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Message-ID: <A765B125120D1346A63912DDE6D8B6315EB0DA@NTXXIAMBX02.xacn.micron.com>
Date: Wed, 12 Nov 2014 00:58:31 +0000
From: bpqw <bpqw@...ron.com>
To: Graham Moore <grmoore@...nsource.altera.com>,
Brian Norris <computersforpeace@...il.com>
CC: Marek Vasut <marex@...x.de>,
"dwmw2@...radead.org" <dwmw2@...radead.org>,
"geert+renesas@...der.be" <geert+renesas@...der.be>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
"shijie8@...il.com" <shijie8@...il.com>, bpqw <bpqw@...ron.com>
Subject: RE: [V5 PATCH 1/1] driver:mtd:spi-nor: Add quad I/O support for
Micron spi nor
>Hi, I'm having trouble with this patch using a Cadence QSPI controller and Micron n25q00 part.
>I can use quad commands in Extended SPI mode, but I can't make this EVCR Quad mode work.
Yes,but if you use quad commands in Extended spi mode,only for Quad commands,the command line is DQ0,
Address/data line is DQ0,DQ1,DQ2 and DQ3(1-x-4).
But if in Quad I/O mode,for all the commands,the command/address/data line will be 4,they are DQ0,DQ1,DQ2 and DQ3(4-x-4).
>The Cadence QSPI Controller has fields to configure the quad transfer, and can support quad opcode,
>quad address, and quad data, or some combination. There is a chart in the docs which shows the combinations for various read commands.
>Problem is, I've tried all of the combinations and all I get is FF with this EVCR patch.
This maybe your spi controller is still extended mode,
Once EVCR bit 7 is set to 0, the spi nor device will operate in quad I/O.Command-address-data line is 4-x-4.
So after send WRITE EVCR command , spi controller also must transfer to quad I/O Mode,and set its Command-address-data line also
Should be 4-x-4 .
>If I don't set the quad mode in the EVCR, then I can use quad read commands no problem.
Yes,you don't set the quad mode in the EVCR,you can use quad read commands,but this patch is for enable Micron SPI nor Quad I/O mode,
If you want to enable it ,you must set EVCR.
>Bottom line, with the Cadence QSPI controller, if I use quad commands in Extended SPI mode, then all good. If I use this EVCR quad mode, then all bad.
>Anybody else have a Cadence QSPI controller and using EVCR quad mode successfully?
>Thanks,
>Graham Moore
Hi,Brian
Whether this patch can be merged?thanks.
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