cf));
+
+       if (new_state != old_state) {
+               if (es.status &
+                   (M16C_STATE_BUS_OFF | M16C_STATE_BUS_RESET)) {
+                       if (!priv->can.restart_ms)
+                               kvaser_usb_simple_msg_async(priv, CMD_STOP_CHIP);
+                       netif_carrier_off(priv->netdev);
                }
-       }
-
-       if (!es.status) {
-               cf->can_id |= CAN_ERR_PROT;
-               cf->data[2] = CAN_ERR_PROT_ACTIVE;
-       }
 
-       if (priv->can.restart_ms &&
-           (old_state >= CAN_STATE_BUS_OFF) &&
-           (priv->can.state < CAN_STATE_BUS_OFF)) {
-               cf->can_id |= CAN_ERR_RESTARTED;
-               netif_carrier_on(priv->netdev);
+               if (priv->can.restart_ms &&
+                   (old_state >= CAN_STATE_BUS_OFF) &&
+                   (new_state < CAN_STATE_BUS_OFF)) {
+                       cf->can_id |= CAN_ERR_RESTARTED;
+                       netif_carrier_on(priv->netdev);
+               }
        }
 
        if (es.error_factor) {