diff options
Diffstat (limited to 'drivers/net/can')
| -rw-r--r-- | drivers/net/can/at91_can.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c index 68b611d0fa6c..fbe58a1a1989 100644 --- a/drivers/net/can/at91_can.c +++ b/drivers/net/can/at91_can.c @@ -437,6 +437,11 @@ static void at91_chip_start(struct net_device *dev) priv->can.state = CAN_STATE_ERROR_ACTIVE; + /* Dummy read to clear latched line error interrupts on + * sam9x5 and newer SoCs. + */ + at91_read(priv, AT91_SR); + /* Enable interrupts */ reg_ier = get_irq_mb_rx(priv) | AT91_IRQ_ERRP | AT91_IRQ_ERR_FRAME; at91_write(priv, AT91_IER, reg_ier); @@ -932,7 +937,7 @@ static void at91_irq_err_state(struct net_device *dev, at91_write(priv, AT91_IER, reg_ier); } -static void at91_irq_err_line(struct net_device *dev) +static void at91_irq_err_line(struct net_device *dev, const u32 reg_sr) { enum can_state new_state, rx_state, tx_state; struct at91_priv *priv = netdev_priv(dev); @@ -942,6 +947,23 @@ static void at91_irq_err_line(struct net_device *dev) at91_get_berr_counter(dev, &bec); can_state_get_by_berr_counter(dev, &bec, &tx_state, &rx_state); + + /* The chip automatically recovers from bus-off after 128 + * occurrences of 11 consecutive recessive bits. + * + * After an auto-recovered bus-off, the error counters no + * longer reflect this fact. On the sam9263 the state bits in + * the SR register show the current state (based on the + * current error counters), while on sam9x5 and newer SoCs + * these bits are latched. + * + * Take any latched bus-off information from the SR register + * into account when calculating the CAN new state, to start + * the standard CAN bus off handling. + */ + if (reg_sr & AT91_IRQ_BOFF) + rx_state = CAN_STATE_BUS_OFF; + new_state = max(tx_state, rx_state); /* state hasn't changed */ @@ -1050,7 +1072,7 @@ static irqreturn_t at91_irq(int irq, void *dev_id) if (reg_sr & get_irq_mb_tx(priv)) at91_irq_tx(dev, reg_sr); - at91_irq_err_line(dev); + at91_irq_err_line(dev, reg_sr); /* Frame Error Interrupt */ if (reg_sr & AT91_IRQ_ERR_FRAME) |