From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1754396AbaIARMf (ORCPT <rfc822;w@1wt.eu>);
	Mon, 1 Sep 2014 13:12:35 -0400
Received: from mout.kundenserver.de ([212.227.126.131]:52717 "EHLO
	mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751047AbaIARMe (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Mon, 1 Sep 2014 13:12:34 -0400
From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
        Hanjun Guo <hanjun.guo@linaro.org>,
        Mark Rutland <Mark.Rutland@arm.com>,
        "linaro-acpi@lists.linaro.org" <linaro-acpi@lists.linaro.org>,
        Will Deacon <Will.Deacon@arm.com>, Lv Zheng <lv.zheng@intel.com>,
        Rob Herring <robh@kernel.org>,
        Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Robert Moore <robert.moore@intel.com>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "grant.likely@linaro.org" <grant.likely@linaro.org>,
        Charles Garcia-Tobin <Charles.Garcia-Tobin@arm.com>,
        Robert Richter <rric@kernel.org>, Jason Cooper <jason@lakedaemon.net>,
        Marc Zyngier <Marc.Zyngier@arm.com>, Liviu Dudau <Liviu.Dudau@arm.com>,
        Mark Brown <broonie@kernel.org>, Bjorn Helgaas <bhelgaas@google.com>,
        "graeme.gregory@linaro.org" <graeme.gregory@linaro.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Sudeep Holla <Sudeep.Holla@arm.com>, Olof Johansson <olof@lixom.net>
Subject: Re: [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI
Date: Mon, 01 Sep 2014 19:11:44 +0200
Message-ID: <21764799.KDNDm9XRax@wuerfel>
User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; )
In-Reply-To: <20140901170447.GF608@arm.com>
References: <1409583961-7466-1-git-send-email-hanjun.guo@linaro.org> <1409583961-7466-2-git-send-email-hanjun.guo@linaro.org> <20140901170447.GF608@arm.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 7Bit
Content-Type: text/plain; charset="us-ascii"
X-Provags-ID: V02:K0:1m8LQQoB6LfOt25jCLyRPlWdCjCh3quL8384sfYOmfI
 QodDlut9nyWOg3v0hfLvRNFV08HdfZcWf963O8MD4YkWpI9w0c
 jEkqezODjsky4SqBAsQwNqhstlPKOYxOMP/1Rf+xG3C7GrCFjt
 kyzTXOpFT2RhN+8J7qY+/atLxgDgTLSpOECW6CKSdgP9ylQaRo
 0b6zyHiXkDHcJ4HP9VmSzFkxmOWK+os+YZ+hgAJil2nfw1+ni8
 E9/mrXcoYHE+NQaBcL3wmB8QYxfBo2KdPawkOog2RTnsAkxjTk
 c7DzzkCQ3H65wJCLa4B4AvfaylL3io4ACCztffdw7fsZqExXuM
 VDS6xr2ukSsPpkzT3Wbo=
X-UI-Out-Filterresults: notjunk:1;
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Monday 01 September 2014 18:04:47 Catalin Marinas wrote:
> On Mon, Sep 01, 2014 at 04:06:00PM +0100, Hanjun Guo wrote:
> > +#ifdef CONFIG_ACPI
> > +/* Configure some sensible defaults for ACPI mode */
> > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > +                                 acpi_handle *ahandle)
> > +{
> > +     if (!ahandle)
> > +             return -ENOSYS;
> > +
> > +     config->phy_interface = PHY_INTERFACE_MODE_MII;
> > +
> > +     config->flags |= SMSC911X_USE_32BIT;
> > +
> > +     config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH;
> > +
> > +     config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL;
> > +
> > +     return 0;
> > +}
> > +#else
> 
> I don't like this and it shows issues we have with ACPI on certain ARM
> platforms. You hard-code these values to match the Juno platform. What
> if we get another SoC which has different configuration here? For DT, we
> have the smsc911x_probe_config_dt() which reads the relevant information
> from DT. I think this kind of configuration would be more suitable as
> _DSD properties and sharing the similar names with DT (but we go back to
> the question about who's in charge of the _DSD properties).

Good point, I totally missed that.

There is of course the possibility to set those values based on the
acpi_device_id, but that is exactly the part that _DSD is trying to
avoid.

> >  static int smsc911x_drv_probe(struct platform_device *pdev)
> >  {
> >       struct device_node *np = pdev->dev.of_node;
> > +     acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
> >       struct net_device *dev;
> >       struct smsc911x_data *pdata;
> >       struct smsc911x_platform_config *config = dev_get_platdata(&pdev->dev);
> > @@ -2436,6 +2464,9 @@ static int smsc911x_drv_probe(struct platform_device *pdev)
> >       }
> >  
> >       retval = smsc911x_probe_config_dt(&pdata->config, np);
> > +     if (retval)
> > +             retval = smsc911x_probe_config_acpi(&pdata->config, ahandle);
> > +
> 
> In most of the ACPI patches so far we check for ACPI first with DT as a
> fall-back if ACPI is not enabled. This changes here.

Does this really make a difference?

> I would prefer
> something which probes only ACPI if the ACPI is enabled (run-time, not
> config) otherwise DT only. E.g.

(example missing?)

I think we should have the equivalent of of_have_populated_dt(), to
check whether acpi is being used to boot, and have that new function
be hardcoded to zero in case of !IS_ENABLED(CONFIG_ACPI).

	Arnd