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From: <Tudor.Ambarus@microchip.com>
To: <p.yadav@ti.com>
Cc: vigneshr@ti.com, richard@nod.at, nsekhar@ti.com,
	linux-kernel@vger.kernel.org, boris.brezillon@collabora.com,
	linux-mtd@lists.infradead.org, miquel.raynal@bootlin.com
Subject: Re: [PATCH v16 00/15] mtd: spi-nor: add xSPI Octal DTR support
Date: Wed, 28 Oct 2020 15:21:02 +0000
Message-ID: <d9d96eda-4cb6-fe68-7469-e73dc7ba2fda@microchip.com> (raw)
In-Reply-To: <20201028124920.pot77v4phkqiswhr@ti.com>

On 10/28/20 2:49 PM, Pratyush Yadav wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Hi Tudor,
> 
> On 28/10/20 07:53AM, Tudor.Ambarus@microchip.com wrote:
>> Hi, Pratyush,
>>
>> On 10/5/20 6:31 PM, Pratyush Yadav wrote:
>>> Tested on Micron MT35X and S28HS flashes for Octal DTR.
>>
>> Do these flashes define the "Command Sequences to Change to
>> Octal DDR (8D-8D-8D) mode" table? Can't we use that table
>> instead of defining our own octal dtr enable functions?
> 
> The Micron flash does not have this table. The Cypress flash does. The
> problem is that one of the samples of the Cypress flash I tested on had
> incorrect data in that table which meant the sequence would fail. The
> newer samples of the flash have the correct data.

Can we differentiate the Cypress flashes? Do you remember what
was the incorrect data?

> 
> I don't know how many of those faulty flashes are out there in the wild.
> IMO, to be on the safe side spi_nor_cypress_octal_dtr_enable() needs to
> be implemented. So from the point of view of this series there is no
> need to parse the Octal DDR enable table.

Meh, we cover manufacturer's mistakes. On the long run, our aim should be
to follow the SFDP standard and if a flash implements it wrong, to either
fix it via a fixup hook (if the fix is minimal), or to skip the faulty
table.

Regarding "Command Sequences to Change to Octal DDR (8D-8D-8D) mode"
table. Have you looked over
https://patchwork.ozlabs.org/project/linux-mtd/patch/1590737775-4798-4-git-send-email-masonccyang@mxic.com.tw/
?
Is there a standard way to determine the offsets of opcode, addr and
data in the cmd seq?

Cheers,
ta
> 
>> I see that Mason used this table for a macronix flash:
>> https://patchwork.ozlabs.org/project/linux-mtd/patch/1590737775-4798-4-git-send-email-masonccyang@mxic.com.tw/
>> https://patchwork.ozlabs.org/project/linux-mtd/patch/1590737775-4798-8-git-send-email-masonccyang@mxic.com.tw/
>>
>> Cheers,
>> ta
> 
> --
> Regards,
> Pratyush Yadav
> Texas Instruments India
> 

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Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-05 15:31 Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 01/15] mtd: spi-nor: core: use EOPNOTSUPP instead of ENOTSUPP Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 02/15] mtd: spi-nor: add spi_nor_controller_ops_{read_reg, write_reg, erase}() Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 03/15] mtd: spi-nor: add support for DTR protocol Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 04/15] mtd: spi-nor: sfdp: get command opcode extension type from BFPT Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 05/15] mtd: spi-nor: sfdp: parse xSPI Profile 1.0 table Pratyush Yadav
2020-10-27  9:58   ` Tudor.Ambarus
2020-10-05 15:31 ` [PATCH v16 06/15] mtd: spi-nor: core: use dummy cycle and address width info from SFDP Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 07/15] mtd: spi-nor: core: do 2 byte reads for SR and FSR in DTR mode Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 08/15] mtd: spi-nor: Introduce SNOR_F_IO_MODE_EN_VOLATILE Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 09/15] mtd: spi-nor: Parse SFDP SCCR Map Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 10/15] mtd: spi-nor: core: enable octal DTR mode when possible Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 11/15] mtd: spi-nor: sfdp: detect Soft Reset sequence support from BFPT Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 12/15] mtd: spi-nor: core: perform a Soft Reset on shutdown Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 13/15] mtd: spi-nor: core: disable Octal DTR mode on suspend Pratyush Yadav
2020-10-05 15:31 ` [PATCH v16 14/15] mtd: spi-nor: spansion: add support for Cypress Semper flash Pratyush Yadav
2020-11-07  7:58   ` Vignesh Raghavendra
2020-11-09 11:45     ` Pratyush Yadav
2020-11-09 13:28     ` Tudor.Ambarus
2020-10-05 15:31 ` [PATCH v16 15/15] mtd: spi-nor: micron-st: allow using MT35XU512ABA in Octal DTR mode Pratyush Yadav
2020-10-06  8:11   ` Tudor.Ambarus
2020-10-28  7:53 ` [PATCH v16 00/15] mtd: spi-nor: add xSPI Octal DTR support Tudor.Ambarus
2020-10-28 12:49   ` Pratyush Yadav
2020-10-28 15:21     ` Tudor.Ambarus [this message]
2020-10-28 20:02       ` Pratyush Yadav
2020-10-29  6:26       ` Vignesh Raghavendra
2020-11-09 17:25 ` Vignesh Raghavendra

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