can: janz-ican3: fix support for CAN_RAW_RECV_OWN_MSGS
The Janz VMOD-ICAN3 firmware does not support any sort of TX-done notification or interrupt. The driver previously used the hardware loopback to attempt to work around this deficiency, but this caused all sockets to receive all messages, even if CAN_RAW_RECV_OWN_MSGS is off. Using the new function ican3_cmp_echo_skb(), we can drop the loopback messages and return the original skbs. This fixes the issues with CAN_RAW_RECV_OWN_MSGS. A private skb queue is used to store the echo skbs. This avoids the need for any index management. Due to a lack of TX-error interrupts, bus errors are permanently enabled, and are used as a TX-error notification. This is used to drop an echo skb when transmission fails. Bus error packets are not generated if the user has not enabled bus error reporting. Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Ira W. Snyder
Marc Kleine-Budde
parent
88b587039c
commit
83702f6927
1 changed files with 157 additions and 46 deletions
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@ -220,6 +220,9 @@ struct ican3_dev {
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/* old and new style host interface */
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unsigned int iftype;
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/* queue for echo packets */
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struct sk_buff_head echoq;
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/*
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* Any function which changes the current DPM page must hold this
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* lock while it is performing data accesses. This ensures that the
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@ -925,7 +928,7 @@ static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
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struct net_device *dev = mod->ndev;
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struct net_device_stats *stats = &dev->stats;
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enum can_state state = mod->can.state;
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u8 status, isrc, rxerr, txerr;
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u8 isrc, ecc, status, rxerr, txerr;
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struct can_frame *cf;
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struct sk_buff *skb;
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@ -941,15 +944,43 @@ static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
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return -EINVAL;
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}
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skb = alloc_can_err_skb(dev, &cf);
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if (skb == NULL)
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return -ENOMEM;
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isrc = msg->data[0];
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ecc = msg->data[2];
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status = msg->data[3];
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rxerr = msg->data[4];
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txerr = msg->data[5];
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/*
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* This hardware lacks any support other than bus error messages to
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* determine if packet transmission has failed.
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*
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* When TX errors happen, one echo skb needs to be dropped from the
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* front of the queue.
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*
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* A small bit of code is duplicated here and below, to avoid error
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* skb allocation when it will just be freed immediately.
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*/
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if (isrc == CEVTIND_BEI) {
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int ret;
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dev_dbg(mod->dev, "bus error interrupt\n");
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/* TX error */
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if (!(ecc & ECC_DIR)) {
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kfree_skb(skb_dequeue(&mod->echoq));
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stats->tx_errors++;
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} else {
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stats->rx_errors++;
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}
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/* bus error reporting is off, return immediately */
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if (!(mod->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
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return 0;
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}
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skb = alloc_can_err_skb(dev, &cf);
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if (skb == NULL)
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return -ENOMEM;
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/* data overrun interrupt */
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if (isrc == CEVTIND_DOI || isrc == CEVTIND_LOST) {
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dev_dbg(mod->dev, "data overrun interrupt\n");
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@ -978,9 +1009,6 @@ static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
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/* bus error interrupt */
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if (isrc == CEVTIND_BEI) {
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u8 ecc = msg->data[2];
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dev_dbg(mod->dev, "bus error interrupt\n");
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mod->can.can_stats.bus_error++;
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cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
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@ -1000,12 +1028,8 @@ static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
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break;
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}
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if (!(ecc & ECC_DIR)) {
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if (!(ecc & ECC_DIR))
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cf->data[2] |= CAN_ERR_PROT_TX;
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stats->tx_errors++;
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} else {
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stats->rx_errors++;
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}
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cf->data[6] = txerr;
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cf->data[7] = rxerr;
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@ -1089,6 +1113,88 @@ static void ican3_handle_message(struct ican3_dev *mod, struct ican3_msg *msg)
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}
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}
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/*
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* The ican3 needs to store all echo skbs, and therefore cannot
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* use the generic infrastructure for this.
