Commit 9684b000 authored by Frank Jungclaus's avatar Frank Jungclaus Committed by Marc Kleine-Budde
Browse files

can: esd_usb: Make use of can_change_state() and relocate checking skb for NULL 



Start a rework initiated by Vincents remarks "You should not report
the greatest of txerr and rxerr but the one which actually increased."
[1] and "As far as I understand, those flags should be set only when
the threshold is reached" [2] .

Therefore make use of can_change_state() to (among others) set the
flags CAN_ERR_CRTL_[RT]X_WARNING and CAN_ERR_CRTL_[RT]X_PASSIVE,
maintain CAN statistic counters for error_warning, error_passive and
bus_off.

Relocate testing alloc_can_err_skb() for NULL to the end of
esd_usb_rx_event(), to have things like can_bus_off(),
can_change_state() working even in out of memory conditions.

Fixes: 96d8e903 ("can: Add driver for esd CAN-USB/2 device")
Signed-off-by: default avatarFrank Jungclaus <frank.jungclaus@esd.eu>
Link: [1] https://lore.kernel.org/all/CAMZ6RqKGBWe15aMkf8-QLf-cOQg99GQBebSm+1wEzTqHgvmNuw@mail.gmail.com/
Link: [2] https://lore.kernel.org/all/CAMZ6Rq+QBO1yTX_o6GV0yhdBj-RzZSRGWDZBS0fs7zbSTy4hmA@mail.gmail.com/
Link: https://lore.kernel.org/all/20230216190450.3901254-3-frank.jungclaus@esd.eu


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 118469f8

drivers/net/can/usb/esd_usb.c

+25 −25
Original line number Diff line number Diff line
@@ -239,41 +239,42 @@ static void esd_usb_rx_event(struct esd_usb_net_priv *priv, 
			   msg->msg.rx.dlc, state, ecc, rxerr, txerr);



		skb = alloc_can_err_skb(priv->netdev, &cf);

		if (skb == NULL) {

			stats->rx_dropped++;

			return;

		}



		if (state != priv->old_state) {

			enum can_state tx_state, rx_state;

			enum can_state new_state = CAN_STATE_ERROR_ACTIVE;



			priv->old_state = state;



			switch (state & ESD_BUSSTATE_MASK) {

			case ESD_BUSSTATE_BUSOFF:

				priv->can.state = CAN_STATE_BUS_OFF;

				cf->can_id |= CAN_ERR_BUSOFF;

				priv->can.can_stats.bus_off++;

				new_state = CAN_STATE_BUS_OFF;

				can_bus_off(priv->netdev);

				break;

			case ESD_BUSSTATE_WARN:

				priv->can.state = CAN_STATE_ERROR_WARNING;

				priv->can.can_stats.error_warning++;

				new_state = CAN_STATE_ERROR_WARNING;

				break;

			case ESD_BUSSTATE_ERRPASSIVE:

				priv->can.state = CAN_STATE_ERROR_PASSIVE;

				priv->can.can_stats.error_passive++;

				new_state = CAN_STATE_ERROR_PASSIVE;

				break;

			default:

				priv->can.state = CAN_STATE_ERROR_ACTIVE;

				new_state = CAN_STATE_ERROR_ACTIVE;

				txerr = 0;

				rxerr = 0;

				break;

			}

		} else {



			if (new_state != priv->can.state) {

				tx_state = (txerr >= rxerr) ? new_state : 0;

				rx_state = (txerr <= rxerr) ? new_state : 0;

				can_change_state(priv->netdev, cf,

						 tx_state, rx_state);

			}

		} else if (skb) {

			priv->can.can_stats.bus_error++;

			stats->rx_errors++;



			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR |

				      CAN_ERR_CNT;

			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;



			switch (ecc & SJA1000_ECC_MASK) {

			case SJA1000_ECC_BIT:
@@ -295,21 +296,20 @@ static void esd_usb_rx_event(struct esd_usb_net_priv *priv, 


			/* Bit stream position in CAN frame as the error was detected */

			cf->data[3] = ecc & SJA1000_ECC_SEG;



			if (priv->can.state == CAN_STATE_ERROR_WARNING ||

			    priv->can.state == CAN_STATE_ERROR_PASSIVE) {

				cf->data[1] = (txerr > rxerr) ?

					CAN_ERR_CRTL_TX_PASSIVE :

					CAN_ERR_CRTL_RX_PASSIVE;

			}

			cf->data[6] = txerr;

			cf->data[7] = rxerr;

		}



		priv->bec.txerr = txerr;

		priv->bec.rxerr = rxerr;



		if (skb) {

			cf->can_id |= CAN_ERR_CNT;

			cf->data[6] = txerr;

			cf->data[7] = rxerr;



			netif_rx(skb);

		} else {

			stats->rx_dropped++;

		}

	}

}