From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Hartkopp Subject: Re: [PATCH 3/3] can: janz-ican3: fix support for CAN_RAW_RECV_OWN_MSGS Date: Mon, 09 Jul 2012 22:57:28 +0200 Message-ID: <4FFB45B8.10400@hartkopp.net> References: <1341863790-5645-1-git-send-email-iws@ovro.caltech.edu> <1341863790-5645-4-git-send-email-iws@ovro.caltech.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mo-p00-ob.rzone.de ([81.169.146.162]:21436 "EHLO mo-p00-ob.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751806Ab2GIU5W (ORCPT ); Mon, 9 Jul 2012 16:57:22 -0400 In-Reply-To: <1341863790-5645-4-git-send-email-iws@ovro.caltech.edu> Sender: linux-can-owner@vger.kernel.org List-ID: To: "Ira W. Snyder" Cc: linux-can@vger.kernel.org On 09.07.2012 21:56, Ira W. Snyder wrote: > 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 can_cmp_echo_skb(), we can drop the loopback > messages and return the original skbs. This fixes the issues with > CAN_RAW_RECV_OWN_MSGS. > > Signed-off-by: Ira W. Snyder > --- > drivers/net/can/janz-ican3.c | 56 ++++++++++++++++++++++------------------- > 1 files changed, 30 insertions(+), 26 deletions(-) > > diff --git a/drivers/net/can/janz-ican3.c b/drivers/net/can/janz-ican3.c > index 08c893c..a49af40 100644 > --- a/drivers/net/can/janz-ican3.c > +++ b/drivers/net/can/janz-ican3.c > @@ -235,7 +235,6 @@ 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 +453,6 @@ 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)); > @@ -1150,6 +1148,21 @@ static int ican3_recv_skb(struct ican3_dev *mod) > /* convert the ICAN3 frame into Linux CAN format */ > ican3_to_can_frame(mod, &desc, cf); > > + /* > + * 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. > + * > + * Also, the netdevice queue needs to be allowed to send packets again. > + */ > + if (can_cmp_echo_skb(skb, ndev, 0)) { > + stats->rx_packets++; > + stats->rx_bytes += can_get_echo_skb(ndev, 0); > + kfree_skb(skb); > + netif_wake_queue(ndev); > + goto err_noalloc; > + } > + > /* receive the skb, update statistics */ > netif_receive_skb(skb); > stats->rx_packets++; > @@ -1177,7 +1190,6 @@ 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; > > @@ -1204,14 +1216,6 @@ static int ican3_napi(struct napi_struct *napi, int budget) > if (received < budget) > napi_complete(napi); > > - spin_lock_irqsave(&mod->lock, flags); > - > - /* Wake up the transmit queue if necessary */ > - if (netif_queue_stopped(mod->ndev) && ican3_txok(mod)) > - netif_wake_queue(mod->ndev); > - > - spin_unlock_irqrestore(&mod->lock, flags); > - > /* re-enable interrupt generation */ > iowrite8(1 << mod->num, &mod->ctrl->int_enable); > return received; > @@ -1422,12 +1426,14 @@ static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev) > 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 +1448,16 @@ 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 and stop transmitting packets. Upon packet reception, check > + * if the ECHO skb and received skb match, and use that to wake the > + * queue. > + */ > + netif_stop_queue(ndev); > + can_put_echo_skb(skb, ndev, 0); > + > + /* > * 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 > @@ -1462,18 +1478,6 @@ static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev) > /* update statistics */ > stats->tx_packets++; > stats->tx_bytes += cf->can_dlc; I think these statistic updates double the traffic as you do them in ican3_recv_skb() again. > - 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 (!ican3_txok(mod)) > - netif_stop_queue(ndev); > > spin_unlock_irqrestore(&mod->lock, flags); > return NETDEV_TX_OK; > @@ -1654,7 +1658,7 @@ static int __devinit ican3_probe(struct platform_device *pdev) > dev = &pdev->dev; > > /* allocate the CAN device and private data */ > - ndev = alloc_candev(sizeof(*mod), 0); > + ndev = alloc_candev(sizeof(*mod), 1); > if (!ndev) { > dev_err(dev, "unable to allocate CANdev\n"); > ret = -ENOMEM;