In the usb drivers, the echo skb is always released by the USB write complete callback.
--- Stéphane
From: Marc Kleine-Budde
Sent: Tuesday, March 9, 2021 11:58
To: Oliver Hartkopp; Stéphane Grosjean; linux-can Mailing List
Subject: Re: [PATCH 3/3] can/peak_usb: add support of ONE_SHOT mode
On 3/9/21 11:53 AM, Oliver Hartkopp wrote:
>> What happens if in one shot mode and the frame is not send? Who takes care of
>> the echo skb?
>
> ONE-SHOT only means that the CAN controller would not retry the
> transmission when e.g. loosing the arbitration or getting an error flag.
>
> The sja1000 does it this way, when the TX interrupt flag is set in the
> interrupt register:
>
> if (isrc & IRQ_TI) {
> /* 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,
> SJA1000_FI) & 0xf;
> stats->tx_packets++;
> can_get_echo_skb(dev, 0, NULL);
> }
> netif_wake_queue(dev);
> can_led_event(dev, CAN_LED_EVENT_TX);
> }
>
>
> Do we need to check this for the other drivers?
Yes.
Marc
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