Subject: Re: [PATCH v3 1/2] flexcan: add err_irq handler for flexcan

From: Marc Kleine-Budde <[email-masked]>
Date: Mon, 23 Jun 2014 09:17:43 +0200

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 <[email-masked]>
> ---
> 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(&regs->esr);
> +	reg_ctrl = flexcan_read(&regs->ctrl);
> +	if (reg_esr & FLEXCAN_ESR_TX_WRN) {

When does the hardware trigger the interrupt?

> +		flexcan_write(reg_esr & ~FLEXCAN_ESR_TX_WRN, &regs->esr);
> +		flexcan_write(reg_ctrl & ~FLEXCAN_CTRL_ERR_MSK, &regs->ctrl);
> +		netif_stop_queue(dev);

Why are you stopping the txqueue?

> +		return IRQ_HANDLED;
> +	}
> +	return IRQ_NONE;
> +}
> +

Marc

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