netdev - Re: [PATCH net v2 1/3] net: hns: support deferred probe when can not obtain irq

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Date:   Mon, 24 Apr 2017 12:28:33 +0200
From:   Matthias Brugger <matthias.bgg@...il.com>
To:     Yankejian <yankejian@...wei.com>, davem@...emloft.net,
        salil.mehta@...wei.com, yisen.zhuang@...wei.com,
        lipeng321@...wei.com, huangdaode@...ilicon.com,
        zhouhuiru@...wei.com
Cc:     netdev@...r.kernel.org, charles.chenxin@...wei.com,
        linuxarm@...wei.com
Subject: Re: [PATCH net v2 1/3] net: hns: support deferred probe when can not
 obtain irq

On 21/04/17 09:44, Yankejian wrote:
> From: lipeng <lipeng321@...wei.com>
>
> In the hip06 and hip07 SoCs, the interrupt lines from the
> DSAF controllers are connected to mbigen hw module.
> The mbigen module is probed with module_init, and, as such,
> is not guaranteed to probe before the HNS driver. So we need
> to support deferred probe.
>
> We check for probe deferral in the hw layer probe, so we not
> probe into the main layer and memories, etc., to later learn
> that we need to defer the probe.
>

Why? This looks like a hack.
 From what I see, we can handle EPROBE_DEFER easily inside hns_ppe_init 
checking the return value of hns_rcb_get_cfg. Like you do in 2/3 of this 
series.

Regards,
Matthias

> Signed-off-by: lipeng <lipeng321@...wei.com>
> Reviewed-by: Yisen Zhuang <yisen.zhuang@...wei.com>
> ---
>  drivers/net/ethernet/hisilicon/hns/hns_dsaf_main.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_main.c b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_main.c
> index 403ea9d..2da5b42 100644
> --- a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_main.c
> +++ b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_main.c
> @@ -2971,6 +2971,18 @@ static int hns_dsaf_probe(struct platform_device *pdev)
>  	struct dsaf_device *dsaf_dev;
>  	int ret;
>
> +	/*
> +	 * Check if we should defer the probe before we probe the
> +	 * dsaf, as it's hard to defer later on.
> +	 */
> +	ret = platform_get_irq(pdev, 0);
> +	if (ret < 0) {
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(&pdev->dev, "Cannot obtain irq\n");
> +
> +		return ret;
> +	}
> +
>  	dsaf_dev = hns_dsaf_alloc_dev(&pdev->dev, sizeof(struct dsaf_drv_priv));
>  	if (IS_ERR(dsaf_dev)) {
>  		ret = PTR_ERR(dsaf_dev);
>