Re: [PATCH v2 1/2] flexcan: add err_irq handler for flexcan

[Marc Kleine-Budde]

On 06/20/2014 04:01 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
> 
>  drivers/net/can/flexcan.c | 31 ++++++++++++++++++++++++++++++-
>  1 file changed, 30 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> index f425ec2..7432ba4 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 +745,23 @@ 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 is the err_irq triggered?

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

poll_state() is does not work, if called from an IRQ
handler.....Depending when err_irq is triggered, is it worth to just
call the normal interrupt handler?

> +     }
> +     return IRQ_HANDLED;

Please return IRQ_HANDLED, only if there really was an interrupt.

> +}
> +
>  static void flexcan_set_bittiming(struct net_device *dev)
>  {
>       const struct flexcan_priv *priv = netdev_priv(dev);
> @@ -944,6 +962,12 @@ static int flexcan_open(struct net_device *dev)
>       if (err)
>               goto out_close;
>  
> +     if (priv->err_irq)
> +             err = request_irq(priv->err_irq, flexcan_err_irq, IRQF_SHARED,
> +                               dev->name, dev);
> +     if (err)
> +             goto out_close;

In case of an error, you don't free() dev->irq.

> +
>       /* start chip and queuing */
>       err = flexcan_chip_start(dev);
>       if (err)
> @@ -1099,7 +1123,7 @@ static int flexcan_probe(struct platform_device *pdev)
>       struct resource *mem;
>       struct clk *clk_ipg = NULL, *clk_per = NULL;
>       void __iomem *base;
> -     int err, irq;
> +     int err, irq, err_irq;
>       u32 clock_freq = 0;
>  
>       if (pdev->dev.of_node)
> @@ -1126,6 +1150,10 @@ static int flexcan_probe(struct platform_device *pdev)
>       if (irq <= 0)
>               return -ENODEV;
>  
> +     err_irq = platform_get_irq(pdev, 1);
> +     if (err_irq <= 0)
> +             err_irq = 0;
> +
>       base = devm_ioremap_resource(&pdev->dev, mem);
>       if (IS_ERR(base))
>               return PTR_ERR(base);
> @@ -1149,6 +1177,7 @@ static int flexcan_probe(struct platform_device *pdev)
>       dev->flags |= IFF_ECHO;
>  
>       priv = netdev_priv(dev);
> +     priv->err_irq = err_irq;
>       priv->can.clock.freq = clock_freq;
>       priv->can.bittiming_const = &flexcan_bittiming_const;
>       priv->can.do_set_mode = flexcan_set_mode;
> 

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
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