Date:   Mon, 24 Apr 2017 16:47:15 +0200
From:   Matthias Brugger <matthias.bgg@...il.com>
To:     "lipeng (Y)" <lipeng321@...wei.com>,
        Yankejian <yankejian@...wei.com>, davem@...emloft.net,
        salil.mehta@...wei.com, yisen.zhuang@...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 24/04/17 13:43, lipeng (Y) wrote:
>
>
> On 2017/4/24 18:28, Matthias Brugger wrote:
>> 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
> Hi Matthias,
>
> mdio && phy is not necessary condition, and port can work well  for port
> + SFP (without mdio &&phy).
>
> BUT irq is the necessary condition,  port can not work well without irq.
>
> So, I check IRQ first,and do not probe dsaf if can't obtain irq(1/3 of
> this series),   and check mdio only when there is phy(2/3 of this series).
>
> And thanks for your review.

I think I didn't explained myself good enough.
I was suggesting the following (not even compile tested):

diff --git a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_ppe.c 
b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_ppe.c
index eba406bea52f..be38d47bc399 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_ppe.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_ppe.c
@@ -510,7 +510,9 @@ int hns_ppe_init(struct dsaf_device *dsaf_dev)

                 hns_ppe_get_cfg(dsaf_dev->ppe_common[i]);

-               hns_rcb_get_cfg(dsaf_dev->rcb_common[i]);
+               ret = hns_rcb_get_cfg(dsaf_dev->rcb_common[i]);
+               if (reg < 0)
+                       goto get_cfg_fail;
         }

         for (i = 0; i < HNS_PPE_COM_NUM; i++)
diff --git a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_rcb.c 
b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_rcb.c
index c20a0f4f8f02..c7e801d0c3b7 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_rcb.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_rcb.c
@@ -492,7 +492,7 @@ static int hns_rcb_get_base_irq_idx(struct 
rcb_common_cb *rcb_common)
   *hns_rcb_get_cfg - get rcb config
   *@..._common: rcb common device
   */
-void hns_rcb_get_cfg(struct rcb_common_cb *rcb_common)
+int hns_rcb_get_cfg(struct rcb_common_cb *rcb_common)
  {
         struct ring_pair_cb *ring_pair_cb;
         u32 i;
@@ -517,10 +517,18 @@ void hns_rcb_get_cfg(struct rcb_common_cb *rcb_common)
                 ring_pair_cb->virq[HNS_RCB_IRQ_IDX_RX] =
                 is_ver1 ? platform_get_irq(pdev, base_irq_idx + i * 2 + 
1) :
                           platform_get_irq(pdev, base_irq_idx + i * 3);
+
+               if ((ring_pair_cb->virq[HNS_RCB_IRQ_IDX_TX] == 
-EPROBE_DEFER) ||
+                   (ring_pair_cb->virq[HNS_RCB_IRQ_IDX_RX] == 
-EPROBE_DEFER)) {
+                       return -EPROBE_DEFER;
+               }
+
                 ring_pair_cb->q.phy_base =
 
RCB_COMM_BASE_TO_RING_BASE(rcb_common->phy_base, i);
                 hns_rcb_ring_pair_get_cfg(ring_pair_cb);
         }
+
+       return 0;
  }

  /**


Regards,
Matthias

>
> lipeng
>
>>
>>> 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);
>>>
>>
>> .
>>
>

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