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Message-ID: <20140702063148.GA10397@shlinux1.ap.freescale.net>
Date: Wed, 2 Jul 2014 14:31:51 +0800
From: Dong Aisheng <b29396@...escale.com>
To: Marc Kleine-Budde <mkl@...gutronix.de>
CC: <linux-can@...r.kernel.org>, <netdev@...r.kernel.org>,
<wg@...ndegger.com>, <devicetree@...r.kernel.org>
Subject: Re: [PATCH 2/3] can: m_can: add bus error handling
On Tue, Jul 01, 2014 at 12:37:07PM +0200, Marc Kleine-Budde wrote:
> On 06/27/2014 12:00 PM, Dong Aisheng wrote:
> > Add bus error, state change, lost message handling mechanism.
> >
> > Signed-off-by: Dong Aisheng <b29396@...escale.com>
> > ---
> > drivers/net/can/m_can.c | 271 +++++++++++++++++++++++++++++++++++++++++------
> > 1 files changed, 240 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/net/can/m_can.c b/drivers/net/can/m_can.c
> > index 61e9a8e..e4aed71 100644
> > --- a/drivers/net/can/m_can.c
> > +++ b/drivers/net/can/m_can.c
> > @@ -83,6 +83,18 @@ enum m_can_reg {
> > M_CAN_TXEFA = 0xf8,
> > };
> >
> > +/* m_can lec values */
> > +enum m_can_lec_type {
> > + LEC_NO_ERROR = 0,
> > + LEC_STUFF_ERROR,
> > + LEC_FORM_ERROR,
> > + LEC_ACK_ERROR,
> > + LEC_BIT1_ERROR,
> > + LEC_BIT0_ERROR,
> > + LEC_CRC_ERROR,
> > + LEC_UNUSED,
> > +};
> > +
> > /* CC Control Register(CCCR) */
> > #define CCCR_CCE BIT(1)
> > #define CCCR_INIT BIT(0)
> > @@ -97,6 +109,19 @@ enum m_can_reg {
> > #define BTR_SJW_SHIFT 0
> > #define BTR_SJW_MASK 0xf
> >
> > +/* Error Counter Register(ECR) */
> > +#define ECR_RP BIT(15)
> > +#define ECR_REC_SHIFT 8
> > +#define ECR_REC_MASK (0x7f << ECR_REC_SHIFT)
> > +#define ECR_TEC_SHIFT 0
> > +#define ECR_TEC_MASK 0xff
> > +
> > +/* Protocol Status Register(PSR) */
> > +#define PSR_BO BIT(7)
> > +#define PSR_EW BIT(6)
> > +#define PSR_EP BIT(5)
> > +#define PSR_LEC_MASK 0x7
> > +
> > /* Interrupt Register(IR) */
> > #define IR_ALL_INT 0xffffffff
> > #define IR_STE BIT(31)
> > @@ -131,10 +156,11 @@ enum m_can_reg {
> > #define IR_RF0F BIT(2)
> > #define IR_RF0W BIT(1)
> > #define IR_RF0N BIT(0)
> > -#define IR_ERR_ALL (IR_STE | IR_FOE | IR_ACKE | IR_BE | IR_CRCE | \
> > - IR_WDI | IR_BO | IR_EW | IR_EP | IR_ELO | IR_BEU | \
> > - IR_BEC | IR_TOO | IR_MRAF | IR_TSW | IR_TEFL | IR_RF1L | \
> > - IR_RF0L)
> > +#define IR_ERR_STATE (IR_BO | IR_EW | IR_EP)
> > +#define IR_ERR_BUS (IR_STE | IR_FOE | IR_ACKE | IR_BE | IR_CRCE | \
> > + IR_WDI | IR_ELO | IR_BEU | IR_BEC | IR_TOO | IR_MRAF | \
> > + IR_TSW | IR_TEFL | IR_RF1L | IR_RF0L)
> > +#define IR_ERR_ALL (IR_ERR_STATE | IR_ERR_BUS)
> >
> > /* Rx FIFO 0/1 Configuration (RXF0C/RXF1C) */
> > #define RXFC_FWM_OFF 24
> > @@ -320,12 +346,175 @@ static int m_can_do_rx_poll(struct net_device *dev, int quota)
> > return num_rx_pkts;
> > }
> >
> > +static int m_can_handle_lost_msg(struct net_device *dev)
> > +{
> > + struct net_device_stats *stats = &dev->stats;
> > + struct sk_buff *skb;
> > + struct can_frame *frame;
> > +
> > + netdev_err(dev, "msg lost in rxf0\n");
> > +
> > + skb = alloc_can_err_skb(dev, &frame);
> > + if (unlikely(!skb))
> > + return 0;
>
> Please rearrange this function differently, so that the stats are
> updated, even if alloc_can_err_skb() fails.
