netdev - Re: [PATCH/RFC net-next] ravb: Add dma queue interrupt support

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Message-ID: <5672F423.6010807@cogentembedded.com>
Date:	Thu, 17 Dec 2015 20:42:59 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Yoshihiro Kaneko <ykaneko0929@...il.com>
Cc:	netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>,
	Simon Horman <horms@...ge.net.au>,
	Magnus Damm <magnus.damm@...il.com>,
	Linux-sh list <linux-sh@...r.kernel.org>
Subject: Re: [PATCH/RFC net-next] ravb: Add dma queue interrupt support

Hello.

On 12/17/2015 07:29 PM, Yoshihiro Kaneko wrote:

>>> From: Kazuya Mizuguchi <kazuya.mizuguchi.ks@...esas.com>
>>>
>>> This patch supports the following interrupts.
>>>
>>> - One interrupt for multiple (descriptor, error, management)
>>> - One interrupt for emac
>>> - Four interrupts for dma queue (best effort rx/tx, network control rx/tx)
>>
>>
>>     You don't say why the current 2-interrupt scheme (implemented by Simon's
>> patch) isn't enpough...
>>
>>> Signed-off-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@...esas.com>
>>> Signed-off-by: Yoshihiro Kaneko <ykaneko0929@...il.com>
>>
>> [...]
>>
>>> diff --git a/drivers/net/ethernet/renesas/ravb.h
>>> b/drivers/net/ethernet/renesas/ravb.h
>>> index 9fbe92a..eada5a1 100644
>>> --- a/drivers/net/ethernet/renesas/ravb.h
>>> +++ b/drivers/net/ethernet/renesas/ravb.h
>>> @@ -157,6 +157,7 @@ enum ravb_reg {
[...]
>>> +#define RAVB_RIx2_ALL  0x8003ffff
>>
>>     No prefix. And there's bit 31 in this register, according to my gen3
>> manual. So, your _ALL isn't really "all bits". I'd rather call it RIx2_QFx.
>> Or even RIE2_QFS and RID2_QFD.
>
> I think that bit 31 is included in the value 0x8003ffff. Or I'm
> missing something?

    Sorry, I misread the code.

>>> +
>>> +/* TIx */
>>
>>     TIE/TID.
>>
>>> +#define RAVB_TIx_ALL   0x000fffff
>>
>>     No prefix. And there's bit 31 in this register, according to my gen3
>> manual.

    Oops, no bit 31 in these regs.

> So, your _ALL isn't really "all bits".
>
> I think the correct value is 0x000f0f0f.

    Indeed, please fix.

>> [...]
>>>
>>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c
>>> b/drivers/net/ethernet/renesas/ravb_main.c
>>> index 120cc25..753b67d 100644
>>> --- a/drivers/net/ethernet/renesas/ravb_main.c
>>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
[...]
>>> @@ -654,7 +679,7 @@ static int ravb_stop_dma(struct net_device *ndev)
>>>    }
>>>
>>>    /* E-MAC interrupt handler */
>>> -static void ravb_emac_interrupt(struct net_device *ndev)
>>> +static void _ravb_emac_interrupt(struct net_device *ndev)
>>
>>
>>     ravb_emac_interrupt_[un]locked() perhaps? Not sure which is more
>> correct... :-)
>
> How about ravb_process_emac_interrupt() ?

    I've made up my mind -- I'd prefer ravb_emac_interrupt_unlocked().

[...]
>>> +static irqreturn_t ravb_multi_interrupt(int irq, void *dev_id)
>>> +{
>>> +       struct net_device *ndev = dev_id;
>>> +       struct ravb_private *priv = netdev_priv(ndev);
>>> +       irqreturn_t result = IRQ_NONE;
>>> +       u32 iss;
>>> +
>>> +       spin_lock(&priv->lock);
>>> +       /* Get interrupt status */
>>> +       iss = ravb_read(ndev, ISS);
>>> +
>>>          /* Error status summary */
>>>          if (iss & ISS_ES) {
>>>                  ravb_error_interrupt(ndev);
>>>                  result = IRQ_HANDLED;
>>>          }
>>>
>>> +       /* Management */
>>
>>
>>     Really? I thought that's gPTP Interrupt...
>
> gPTP seems to be a part of Management related interrupts.

    ISS.CGIM is still described as gPTP interrupt mirror in my gen3 manual.

>>>          if (iss & ISS_CGIS)
>>>                  result = ravb_ptp_interrupt(ndev);
>>>
>>> @@ -776,6 +843,55 @@ static irqreturn_t ravb_interrupt(int irq, void
>>> *dev_id)
[...]

> Thanks,
> kaneko

MBR, Sergei

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