From: Boris Brezillon <boris.brezillon@bootlin.com>
To: Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com>
Cc: "juliensu@mxic.com.tw" <juliensu@mxic.com.tw>,
"zhengxunli@mxic.com.tw" <zhengxunli@mxic.com.tw>,
"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
"masonccyang@mxic.com.tw" <masonccyang@mxic.com.tw>,
"linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>
Subject: Re: Query: spi-nor: dummy buswidth calculation
Date: Tue, 4 Sep 2018 14:30:28 +0200 [thread overview]
Message-ID: <20180904143028.4629fe10@bbrezillon> (raw)
In-Reply-To: <VI1PR04MB1038E10EBE458DD72A1070C499030@VI1PR04MB1038.eurprd04.prod.outlook.com>
+Macronix team
On Tue, 4 Sep 2018 09:28:11 +0000
Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com> wrote:
> Hi Boris,
>
> I have query regarding dummy bus width calculation for the read commands, added in the patch series [1]
>
> In func m25p80_read(), dummy.buswidth is being assigned as
> + op.dummy.buswidth = op.addr.buswidth;
>
> Above, buswidth for dummy commands are being assigned and are marked equal to the buswidth of the address command.
> This is true for case when we are doing operation in 1-4-4 or 1-2-2 protocol where data as well as address are running on same data lines and having same buswidth.
>
> I am adding support of octal commands in framework and for this needs to add support for 1-1-8 protocol for Micron flash MT35XU512ABA1G12.
> For octal command, 7Ch, flash is sending data and the dummy on the 8 data lines and address on 1 data line.
Interesting. Macronix is also working on octo-mode support. I think we
should sync instead of duplicating the work.
>
> If I do below code change, then I am getting correct data else there is data corruption only in the first byte read.
> - op.dummy.buswidth = op.addr.buswidth;
> + op.dummy.buswidth = spi_nor_get_protocol_data_nbits(nor->read_proto);
Regarding this particular aspect, I just followed what was done before
the conversion to spi_mem_exec_op(). Maybe it was not correct though.
Regards,
Boris
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next prev parent reply other threads:[~2018-09-04 12:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-04 9:28 Query: spi-nor: dummy buswidth calculation Yogesh Narayan Gaur
2018-09-04 12:30 ` Boris Brezillon [this message]
2018-09-04 13:10 ` Cyrille Pitchen
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