>
Good suggestion.
Will change them all with other places having the same issue.
> > +
> > + frame->can_id |= CAN_ERR_CRTL;
> > + frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
> > + stats->rx_errors++;
> > + stats->rx_over_errors++;
> > +
> > + netif_receive_skb(skb);
> > +
> > + return 1;
> > +}
> > +
> > +static int m_can_handle_bus_err(struct net_device *dev,
> > + enum m_can_lec_type lec_type)
> > +{
> > + struct m_can_priv *priv = netdev_priv(dev);
> > + struct net_device_stats *stats = &dev->stats;
> > + struct can_frame *cf;
> > + struct sk_buff *skb;
> > +
> > + /* early exit if no lec update */
> > + if (lec_type == LEC_UNUSED)
> > + return 0;
> > +
> > + /* propagate the error condition to the CAN stack */
> > + skb = alloc_can_err_skb(dev, &cf);
> > + if (unlikely(!skb))
> > + return 0;
>
> same here
>
> > +
> > + /*
> > + * check for 'last error code' which tells us the
> > + * type of the last error to occur on the CAN bus
> > + */
> > + priv->can.can_stats.bus_error++;
> > + stats->rx_errors++;
> > + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
> > + cf->data[2] |= CAN_ERR_PROT_UNSPEC;
> > +
> > + switch (lec_type) {
> > + case LEC_STUFF_ERROR:
> > + netdev_dbg(dev, "stuff error\n");
> > + cf->data[2] |= CAN_ERR_PROT_STUFF;
> > + break;
> > + case LEC_FORM_ERROR:
> > + netdev_dbg(dev, "form error\n");
> > + cf->data[2] |= CAN_ERR_PROT_FORM;
> > + break;
> > + case LEC_ACK_ERROR:
> > + netdev_dbg(dev, "ack error\n");
> > + cf->data[3] |= (CAN_ERR_PROT_LOC_ACK |
> > + CAN_ERR_PROT_LOC_ACK_DEL);
> > + break;
> > + case LEC_BIT1_ERROR:
> > + netdev_dbg(dev, "bit1 error\n");
> > + cf->data[2] |= CAN_ERR_PROT_BIT1;
> > + break;
> > + case LEC_BIT0_ERROR:
> > + netdev_dbg(dev, "bit0 error\n");
> > + cf->data[2] |= CAN_ERR_PROT_BIT0;
> > + break;
> > + case LEC_CRC_ERROR:
> > + netdev_dbg(dev, "CRC error\n");
> > + cf->data[3] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
> > + CAN_ERR_PROT_LOC_CRC_DEL);
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > + netif_receive_skb(skb);
> > + stats->rx_packets++;
> > + stats->rx_bytes += cf->can_dlc;
> > +
> > + return 1;
> > +}
> > +
> > +static int m_can_get_berr_counter(const struct net_device *dev,
> > + struct can_berr_counter *bec)
> > +{
> > + struct m_can_priv *priv = netdev_priv(dev);
> > + unsigned int ecr;
>
> This function might be called, even if the interface is down. You might
> have to enable the clock(s) here.
