On 06/23/2014 03:37 PM, Marc Kleine-Budde wrote: > -----Original Message----- > From: Marc Kleine-Budde [mailto:m...@pengutronix.de] > Sent: Monday, June 23, 2014 3:37 PM > To: Zhao Qiang-B45475; linuxppc-dev@lists.ozlabs.org; linux- > c...@vger.kernel.org; w...@grandegger.com; Wood Scott-B07421 > Subject: Re: [PATCH v3 1/2] flexcan: add err_irq handler for flexcan > > On 06/23/2014 09:26 AM, qiang.z...@freescale.com wrote: > > > > On 06/23/2014 03:18 PM, Marc Kleine-Budde wrote: > > > >> > >> On 06/23/2014 09:11 AM, Zhao Qiang wrote: > >>> when flexcan is not physically linked, command 'cantest' will > >>> trigger an err_irq, add err_irq handler for it. > >>> > >>> Signed-off-by: Zhao Qiang <b45...@freescale.com> > >>> --- > >>> Changes for v2: > >>> - use a space instead of tab > >>> - use flexcan_poll_state instead of print Changes for v3: > >>> - return IRQ_HANDLED if err is triggered > >>> - stop transmitted packets when there is an err_interrupt > >>> > >>> drivers/net/can/flexcan.c | 35 ++++++++++++++++++++++++++++++++++- > >>> 1 file changed, 34 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c > >>> index f425ec2..6802a25 100644 > >>> --- a/drivers/net/can/flexcan.c > >>> +++ b/drivers/net/can/flexcan.c > >>> @@ -208,6 +208,7 @@ struct flexcan_priv { > >>> void __iomem *base; > >>> u32 reg_esr; > >>> u32 reg_ctrl_default; > >>> + unsigned int err_irq; > >>> > >>> struct clk *clk_ipg; > >>> struct clk *clk_per; > >>> @@ -744,6 +745,24 @@ static irqreturn_t flexcan_irq(int irq, void > >> *dev_id) > >>> return IRQ_HANDLED; > >>> } > >>> > >>> +static irqreturn_t flexcan_err_irq(int irq, void *dev_id) { > >>> + struct net_device *dev = dev_id; > >>> + struct flexcan_priv *priv = netdev_priv(dev); > >>> + struct flexcan_regs __iomem *regs = priv->base; > >>> + u32 reg_ctrl, reg_esr; > >>> + > >>> + reg_esr = flexcan_read(®s->esr); > >>> + reg_ctrl = flexcan_read(®s->ctrl); > >>> + if (reg_esr & FLEXCAN_ESR_TX_WRN) { > >> > >> When does the hardware trigger the interrupt? > > > > When there is no wire link between tx and rx, tx start transfer and > doesn’t get the ack. > > You are testing for the warning interrupt, not for the > FLEXCAN_ESR_ACK_ERR (which is triggered there isn't any ACK). > > >>> + flexcan_write(reg_esr & ~FLEXCAN_ESR_TX_WRN, ®s->esr); > >>> + flexcan_write(reg_ctrl & ~FLEXCAN_CTRL_ERR_MSK, ®s->ctrl); > >>> + netif_stop_queue(dev); > >> > >> Why are you stopping the txqueue? > > > > There is no wire link, tx can't transfer successfully. > > You are testing for the warning interrupt, which is triggered if the > error counter increases from 95 to 96. And the error counter can increase > due to several reasons. No link is only one of them. If the CAN core > cannot transmit new packages any more the flow control in the driver will > take care.
When Tx error counter increases from 95 to 96, there must be issue for tx, So why can't I stop the txqueue? You said that there are several reasons, would you like to take some examples? > > What about calling the normal interrupt if er err_irq occurs, as this > function will take care of both normal and error interrupts anyway? Calling the normal interrupt doesn't work. > > Marc > > -- > Pengutronix e.K. | Marc Kleine-Budde | > Industrial Linux Solutions | Phone: +49-231-2826-924 | > Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | > Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de | _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
