From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Grandegger Subject: Re: [PATCH] CAN: Add Flexcan CAN controller driver Date: Thu, 22 Jul 2010 11:25:18 +0200 Message-ID: <4C480E7E.70607@grandegger.com> References: <1279144811-12251-1-git-send-email-mkl@pengutronix.de> <4C3F55A9.8030307@grandegger.com> <4C405CEC.3000701@pengutronix.de> <4C475BA6.3030505@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Marc Kleine-Budde Return-path: In-Reply-To: <4C475BA6.3030505-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org Errors-To: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org List-Id: netdev.vger.kernel.org On 07/21/2010 10:42 PM, Marc Kleine-Budde wrote: > Marc Kleine-Budde wrote: >> Wolfgang Grandegger wrote: >>> I realized a few issues. You can add my "acked-by" when they are fixed. >> >> thanks for the review. > > [...] > >>>> +static void flexcan_poll_err_frame(struct net_device *dev, >>>> + struct can_frame *cf, u32 reg_esr) >>>> +{ >>>> + struct flexcan_priv *priv = netdev_priv(dev); >>>> + int error_warning = 0, rx_errors = 0, tx_errors = 0; >>>> + >>>> + if (reg_esr & FLEXCAN_ESR_BIT1_ERR) { >>>> + rx_errors = 1; >>>> + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR; >>>> + cf->data[2] |= CAN_ERR_PROT_BIT1; >>>> + } >>>> + >>>> + if (reg_esr & FLEXCAN_ESR_BIT0_ERR) { >>>> + rx_errors = 1; >>>> + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR; >>>> + cf->data[2] |= CAN_ERR_PROT_BIT0; >>>> + } >>>> + >>>> + if (reg_esr & FLEXCAN_ESR_FRM_ERR) { >>>> + rx_errors = 1; >>>> + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR; >>>> + cf->data[2] |= CAN_ERR_PROT_FORM; >>>> + } >>>> + >>>> + if (reg_esr & FLEXCAN_ESR_STF_ERR) { >>>> + rx_errors = 1; >>>> + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR; >>>> + cf->data[2] |= CAN_ERR_PROT_STUFF; >>>> + } >>>> + >>>> + >>>> + if (reg_esr & FLEXCAN_ESR_ACK_ERR) { >>>> + tx_errors = 1; >>>> + cf->can_id |= CAN_ERR_ACK; >>> This is a bus-error as well. Therefore I think it should be: >>> >>> if (reg_esr & FLEXCAN_ESR_ACK_ERR) { >>> tx_errors = 1; >>> cf->can_id |= CAN_ERR_ACK; >>> cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR; >>> cf->data[3] |= CAN_ERR_PROT_LOC_ACK; /* ACK slot */ >>> } >>> >>> I need to check what CAN_ERR_ACK is intended for. Then, cf->can_id could >>> be preset with "CAN_ERR_PROT | CAN_ERR_BUSERROR" at the beginning. > > This controller issues an ACK error if there are no other nodes on the > CAN bus to send a ACK that the message has been received. Or all > remaining Nodes are in bus off state. Mainly this bus error can cause the infamous IRQ and message flooding when no cable is connected. > From the datasheet: > "This bit indicates that an acknowledge (ACK) error has been detected by > the transmitter node; that is, a dominant bit has not been detected > during the ACK SLOT." That's what the above error describes, like on the SJA1000, apart from setting CAN_ERR_ACK. Setting CAN_ERR_ACK is somehow bogus, but just leave it for the time being. I will fix it globally when time permits. Wolfgang.