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Date: Thu, 25 Apr 2024 12:58:18 +0300
From: Andy Shevchenko <andy@kernel.org>
To: Marek =?iso-8859-1?Q?Beh=FAn?= <kabel@kernel.org>
Cc: Gregory CLEMENT <gregory.clement@bootlin.com>,
	Arnd Bergmann <arnd@arndb.de>, soc@kernel.org, arm@kernel.org,
	Hans de Goede <hdegoede@redhat.com>,
	Ilpo =?iso-8859-1?Q?J=E4rvinen?= <ilpo.jarvinen@linux.intel.com>,
	Olivia Mackall <olivia@selenic.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-crypto@vger.kernel.org
Subject: Re: [PATCH v7 6/9] platform: cznic: turris-omnia-mcu: Add support
 for MCU provided TRNG
Message-ID: <ZiopOgbF18MObiOj@smile.fi.intel.com>
References: <20240424173809.7214-1-kabel@kernel.org>
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 <Zilhvv3ffWMDL1Uj@smile.fi.intel.com>
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Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo

On Wed, Apr 24, 2024 at 10:47:11PM +0300, Andy Shevchenko wrote:
> On Wed, Apr 24, 2024 at 08:51:23PM +0200, Marek Beh?n wrote:
> > On Wed, 24 Apr 2024 21:33:44 +0300
> > Andy Shevchenko <andy@kernel.org> wrote:
> > > On Wed, Apr 24, 2024 at 07:38:05PM +0200, Marek Beh?n wrote:

...

> > > > +static void omnia_irq_mapping_drop(void *res)
> > > > +{
> > > > +	irq_dispose_mapping((unsigned int)(unsigned long)res);
> > > > +}
> > > 
> > > Leftover?
> > 
> > What do you mean? I dropped the devm-helpers.h changes, now I do
> > devm_add_action_or_reset() manually, with this function as the action.
> 
> But why?

...

> > > > +	irq_idx = omnia_int_to_gpio_idx[__bf_shf(INT_TRNG)];
> > > > +	irq = gpiod_to_irq(gpiochip_get_desc(&mcu->gc, irq_idx));
> > > > +	if (irq < 0)
> > > > +		return dev_err_probe(dev, irq, "Cannot get TRNG IRQ\n");
> 
> > > > +	err = devm_add_action_or_reset(dev, omnia_irq_mapping_drop,
> > > > +				       (void *)(unsigned long)irq);
> > > > +	if (err)
> > > > +		return err;
> > > 
> > > Are you sure it's correct now?
> > 
> > Yes, why wouldn't it?
> 
> For what purpose? I don't see drivers doing that. Are you expecting that
> the same IRQ mapping will be reused for something else? Can you elaborate
> how? (I can imagine one theoretical / weird case how to achieve that,
> but impractical.)
> 
> Besides above, this is asymmetrical call to gpiod_to_irq(). If we really care
> about this, it should be provided by GPIO library.

FWIW, gpiochip_irqchip_remove() disposes mappings for internally allocated IRQ
domains. So with your code it even might be a double-disposal.

-- 
With Best Regards,
Andy Shevchenko