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Date: Sat, 04 Feb 2017 23:27:12 +0100
From: =?UTF-8?Q?Rafa=C5=82_Mi=C5=82ecki?= <rafal@milecki.pl>
To: Marek Vasut <marek.vasut@gmail.com>
Cc: =?UTF-8?Q?Rafa=C5=82_Mi=C5=82ecki?= <zajec5@gmail.com>, David Woodhouse
 <dwmw2@infradead.org>, Brian Norris <computersforpeace@gmail.com>, Boris
 Brezillon <boris.brezillon@free-electrons.com>, Richard Weinberger
 <richard@nod.at>, Cyrille Pitchen <cyrille.pitchen@atmel.com>,
 linux-mtd@lists.infradead.org, Hauke Mehrtens <hauke@hauke-m.de>
Subject: Re: [PATCH V3] mtd: bcm47xxsflash: support reading flash out of
 mapping window
In-Reply-To: <a39c07ff-a17a-306e-88c0-fc79105ac608@gmail.com>
References: <20170123115154.3364-1-zajec5@gmail.com>
 <a39c07ff-a17a-306e-88c0-fc79105ac608@gmail.com>
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On 2017-02-04 23:01, Marek Vasut wrote:
> On 01/23/2017 12:51 PM, Rafał Miłecki wrote:
>> From: Rafał Miłecki <rafal@milecki.pl>
>> 
>> For reading flash content we use MMIO but it's possible to read only
>> first 16 MiB this way. It's simply an arch design/limitation.
>> To support flash sizes bigger than 16 MiB implement indirect access
>> using ChipCommon registers.
>> This has been tested using MX25L25635F.
>> 
>> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
>> ---
>> V2: Simplify line writing to buf
>>     Add some trivial comment for OPCODE_ST_READ4B
>>     Both requested by Marek
>> V3: Use as much as possible MMIO access for read crossing boundary 
>> (performance)
> 
> It's not because of performance, but because you can start reading at 
> 15
> MiB offset and read 2 MiB , at which point the previous patch would IMO
> fail.

It never failed. It was slow but was working as expected.


> Acked-by: Marek Vasut <marek.vasut@gmail.com>
> 
> Thanks!

Thanks