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From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: arvind Yadav <arvind.yadav.cs@gmail.com>
Cc: robert.jarzmik@free.fr, dwmw2@infradead.org,
	computersforpeace@gmail.com, marek.vasut@gmail.com,
	richard@nod.at, cyrille.pitchen@atmel.com,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [V2] mtd: devices: docg3:- Handle return value of devm_ioremap.
Date: Mon, 12 Dec 2016 18:04:44 +0100	[thread overview]
Message-ID: <20161212180444.22a1f4ff@bbrezillon> (raw)
In-Reply-To: <80fc935a-39aa-eaca-e75c-02078c3dab05@gmail.com>

Hi Arvind,

On Mon, 12 Dec 2016 21:33:05 +0530
arvind Yadav <arvind.yadav.cs@gmail.com> wrote:

> There is problem, if you will use devm_ioremap_resource instead of 
> devm_ioremap,
> than devm_ioremap_resource will call request_mem_region().
> request_mem_region() allows to tell the kernel that this driver is going 
> to use
> this range of I/O addresses, which will prevent other drivers to make an
> overlapping call to request_mem_region If other driver want to use same 
> address
> space to access then it will not allow. Means we can not share same 
> address space
> between two driver.

The question is, is it required here? In general, allowing 2 different
drivers from touching the same iomem region is a bad idea, so, if
there's a reason to allow that here, I'd like to know more about it.

Thanks,

Boris

  parent reply	other threads:[~2016-12-12 17:05 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-12  3:00 [V2] mtd: devices: docg3:- Handle return value of devm_ioremap Arvind Yadav
2016-12-12  4:10 ` Marek Vasut
2016-12-12  8:42 ` Boris Brezillon
2016-12-12 16:03   ` arvind Yadav
2016-12-12 16:32     ` Robert Jarzmik
2016-12-12 17:00       ` Boris Brezillon
2016-12-12 17:04     ` Boris Brezillon [this message]
2016-12-12 18:15       ` arvind Yadav

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