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From: Arnd Bergmann <arnd@arndb.de>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Jaedon Shin <jaedon.shin@gmail.com>,
	Alan Cooper <alcooperx@gmail.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	bcm-kernel-feedback-list@broadcom.com, linux-mmc@vger.kernel.org
Subject: Re: [PATCH] mmc: sdhci-brcmstb: Add SDHCI_QUIRK2_BROKEN_64_BIT_DMA
Date: Mon, 29 Aug 2016 11:44:32 +0200	[thread overview]
Message-ID: <5229438.Oa2AiqCmJN@wuerfel> (raw)
In-Reply-To: <7edcef69-d364-8845-a677-3827a50f4da1@gmail.com>

On Saturday, August 27, 2016 12:56:10 PM CEST Florian Fainelli wrote:
> 
> Finally, Arnd's suggestions of using "dma-ranges" is fine, but I do not
> think we quite need this here because we really need to advertise the
> right set of capabilities based on the generation/version of the
> controller deployed in specific chips.

To be more specific here, I think that without the dma-ranges property
you should never be able to set a dma-mask larger than the 32-bit
mask, so if you have machines that are capable of high DMA, you
should definitely add the property in the bus, even if that is
currently ignored.

I've suggested a patch before, but I believe both ARM and MIPS ignore
this at the moment, and just allow drivers to set arbitrary masks
even when the bus does not have a dma-ranges property, and that
is a bug.

	Arnd

  parent reply	other threads:[~2016-08-29  9:44 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20160808015803.2528-1-jaedon.shin@gmail.com>
     [not found] ` <8f42998e-6d5b-2ac7-3814-f7a4d6e8a6b9@intel.com>
     [not found]   ` <CAOGqxeX8kcD9rX4nd+o=RTggEoPLZfK40GdBWKTT6-BTpxSvbg@mail.gmail.com>
     [not found]     ` <AD331215-7115-426D-A089-263D6A0E54BF@gmail.com>
     [not found]       ` <CAPDyKFqkoF2GU6QGc7GW1S2p8+A=XpU48sREcLiSkadPKHuibw@mail.gmail.com>
2016-08-19 14:05         ` [PATCH] mmc: sdhci-brcmstb: Add SDHCI_QUIRK2_BROKEN_64_BIT_DMA Jaedon Shin
2016-08-25 16:41           ` Florian Fainelli
2016-08-26  6:49             ` Ulf Hansson
2016-08-26 13:29               ` Arnd Bergmann
2016-08-27  4:02             ` Jaedon Shin
2016-08-27 19:56               ` Florian Fainelli
2016-08-28 10:53                 ` Jaedon Shin
2016-08-29  9:44                 ` Arnd Bergmann [this message]
2016-08-29 15:40                   ` Alan Cooper
2016-08-30 14:04                     ` Arnd Bergmann

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