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*/
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static void ican3_put_echo_skb(struct ican3_dev *mod, struct sk_buff *skb)
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{
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struct sock *srcsk = skb->sk;
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if (atomic_read(&skb->users) != 1) {
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struct sk_buff *old_skb = skb;
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skb = skb_clone(old_skb, GFP_ATOMIC);
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kfree_skb(old_skb);
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if (!skb)
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return;
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} else {
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skb_orphan(skb);
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}
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skb->sk = srcsk;
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/* save this skb for tx interrupt echo handling */
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skb_queue_tail(&mod->echoq, skb);
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}
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static unsigned int ican3_get_echo_skb(struct ican3_dev *mod)
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{
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struct sk_buff *skb = skb_dequeue(&mod->echoq);
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struct can_frame *cf;
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u8 dlc;
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/* this should never trigger unless there is a driver bug */
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if (!skb) {
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netdev_err(mod->ndev, "BUG: echo skb not occupied\n");
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return 0;
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}
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cf = (struct can_frame *)skb->data;
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dlc = cf->can_dlc;
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/* check flag whether this packet has to be looped back */
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if (skb->pkt_type != PACKET_LOOPBACK) {
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kfree_skb(skb);
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return dlc;
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}
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skb->protocol = htons(ETH_P_CAN);
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skb->pkt_type = PACKET_BROADCAST;
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skb->ip_summed = CHECKSUM_UNNECESSARY;
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skb->dev = mod->ndev;
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netif_receive_skb(skb);
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return dlc;
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}
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/*
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* Compare an skb with an existing echo skb
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*
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* This function will be used on devices which have a hardware loopback.
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* On these devices, this function can be used to compare a received skb
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* with the saved echo skbs so that the hardware echo skb can be dropped.
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*
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* Returns true if the skb's are identical, false otherwise.
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*/
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static bool ican3_echo_skb_matches(struct ican3_dev *mod, struct sk_buff *skb)
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{
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struct can_frame *cf = (struct can_frame *)skb->data;
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struct sk_buff *echo_skb = skb_peek(&mod->echoq);
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struct can_frame *echo_cf;
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if (!echo_skb)
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return false;
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echo_cf = (struct can_frame *)echo_skb->data;
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if (cf->can_id != echo_cf->can_id)
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return false;
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if (cf->can_dlc != echo_cf->can_dlc)
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return false;
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return memcmp(cf->data, echo_cf->data, cf->can_dlc) == 0;
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}
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/*
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* Check that there is room in the TX ring to transmit another skb
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*
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@ -1099,6 +1205,10 @@ static bool ican3_txok(struct ican3_dev *mod)
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struct ican3_fast_desc __iomem *desc;
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u8 control;
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/* check that we have echo queue space */
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if (skb_queue_len(&mod->echoq) >= ICAN3_TX_BUFFERS)
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return false;
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/* copy the control bits of the descriptor */
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ican3_set_page(mod, mod->fasttx_start + (mod->fasttx_num / 16));
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desc = mod->dpm + ((mod->fasttx_num % 16) * sizeof(*desc));
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@ -1149,10 +1259,27 @@ static int ican3_recv_skb(struct ican3_dev *mod)
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/* convert the ICAN3 frame into Linux CAN format */
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ican3_to_can_frame(mod, &desc, cf);
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/* receive the skb, update statistics */
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netif_receive_skb(skb);
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/*
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* If this is an ECHO frame received from the hardware loopback
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* feature, use the skb saved in the ECHO stack instead. This allows
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* the Linux CAN core to support CAN_RAW_RECV_OWN_MSGS correctly.
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*
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* Since this is a confirmation of a successfully transmitted packet
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* sent from this host, update the transmit statistics.
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*
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* Also, the netdevice queue needs to be allowed to send packets again.
