From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ira W. Snyder" Subject: [PATCH] can: janz-ican3: fix support for CAN_RAW_RECV_OWN_MSGS Date: Fri, 13 Jul 2012 08:20:30 -0700 Message-ID: <1342192830-31538-1-git-send-email-iws@ovro.caltech.edu> References: <4FFFE3AF.4020907@pengutronix.de> Return-path: Received: from ovro.ovro.caltech.edu ([192.100.16.2]:49372 "EHLO ovro.ovro.caltech.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755669Ab2GMPUd (ORCPT ); Fri, 13 Jul 2012 11:20:33 -0400 Received: from localhost (localhost [127.0.0.1]) by ovro.ovro.caltech.edu (Postfix) with ESMTP id 5BD9E222FA for ; Fri, 13 Jul 2012 08:20:32 -0700 (PDT) In-Reply-To: <4FFFE3AF.4020907@pengutronix.de> Sender: linux-can-owner@vger.kernel.org List-ID: To: linux-can@vger.kernel.org Cc: "Ira W. Snyder" From: "Ira W. Snyder" 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. Signed-off-by: Ira W. Snyder --- This is a squashed together version of the first two patches in the series. drivers/net/can/janz-ican3.c | 156 +++++++++++++++++++++++++++++++++++------- 1 files changed, 130 insertions(+), 26 deletions(-) diff --git a/drivers/net/can/janz-ican3.c b/drivers/net/can/janz-ican3.c index 08c893c..5fff829 100644 --- a/drivers/net/can/janz-ican3.c +++ b/drivers/net/can/janz-ican3.c @@ -220,6 +220,9 @@ struct ican3_dev { /* old and new style host interface */ unsigned int iftype; + /* queue for echo packets */ + struct sk_buff_head echoq; + /* * Any function which changes the current DPM page must hold this * lock while it is performing data accesses. This ensures that the @@ -235,7 +238,6 @@ struct ican3_dev { /* fast host interface */ unsigned int fastrx_start; - unsigned int fastrx_int; unsigned int fastrx_num; unsigned int fasttx_start; unsigned int fasttx_num; @@ -454,7 +456,6 @@ static void __devinit ican3_init_fast_host_interface(struct ican3_dev *mod) /* save the start recv page */ mod->fastrx_start = mod->free_page; mod->fastrx_num = 0; - mod->fastrx_int = 0; /* build a single fast tohost queue descriptor */ memset(&desc, 0, sizeof(desc)); @@ -1091,6 +1092,87 @@ static void ican3_handle_message(struct ican3_dev *mod, struct ican3_msg *msg) } /* + * The ican3 needs to store all echo skbs, and therefore cannot + * use the generic infrastructure for this. + */ +static void ican3_put_echo_skb(struct ican3_dev *mod, struct sk_buff *skb) +{ + struct sock *srcsk = skb->sk; + + if (atomic_read(&skb->users) != 1) { + struct sk_buff *old_skb = skb; + + skb = skb_clone(old_skb, GFP_ATOMIC); + kfree_skb(old_skb); + if (!skb) + return; + } else + skb_orphan(skb); + + skb->sk = srcsk; + + /* save this skb for tx interrupt echo handling */ + skb_queue_tail(&mod->echoq, skb); +} + +static unsigned int ican3_get_echo_skb(struct ican3_dev *mod) +{ + struct sk_buff *skb = skb_dequeue(&mod->echoq); + struct can_frame *cf; + u8 dlc; + + if (!skb) + return 0; + + /* check flag whether this packet has to be looped back */ + if (!(mod->ndev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK) { + kfree_skb(skb); + return 0; + } + + /* make settings for echo to reduce code in irq context */ + skb->protocol = htons(ETH_P_CAN); + skb->pkt_type = PACKET_BROADCAST; + skb->ip_summed = CHECKSUM_UNNECESSARY; + skb->dev = mod->ndev; + + cf = (struct can_frame *)skb->data; + dlc = cf->can_dlc; + netif_receive_skb(skb); + + return dlc; +} + +/* + * Compare an skb with an existing echo skb + * + * This function will be used on devices which have a hardware loopback. + * On these devices, this function can be used to compare a received skb + * with the saved echo skbs so that the hardware echo skb can be dropped. + * + * Returns true if the skb's are identical, false otherwise. + */ +static bool ican3_cmp_echo_skb(struct ican3_dev *mod, struct sk_buff *skb) +{ + struct can_frame *cf = (struct can_frame *)skb->data; + struct sk_buff *echo_skb = skb_peek(&mod->echoq); + + if (echo_skb) { + struct can_frame *echo_cf = (struct can_frame *)echo_skb->data; + + if (cf->can_id != echo_cf->can_id) + return false; + + if (cf->can_dlc != echo_cf->can_dlc) + return false; + + return memcmp(cf->data, echo_cf->data, cf->can_dlc) == 0; + } + + return false; +} + +/* * Check that there is room in the TX ring to transmit another skb * * LOCKING: must hold mod->lock @@ -1100,6 +1182,10 @@ static bool ican3_txok(struct ican3_dev *mod) struct ican3_fast_desc __iomem *desc; u8 control; + /* check that we have echo queue space */ + if (skb_queue_len(&mod->echoq) >= ICAN3_TX_BUFFERS) + return false; + /* copy the control bits of the descriptor */ ican3_set_page(mod, mod->fasttx_start + (mod->fasttx_num / 16)); desc = mod->dpm + ((mod->fasttx_num % 16) * sizeof(*desc)); @@ -1150,10 +1236,27 @@ static int ican3_recv_skb(struct ican3_dev *mod) /* convert the ICAN3 frame into Linux CAN format */ ican3_to_can_frame(mod, &desc, cf); - /* receive the skb, update statistics */ - netif_receive_skb(skb); + /* + * If this is an ECHO frame received from the hardware loopback + * feature, use the skb saved in the ECHO stack instead. This allows + * the Linux CAN core to support CAN_RAW_RECV_OWN_MSGS correctly. + * + * Since this is a confirmation of a successfully transmitted packet + * sent from this host, update the transmit statistics. + * + * Also, the netdevice queue needs to be allowed to send packets again. + */ + if (ican3_cmp_echo_skb(mod, skb)) { + stats->tx_packets++; + stats->tx_bytes += ican3_get_echo_skb(mod); + kfree_skb(skb); + goto err_noalloc; + } + + /* update statistics, receive the skb */ stats->rx_packets++; stats->rx_bytes += cf->can_dlc; + netif_receive_skb(skb); err_noalloc: /* toggle the valid bit and return the descriptor to the ring */ @@ -1176,13 +1279,13 @@ err_noalloc: static int ican3_napi(struct napi_struct *napi, int budget) { struct ican3_dev *mod = container_of(napi, struct ican3_dev, napi); - struct ican3_msg msg; unsigned long flags; int received = 0; int ret; /* process all communication messages */ while (true) { + struct ican3_msg msg; ret = ican3_recv_msg(mod, &msg); if (ret) break; @@ -1199,11 +1302,6 @@ static int ican3_napi(struct napi_struct *napi, int budget) received++; } - /* We have processed all packets that the adapter had, but it - * was less than our budget, stop polling */ - if (received < budget) - napi_complete(napi); - spin_lock_irqsave(&mod->lock, flags); /* Wake up the transmit queue if necessary */ @@ -1212,6 +1310,11 @@ static int ican3_napi(struct napi_struct *napi, int budget) spin_unlock_irqrestore(&mod->lock, flags); + /* We have processed all packets that the adapter had, but it + * was less than our budget, stop polling */ + if (received < budget) + napi_complete(napi); + /* re-enable interrupt generation */ iowrite8(1 << mod->num, &mod->ctrl->int_enable); return received; @@ -1408,6 +1511,9 @@ static int ican3_stop(struct net_device *ndev) return ret; } + /* drop all outstanding echo skbs */ + skb_queue_purge(&mod->echoq); + /* close the CAN layer */ close_candev(ndev); return 0; @@ -1416,18 +1522,19 @@ static int ican3_stop(struct net_device *ndev) static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev) { struct ican3_dev *mod = netdev_priv(ndev); - struct net_device_stats *stats = &ndev->stats; struct can_frame *cf = (struct can_frame *)skb->data; struct ican3_fast_desc desc; void __iomem *desc_addr; unsigned long flags; + if (can_dropped_invalid_skb(ndev, skb)) + return NETDEV_TX_OK; + spin_lock_irqsave(&mod->lock, flags); /* check that we can actually transmit */ if (!ican3_txok(mod)) { - dev_err(mod->dev, "no free descriptors, stopping queue\n"); - netif_stop_queue(ndev); + dev_err(mod->dev, "BUG: no free descriptors\n"); spin_unlock_irqrestore(&mod->lock, flags); return NETDEV_TX_BUSY; } @@ -1442,6 +1549,14 @@ static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev) can_frame_to_ican3(mod, cf, &desc); /* + * This hardware doesn't have TX-done notifications, so we'll try and + * emulate it the best we can using ECHO skbs. Add the skb to the ECHO + * stack. Upon packet reception, check if the ECHO skb and received + * skb match, and use that to wake the queue. + */ + ican3_put_echo_skb(mod, skb); + + /* * the programming manual says that you must set the IVALID bit, then * interrupt, then set the valid bit. Quite weird, but it seems to be * required for this to work @@ -1459,19 +1574,7 @@ static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev) mod->fasttx_num = (desc.control & DESC_WRAP) ? 0 : (mod->fasttx_num + 1); - /* update statistics */ - stats->tx_packets++; - stats->tx_bytes += cf->can_dlc; - kfree_skb(skb); - - /* - * This hardware doesn't have TX-done notifications, so we'll try and - * emulate it the best we can using ECHO skbs. Get the next TX - * descriptor, and see if we have room to send. If not, stop the queue. - * It will be woken when the ECHO skb for the current packet is recv'd. - */ - - /* copy the control bits of the descriptor */ + /* if there is no free descriptor space, stop the transmit queue */ if (!ican3_txok(mod)) netif_stop_queue(ndev); @@ -1667,6 +1770,7 @@ static int __devinit ican3_probe(struct platform_device *pdev) mod->dev = &pdev->dev; mod->num = pdata->modno; netif_napi_add(ndev, &mod->napi, ican3_napi, ICAN3_RX_BUFFERS); + skb_queue_head_init(&mod->echoq); spin_lock_init(&mod->lock); init_completion(&mod->termination_comp); init_completion(&mod->buserror_comp); -- 1.7.8.6