On Wed, May 09, 2018 at 02:43:43PM +0200, Lukas Wunner wrote:
> When sending packets as fast as possible using "cangen -g 0 -i -x", the
> HI-3110 occasionally latches the interrupt pin high on completion of a
> packet, but doesn't set the TXCPLT bit in the INTF register. The INTF
> register contains 0x00 as if no interrupt has occurred. Even waiting
> for a few milliseconds after the interrupt doesn't help.
>
> Work around this apparent erratum by instead checking the TXMTY bit in
> the STATF register ("TX FIFO empty"). We know that we've queued up a
> packet for transmission if priv->tx_len is nonzero. If the TX FIFO is
> empty, transmission of that packet must have completed.
>
> Note that this is congruent with our handling of received packets, which
> likewise gleans from the STATF register whether a packet is waiting in
> the RX FIFO, instead of looking at the INTF register.
I should have mentioned, to verify the existence of the erratum and the
validity of the patch, you can apply the little debug patch below, then
run "cangen -g 0 -i -x". You should see error messages in dmesg within
a few minutes.
-- >8 --
diff --git a/drivers/net/can/spi/hi311x.c b/drivers/net/can/spi/hi311x.c
index 53e320c..48b5c63 100644
--- a/drivers/net/can/spi/hi311x.c
+++ b/drivers/net/can/spi/hi311x.c
@@ -739,6 +739,9 @@ static irqreturn_t hi3110_can_ist(int irq, void *dev_id)
}
if (priv->tx_len && statf & HI3110_STAT_TXMTY) {
+ if (!(intf & HI3110_INT_TXCPLT))
+ dev_err(&spi->dev, "TX FIFO empty and TX was
queued but TXCPLT not set\n");
+
net->stats.tx_packets++;
net->stats.tx_bytes += priv->tx_len - 1;
can_led_event(net, CAN_LED_EVENT_TX);
