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Subject: Re: [PATCH v2 1/3] drivers/of: recognize status property of dt memory
 nodes
To: Reza Arbab <arbab@linux.vnet.ibm.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>, Rob Herring <robh+dt@kernel.org>,
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        Jonathan Corbet <corbet@lwn.net>,
        Andrew Morton <akpm@linux-foundation.org>
References: <1473883618-14998-1-git-send-email-arbab@linux.vnet.ibm.com>
 <1473883618-14998-2-git-send-email-arbab@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>,
        Nathan Fontenot <nfont@linux.vnet.ibm.com>,
        Stewart Smith <stewart@linux.vnet.ibm.com>,
        Alistair Popple <apopple@au1.ibm.com>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        devicetree@vger.kernel.org, linux-mm@kvack.org
From: Balbir Singh <bsingharora@gmail.com>
Message-ID: <bdbcc833-1a56-69aa-b433-ec4ce685d3cd@gmail.com>
Date: Mon, 19 Sep 2016 20:11:39 +1000
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On 15/09/16 06:06, Reza Arbab wrote:
> Respect the standard dt "status" property when scanning memory nodes in
> early_init_dt_scan_memory(), so that if the property is present and not
> "okay", no memory will be added.
> 
> The use case at hand is accelerator or device memory, which may be
> unusable until post-boot initialization of the memory link. Such a node
> can be described in the dt as any other, given its status is "disabled".
> Per the device tree specification,
> 
> "disabled"
> 	Indicates that the device is not presently operational, but it
> 	might become operational in the future (for example, something
> 	is not plugged in, or switched off).
> 
> Once such memory is made operational, it can then be hotplugged.
> 
> Signed-off-by: Reza Arbab <arbab@linux.vnet.ibm.com>

Makes sense, so basically a /memory@  with missing status or status = "okay"
are added, others are skipped. No memblocks corresponding to those nodes
are created either.

Balbir Singh