Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v12 4/5] dma-buf: heaps: Add CMA heap to dmabuf heaps
To:     Benjamin Gaignard <benjamin.gaignard@linaro.org>,
        Brian Starkey <Brian.Starkey@arm.com>
CC:     John Stultz <john.stultz@linaro.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Laura Abbott <labbott@redhat.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Liam Mark <lmark@codeaurora.org>,
        Pratik Patel <pratikp@codeaurora.org>,
        Vincent Donnefort <Vincent.Donnefort@arm.com>,
        Sudipto Paul <Sudipto.Paul@arm.com>,
        Christoph Hellwig <hch@infradead.org>,
        Chenbo Feng <fengc@google.com>,
        Alistair Strachan <astrachan@google.com>,
        Hridya Valsaraju <hridya@google.com>,
        Hillf Danton <hdanton@sina.com>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        nd <nd@arm.com>
References: <20191018052323.21659-1-john.stultz@linaro.org>
 <20191018052323.21659-5-john.stultz@linaro.org>
 <20191018112124.grjgqrn3ckuc7n4v@DESKTOP-E1NTVVP.localdomain>
 <CA+M3ks6KqqXCfqA6VDKnQOsvFLQfaGrUnA+eesnyzMRniFB00A@mail.gmail.com>
From:   "Andrew F. Davis" <afd@ti.com>
Message-ID: <5a172663-21d5-5f5d-c9d3-f643d8dadc34@ti.com>
Date:   Fri, 18 Oct 2019 09:54:52 -0400
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.9.0
MIME-Version: 1.0
In-Reply-To: <CA+M3ks6KqqXCfqA6VDKnQOsvFLQfaGrUnA+eesnyzMRniFB00A@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 10/18/19 8:03 AM, Benjamin Gaignard wrote:
> Le ven. 18 oct. 2019 à 13:21, Brian Starkey <Brian.Starkey@arm.com> a écrit :
>>
>> On Fri, Oct 18, 2019 at 05:23:22AM +0000, John Stultz wrote:
>>> This adds a CMA heap, which allows userspace to allocate
>>> a dma-buf of contiguous memory out of a CMA region.
>>>
>>> This code is an evolution of the Android ION implementation, so
>>> thanks to its original author and maintainters:
>>>   Benjamin Gaignard, Laura Abbott, and others!
>>>
>>> NOTE: This patch only adds the default CMA heap. We will enable
>>> selectively adding other CMA memory regions to the dmabuf heaps
>>> interface with a later patch (which requires a dt binding)
> 
> Maybe we can use "no-map" DT property to trigger that. If set do not expose the
> cma heap.


"no-map" means it can't be used as a regular CMA either, we want some
way to both have it as a device usable CMA but also not be exposed to
userspace if needed.

Andrew

> 
> Benjamin
>>
>> That'll teach me for reading my email in FIFO order.
>>
>> This approach makes sense to me.
>>
>> -Brian
>>