From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Naga Sureshkumar Relli <nagasure@xilinx.com>
Cc: Boris Brezillon <boris.brezillon@bootlin.com>,
"richard@nod.at" <richard@nod.at>,
"dwmw2@infradead.org" <dwmw2@infradead.org>,
"computersforpeace@gmail.com" <computersforpeace@gmail.com>,
"marek.vasut@gmail.com" <marek.vasut@gmail.com>,
"kyungmin.park@samsung.com" <kyungmin.park@samsung.com>,
"absahu@codeaurora.org" <absahu@codeaurora.org>,
"peterpandong@micron.com" <peterpandong@micron.com>,
"frieder.schrempf@exceet.de" <frieder.schrempf@exceet.de>,
"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Michal Simek <michals@xilinx.com>,
"nagasureshkumarrelli@gmail.com" <nagasureshkumarrelli@gmail.com>
Subject: Re: [LINUX PATCH v10 1/2] dt-bindings: mtd: arasan: Add device tree binding documentation
Date: Tue, 21 Aug 2018 11:52:38 +0200 [thread overview]
Message-ID: <20180821115238.1ad4dcb8@xps13> (raw)
In-Reply-To: <MWHPR02MB2623E78222225D1CE8167463AF310@MWHPR02MB2623.namprd02.prod.outlook.com>
Hi Naga,
Naga Sureshkumar Relli <nagasure@xilinx.com> wrote on Tue, 21 Aug 2018
09:22:07 +0000:
> Hi Boris,
>
> > -----Original Message-----
> > From: Boris Brezillon [mailto:boris.brezillon@bootlin.com]
> > Sent: Tuesday, August 21, 2018 11:30 AM
> > To: Naga Sureshkumar Relli <nagasure@xilinx.com>
> > Cc: miquel.raynal@bootlin.com; richard@nod.at; dwmw2@infradead.org;
> > computersforpeace@gmail.com; marek.vasut@gmail.com; kyungmin.park@samsung.com;
> > absahu@codeaurora.org; peterpandong@micron.com; frieder.schrempf@exceet.de; linux-
> > mtd@lists.infradead.org; linux-kernel@vger.kernel.org; Michal Simek <michals@xilinx.com>;
> > nagasureshkumarrelli@gmail.com
> > Subject: Re: [LINUX PATCH v10 1/2] dt-bindings: mtd: arasan: Add device tree binding
> > documentation
> >
> > On Tue, 21 Aug 2018 05:47:18 +0000
> > Naga Sureshkumar Relli <nagasure@xilinx.com> wrote:
> >
> > > > > +Required properties:
> > > > > +- compatible: Should be "xlnx,zynqmp-nand" or "arasan,nfc-v3p10"
> > > >
> > > > In your example it's not an "or" since both are defined.
> > > In our previous discussion
> > > (https://lore.kernel.org/patchwork/patch/748901/)
> > > We decided to have compatible strings like " compatible = "<soc-vendor>,<ip-revision>",
> > "arasan,<ip-revision>";"
> > > So it should be either of these.
> > > so I will write something like below
> > > "Possible values are "xlnx,zynqmp-nand"
> > > "arasan,nfc-v3p10"
> > > And in example I will mention any one compatible.
> > > Is it ok?
> >
> > Hm, why do you need arasan,nfc-v3p10 at all if it's supposed to be overloaded by a soc specific
> > compat?
> Actually we put these compatible strings based on the comments on v7 series.
> Anyway I will just keep "xlnx,zynqmp-nand" as compatible.
> >
> > > > > +
> > > > > +Optional properties:
> > > > > +- arasan,has-mdma: Enables DMA support
> > > >
> > > > Can't you detect that based on the compatible (or thanks to a
> > > > register). If it's something you choose when configuring the IP and can't detect at
> > runtime I guess it's fine.
> > > There is no way to select DMA when configuring the IP.
> > > But it has internal DMA and there is a register to select PIO or DMA while starting a
> > transfer.
> > > So if user really don't want DMA, then we will never set DMA in the code based on DT
> > property.
> >
> > If it's a purely SW choice, then is shouldn't be described in the DT.
> > You can use a module param, but I'm not even sure why one would want to disable DMA.
> UBIFS doesn't work with DMA, hence we are using a DT property to operate the driver in IO.
> But as you pointed (use virt_is_valid()), with this we can switch our driver to operate in PIO or DMA.
> I will remove this from DT.
I don't get why UBIFS would not work with DMA? This is a significant
drawback.
Miquèl
next prev parent reply other threads:[~2018-08-21 9:52 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-17 13:19 [LINUX PATCH v10 0/2] Add support for Arasan NAND Flash controller Naga Sureshkumar Relli
2018-08-17 13:19 ` [LINUX PATCH v10 1/2] dt-bindings: mtd: arasan: Add device tree binding documentation Naga Sureshkumar Relli
2018-08-20 12:33 ` Boris Brezillon
2018-08-21 5:47 ` Naga Sureshkumar Relli
2018-08-21 5:59 ` Boris Brezillon
2018-08-21 9:22 ` Naga Sureshkumar Relli
2018-08-21 9:52 ` Miquel Raynal [this message]
2018-08-21 10:44 ` Naga Sureshkumar Relli
2018-08-21 10:52 ` Boris Brezillon
2018-08-21 11:10 ` Boris Brezillon
2018-08-17 13:19 ` [LINUX PATCH v10 2/2] mtd: rawnand: arasan: Add support for Arasan NAND Flash Controller Naga Sureshkumar Relli
2018-08-17 14:37 ` Miquel Raynal
2018-08-18 4:48 ` Naga Sureshkumar Relli
2018-08-17 15:30 ` kbuild test robot
2018-08-17 17:59 ` Boris Brezillon
2018-08-18 5:49 ` Naga Sureshkumar Relli
2018-08-20 8:53 ` Boris Brezillon
2018-08-20 10:49 ` Naga Sureshkumar Relli
2018-08-20 12:10 ` Boris Brezillon
2018-08-20 12:21 ` Naga Sureshkumar Relli
2018-08-20 12:24 ` Boris Brezillon
2018-08-20 16:40 ` Boris Brezillon
2018-08-21 6:40 ` Naga Sureshkumar Relli
2018-08-21 7:31 ` Miquel Raynal
2018-09-11 5:23 ` Naga Sureshkumar Relli
2018-09-22 7:53 ` Miquel Raynal
2018-09-22 8:13 ` Boris Brezillon
2018-09-24 8:42 ` Naga Sureshkumar Relli
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