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Message-ID: <1990e269-44fe-b45f-09b5-0c84f21778fc@omp.ru>
Date: Mon, 12 Feb 2024 23:19:43 +0300
From: Sergey Shtylyov <s.shtylyov@....ru>
To: claudiu beznea <claudiu.beznea@...on.dev>, <davem@...emloft.net>,
<edumazet@...gle.com>, <kuba@...nel.org>, <pabeni@...hat.com>
CC: <netdev@...r.kernel.org>, <linux-renesas-soc@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, Claudiu Beznea
<claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH net-next v2 5/5] net: ravb: Add runtime PM support
On 2/12/24 10:56 AM, claudiu beznea wrote:
[...]
>>> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>>>
>>> Add runtime PM support for the ravb driver. As the driver is used by
>>> different IP variants, with different behaviors, to be able to have the
>>> runtime PM support available for all devices, the preparatory commits
>>> moved all the resources parsing and allocations in the driver's probe
>>> function and kept the settings for ravb_open(). This is due to the fact
>>> that on some IP variants-platforms tuples disabling/enabling the clocks
>>> will switch the IP to the reset operation mode where registers' content is
>>
>> This pesky "registers' content" somehow evaded me -- should be "register
>> contents" as well...
>>
>>> lost and reconfiguration needs to be done. For this the rabv_open()
>>> function enables the clocks, switches the IP to configuration mode, applies
>>> all the registers settings and switches the IP to the operational mode. At
>>> the end of ravb_open() IP is ready to send/receive data.
>>>
>>> In ravb_close() necessary reverts are done (compared with ravb_open()), the
>>> IP is switched to reset mode and clocks are disabled.
>>>
>>> The ethtool APIs or IOCTLs that might execute while the interface is down
>>> are either cached (and applied in ravb_open()) or rejected (as at that time
>>> the IP is in reset mode). Keeping the IP in the reset mode also increases
>>> the power saved (according to the hardware manual).
>>>
>>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>>> Reviewed-by: Sergey Shtylyov <s.shtylyov@....ru>
>> [...]
>>
>>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
>>> index f4be08f0198d..5bbfdfeef8a9 100644
>>> --- a/drivers/net/ethernet/renesas/ravb_main.c
>>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
>>> @@ -1939,16 +1939,21 @@ static int ravb_open(struct net_device *ndev)
>>> {
>>> struct ravb_private *priv = netdev_priv(ndev);
>>> const struct ravb_hw_info *info = priv->info;
>>> + struct device *dev = &priv->pdev->dev;
>>> int error;
>>>
>>> napi_enable(&priv->napi[RAVB_BE]);
>>> if (info->nc_queues)
>>> napi_enable(&priv->napi[RAVB_NC]);
>>>
>>> + error = pm_runtime_resume_and_get(dev);
>>> + if (error < 0)
>>> + goto out_napi_off;
>>
>> Well, s/error/ret/ -- it would fit better here...
>
> Using error is the "trademark" of this driver, it is used all around the
> driver. I haven't introduced it here, I don't like it. The variable error
Heh, because it's my usual style. Too bad you don't like it... :-)
> in this particular function is here from the beginning of the driver.
I think it's well suited for the functions returning either 0 or a
(negative) error code. It's *if* (error < 0) that confuses me (as this
API can return positive numbers in case of success...
> So, I don't consider changing error to ret is the scope of this series.
OK, you're probably right... are you going to respin the series because
of Biju's comments?
[...]
>>> @@ -3066,6 +3089,12 @@ static void ravb_remove(struct platform_device *pdev)
>>> struct net_device *ndev = platform_get_drvdata(pdev);
>>> struct ravb_private *priv = netdev_priv(ndev);
>>> const struct ravb_hw_info *info = priv->info;
>>> + struct device *dev = &priv->pdev->dev;
>>> + int error;
>>> +
>>> + error = pm_runtime_resume_and_get(dev);
>>> + if (error < 0)
>>> + return;
>>
>> Again, s/erorr/ret/ in this case.
>
> error was used here to comply with the rest of the driver. So, if you still
> want me to change it here and in ravb_remove() please confirm.
No, we are good enough without that; I'll consider doing a cleanup
when/if I have time. :-)
> Thank you,
> Claudiu Beznea
MBR, Sergey
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