can: sja1000: sja1000_err(): use error counter for error state

The CAN controller sends the EPI interrupt whenever it reaches the error
passive status or enters the error active status from the error passive
status.

Instead of keeping track of the controller status in the driver, read the
txerr and rxerr counters and use can_state_get_by_berr_counter() to
determine the state of the CAN controller.

Suggested-by: Achim Baumgartner <abaumgartner@topcon.com>
Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Link: https://patch.msgid.link/20260123-sja1000-state-handling-v2-2-687498087dad@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index ae3244b63b6504ed04686e3b68647be7c63f0a96..67fccc15ed20435db9cde9f30e3ba7377d99979a 100644 (file)
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -407,10 +407,9 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
 {
        struct sja1000_priv *priv = netdev_priv(dev);
        struct net_device_stats *stats = &dev->stats;
+       enum can_state state, rx_state, tx_state;
        struct can_frame *cf;
        struct sk_buff *skb;
-       enum can_state state = priv->can.state;
-       enum can_state rx_state, tx_state;
        struct can_berr_counter bec;
        uint8_t ecc, alc;
        int ret = 0;
@@ -418,6 +417,12 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
        skb = alloc_can_err_skb(dev, &cf);
 
        sja1000_get_berr_counter(dev, &bec);
+       can_state_get_by_berr_counter(dev, &bec, &tx_state, &rx_state);
+
+       if (status & SR_BS)
+               rx_state = CAN_STATE_BUS_OFF;
+
+       state = max(tx_state, rx_state);
 
        if (isrc & IRQ_DOI) {
                /* data overrun interrupt */
@@ -440,18 +445,6 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
                if (priv->flags & SJA1000_QUIRK_RESET_ON_OVERRUN)
                        ret = IRQ_WAKE_THREAD;
        }
-
-       if (isrc & IRQ_EI) {
-               /* error warning interrupt */
-               netdev_dbg(dev, "error warning interrupt\n");
-
-               if (status & SR_BS)
-                       state = CAN_STATE_BUS_OFF;
-               else if (status & SR_ES)
-                       state = CAN_STATE_ERROR_WARNING;
-               else
-                       state = CAN_STATE_ERROR_ACTIVE;
-       }
        if (state != CAN_STATE_BUS_OFF && skb) {
                cf->can_id |= CAN_ERR_CNT;
                cf->data[6] = bec.txerr;
@@ -493,15 +486,6 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
                        stats->rx_errors++;
                }
        }
-       if (isrc & IRQ_EPI) {
-               /* error passive interrupt */
-               netdev_dbg(dev, "error passive interrupt\n");
-
-               if (state == CAN_STATE_ERROR_PASSIVE)
-                       state = CAN_STATE_ERROR_WARNING;
-               else
-                       state = CAN_STATE_ERROR_PASSIVE;
-       }
        if (isrc & IRQ_ALI) {
                /* arbitration lost interrupt */
                netdev_dbg(dev, "arbitration lost interrupt\n");
@@ -514,9 +498,6 @@ static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
        }
 
        if (state != priv->can.state) {
-               tx_state = bec.txerr >= bec.rxerr ? state : 0;
-               rx_state = bec.txerr <= bec.rxerr ? state : 0;
-
                can_change_state(dev, cf, tx_state, rx_state);
 
                if(state == CAN_STATE_BUS_OFF)