>
Ok, got it, thanks for the info.
> > + ecr = m_can_read(priv, M_CAN_ECR);
> > + bec->rxerr = (ecr & ECR_REC_MASK) >> ECR_REC_SHIFT;
> > + bec->txerr = ecr & ECR_TEC_MASK;
> > +
> > + return 0;
> > +}
> > +
> > +static int m_can_handle_state_change(struct net_device *dev,
> > + enum can_state new_state)
> > +{
> > + struct m_can_priv *priv = netdev_priv(dev);
> > + struct net_device_stats *stats = &dev->stats;
> > + struct can_frame *cf;
> > + struct sk_buff *skb;
> > + struct can_berr_counter bec;
> > + unsigned int ecr;
> > +
> > + /* propagate the error condition to the CAN stack */
> > + skb = alloc_can_err_skb(dev, &cf);
> > + if (unlikely(!skb))
> > + return 0;
>
> Please rearrange the function, so that the stats and more important
> bus-off are handled correctly, even if this fails.
>
Will do it.
> > +
> > + m_can_get_berr_counter(dev, &bec);
> > +
> > + switch (new_state) {
> > + case CAN_STATE_ERROR_ACTIVE:
> > + /* error warning state */
> > + priv->can.can_stats.error_warning++;
> > + priv->can.state = CAN_STATE_ERROR_WARNING;
> > + cf->can_id |= CAN_ERR_CRTL;
> > + cf->data[1] = (bec.txerr > bec.rxerr) ?
> > + CAN_ERR_CRTL_TX_WARNING :
> > + CAN_ERR_CRTL_RX_WARNING;
> > + cf->data[6] = bec.txerr;
> > + cf->data[7] = bec.rxerr;
> > + break;
> > + case CAN_STATE_ERROR_PASSIVE:
> > + /* error passive state */
> > + priv->can.can_stats.error_passive++;
> > + priv->can.state = CAN_STATE_ERROR_PASSIVE;
> > + cf->can_id |= CAN_ERR_CRTL;
> > + ecr = m_can_read(priv, M_CAN_ECR);
> > + if (ecr & ECR_RP)
> > + cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
> > + if (bec.txerr > 127)
> > + cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
> > + cf->data[6] = bec.txerr;
> > + cf->data[7] = bec.rxerr;
> > + break;
> > + case CAN_STATE_BUS_OFF:
> > + /* bus-off state */
> > + priv->can.state = CAN_STATE_BUS_OFF;
> > + cf->can_id |= CAN_ERR_BUSOFF;
> > + /*
> > + * disable all interrupts in bus-off mode to ensure that
> > + * the CPU is not hogged down
> > + */
> > + m_can_enable_all_interrupts(priv, false);
> > + can_bus_off(dev);
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > + netif_receive_skb(skb);
> > + stats->rx_packets++;
> > + stats->rx_bytes += cf->can_dlc;
>
> don't acces "cf" after netif_receive_sb();
>
Got it.
> > +
> > + return 1;
> > +}
> > +
> > static int m_can_poll(struct napi_struct *napi, int quota)
> > {
> > struct net_device *dev = napi->dev;
> > struct m_can_priv *priv = netdev_priv(dev);
> > u32 work_done = 0;
> > - u32 irqstatus;
> > + u32 irqstatus, psr;
> >
> > irqstatus = m_can_read(priv, M_CAN_IR);
> > if (irqstatus)
> > @@ -337,6 +526,48 @@ static int m_can_poll(struct napi_struct *napi, int quota)
> > if (!irqstatus)
> > goto end;
> >
> > + psr = m_can_read(priv, M_CAN_PSR);
> > + if (irqstatus & IR_ERR_STATE) {
> > + if ((psr & PSR_EW) &&
> > + (priv->can.state != CAN_STATE_ERROR_WARNING)) {
> > + netdev_dbg(dev, "entered error warning state\n");
> > + work_done += m_can_handle_state_change(dev,
> > + CAN_STATE_ERROR_WARNING);
> > + }
> > +
> > + if ((psr & PSR_EP) &&
> > + (priv->can.state != CAN_STATE_ERROR_PASSIVE)) {
> > + netdev_dbg(dev, "entered error warning state\n");
> > + work_done += m_can_handle_state_change(dev,
> > + CAN_STATE_ERROR_PASSIVE);
> > + }
> > +
> > + if ((psr & PSR_BO) &&
> > + (priv->can.state != CAN_STATE_BUS_OFF)) {
> > + netdev_dbg(dev, "entered error warning state\n");
> > + work_done += m_can_handle_state_change(dev,
> > + CAN_STATE_BUS_OFF);
> > + }
>
> You might want to push this into a seperate function.
