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From:   Tomasz Figa <tfiga@chromium.org>
Date:   Tue, 6 Mar 2018 11:04:48 +0900
Message-ID: <CAAFQd5DCGgFWvpfFgkP-L+4WC9HRyqtCHiTUGRpA5PGx-QgpLg@mail.gmail.com>
Subject: Re: [RESEND PATCH v6 13/14] iommu/rockchip: Add runtime PM support
To:     JeffyChen <jeffy.chen@rock-chips.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Ricky Liang <jcliang@chromium.org>,
        Robin Murphy <robin.murphy@arm.com>,
        simon xue <xxm@rock-chips.com>,
        Heiko Stuebner <heiko@sntech.de>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        open@263.net,
        "list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>, Joerg
        Roedel <joro@8bytes.org>, list@263.net:IOMMU DRIVERS
        <iommu@lists.linux-foundation.org>, Joerg Roedel <joro@8bytes.org>," 
        <linux-arm-kernel@lists.infradead.org>
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Hi Jeffy,

On Tue, Mar 6, 2018 at 10:57 AM, JeffyChen <jeffy.chen@rock-chips.com> wrote:
> Hi Tomasz,
>
> Thanks for your reply.
>
> On 03/05/2018 09:49 PM, Tomasz Figa wrote:
>>>
>>> >  struct rk_iommudata {
>>> >+       struct device_link *link; /* runtime PM link from IOMMU to
>>> > master */
>>
>> Kerneldoc comment for the struct could be added instead.
>
> i saw this in the kerneldoc:
>
> * An MMU device exists alongside a busmaster device, both are in the same
>   power domain.  The MMU implements DMA address translation for the
> busmaster
>   device and shall be runtime resumed and kept active whenever and as long
>   as the busmaster device is active.  The busmaster device's driver shall
>   not bind before the MMU is bound.  To achieve this, a device link with
>   runtime PM integration is added from the busmaster device (consumer)
>   to the MMU device (supplier).  The effect with regards to runtime PM
>   is the same as if the MMU was the parent of the master device.
>
>
> maybe we can use something like:
> device link with runtime PM integration from the master (consumer) to the
> IOMMU (supplier).

Sorry, I meant that kerneldoc comment style could be used to document
this struct.

https://www.kernel.org/doc/html/v4.15/doc-guide/kernel-doc.html#writing-kernel-doc-comments

Best regards,
Tomasz