Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Andy Duan <fugang.duan@nxp.com>
To:     Greg KH <gregkh@linuxfoundation.org>,
        Sherry Sun <sherry.sun@nxp.com>
CC:     "hch@infradead.org" <hch@infradead.org>,
        "vincent.whitchurch@axis.com" <vincent.whitchurch@axis.com>,
        "sudeep.dutt@intel.com" <sudeep.dutt@intel.com>,
        "ashutosh.dixit@intel.com" <ashutosh.dixit@intel.com>,
        "arnd@arndb.de" <arnd@arndb.de>, "kishon@ti.com" <kishon@ti.com>,
        "lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        dl-linux-imx <linux-imx@nxp.com>
Subject: RE: [EXT] Re: [PATCH V5 0/2] Change vring space from nomal memory to
 dma coherent memory
Thread-Topic: [EXT] Re: [PATCH V5 0/2] Change vring space from nomal memory to
 dma coherent memory
Thread-Index: AQHWrPBWlkaK3Q/in0Cw78FI6wskoqmsmAkAgAAzuWA=
Date:   Wed, 28 Oct 2020 10:17:39 +0000
Message-ID: <AM8PR04MB7315D583A9490E642ED13071FF170@AM8PR04MB7315.eurprd04.prod.outlook.com>
References: <20201028020305.10593-1-sherry.sun@nxp.com>
 <20201028055836.GA244690@kroah.com>
 <AM0PR04MB4947032368486CC9874C812692170@AM0PR04MB4947.eurprd04.prod.outlook.com>
 <20201028070712.GA1649838@kroah.com>
In-Reply-To: <20201028070712.GA1649838@kroah.com>
Accept-Language: zh-CN, en-US
Content-Language: en-US
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: b58ec37d-33b7-4339-e1b7-08d87b2ab2e3
X-MS-Exchange-CrossTenant-originalarrivaltime: 28 Oct 2020 10:17:39.2718
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: NYwpUAm3DF1uJGSKZJFjEEgViDXpNGfIJhB6xgRKp8Vo+sQGZ2owBW91I08o9B1RzcpVgP9LdJ2jDl+8Aa0KrQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM8PR04MB7331
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Greg KH <gregkh@linuxfoundation.org> Sent: Wednesday, October 28, 202=
0 3:07 PM
> On Wed, Oct 28, 2020 at 06:05:28AM +0000, Sherry Sun wrote:
> > Hi Greg,
> >
> > > Subject: Re: [PATCH V5 0/2] Change vring space from nomal memory to
> > > dma coherent memory
> > >
> > > On Wed, Oct 28, 2020 at 10:03:03AM +0800, Sherry Sun wrote:
> > > > Changes in V5:
> > > > 1. Reorganize the vop_mmap function code in patch 1, which is done
> > > > by
> > > Christoph.
> > > > 2. Completely remove the unnecessary code related to reassign the
> > > > used ring for card in patch 2.
> > > >
> > > > The original vop driver only supports dma coherent device, as it
> > > > allocates and maps vring by _get_free_pages and dma_map_single,
> > > > but not use dma_sync_single_for_cpu/device to sync the updates of
> > > > device_page/vring between EP and RC, which will cause memory
> > > > synchronization problem for device don't support hardware dma coher=
ent.
> > > >
> > > > And allocate vrings use dma_alloc_coherent is a common way in
> > > > kernel, as the memory interacted between two systems should use
> > > > consistent memory to avoid caching effects. So here add
> > > > noncoherent platform
> > > support for vop driver.
> > > > Also add some related dma changes to make sure noncoherent
> > > > platform works well.
> > > >
> > > > Sherry Sun (2):
> > > >   misc: vop: change the way of allocating vrings and device page
> > > >   misc: vop: do not allocate and reassign the used ring
> > > >
> > > >  drivers/misc/mic/bus/vop_bus.h     |   2 +
> > > >  drivers/misc/mic/host/mic_boot.c   |   9 ++
> > > >  drivers/misc/mic/host/mic_main.c   |  43 ++------
> > > >  drivers/misc/mic/vop/vop_debugfs.c |   4 -
> > > >  drivers/misc/mic/vop/vop_main.c    |  70 +-----------
> > > >  drivers/misc/mic/vop/vop_vringh.c  | 166 ++++++++++---------------=
----
> > > >  include/uapi/linux/mic_common.h    |   9 +-
> > > >  7 files changed, 85 insertions(+), 218 deletions(-)
> > >
> > > Have you all seen:
> > >
> > > https://eur01.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%25
> > >
> 2Flore.kernel.org%2Fr%2F8c1443136563de34699d2c084df478181c205db4.16
> > >
> 03854416.git.sudeep.dutt%40intel.com&amp;data=3D04%7C01%7Csherry.sun%
> > >
> 40nxp.com%7Cc19c987667434969847e08d87b0685e8%7C686ea1d3bc2b4c6f
> > >
> a92cd99c5c301635%7C0%7C0%7C637394615238940323%7CUnknown%7CTW
> > >
> FpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJX
> > >
> VCI6Mn0%3D%7C1000&amp;sdata=3DZq%2FtHWTq%2BuIVBYXFGoeBmq0JJzYd
> > > 9zDyv4NVN4TpC%2FU%3D&amp;reserved=3D0
> > >
> > > Looks like this code is asking to just be deleted, is that ok with yo=
u?
> >
> > Yes, I saw that patch. I'm ok with it.
>=20
> Great, can you please provide a "Reviewed-by:" or "Acked-by:" for it?
>=20
> thanks,
>=20
> greg k-h

Sherry took much effort on the features support on i.MX series like i.MX8QM=
/i.MX8QXP/i.MX8MM.

Now it is a pity to delete the vop code.

One question,=20
can we resubmit vop code by clean up, now only for i.MX series as Dutt's su=
ggestion ?
Or we have to drop the design and switch to select other solutions ?

Thanks,
Andy