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Message-ID: <ee783b61-95fc-44ab-a311-0ca7d058ac39@tuxon.dev>
Date: Mon, 8 Jan 2024 10:58:41 +0200
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Subject: Re: [PATCH net-next v3 08/19] net: ravb: Move the IRQs get and
 request in the probe function
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To: Sergey Shtylyov <s.shtylyov@omp.ru>, davem@davemloft.net,
 edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
 richardcochran@gmail.com, p.zabel@pengutronix.de,
 yoshihiro.shimoda.uh@renesas.com, wsa+renesas@sang-engineering.com
Cc: netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
 linux-kernel@vger.kernel.org, geert+renesas@glider.be,
 Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
References: <20240105082339.1468817-1-claudiu.beznea.uj@bp.renesas.com>
 <20240105082339.1468817-9-claudiu.beznea.uj@bp.renesas.com>
 <02548b1b-d32c-78b1-f1b6-5fdb505d31bb@omp.ru>
From: claudiu beznea <claudiu.beznea@tuxon.dev>
In-Reply-To: <02548b1b-d32c-78b1-f1b6-5fdb505d31bb@omp.ru>
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On 07.01.2024 20:24, Sergey Shtylyov wrote:
> On 1/5/24 11:23 AM, Claudiu wrote:
> 
>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>
>> The runtime PM implementation will disable clocks at the end of
>> ravb_probe(). As some IP variants switch to reset mode as a result of
>> setting module standby through clock disable APIs, to implement runtime PM
>> the resource parsing and requesting are moved in the probe function and IP
>> settings are moved in the open function. This is done because at the end of
>> the probe some IP variants will switch anyway to reset mode and the
>> registers content is lost. Also keeping only register specific operations
>> in the ravb_open()/ravb_close() functions will make them faster.
>>
>> Commit moves IRQ requests to ravb_probe() to have all the IRQs ready when
>> the interface is open. As now IRQs gets and requests are in a single place
>> there is no need to keep intermediary data (like ravb_rx_irqs[] and
>> ravb_tx_irqs[] arrays or IRQs in struct ravb_private).
> 
>    There's one thing that you probably didn't take into account: after
> you call request_irq(), you should be able to handle your IRQ as it's
> automatically unmasked, unless you pass IRQF_NO_AUTOEN to request_irq().
> Your device may be held i reset or even powered off but if you pass IRQF_SHARED to request_irq() (you do in a single IRQ config), you must
> be prepared to get your device's registers read (in order to ascertain
> whether it's your IRQ or not). And you can't even pass IRQF_NO_AUTOEN
> along with IRQF_SHARED, according to my reading of the IRQ code...

Good point!

> 
>> This is a preparatory change to add runtime PM support for all IP variants.
> 
>   I don't readily see why this is necessary for the full-fledged RPM
> support...

I tried to speed up the ravb_open()/ravb_close() but missed the IRQF_SHARED
IRQ. As there is only one IRQ requested w/ IRQF_SHARED, are you OK with
still keeping the rest of IRQs handled as proposed by this patch?

> 
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> 
>    Unfortunately, I have to NAK this patch, at least in its current
> form...
> 
> [...]
> 
> MBR, Sergey