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Subject: Re: [PATCH v1 2/2] mtd: rawnand: Add NAND controller support on Intel
 LGM SoC
To:     Boris Brezillon <boris.brezillon@collabora.com>
Cc:     Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        anders.roxell@linaro.org, andriy.shevchenko@intel.com,
        arnd@arndb.de, brendanhiggins@google.com, cheol.yong.kim@intel.com,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mtd@lists.infradead.org, masonccyang@mxic.com.tw,
        miquel.raynal@bootlin.com, piotrs@cadence.com,
        qi-ming.wu@intel.com, richard@nod.at, robh+dt@kernel.org,
        tglx@linutronix.de, vigneshr@ti.com
References: <20200414022433.36622-3-vadivel.muruganx.ramuthevar@linux.intel.com>
 <20200415220533.733834-1-martin.blumenstingl@googlemail.com>
 <c33c8653-16a2-5bcd-97a9-511d958b755a@linux.intel.com>
 <20200416113822.2ef326cb@collabora.com>
From:   "Ramuthevar, Vadivel MuruganX" 
        <vadivel.muruganx.ramuthevar@linux.intel.com>
Message-ID: <18568cf6-2955-472e-7b68-eb35e654a906@linux.intel.com>
Date:   Thu, 16 Apr 2020 17:45:49 +0800
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Hi Boris,

     Thank you for prompt reply...

On 16/4/2020 5:38 pm, Boris Brezillon wrote:
> On Thu, 16 Apr 2020 17:35:26 +0800
> "Ramuthevar, Vadivel MuruganX"
> <vadivel.muruganx.ramuthevar@linux.intel.com> wrote:
>
>> Hi Martin,
>>
>>       Thank you so much for review comments and your time...
>>
>> On 16/4/2020 6:05 am, Martin Blumenstingl wrote:
>>> Hi,
>>>
>>> first of all: thank you for working on upstreaming this.
>>> Especially since you are going to use the new exec_op style in v2 as
>>> Boris suggested.
>>>   
>>>> From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
>>>>
>>>> This patch adds the new IP of Nand Flash Controller(NFC) support
>>>> on Intel's Lightning Mountain(LGM) SoC.
>>>>
>>>> DMA is used for burst data transfer operation, also DMA HW supports
>>>> aligned 32bit memory address and aligned data access by default.
>>>> DMA burst of 8 supported. Data register used to support the read/write
>>>> operation from/to device.
>>> I am wondering how this new hardware is different from the Lantiq NAND
>>> controller IP - for which there is already a driver in mainline (it's
>>> in drivers/mtd/nand/raw/xway_nand.c).
>>> The CON and WAIT registers look suspiciously similar.
>>>
>>> As far as I understand the "old" SoCs (VRX200 and earlier) don't have
>>> a built-in ECC engine. This seems to have changed with ARX300 though
>>> (again, AFAIK).
>>>
>>> A bit of lineage on these SoCs (initially these were developed by
>>> Infineon. Lantiq then started as an Infineon spin-off in 2009 and
>>> was then acquired by Intel in 2015):
>>> - Danube
>>> - ARX100 from 2008/2009
>>> - VRX200 from 2009/2010
>>> - ARX300 from 2014
>>> - GRX350 from 2015/2016
>>> - GRX550 from 2017
>>> - and now finally: LGM from 2020 (est.)
>>>
>>> The existing xway_nand driver supports the Danube, ARX100 and VRX200
>>> SoCs.
>> Lantiq upstreamed a driver for an older version of this IP core 8 years
>> ago, see here:
>> https://elixir.bootlin.com/linux/v5.5.6/source/drivers/mtd/nand/raw/xway_nand.c
>> It does not support DMA and ECC.
> Then let's just extend this driver to support the new features. Plus,
We do not have the platform to test also it's very old legacy driver .
> we'll be happy to have one more of the existing driver converted to
> ->exec_op() ;-).

I have completely adapted to ->exec_op() hook up to replace the legacy 
call-back.

Regards
Vadivel
>
>> This upstream driver works with the xrx200, I do not know how well it
>> works with other SoCs.
>>
>> Regards
>> Vadivel
>>>
>>> Best regards,
>>> Martin