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Subject: Re: [PATCH v13 2/8] mtd: rawnand: rockchip: NFC drivers for RK3308,
 RK2928 and others
To:     Miquel Raynal <miquel.raynal@bootlin.com>
Cc:     Yifeng <yifeng.zhao@rock-chips.com>, richard@nod.at,
        vigneshr@ti.com, robh+dt@kernel.org, devicetree@vger.kernel.org,
        heiko@sntech.de, linux-kernel@vger.kernel.org,
        linux-rockchip@lists.infradead.org, linux-mtd@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org
References: <20201028095326.15562-1-yifeng.zhao@rock-chips.com>
 <20201028095326.15562-3-yifeng.zhao@rock-chips.com>
 <a8a7875b-f08b-62c6-a630-245687e0df3b@gmail.com>
 <e02e13a0-769d-6b73-c87e-5b7d75fd4254@rock-chips.com>
 <0b417fc2-3503-9bf6-914d-0f8b38df1914@gmail.com>
 <20201102140725.66e7dcb1@xps13>
From:   Johan Jonker <jbx6244@gmail.com>
Message-ID: <5ad70fa0-05a9-e1e7-32cc-32933ff25ae9@gmail.com>
Date:   Mon, 2 Nov 2020 14:11:34 +0100
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Hi,

On 11/2/20 2:07 PM, Miquel Raynal wrote:
> Hi Johan, Yifeng
> 
> Johan Jonker <jbx6244@gmail.com> wrote on Mon, 2 Nov 2020 13:57:56
> +0100:
> 
>> Hi Yifeng,
>>
>> Don't poke with "ecc->bytes" ones it is set in rk_nfc_ecc_init(). It
>> will not be noted by the MTD frame work or userspace. I think there's
>> currently no way to let the user know that a different ECC must be used.
>> Neither can the user set ECC on the fly.
>>
>> Example R/W flow:
>>
>>         nand_select_target()
>> 	chip->ecc.write_page_raw()
>> 	chip->ecc.write_page()
>>
>> [..]
>>
>> 	chip->ecc.read_page_raw()
>> 	chip->ecc.read_page()
>>         nand_deselect_target()
>>
>> A write/read with:
>>
>> rk_nfc_read_page_hwecc()
>> rk_nfc_write_page_hwecc()
>>
>> or
>>
>> rk_nfc_read_page_raw()
>> rk_nfc_write_page_raw()
>>
>> must end up with the same result. If we can't archive that, then we
>> shouldn't offer RAW mode to the user for now. If Miquel agrees you
>> should just get the driver ready now without these 2 functions and round
>> things up.
> 
> What about just not supporting the BootROM area if it was marked
> "reserved" by the BRom in the DT?

Should we just fill the buffers with '0xff' for boot blocks?

> 
> Raw accessors is really a nice and basic feature that I would like to
> have in every new driver.
> 
> Thanks,
> Miquèl
>