>
Yes, could do like that.
> > + }
> > +
> > + if (irqstatus & IR_ERR_BUS) {
> > + if (irqstatus & IR_RF0L)
> > + work_done += m_can_handle_lost_msg(dev);
> > +
> > + /* handle lec errors on the bus */
> > + if (psr & LEC_UNUSED)
> > + work_done += m_can_handle_bus_err(dev,
> > + psr & LEC_UNUSED);
> > +
> > + /* other unproccessed error interrupts */
> > + if (irqstatus & IR_WDI)
> > + netdev_err(dev, "Message RAM Watchdog event due to missing READY\n");
> > + if (irqstatus & IR_TOO)
> > + netdev_err(dev, "Timeout reached\n");
> > + if (irqstatus & IR_MRAF)
> > + netdev_err(dev, "Message RAM access failure occurred\n");
>
> same here
Got it.
> > + }
> > +
> > if (irqstatus & IR_RF0N)
> > /* handle events corresponding to receive message objects */
> > work_done += m_can_do_rx_poll(dev, (quota - work_done));
> > @@ -369,31 +600,18 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
> > if (ir & IR_ALL_INT)
> > m_can_write(priv, M_CAN_IR, ir);
> >
> > - if (ir & IR_ERR_ALL) {
> > - netdev_dbg(dev, "bus error\n");
> > - /* TODO: handle bus error */
> > - }
> > -
> > - /* save irqstatus for later using */
> > - priv->irqstatus = ir;
> > -
> > /*
> > * schedule NAPI in case of
> > * - rx IRQ
> > - * - state change IRQ(TODO)
> > - * - bus error IRQ and bus error reporting (TODO)
> > + * - state change IRQ
> > + * - bus error IRQ and bus error reporting
> > */
> > - if (ir & IR_RF0N) {
> > + if ((ir & IR_RF0N) || (ir & IR_ERR_ALL)) {
> > + priv->irqstatus = ir;
> > m_can_enable_all_interrupts(priv, false);
> > napi_schedule(&priv->napi);
> > }
> >
> > - /* FIFO overflow */
> > - if (ir & IR_RF0L) {
> > - dev->stats.rx_over_errors++;
> > - dev->stats.rx_errors++;
> > - }
> > -
> > /* transmission complete interrupt */
> > if (ir & IR_TC) {
> > netdev_dbg(dev, "tx complete\n");
> > @@ -446,7 +664,6 @@ static int m_can_set_bittiming(struct net_device *dev)
> > * - setup bittiming
> > * - TODO:
> > * 1) other working modes support like monitor, loopback...
> > - * 2) lec error status report enable
> > */
> > static void m_can_chip_config(struct net_device *dev)
> > {
> > @@ -515,14 +732,6 @@ static int m_can_set_mode(struct net_device *dev, enum can_mode mode)
> > return 0;
> > }
> >
> > -static int m_can_get_berr_counter(const struct net_device *dev,
> > - struct can_berr_counter *bec)
> > -{
> > - /* TODO */
> > -
> > - return 0;
> > -}
> > -
> > static void free_m_can_dev(struct net_device *dev)
> > {
> > free_candev(dev);
> >
>
> Marc
>
Thanks
Regards
Dong Aisheng
> --
> 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 |
>
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