Re: [PATCH] mmc: disable card sleep via device-tree

From: Lukasz Majewski <lukma@denx.de>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Fabio Estevam <fabio.estevam@nxp.com>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Chanho Min <chanho.min@lge.com>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree@vger.kernel.org>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	Stanislav Meduna <stanislav.meduna@nxtcontrol.com>
Subject: Re: [PATCH] mmc: disable card sleep via device-tree
Date: Mon, 30 Apr 2018 11:31:57 +0200	[thread overview]
Message-ID: <20180430113157.37a09e5c@jawa> (raw)
In-Reply-To: <CACRpkdbzvnSHPQOZjs3WcL9pOMz3R0W9P9Gre5n_G40udTMUjQ@mail.gmail.com>

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On Mon, 30 Apr 2018 11:13:45 +0200
Hi Linus,

> On Sun, Apr 22, 2018 at 11:31 PM, Lukasz Majewski <lukma@denx.de>
> wrote:
> 
> > From: Stanislav Meduna <stanislav.meduna@nxtcontrol.com>
> >
> > On a TQMa53 module the mmc_sleep leaves the eMMC card in a state
> > that the imx53 rom boot code is unable to probe, resulting in
> > reboot hanging. Add a device tree property to disable sleeping
> > on suspend.
> >
> > For TQMa53 modules the exact commit to cause hang after reboot
> > (v3.10 -> v3.11):
> > commit 486fdbbc1483 ("mmc: core: Add shutdown callback for (e)MMC
> > bus_ops")
> >
> > [The exact discussion can be found here:
> > https://patchwork.kernel.org/patch/8881401/
> > "i.MX53 restart via watchdog does not work"
> >
> > Signed-off-by: Stanislav Meduna <stanislav.meduna@nxtcontrol.com>
> > Signed-off-by: Lukasz Majewski <lukma@denx.de>  
> (...)
> 
> >  Optional properties:
> >  -broken-hpi : Use this to indicate that the mmc-card has a broken
> > hpi implementation, and that hpi should not be used
> > +-no-sleep-on-suspend : Do not put the card to sleep when
> > suspending.
> > +              There are boards with bootloaders that are unable
> > +              to probe such card when rebooting.  
> 
> As far as I understand this problem is not coming from the host
> controller itself,
> so it should not be tagged on to the host controller either. Rather
> the problem is how the specific system has integrated the host
> controller, the problem is in the fixture of this specific machine,
> as you say, in the i.MX53 ROM.
> 
> In that case, I would say use this:
> 
> if (of_machine_is_compatible("fsl,imx53")) {
>    ..activate quirk...
> }

I see. Thanks for pointing this.

> 
> Yours,
> Linus Walleij

Best regards,

Lukasz Majewski

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