linux-kernel - Re: [PATCH net-next v4 08/15] net: ravb: Move the IRQs get and request in the probe function

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Date: Sun, 28 Jan 2024 21:01:35 +0300
From: Sergey Shtylyov <s.shtylyov@....ru>
To: Claudiu <claudiu.beznea@...on.dev>, <davem@...emloft.net>,
	<edumazet@...gle.com>, <kuba@...nel.org>, <pabeni@...hat.com>,
	<richardcochran@...il.com>, <p.zabel@...gutronix.de>,
	<geert+renesas@...der.be>
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 v4 08/15] net: ravb: Move the IRQs get and
 request in the probe function

Hello!

   I suggest the following subject "net: ravb: Move getting/requesting IRQs in
the probe() method".

On 1/23/24 3:58 PM, Claudiu wrote:

> From: Claudiu Beznea <claudiu.beznea.uj@...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 

   Register contents?

> 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

   Again, getting/requesting IRQs.

> there is no need to keep intermediary data (like ravb_rx_irqs[] and
> ravb_tx_irqs[] arrays or IRQs in struct ravb_private).
> 
> In order to avoid accessing the IP registers while the IP is runtime
> suspended (e.g. in the timeframe b/w the probe requests shared IRQs and
> IP clocks are enabled) in the interrupt handlers were introduced
> pm_runtime_active() checks. The device runtime PM usage counter has been
> incremented to avoid disabling the device's clocks while the check is in
> progress (if any).

   Oh, so this scheme does have some complications...

> This is a preparatory change to add runtime PM support for all IP variants.
> 
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>

   With the above fixed:

Reviewed-by: Sergey Shtylyov <s.shtylyov@....ru>

[...]

MBR, Sergey