can: sja1000: Add support for listen-only mode and one-shot mode

One-shot mode uses the TCS bit of the status register to discern
whether a transmission was successful or not. On a failed
transmission, the frame is not echoed back.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 24 insertions, 7 deletions

diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index 4c4f33d482d2..25011dbe1b96 100644
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -156,8 +156,13 @@ static void set_normal_mode(struct net_device *dev)
                 }
 
                 /* set chip to normal mode */
-                priv->write_reg(priv, REG_MOD, 0x00);
+                if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+                        priv->write_reg(priv, REG_MOD, MOD_LOM);
+                else
+                        priv->write_reg(priv, REG_MOD, 0x00);
+
                 udelay(10);
+
                 status = priv->read_reg(priv, REG_MOD);
         }
 
@@ -310,7 +315,10 @@ static netdev_tx_t sja1000_start_xmit(struct sk_buff *skb,
 
         can_put_echo_skb(skb, dev, 0);
 
-        sja1000_write_cmdreg(priv, CMD_TR);
+        if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
+                sja1000_write_cmdreg(priv, CMD_TR | CMD_AT);
+        else
+                sja1000_write_cmdreg(priv, CMD_TR);
 
         return NETDEV_TX_OK;
 }
@@ -505,10 +513,18 @@ irqreturn_t sja1000_interrupt(int irq, void *dev_id)
                         netdev_warn(dev, "wakeup interrupt\n");
 
                 if (isrc & IRQ_TI) {
-                        /* transmission complete interrupt */
-                        stats->tx_bytes += priv->read_reg(priv, REG_FI) & 0xf;
-                        stats->tx_packets++;
-                        can_get_echo_skb(dev, 0);
+                        /* transmission buffer released */
+                        if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT &&
+                            !(status & SR_TCS)) {
+                                stats->tx_errors++;
+                                can_free_echo_skb(dev, 0);
+                        } else {
+                                /* transmission complete */
+                                stats->tx_bytes +=
+                                        priv->read_reg(priv, REG_FI) & 0xf;
+                                stats->tx_packets++;
+                                can_get_echo_skb(dev, 0);
+                        }
                         netif_wake_queue(dev);
                 }
                 if (isrc & IRQ_RI) {
@@ -605,7 +621,8 @@ struct net_device *alloc_sja1000dev(int sizeof_priv)
         priv->can.do_set_mode = sja1000_set_mode;
         priv->can.do_get_berr_counter = sja1000_get_berr_counter;
         priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
-                CAN_CTRLMODE_BERR_REPORTING;
+                CAN_CTRLMODE_BERR_REPORTING | CAN_CTRLMODE_LISTENONLY |
+                CAN_CTRLMODE_ONE_SHOT;
 
         spin_lock_init(&priv->cmdreg_lock);