From: Pratyush Yadav <p.yadav@ti.com>
To: <masonccyang@mxic.com.tw>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>,
Boris Brezillon <boris.brezillon@collabora.com>,
Mark Brown <broonie@kernel.org>, <juliensu@mxic.com.tw>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>,
<linux-mediatek@lists.infradead.org>,
<linux-mtd@lists.infradead.org>, <linux-spi@vger.kernel.org>,
Ludovic Desroches <ludovic.desroches@microchip.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Miquel Raynal <miquel.raynal@bootlin.com>,
Nicolas Ferre <nicolas.ferre@microchip.com>,
Sekhar Nori <nsekhar@ti.com>, Richard Weinberger <richard@nod.at>,
Tudor Ambarus <tudor.ambarus@microchip.com>,
Vignesh Raghavendra <vigneshr@ti.com>
Subject: Re: [PATCH v5 09/19] mtd: spi-nor: sfdp: parse xSPI Profile 1.0 table
Date: Thu, 21 May 2020 14:44:36 +0530 [thread overview]
Message-ID: <20200521091434.rigqlyuwszyyikj4@ti.com> (raw)
In-Reply-To: <OFF5A6BA99.395182B5-ON4825856F.002B2F98-4825856F.002CD973@mxic.com.tw>
On 21/05/20 04:09PM, masonccyang@mxic.com.tw wrote:
>
> Hi Pratyush,
>
> > > > > > + /* Get 8D-8D-8D fast read opcode and dummy cycles. */
> > > > > > + opcode = FIELD_GET(PROFILE1_DWORD1_RD_FAST_CMD, table[0]);
> > > > > > +
> > > > > > + /*
> > > > > > + * Update the fast read settings. We set the default dummy
> > > cycles to
> > > > > 20
> > > > > > + * here. Flashes can change this value if they need to when
> > > enabling
> > > > > > + * octal mode.
> > > > > > + */
> > > > > > +
> spi_nor_set_read_settings(¶ms->reads[SNOR_CMD_READ_8_8_8_DTR],
> > > > > > + 0, 20, opcode,
> > > > > > + SNOR_PROTO_8_8_8_DTR);
> > > > > > +
> > > > >
> > > > >
> > > > > I thought we have a agreement that only do parse here, no other
> read
> > > > > parameters setting.
> > > >
> > > > Yes, and I considered it. But it didn't make much sense to me to
> > > > introduce an extra member in struct spi_nor just to make this call
> in
> > > > some other function later.
> > > >
> > > > Why exactly do you think doing this here is bad? The way I see it,
> we
> > > > avoid carrying around an extra member in spi_nor and this also
> allows
> > > > flashes to change the read settings easily in a post-sfdp hook. The
> > > > 4bait parsing function does something similar.
> > >
> > > I think it's not a question for good or bad.
> > >
> > > 4bait parsing function parse the 4-Byte Address Instruction Table
> > > and set up read/pp parameters there for sure.
> > >
> > > Here we give the function name spi_nor_parse_profile1() but also
> >
> > But the function that parses 4bait table is also called
> > spi_nor_parse_4bait().
> >
> > > do others setting that has nothing to do with it,
> >
> > Why has setting read opcode and dummy cycles got nothing to do with it?
> > The purpose of the Profile 1.0 table is to tell us the Read Fast
> > command and dummy cycles, among other things. I think it _does_ have
> > something to do with it.
>
> As you know I mean this function just do parse parameter of profile 1
> table
> and keep these value data for later usage.
>
> A device supports xSPI profile table could work in either 8S-8S-8S or
> 8D-8D-8D mode.
> It seems to setup these parameters somewhere out here is betters.
As far as I know, the Profile 1.0 table only describes 8D-8D-8D mode. I
see no mention of 8S-8S-8S in JESD251 or JESD216D.01. No field in the
table describes anything related to 8S. In fact, searching for "8S" in
the JESD251 spec yields 0 results.
Anyway, you should set up 8S parameters in SNOR_CMD_READ_8_8_8, not
SNOR_CMD_READ_8_8_8_DTR. 8D configuration is independent of 8S
configuration.
PS: If you have any more comments, please send them now. The merge
window is getting close, and I'd like to see this make it in.
--
Regards,
Pratyush Yadav
Texas Instruments India
next prev parent reply other threads:[~2020-05-21 9:15 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 14:26 [PATCH v5 00/19] mtd: spi-nor: add xSPI Octal DTR support Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 01/19] spi: spi-mem: allow specifying whether an op is DTR or not Pratyush Yadav
2020-05-21 8:27 ` masonccyang
2020-05-22 10:45 ` Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 02/19] spi: atmel-quadspi: reject DTR ops Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 03/19] spi: spi-mtk-nor: " Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 04/19] spi: spi-mem: allow specifying a command's extension Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 05/19] mtd: spi-nor: add support for DTR protocol Pratyush Yadav
2020-05-21 9:24 ` masonccyang
2020-05-21 12:52 ` Pratyush Yadav
2020-05-22 6:30 ` masonccyang
2020-05-22 8:37 ` Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 06/19] mtd: spi-nor: sfdp: default to addr_width of 3 for configurable widths Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 07/19] mtd: spi-nor: sfdp: prepare BFPT parsing for JESD216 rev D Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 08/19] mtd: spi-nor: sfdp: get command opcode extension type from BFPT Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 09/19] mtd: spi-nor: sfdp: parse xSPI Profile 1.0 table Pratyush Yadav
2020-05-20 7:59 ` masonccyang
2020-05-20 8:55 ` Pratyush Yadav
2020-05-20 9:40 ` masonccyang
2020-05-20 10:37 ` Pratyush Yadav
2020-05-21 8:09 ` masonccyang
2020-05-21 9:14 ` Pratyush Yadav [this message]
2020-05-19 14:26 ` [PATCH v5 10/19] mtd: spi-nor: core: use dummy cycle and address width info from SFDP Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 11/19] mtd: spi-nor: core: do 2 byte reads for SR and FSR in DTR mode Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 12/19] mtd: spi-nor: core: enable octal DTR mode when possible Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 13/19] mtd: spi-nor: sfdp: do not make invalid quad enable fatal Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 14/19] mtd: spi-nor: sfdp: detect Soft Reset sequence support from BFPT Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 15/19] mtd: spi-nor: core: perform a Soft Reset on shutdown Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 16/19] mtd: spi-nor: core: disable Octal DTR mode on suspend Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 17/19] mtd: spi-nor: core: expose spi_nor_default_setup() in core.h Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 18/19] mtd: spi-nor: spansion: add support for Cypress Semper flash Pratyush Yadav
2020-05-19 14:26 ` [PATCH v5 19/19] mtd: spi-nor: micron-st: allow using MT35XU512ABA in Octal DTR mode Pratyush Yadav
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