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*/
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if (ican3_echo_skb_matches(mod, skb)) {
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stats->tx_packets++;
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stats->tx_bytes += ican3_get_echo_skb(mod);
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kfree_skb(skb);
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goto err_noalloc;
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}
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/* update statistics, receive the skb */
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stats->rx_packets++;
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stats->rx_bytes += cf->can_dlc;
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netif_receive_skb(skb);
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err_noalloc:
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/* toggle the valid bit and return the descriptor to the ring */
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@ -1175,13 +1302,13 @@ static int ican3_recv_skb(struct ican3_dev *mod)
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static int ican3_napi(struct napi_struct *napi, int budget)
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{
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struct ican3_dev *mod = container_of(napi, struct ican3_dev, napi);
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struct ican3_msg msg;
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unsigned long flags;
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int received = 0;
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int ret;
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/* process all communication messages */
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while (true) {
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struct ican3_msg msg;
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ret = ican3_recv_msg(mod, &msg);
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if (ret)
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break;
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@ -1353,7 +1480,6 @@ static int __devinit ican3_startup_module(struct ican3_dev *mod)
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static int ican3_open(struct net_device *ndev)
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{
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struct ican3_dev *mod = netdev_priv(ndev);
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u8 quota;
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int ret;
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/* open the CAN layer */
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@ -1363,19 +1489,6 @@ static int ican3_open(struct net_device *ndev)
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return ret;
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}
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/* set the bus error generation state appropriately */
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if (mod->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
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quota = ICAN3_BUSERR_QUOTA_MAX;
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else
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quota = 0;
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ret = ican3_set_buserror(mod, quota);
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if (ret) {
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dev_err(mod->dev, "unable to set bus-error\n");
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close_candev(ndev);
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return ret;
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}
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/* bring the bus online */
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ret = ican3_set_bus_state(mod, true);
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if (ret) {
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@ -1407,6 +1520,9 @@ static int ican3_stop(struct net_device *ndev)
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return ret;
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}
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/* drop all outstanding echo skbs */
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skb_queue_purge(&mod->echoq);
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/* close the CAN layer */
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close_candev(ndev);
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return 0;
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@ -1415,7 +1531,6 @@ static int ican3_stop(struct net_device *ndev)
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static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev)
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{
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struct ican3_dev *mod = netdev_priv(ndev);
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struct net_device_stats *stats = &ndev->stats;
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struct can_frame *cf = (struct can_frame *)skb->data;
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struct ican3_fast_desc desc;
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void __iomem *desc_addr;
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@ -1428,8 +1543,7 @@ static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev)
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/* check that we can actually transmit */
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if (!ican3_txok(mod)) {
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dev_err(mod->dev, "no free descriptors, stopping queue\n");
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netif_stop_queue(ndev);
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dev_err(mod->dev, "BUG: no free descriptors\n");
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spin_unlock_irqrestore(&mod->lock, flags);
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return NETDEV_TX_BUSY;
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}
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@ -1443,6 +1557,14 @@ static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev)
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/* convert the Linux CAN frame into ICAN3 format */
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can_frame_to_ican3(mod, cf, &desc);
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/*
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* This hardware doesn't have TX-done notifications, so we'll try and
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* emulate it the best we can using ECHO skbs. Add the skb to the ECHO
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* stack. Upon packet reception, check if the ECHO skb and received
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* skb match, and use that to wake the queue.
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*/
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ican3_put_echo_skb(mod, skb);
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/*
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* the programming manual says that you must set the IVALID bit, then
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* interrupt, then set the valid bit. Quite weird, but it seems to be
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@ -1461,19 +1583,7 @@ static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev)
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mod->fasttx_num = (desc.control & DESC_WRAP) ? 0
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: (mod->fasttx_num + 1);
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/* update statistics */
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stats->tx_packets++;
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stats->tx_bytes += cf->can_dlc;
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kfree_skb(skb);
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/*
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* This hardware doesn't have TX-done notifications, so we'll try and
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* emulate it the best we can using ECHO skbs. Get the next TX
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* descriptor, and see if we have room to send. If not, stop the queue.
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* It will be woken when the ECHO skb for the current packet is recv'd.
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*/
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/* copy the control bits of the descriptor */
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/* if there is no free descriptor space, stop the transmit queue */
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if (!ican3_txok(mod))
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netif_stop_queue(ndev);
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@ -1669,6 +1779,7 @@ static int __devinit ican3_probe(struct platform_device *pdev)
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mod->dev = &pdev->dev;
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mod->num = pdata->modno;
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netif_napi_add(ndev, &mod->napi, ican3_napi, ICAN3_RX_BUFFERS);
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skb_queue_head_init(&mod->echoq);
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spin_lock_init(&mod->lock);
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init_completion(&mod->termination_comp);
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init_completion(&mod->buserror_comp);
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